Science.gov

Sample records for nearby core-collapse supernovae

  1. Core-collapse Supernovae

    SciTech Connect

    Hix, William Raphael; Lentz, E. J.; Baird, Mark L; Chertkow, Merek A; Lee, Ching-Tsai; Blondin, J. M.; Bruenn, S. W.; Messer, Bronson; Mezzacappa, Anthony

    2013-01-01

    Marking the inevitable death of a massive star, and the birth of a neutron star or black hole, core-collapse supernovae bring together physics at a wide range in spatial scales, from kilometer-sized hydrodynamic motions (growing to gigameter scale) down to femtometer scale nuclear reactions. Carrying 10$^{51}$ ergs of kinetic energy and a rich-mix of newly synthesized atomic nuclei, core-collapse supernovae are the preeminent foundries of the nuclear species which make up ourselves and our solar system. We will discuss our emerging understanding of the convectively unstable, neutrino-driven explosion mechanism, based on increasingly realistic neutrino-radiation hydrodynamic simulations that include progressively better nuclear and particle physics. Recent multi-dimensional models with spectral neutrino transport from several research groups, which slowly develop successful explosions for a range of progenitors, have motivated changes in our understanding of the neutrino reheating mechanism. In a similar fashion, improvements in nuclear physics, most notably explorations of weak interactions on nuclei and the nuclear equation of state, continue to refine our understanding of how supernovae explode. Recent progress on both the macroscopic and microscopic effects that affect core-collapse supernovae are discussed.

  2. Directed Searches for Broadband Extended Gravitational Wave Emission in Nearby Energetic Core-collapse Supernovae

    NASA Astrophysics Data System (ADS)

    van Putten, Maurice H. P. M.

    2016-03-01

    Core-collapse supernovae (CC-SNe) are factories of neutron stars and stellar-mass black holes. SNe Ib/c stand out as potentially originating in relatively compact stellar binaries and they have a branching ratio of about 1% into long gamma-ray bursts. The most energetic events probably derive from central engines harboring rapidly rotating black holes, wherein the accretion of fall-back matter down to the innermost stable circular orbit (ISCO) offers a window into broadband extended gravitational wave emission (BEGE). To search for BEGE, we introduce a butterfly filter in time-frequency space by time-sliced matched filtering. To analyze long epochs of data, we propose using coarse-grained searches followed by high-resolution searches on events of interest. We illustrate our proposed coarse-grained search on two weeks of LIGO S6 data prior to SN 2010br (z = 0.002339) using a bank of up to 64,000 templates of one-second duration covering a broad range in chirp frequencies and bandwidth. Correlating events with signal-to-noise ratios > 6 from the LIGO L1 and H1 detectors reduces the total to a few events of interest. Lacking any further properties reflecting a common excitation by broadband gravitational radiation, we disregarded these as spurious. This new pipeline may be used to systematically search for long-duration chirps in nearby CC-SNe from robotic optical transient surveys using embarrassingly parallel computing.

  3. Metamorphosis of SN 2014C: Delayed Interaction between a Hydrogen Poor Core-collapse Supernova and a Nearby Circumstellar Shell

    NASA Astrophysics Data System (ADS)

    Milisavljevic, D.; Margutti, R.; Kamble, A.; Patnaude, D. J.; Raymond, J. C.; Eldridge, J. J.; Fong, W.; Bietenholz, M.; Challis, P.; Chornock, R.; Drout, M. R.; Fransson, C.; Fesen, R. A.; Grindlay, J. E.; Kirshner, R. P.; Lunnan, R.; Mackey, J.; Miller, G. F.; Parrent, J. T.; Sanders, N. E.; Soderberg, A. M.; Zauderer, B. A.

    2015-12-01

    We present optical observations of supernova SN 2014C, which underwent an unprecedented slow metamorphosis from H-poor type Ib to H-rich type IIn over the course of one year. The observed spectroscopic evolution is consistent with the supernova having exploded in a cavity before encountering a massive shell of the progenitor star’s stripped hydrogen envelope. Possible origins for the circumstellar shell include a brief Wolf-Rayet fast wind phase that overtook a slower red supergiant wind, eruptive ejection, or confinement of circumstellar material by external influences of neighboring stars. An extended high velocity Hα absorption feature seen in near-maximum light spectra implies that the progenitor star was not completely stripped of hydrogen at the time of core collapse. Archival pre-explosion Subaru Telescope Suprime-Cam and Hubble Space Telescope Wide Field Planetary Camera 2 images of the region obtained in 2009 show a coincident source that is most likely a compact massive star cluster in NGC 7331 that hosted the progenitor system. By comparing the emission properties of the source with stellar population models that incorporate interacting binary stars we estimate the age of the host cluster to be 30-300 Myr, and favor ages closer to 30 Myr in light of relatively strong Hα emission. SN 2014C is the best observed member of a class of core-collapse supernovae that fill the gap between events that interact strongly with dense, nearby environments immediately after explosion and those that never show signs of interaction. Better understanding of the frequency and nature of this intermediate population can contribute valuable information about the poorly understood final stages of stellar evolution.

  4. METAMORPHOSIS OF SN 2014C: DELAYED INTERACTION BETWEEN A HYDROGEN POOR CORE-COLLAPSE SUPERNOVA AND A NEARBY CIRCUMSTELLAR SHELL

    SciTech Connect

    Milisavljevic, D.; Margutti, R.; Kamble, A.; Patnaude, D. J.; Raymond, J. C.; Challis, P.; Drout, M. R.; Grindlay, J. E.; Kirshner, R. P.; Lunnan, R.; Miller, G. F.; Parrent, J. T.; Sanders, N. E.; Eldridge, J. J.; Fong, W.; Bietenholz, M.; Chornock, R.; Fransson, C.; Fesen, R. A.; Mackey, J.; and others

    2015-12-20

    We present optical observations of supernova SN 2014C, which underwent an unprecedented slow metamorphosis from H-poor type Ib to H-rich type IIn over the course of one year. The observed spectroscopic evolution is consistent with the supernova having exploded in a cavity before encountering a massive shell of the progenitor star’s stripped hydrogen envelope. Possible origins for the circumstellar shell include a brief Wolf–Rayet fast wind phase that overtook a slower red supergiant wind, eruptive ejection, or confinement of circumstellar material by external influences of neighboring stars. An extended high velocity Hα absorption feature seen in near-maximum light spectra implies that the progenitor star was not completely stripped of hydrogen at the time of core collapse. Archival pre-explosion Subaru Telescope Suprime-Cam and Hubble Space Telescope Wide Field Planetary Camera 2 images of the region obtained in 2009 show a coincident source that is most likely a compact massive star cluster in NGC 7331 that hosted the progenitor system. By comparing the emission properties of the source with stellar population models that incorporate interacting binary stars we estimate the age of the host cluster to be 30–300 Myr, and favor ages closer to 30 Myr in light of relatively strong Hα emission. SN 2014C is the best observed member of a class of core-collapse supernovae that fill the gap between events that interact strongly with dense, nearby environments immediately after explosion and those that never show signs of interaction. Better understanding of the frequency and nature of this intermediate population can contribute valuable information about the poorly understood final stages of stellar evolution.

  5. Remnants of Core-Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Lopez, Laura

    2015-04-01

    Supernovae (SNe) play an essential role in the Universe, and they are detected routinely through dedicated surveys. However, most of these SNe are often too distant (~1-100 Mpc) to resolve the SN ejecta and immediate surroundings of the exploded stars. Fortunately, supernova remnants (SNRs) offer the means to study explosions and dynamics at sub-pc scales. SNRs are observable for up to 105 years after the explosions across the electromagnetic spectrum, and almost 400 SNRs have now been identified in the Milky Way and nearby galaxies. In this talk, I will review recent advances in the understanding of core-collapse (CC) SNe based on studies of SNRs. In particular, I will highlight investigations of SNR (a)symmetry and of heavy metal (like iron and titanium) abundances which give insight to the nature and mechanisms of the originating explosions.

  6. Core-collapse supernova explosion simulations

    SciTech Connect

    Cardall, Christian Y

    2011-01-01

    Neutrinos play important roles in the pre-collapse evolution, explosion, and aftermath of core-collapse supernovae. Detected neutrino signals from core-collapse supernovae would provide insight into the explosion mechanism and unknown neutrino mixing parameters. Achieving these goals requires large-scale, multiphysics simulations. For many years, several groups have performed such simulations with increasing realism. Current simulations and plans for future work of the Oak Ridge group are described.

  7. NAPA Observations of Core-Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Ryder, Stuart; Stockdale, Christopher; van Dyk, Schuyler; Panagia, Nino; Amy, Shaun; Immler, Stefan; Burlon, Davide; Kotak, Rubina; Polshaw, Joe

    2014-04-01

    We propose to continue NAPA observations of nearby core-collapse supernovae (CCSNe) to: (1) Determine the physics of SNe through the study of the mass-loss rate, absorption mechanisms, and density distribution of the circumstellar medium (CSM) laid down by the pre-SN stellar wind; (2) Improve our understanding of the various subgroupings (Type Ib, Ic, IIL, IIP, IIn, IIb) which characterise the range of CCSN progenitor systems; and (3) Provide targets for Chandra/Swift X-ray ToO which is sensitive to the thermal emission from the SN shock and, thus, complementary to the non-thermal radio observations. To date we have detected and then monitored 4 out of 6 CCSNe out to distances ~30 Mpc, something not possible prior to CABB. By combining our data with optical and X-ray observations for the Type IIb SN 2011hs and the Type IIP SN 2011ja, we could confirm that their progenitors were a Wolf-Rayet star, and a red supergiant, respectively.

  8. NAPA Observations of Core-Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Ryder, Stuart; Stockdale, Christopher; van Dyk, Schuyler; Panagia, Nino; Amy, Shaun; Immler, Stefan; Burlon, Davide; Kotak, Rubina; Polshaw, Joe; Romero-Canizales, Cristina

    2014-10-01

    We propose to continue NAPA observations of nearby core-collapse supernovae (CCSNe) to: (1) Determine the physics of SNe through the study of the mass-loss rate, absorption mechanisms, and density distribution of the circumstellar medium (CSM) laid down by the pre-SN stellar wind; (2) Improve our understanding of the various subgroupings (Type Ib, Ic, IIL, IIP, IIn, IIb) which characterise the range of CCSN progenitor systems; and (3) Provide targets for Chandra/Swift X-ray ToO which is sensitive to the thermal emission from the SN shock and, thus, complementary to the non-thermal radio observations. To date we have detected and then monitored 4 out of 6 CCSNe out to distances ~30 Mpc, something not possible prior to CABB. By combining our data with optical and X-ray observations for the Type IIb SN 2011hs and the Type IIP SN 2011ja, we could confirm that their progenitors were a Wolf-Rayet star, and a red supergiant, respectively.

  9. Essential ingredients in core-collapse supernovae

    SciTech Connect

    Hix, W. Raphael; Lentz, Eric J.; Chertkow, M. Austin; Harris, J. Austin; Endeve, Eirik; Baird, Mark; Messer, O. E. Bronson; Mezzacappa, Anthony; Bruenn, Stephen; Blondin, John

    2014-04-15

    Carrying 10{sup 44} joules of kinetic energy and a rich mix of newly synthesized atomic nuclei, core-collapse supernovae are the preeminent foundries of the nuclear species which make up our solar system and ourselves. Signaling the inevitable death of a massive star, and the birth of a neutron star or black hole, core-collapse supernovae combine physics over a wide range in spatial scales, from kilometer-sized hydrodynamic motions (eventually growing to gigameter scale) down to femtometer-scale nuclear reactions. We will discuss our emerging understanding of the convectively-unstable, neutrino-driven explosion mechanism, based on increasingly realistic neutrino radiation hydrodynamic simulations that include progressively better nuclear and particle physics. Multi-dimensional models with spectral neutrino transport from several research groups, which slowly develop successful explosions for a range of progenitors, have recently motivated changes in our understanding of the neutrino reheating mechanism. In a similar fashion, improvements in nuclear physics, most notably explorations of weak interactions on nuclei and the nuclear equation of state, continue to refine our understanding of the births of neutron stars and the supernovae that result. Recent progress on both the macroscopic and microscopic effects that affect core-collapse supernovae are discussed.

  10. Essential Ingredients in Core-collapse Supernovae

    SciTech Connect

    Hix, William Raphael; Lentz, E. J.; Endeve, Eirik; Baird, Mark L.; Chertkow, Merek A.; Harris, James A.; Messer, Bronson; Mezzacappa, Anthony; Bruenn, S. W.; Blondin, J. M.

    2014-03-27

    Marking the inevitable death of a massive star, and the birth of a neutron star or black hole, core-collapse supernovae bring together physics at a wide range in spatial scales, from kilometer-sized hydrodynamic motions (eventually growing to gigameter scale) down to femtometer scale nuclear reactions. Carrying 10$^{44}$ joules of kinetic energy and a rich-mix of newly synthesized atomic nuclei, core-collapse supernovae are the preeminent foundries of the nuclear species which make up ourselves and our solar system. We will discuss our emerging understanding of the convectively unstable, neutrino-driven explosion mechanism, based on increasingly realistic neutrino-radiation hydrodynamic simulations that include progressively better nuclear and particle physics. Recent multi-dimensional models with spectral neutrino transport from several research groups, which slowly develop successful explosions for a range of progenitors, have motivated changes in our understanding of the neutrino reheating mechanism. In a similar fashion, improvements in nuclear physics, most notably explorations of weak interactions on nuclei and the nuclear equation of state, continue to refine our understanding of how supernovae explode. Recent progress on both the macroscopic and microscopic effects that affect core-collapse supernovae are discussed.

  11. Essential Ingredients in Core-collapse Supernovae

    DOE PAGES

    Hix, William Raphael; Lentz, E. J.; Endeve, Eirik; Baird, Mark L.; Chertkow, Merek A.; Harris, James A.; Messer, Bronson; Mezzacappa, Anthony; Bruenn, S. W.; Blondin, J. M.

    2014-03-27

    Marking the inevitable death of a massive star, and the birth of a neutron star or black hole, core-collapse supernovae bring together physics at a wide range in spatial scales, from kilometer-sized hydrodynamic motions (eventually growing to gigameter scale) down to femtometer scale nuclear reactions. Carrying 10more » $$^{44}$$ joules of kinetic energy and a rich-mix of newly synthesized atomic nuclei, core-collapse supernovae are the preeminent foundries of the nuclear species which make up ourselves and our solar system. We will discuss our emerging understanding of the convectively unstable, neutrino-driven explosion mechanism, based on increasingly realistic neutrino-radiation hydrodynamic simulations that include progressively better nuclear and particle physics. Recent multi-dimensional models with spectral neutrino transport from several research groups, which slowly develop successful explosions for a range of progenitors, have motivated changes in our understanding of the neutrino reheating mechanism. In a similar fashion, improvements in nuclear physics, most notably explorations of weak interactions on nuclei and the nuclear equation of state, continue to refine our understanding of how supernovae explode. Recent progress on both the macroscopic and microscopic effects that affect core-collapse supernovae are discussed.« less

  12. Essential ingredients in core-collapse supernovae

    NASA Astrophysics Data System (ADS)

    Hix, W. Raphael; Lentz, Eric J.; Endeve, Eirik; Baird, Mark; Chertkow, M. Austin; Harris, J. Austin; Messer, O. E. Bronson; Mezzacappa, Anthony; Bruenn, Stephen; Blondin, John

    2014-04-01

    Carrying 1044 joules of kinetic energy and a rich mix of newly synthesized atomic nuclei, core-collapse supernovae are the preeminent foundries of the nuclear species which make up our solar system and ourselves. Signaling the inevitable death of a massive star, and the birth of a neutron star or black hole, core-collapse supernovae combine physics over a wide range in spatial scales, from kilometer-sized hydrodynamic motions (eventually growing to gigameter scale) down to femtometer-scale nuclear reactions. We will discuss our emerging understanding of the convectively-unstable, neutrino-driven explosion mechanism, based on increasingly realistic neutrino radiation hydrodynamic simulations that include progressively better nuclear and particle physics. Multi-dimensional models with spectral neutrino transport from several research groups, which slowly develop successful explosions for a range of progenitors, have recently motivated changes in our understanding of the neutrino reheating mechanism. In a similar fashion, improvements in nuclear physics, most notably explorations of weak interactions on nuclei and the nuclear equation of state, continue to refine our understanding of the births of neutron stars and the supernovae that result. Recent progress on both the macroscopic and microscopic effects that affect core-collapse supernovae are discussed.

  13. Nuclear Physics in Core-Collapse Supernovae

    SciTech Connect

    Liebendoerfer, Matthias; Fischer, T.; Froelich, C.; Hix, William Raphael; Langanke, Karlheinz; Martinez-Pinedo, Gabriel; Mezzacappa, Anthony; Scheidegger, Simon; Thielemann, Friedrich-Karl W.; Whitehouse, Stuart

    2008-01-01

    Core-collapse and the launch of a supernova explosion form a very short episode of few seconds in the evolution of a massive star, during which an enormous gravitational energy of several times 1053 erg is transformed into observable neutrino-, kinetic-, and electromagnetic radiation energy. We emphasize the wide range of matter conditions that prevail in a supernova event and sort the conditions into distinct regimes in the density and entropy phase diagram to briefly discuss their different impact on the neutrino signal, gravitational wave emission, and ejecta.

  14. Critical conditions for core-collapse supernovae.

    PubMed

    Keshet, Uri; Balberg, Shmuel

    2012-06-22

    The explosion of a core-collapse supernova can be approximated by the breakdown of steady-state solutions for accretion onto a proto-neutron star (PNS). We analytically show that as the neutrino luminosity exceeds a critical value L(c), the neutrinosphere pressure exceeds the hydrostatic limit even for an optimal shock radius R. This yields L(c) [proportionally] M(2)T(2) (with logarithmic corrections) and R [proportionally] M/T, in agreement with numerical results, where M and T are the PNS mass and neutrino temperature, respectively. The near-critical flow can be approximated as a ballistic shell on top of an isothermal layer. PMID:23004581

  15. The Mid-infrared Light Curve of Nearby Core-collapse Supernova SN 2011dh (PTF 11eon)

    NASA Astrophysics Data System (ADS)

    Helou, George; Kasliwal, Mansi M.; Ofek, Eran O.; Arcavi, Iair; Surace, Jason; Gal-Yam, Avishay

    2013-11-01

    We present Spitzer observations at 3.6 and 4.5 μm of the supernova SN 2011dh (PTF 11eon) in M51 from 18 days to 625 days after explosion. The mid-infrared emission peaks at 24 days after explosion at a few ×107 L ⊙, and decays more slowly than the visible-light bolometric luminosity. The infrared color temperature cools for the first 90 days and then is constant. Simple numerical models of a thermal echo can qualitatively reproduce the early behavior. At late times, the mid-IR light curve cannot be explained by a simple thermal echo model, suggesting additional dust heating or line emission mechanisms. We also propose that thermal echoes can serve as effective probes to uncover supernovae in heavily obscured environments, and speculate that under the right conditions, integrating the early epoch of the mid-infrared light curve may constrain the total energy in the shock breakout flash.

  16. THE MID-INFRARED LIGHT CURVE OF NEARBY CORE-COLLAPSE SUPERNOVA SN 2011dh (PTF 11eon)

    SciTech Connect

    Helou, George; Surace, Jason; Kasliwal, Mansi M.; Ofek, Eran O.; Arcavi, Iair; Gal-Yam, Avishay

    2013-11-20

    We present Spitzer observations at 3.6 and 4.5 μm of the supernova SN 2011dh (PTF 11eon) in M51 from 18 days to 625 days after explosion. The mid-infrared emission peaks at 24 days after explosion at a few ×10{sup 7} L {sub ☉}, and decays more slowly than the visible-light bolometric luminosity. The infrared color temperature cools for the first 90 days and then is constant. Simple numerical models of a thermal echo can qualitatively reproduce the early behavior. At late times, the mid-IR light curve cannot be explained by a simple thermal echo model, suggesting additional dust heating or line emission mechanisms. We also propose that thermal echoes can serve as effective probes to uncover supernovae in heavily obscured environments, and speculate that under the right conditions, integrating the early epoch of the mid-infrared light curve may constrain the total energy in the shock breakout flash.

  17. Fingerprinting Hydrogen in Core-Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Nance, Sarafina; Parrent, Jerod; Soderberg, Alicia Margarita

    2016-01-01

    This is a preliminary report on the mass of remaining hydrogen envelopes for stars massive enough to explode under core collapse. Using the stellar evolution code, MESA, our initial findings suggest that a significant fraction of massive stars with M_ZAMS = 20-60 Msun lose all but 10^-3 Msun -10^-1 Msun as they near eventual core collapse. This result is dependent on the mass-loss prescription, degree of rotation, metallicity, rates of nuclear burning in the core, and the final stellar configuration. Nevertheless, each of our test cases include a few stars that retain trace amounts of surface hydrogen, which would then be detected as faint H in type IIb/Ib/Ic supernova spectra. We also compare our findings to the progenitor candidate identified for iPTF13bvn using the most recent photometric corrections. We agree with the previous conclusion found by Groh et al. (2013) that the progenitor had an initial mass of 32 Msun, but now with an additional condition of 0.06 Msun of hydrogen on its surface just prior to the explosion. We demonstrate through our study that not all Type Ib supernovae are fully devoid of hydrogen at the time of explosion, which has implications for the nature of the progenitor star and thus provides impetus for a revised classification scheme for 'stripped envelope' supernovae. This work was supported in part by the NSF REU and DoD ASSURE programs under NSF grant no. 1262851 and by the Smithsonian Institution.

  18. Gravitational Waves from Core Collapse Supernovae

    SciTech Connect

    Yakunin, Konstantin; Marronetti, Pedro; Mezzacappa, Anthony; Bruenn, S. W.; Lee, Ching-Tsai; Chertkow, Merek A; Hix, William Raphael; Blondin, J. M.; Lentz, Eric J; Messer, Bronson; Yoshida, S.

    2010-01-01

    We present the gravitational wave signatures for a suite of axisymmetric core collapse supernova models with progenitor masses between 12 and 25 M{sub odot}. These models are distinguished by the fact that they explode and contain essential physics (in particular, multi-frequency neutrino transport and general relativity) needed for a more realistic description. Thus, we are able to compute complete waveforms (i.e. through explosion) based on non-parameterized, first-principles models. This is essential if the waveform amplitudes and time scales are to be computed more precisely. Fourier decomposition shows that the gravitational wave signals we predict should be observable by AdvLIGO across the range of progenitors considered here. The fundamental limitation of these models is in their imposition of axisymmetry. Further progress will require counterpart three-dimensional models.

  19. Metallicity Gradients of Stripped Core-Collapse Supernovae Host Galaxies

    NASA Astrophysics Data System (ADS)

    Fierroz, David F.; Modjaz, M.

    2013-01-01

    We examine a sample of over 30 galaxies that have hosted stripped core-collapse supernovae including SN IIb, SN Ib, SN Ic and SN Ic with broad lines (SN Ic-BL). The supernovae were discovered by both targeted and untargeted surveys including the Katzman Automatic Imaging Telescope (KAIT), the Nearby Supernova Factory (SNF) and the Palomar Transient Factory (PTF). The metallicity of the supernova environment is expected to play an important role during the short lifetimes of the massive stellar progenitors and likely influences the class of the explosion. We obtain spectra to measure metallicity at the nucleus of the galaxy as well as at HII regions going out to radii that include the supernova site. We use three different oxygen-abundance scales to calibrate and compare metallicities across core-collapse classes. By interpolating the metallicity across the host galaxy we construct our own metallicity gradients that can include SN that have no HII regions at their position and remove the selection effect in place by prior studies. This new feature allows us to probe SN environmental metallicities, even at sites that don’t have recent star formation activity.

  20. Ultraviolet observations of core-collapse supernovae

    NASA Astrophysics Data System (ADS)

    Pritchard, Tyler Anthony

    Ultraviolet observations of Core Collapse Supernovae (CCSNe) have traditionally lagged behind observations in the optical and near-infrared. With the launch of Swift in 2004 this began to change. The systematic study of UV emission from these objects provides information about supernovae temperature, radius, metallicity and luminosity that may be difficult to obtain from the ground - especially at early times where upwards of 80% of the SNe bolometric flux may come from the UV region. We begin with the examination of an extraordinary Type IIn supernova SN 2007pk, which was at the time the earliest observed Type IIn SNe in the UV, and characterize the explosion properties while examining how the early observed UV emission compares with other observed CCSNe at early times. Building upon this we assemble the largest sample of CCSNe in the UV and examine the UV and bolometric characteristics of CCSNe by subtype. Using these bolometric light curves we go on to calculate empirically based bolometric corrections and UV- ux corrections for use by observers when observing filters are limited or UV observations are unable to be obtained. We improve upon this by identifying a small subsample of Type II Plateau SNe which have simultaneous ground based optical - near infrared data, and improve our bolometric light curve calculation method to more accurately determine bolometric light curve, corrections and UV corrections. Finally, we use recent hydrodynamical models to examine the accuracy of current modeling techniques to reproduce Type IIP SNe, the implications of progenitor properties on the light curves of the SNe, and possibility of future diagnostics for progenitor metalicity, radius, and explosion energies from Type IIP light curves and models.

  1. The UV Properties of Core Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Pritchard, Tyler A.; Roming, P.

    2014-01-01

    With the advent of robotic telescope transient surveys in the 1990's, the study of Supernovae (SNe) in the optical and infrared wavelengths underwent a revolution as the number of SNe discovered per year increased by well over an order of magnitude in the ensuing decade. UV studies of these objects lagged behind their optical/NIR counterparts, however, due to a limited observing capability. With the launch of Swift in 2005 a similar revolution took place in the UV as it was finally possible to regularly obtain well-sampled UV and optical observations with the Swift UV/Optical Telescope (UVOT; λc = 1928, 2246, 2600 Å). In 2007 Swift/UVOT observed SN 2007pk, which was at the time the earliest observed Type IIn SNe in the UV, and whose study led us to understand the need for a more comprehensive sampling of Core Collapse Supernovae (CCSNe) observations than had previously been performed. Using data from Swift’s launch to the end of 2012, we produce a study of the UV characteristics of CCSNe, dependant upon SNe subtype. We find that at early times or around peak magnitude, contingent upon subtype, a majority of the supernovae flux can occur in the UV regime. However, due to ground based observing constraints this flux often goes unmeasured. This missing flux, and associated corrections, has implications for SNe explosion models which use bolometric light curves to examine factors including: supernovae explosion energy, progenitor radius, CSM winds, and metallicity. We then calculate bolometric light curves for this sample of CCSNe, along with empirical UV-corrections from these for bolometric light curves that have been generated without UV data. We then refine these corrections using a smaller sample of Type IIP SNe from the Carnegie Supernovae Project that overlap with Swift observations, resulting in bolometric light curves with a comprehensive UV-NIR coverage. Finally, using recent numerical simulations we compare variations in observed model light curves due

  2. On the progenitors of core-collapse supernovae

    NASA Astrophysics Data System (ADS)

    Leonard, Douglas C.

    2011-11-01

    Theory holds that a star born with an initial mass between about 8 and 140 times the mass of the Sun will end its life through the catastrophic gravitational collapse of its iron core to a neutron star or black hole. This core collapse process is thought to usually be accompanied by the ejection of the star's envelope as a supernova. This established theory is now being tested observationally, with over three dozen core-collapse supernovae having had the properties of their progenitor stars directly measured through the examination of high-resolution images taken prior to the explosion. Here I review what has been learned from these studies and briefly examine the potential impact on stellar evolution theory, the existence of "failed supernovae", and our understanding of the core-collapse explosion mechanism.

  3. Core Collapse Supernova Models and Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Nomoto, Ken'ichi

    2014-01-01

    After the Big Bang, production of heavy elements in the early Universe takes place in the first stars and their supernova explosions. The nature of the first supernovae, however, has not been well understood. The signature of nucleosynthesis yields of the first supernovae can be seen in the elemental abundance patterns observed in extremely metal-poor stars. Interestingly, those abundance patterns show some peculiarities relative to the solar abundance pattern, which should provide important clues to understanding the nature of early generations of supernovae. We review the recent results of the nucleosynthesis yields of massive stars. We examine how those yields are affected by some hydrodynamical effects during the supernova explosions, namely, explosion energies from those of hypernovae to faint supernovae, mixing and fallback of processed materials, asphericity, etc. Those parameters in the supernova nucleosynthesis models are constrained from observational data of supernovae and metal-poor stars.

  4. Weak-interaction processes in core-collapse supernovae

    SciTech Connect

    Langanke, K.

    2015-02-24

    Weak interaction processes play an important role for the dynamics of a core-collapse supernova. Due to progress of nuclear modeling and constrained by data it has been possible to improve the rates of these processes for supernova conditions decisively. This manuscript describes the recent advances and the current status in deriving electron capture rates on nuclei and of inelastic neutrino-nucleus scattering for applications in supernova simulations and briefly discusses their impact on such studies.

  5. Computational Astrophysics at the Bleeding Edge: Simulating Core Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Mezzacappa, Anthony

    2013-04-01

    Core collapse supernovae are the single most important source of elements in the Universe, dominating the production of elements between oxygen and iron and likely responsible for half the elements heavier than iron. They result from the death throes of massive stars, beginning with stellar core collapse and the formation of a supernova shock wave that must ultimately disrupt such stars. Past, first-principles models most often led to the frustrating conclusion the shock wave stalls and is not revived, at least given the physics included in the models. However, recent progress in the context of two-dimensional, first-principles supernova models is reversing this trend, giving us hope we are on the right track toward a solution of one of the most important problems in astrophysics. Core collapse supernovae are multi-physics events, involving general relativity, hydrodynamics and magnetohydrodynamics, nuclear burning, and radiation transport in the form of neutrinos, along with a detailed nuclear physics equation of state and neutrino weak interactions. Computationally, simulating these catastrophic stellar events presents an exascale computing challenge. I will discuss past models and milestones in core collapse supernova theory, the state of the art, and future requirements. In this context, I will present the results and plans of the collaboration led by ORNL and the University of Tennessee.

  6. Cosmic core-collapse supernovae from upcoming sky surveys

    SciTech Connect

    Lien, Amy; Fields, Brian D. E-mail: bdfields@illinois.edu

    2009-01-15

    Large synoptic (repeated scan) imaging sky surveys are poised to observe enormous numbers of core-collapse supernovae. We quantify the discovery potential of such surveys, and apply our results to upcoming projects, including DES, Pan-STARRS, and LSST. The latter two will harvest core-collapse supernovae in numbers orders of magnitude greater than have ever been observed to date. These surveys will map out the cosmic core-collapse supernova redshift distribution via direct counting, with very small statistical uncertainties out to a redshift depth which is a strong function of the survey limiting magnitude. This supernova redshift history encodes rich information about cosmology, star formation, and supernova astrophysics and phenomenology; the large statistics of the supernova sample will be crucial to disentangle possible degeneracies among these issues. For example, the cosmic supernova rate can be measured to high precision out to z {approx} 0.5 for all core-collapse types, and out to redshift z {approx} 1 for Type IIn events if their intrinsic properties remain the same as those measured locally. A precision knowledge of the cosmic supernova rate would remove the cosmological uncertainties in the study of the wealth of observable properties of the cosmic supernova populations and their evolution with environment and redshift. Because of the tight link between supernovae and star formation, synoptic sky surveys will also provide precision measurements of the normalization and z {approx}< 1 history of cosmic star-formation rate in a manner independent of and complementary to than current data based on UV and other proxies for massive star formation. Furthermore, Type II supernovae can serve as distance indicators and would independently cross-check Type Ia distances measured in the same surveys. Arguably the largest and least-controlled uncertainty in all of these efforts comes from the poorly-understood evolution of dust obscuration of supernovae in their host

  7. Neutrinos and nucleosynthesis in core-collapse supernovae

    SciTech Connect

    Fröhlich, C.; Casanova, J.; Hempel, M.; Liebendörfer, M.; Melton, C. A.; Perego, A.

    2014-01-01

    Massive stars (M > 8-10 M{sub ⊙}) undergo core collapse at the end of their life and explode as supernova with ~ 10⁵¹ erg of kinetic energy. While the detailed supernova explosion mechanism is still under investigation, reliable nucleosynthesis calculations based on successful explosions are needed to explain the observed abundances in metal-poor stars and to predict supernova yields for galactic chemical evolution studies. To predict nucleosynthesis yields for a large number of progenitor stars, computationally efficient explosion models are required. We model the core collapse, bounce and subsequent explosion of massive stars assuming spherical symmetry and using detailed microphysics and neutrino physics combined with a novel method to artificially trigger the explosion (PUSH). We discuss the role of neutrinos, the conditions in the ejecta, and the resulting nucleosynthesis.

  8. CORE-COLLAPSE SUPERNOVAE MISSED BY OPTICAL SURVEYS

    SciTech Connect

    Mattila, S.; Kankare, E.; Dahlen, T.; Efstathiou, A.; Melinder, J.; Oestlin, G.; Alonso-Herrero, A.; Ryder, S.; Vaeisaenen, P.

    2012-09-10

    We estimate the fraction of core-collapse supernovae (CCSNe) that remain undetected by optical SN searches due to obscuration by large amounts of dust in their host galaxies. This effect is especially important in luminous and ultraluminous infrared galaxies, which are locally rare but dominate the star formation at redshifts of z {approx} 1-2. We perform a detailed investigation of the SN activity in the nearby luminous infrared galaxy Arp 299 and estimate that up to 83% of the SNe in Arp 299 and in similar galaxies in the local universe are missed by observations at optical wavelengths. For rest-frame optical surveys we find the fraction of SNe missed due to high dust extinction to increase from the average local value of {approx}19% to {approx}38% at z {approx} 1.2 and then remain roughly constant up to z {approx} 2. It is therefore crucial to take into account the effects of obscuration by dust when determining SN rates at high redshift and when predicting the number of CCSNe detectable by future high-z surveys such as LSST, JWST, and Euclid. For a sample of nearby CCSNe (distances 6-15 Mpc) detected during the last 12 yr, we find a lower limit for the local CCSN rate of 1.5{sup +0.4}{sub -0.3} Multiplication-Sign 10{sup -4} yr{sup -1} Mpc{sup -3}, consistent with that expected from the star formation rate. Even closer, at distances less than {approx}6 Mpc, we find a significant increase in the CCSN rate, indicating a local overdensity of star formation caused by a small number of galaxies that have each hosted multiple SNe.

  9. Multidimensional, multiphysics simulations of core-collapse supernovae

    SciTech Connect

    Messer, Bronson; Mezzacappa, Anthony; Blondin, J. M.; Bruenn, S. W.; Hix, William Raphael

    2008-01-01

    CHIMERA is a multi-dimensional radiation hydrodynamics code designed to study core-collapse supernovae. The code is made up of three essentially independent parts: a hydrodynamics module, a nuclear burning module, and a neutrino transport solver combined within an operator-split approach. We review the code s architecture and some recently improved implementations used in the code. We also briefly discuss preliminary results obtained with the code in three spatial dimensions.

  10. Multidimensional, multiphysics simulations of core-collapse supernovae

    SciTech Connect

    Messer, Bronson; Mezzacappa, Anthony; Blondin, J. M.; Bruenn, S. W.; Hix, William Raphael

    2008-01-01

    CHIMERA is a multi-dimensional radiation hydrodynamics code designed to study core-collapse supernovae. The code is made up of three essentially independent parts: a hydrodynamics module, a nuclear burning module, and a neutrino transport solver combined within an operator-split approach. We review the code's architecture and some recently improved implementations used in the code. We also briefly discuss preliminary results obtained with the code in three spatial dimensions.

  11. Towards the Core-Collapse Supernova Explosion Mechanism

    SciTech Connect

    Cardall, Christian Y; Endeve, Eirik; Budiardja, R. D.; Marronetti, Pedro; Mezzacappa, Anthony

    2012-01-01

    Core-collapse supernovae are amazing displays of astrohysical fireworks - and the optical emission is only a tiny part of the story. These events involve virtually all branches of physics and spawn phenomena observale by every kind of astronomical observation. This richness of theory and observation presents a formidable challenge to their understanding via computer simulations, but we are entering a new era of realism and maturity in modeling the key processes by collapse and explosion.

  12. The rp-Process in Core-collapse Supernovae

    SciTech Connect

    Wanajo, Shinya

    2006-07-12

    Recent hydrodynamic simulations of core-collapse supernovae with accurate neutrino transport suggest that the bulk of the neutrino-heated ejecta is proton rich, in which the production of some interesting proton-rich nuclei is expected. However, there are a number of waiting point nuclei with the {beta}+-lives of a few minutes, which prevent the production of heavy proton-rich nuclei beyond iron in explosive events such as core-collapse supernovae. In this study, it is shown that the rapid proton-capture (rp) process takes place by bypassing these waiting points via neutron-capture reactions even in the proton-rich environment, if there is an intense neutrino flux as expected during the early phase of the neutrino-driven winds of core-collapse supernovae. The nucleosynthesis calculations imply that the neutrino-driven winds can be potentially the origin of light p-nuclei including 92,94Mo and 96,98Ru, which cannot be explained by other astrophysical sites.

  13. Evaluating nuclear physics inputs in core-collapse supernova models

    SciTech Connect

    Lentz, Eric J; Hix, William Raphael; Baird, Mark L; Messer, Bronson; Mezzacappa, Anthony

    2010-01-01

    Core-collapse supernova models depend on the details of the nuclear and weak interaction physics inputs just as they depend on the details of the macroscopic physics (transport, hydrodynamics, etc.), numerical methods, and progenitors. We present the results of our ongoing comparison studies of nuclear and weak interaction physics inputs to core collapse supernova models using the spherically-symmetric, general relativistic, neutrino radiation hydrodynamics code Agile-Boltztran. We focus on comparisons of the effects of the nuclear EoS and the effects of improving the opacities, particularly neutrino--nucleon interactions. We present the results of our ongoing comparison studies of nuclear and weak interaction physics inputs to core collapse supernova models using the spherically-symmetric, general relativistic, neutrino radiation hydrodynamics code Agile-Boltztran. We focus on comparisons of the effects of the nuclear EoS and the effects of improving the opacities, particularly neutrino--nucleon interactions. We also investigate the feedback between different EoSs and opacities in the context of different progenitors.

  14. On Rapidly Rotating Magnetic Core-Collapse Supernovae

    SciTech Connect

    Wilson, J R; Mathews, G J; Dalhed, H E

    2004-12-20

    The authors have analyzed magnetic effects which may occur in rapidly rotating core collapse supernovae. They consider effects from both magnetic turbulence and the formation of magnetic bubbles. For magnetic turbulence they have made a perturbative analysis for the spherically symmetric core-collapse supernova model that incorporates the build up of magnetic field energy in the matter accreting onto the proto-neutron star shortly after collapse and bounce. This significantly modifies the pressure profile and increases the heating of the material above the proto-neutron star resulting in an explosion even in rotating stars which would not explode otherwise. Regarding magnetic bubbles it is shown that a model with an initial uniform magnetic field ({approx} 10{sup 8}) gauss and uniform angular velocity of ({approx} 0.1 rad sec{sup -1}) can form magnetic bubbles due to the very non homologous nature of the collapse. It is estimated that the buoyancy of the bubbles causes matter in the proto-neutron star to rise, carrying neutrino-rich material to the neutron-star surface. This increases the neutrino luminosity sufficiently at early times to achieve a successful neutrino-driven explosion. Both magnetic mechanisms thus provide new means for initiating a Type II core-collapse supernova.

  15. Late time emission from core-collapse supernovae.

    NASA Astrophysics Data System (ADS)

    Kozma, C.

    The evolution and emission from the ejecta of core-collapse supernovae are modeled for epochs later than 200 days. The emission at these times reflects the nucleosynthesis in the progenitor star and in the explosion, as well as the hydrodynamical structure of the explosion. The results are compared to observations of SN 1987A. Contents: 1. Introduction. 2. Supernovae. 3. SN 1987A. 4. Late time emission (Gamma-ray thermalization (Astrophys. J., Vol. 390, p. 602 - 621 (10 May 1992); The freeze-out phase (Astrophys. J., Lett., Vol. 408, p. L25 - L28 (1 May 1993); Late spectral evolution of SN 1987A (C. Kozma, C. Fransson).

  16. Core-collapse supernova remnants and interactions with their surroundings

    NASA Astrophysics Data System (ADS)

    Brantseg, Thomas Felton

    This thesis examines three core-collapse supernova remnants (SNR)---the Cygnus Loop in the Milky Way and 0453-68.5 and 0540-69.3 in the Large Magellanic Cloud---of varying ages and in varying states of interaction with the surrounding interstellar medium (ISM), using X-ray imaging spectroscopy with Chandra and supplemental data from other wavelengths. We use results from our analysis to address three main questions. First, we examine the applicability of the common Sedov-Taylor adiabatic blast wave model to core-collapse supernovae. Second, we determine the elemental abundances around the shell of these supernova remnants to determine if the use of SNRs as a gauge of abundances in the ISM is justified. Finally, we examine the pulsar wind nebulae (PWNe) in 0453-68.5 and 0540-69.3 and search for evidence of interaction between these PWNe and their immediate surroundings. We see highly inhomogeneous ISM surrounding all three surveyed SNRs, contrary to the key assumption in the Sedov-Taylor model of a uniform surrounding medium. In all three studied SNRs, we find that shock speeds are dependent on the density of the surrounding material. As subsidiary results, we also find depleted elemental abundances of oxygen, magnesium, and silicon, relative to typical ISM, around all three studied supernova remnants. Although this subsidiary result is not conclusive, we believe that it merits a followup study. In 0540-69.3 and 0453-68.5, which contain central pulsars, we find that the explosion directionality, which can be inferred from the pulsar's proper motion relative to the SNR, is not related to the morphology of the SNR itself. We conclude from this that the asymmetric shapes common in core-collapse supernova remnants can be more a function of the complex environments surrounding the progenitors of core-collapse supernovae than of the supernova explosions themselves. Finally, we see that the PWN in 0453-68.5 shows signs of having mixed with the surrounding thermal- emitting

  17. Bolometric and UV light curves of core-collapse supernovae

    SciTech Connect

    Pritchard, T. A.; Roming, P. W. A.; Brown, Peter J.; Bayless, Amanda J.; Frey, Lucille H.

    2014-06-01

    The Swift UV-Optical Telescope (UVOT) has been observing core-collapse supernovae (CCSNe) of all subtypes in the UV and optical since 2005. Here we present 50 CCSNe observed with the Swift UVOT, analyzing their UV properties and behavior. Where we have multiple UV detections in all three UV filters (λ {sub c} = 1928-2600 Å), we generate early time bolometric light curves, analyze the properties of these light curves and the UV contribution to them, and derive empirical corrections for the UV-flux contribution to optical-IR based bolometric light curves.

  18. Pasta phases in core-collapse supernova matter

    NASA Astrophysics Data System (ADS)

    Pais, Helena; Chiacchiera, Silvia; Providência, Constança

    2016-04-01

    The pasta phase in core-collapse supernova matter (finite temperatures and fixed proton fractions) is studied within relativistic mean field models. Three different calculations are used for comparison, the Thomas-Fermi (TF), the Coexisting Phases (CP) and the Compressible Liquid Drop (CLD) approximations. The effects of including light clusters in nuclear matter and the densities at which the transitions between pasta configurations and to uniform matter occur are also investigated. The free energy and pressure, in the space of particle number densities and temperatures expected to cover the pasta region, are calculated. Finally, a comparison with a finite temperature Skyrme-Hartree-Fock calculation is drawn.

  19. Long gamma-ray Bursts and Type Ic Core CollapseSupernovae have Similar Environments

    SciTech Connect

    Kelly, P.L.; Kirshner, R.P.; Pahre, M.

    2007-12-04

    When the afterglow fades at the site of a long-duration {gamma}-ray burst (LGRB), Type Ic supernovae (SN Ic) are the only type of core collapse supernova observed. Recent work found that a sample of LGRB had different environments from a collection of core-collapse supernovae identified in a high-redshift sample from colors and light curves. LGRB were in the brightest regions of their hosts, but the core-collapse sample followed the overall distribution of the galaxy light. Here we examine 263 fully spectroscopically-typed supernovae found in nearby (z < 0.06) galaxies for which we have constructed surface photometry from the Sloan Digital Sky Survey (SDSS). The distributions of the thermonuclear supernovae (SN Ia) and some varieties of core-collapse supernovae (SN II and SN Ib) follow the galaxy light, but the SN Ic (like LGRB) are much more likely to erupt in the brightest regions of their hosts. The high-redshift hosts of LGRB are overwhelmingly irregulars, without bulges, while many low redshift SN Ic hosts are spirals with small bulges. When we remove the bulge light from our low-redshift sample, the SN Ic and LGRB distributions agree extremely well. If both LGRB and SN Ic stem from very massive stars, then it seems plausible that the conditions necessary for forming SN Ic are also required for LGRB. Additional factors, including metallicity, may determine whether the stellar evolution of a massive star leads to a LGRB with an underlying broad-lined SN Ic, or simply a SN Ic without a {gamma}-ray burst.

  20. Symmetry energy impact in simulations of core-collapse supernovae

    NASA Astrophysics Data System (ADS)

    Fischer, Tobias; Hempel, Matthias; Sagert, Irina; Suwa, Yudai; Schaffner-Bielich, Jürgen

    2014-02-01

    We present a review of a broad selection of nuclear matter equations of state (EOSs) applicable in core-collapse supernova studies. The large variety of nuclear matter properties, such as the symmetry energy, which are covered by these EOSs leads to distinct outcomes in supernova simulations. Many of the currently used EOS models can be ruled out by nuclear experiments, nuclear many-body calculations, and observations of neutron stars. In particular the two classical supernova EOS describe neutron matter poorly. Nevertheless, we explore their impact in supernova simulations since they are commonly used in astrophysics. They serve as extremely soft and stiff representative nuclear models. The corresponding supernova simulations represent two extreme cases, e.g., with respect to the protoneutron star (PNS) compactness and shock evolution. Moreover, in multi-dimensional supernova simulations EOS differences have a strong effect on the explosion dynamics. Because of the extreme behaviors of the classical supernova EOSs we also include DD2, a relativistic mean field EOS with density-dependent couplings, which is in satisfactory agreement with many current nuclear and observational constraints. This is the first time that DD2 is applied to supernova simulations and compared with the classical supernova EOS. We find that the overall behaviour of the latter EOS in supernova simulations lies in between the two extreme classical EOSs. As pointed out in previous studies, we confirm the impact of the symmetry energy on the electron fraction. Furthermore, we find that the symmetry energy becomes less important during the post-bounce evolution, where conversely the symmetric part of the EOS becomes increasingly dominating, which is related to the high temperatures obtained. Moreover, we study the possible impact of quark matter at high densities and light nuclear clusters at low and intermediate densities.

  1. Parametric initial conditions for core-collapse supernova simulations

    NASA Astrophysics Data System (ADS)

    Suwa, Yudai; Müller, Ewald

    2016-08-01

    We investigate a method to construct parametrized progenitor models for core-collapse supernova simulations. Different from all modern core-collapse supernova studies, which rely on progenitor models from stellar evolution calculations, we follow the methodology of Baron & Cooperstein to construct initial models. Choosing parametrized spatial distributions of entropy and electron fraction as a function of mass coordinate and solving the equation of hydrostatic equilibrium, we obtain the initial density structures of our progenitor models. First, we calculate structures with parameters fitting broadly the evolutionary model s11.2 of Woosley et al. (2002). We then demonstrate the reliability of our method by performing general relativistic hydrodynamic simulations in spherical symmetry with the isotropic diffusion source approximation to solve the neutrino transport. Our comprehensive parameter study shows that initial models with a small central entropy (≲0.4 kB nucleon-1) can explode even in spherically symmetric simulations. Models with a large entropy (≳6 kB nucleon-1) in the Si/O layer have a rather large explosion energy (˜4 × 1050 erg) at the end of the simulations, which is still rapidly increasing.

  2. The r-PROCESS in Core-Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Wanajo, Shinya; Kajino, Toshitaka; Mathews, Grant J.; Otsuki, Kaori

    We present calculations of r-process nucleosynthesis in neutrino-driven winds from the nascent neutron stars of core-collapse supernovae. A full dynamical reaction network for both the α-rich freezeout and the subsequent r-process is employed. The physical properties of the neutrino-heated ejecta are deduced from a general relativistic model in which spherical symmetry and steady flow are assumed. Our results suggest that proto-neutron stars with a large compaction ratio provide the most robust physical conditions for the r-process. This is due to the short dynamical timescale of material in the wind. Our results have confirmed that the neutrino-driven wind scenario is still a promising site in which to form the solar r-process abundances. However, our best results seem to imply both a rather soft neutron-star equation of state and a massive proto-neutron star which is difficult to achieve with standard core-collapse models. We propose that the most favorable conditions perhaps require that a massive supernova progenitor forms a massive proto-neutron star by accretion after a failed initial neutrino burst.

  3. The Multi-Dimensional Character of Core-Collapse Supernovae

    SciTech Connect

    Hix, William Raphael; Lentz, E. J.; Bruenn, S. W.; Mezzacappa, Anthony; Messer, Bronson; Endeve, Eirik; Blondin, J. M.; Harris, James Austin; Marronetti, Pedro; Yakunin, Konstantin N

    2016-01-01

    Core-collapse supernovae, the culmination of massive stellar evolution, are spectacular astronomical events and the principle actors in the story of our elemental origins. Our understanding of these events, while still incomplete, centers around a neutrino-driven central engine that is highly hydrodynamically unstable. Increasingly sophisticated simulations reveal a shock that stalls for hundreds of milliseconds before reviving. Though brought back to life by neutrino heating, the development of the supernova explosion is inextricably linked to multi-dimensional fluid flows. In this paper, the outcomes of three-dimensional simulations that include sophisticated nuclear physics and spectral neutrino transport are juxtaposed to learn about the nature of the three dimensional fluid flow that shapes the explosion. Comparison is also made between the results of simulations in spherical symmetry from several groups, to give ourselves confidence in the understanding derived from this juxtaposition.

  4. Viscosity and Rotation in Core-Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Thompson, Todd A.; Quataert, Eliot; Burrows, Adam

    2005-02-01

    We construct models of core-collapse supernovae in one spatial dimension, including rotation, angular momentum transport, and viscous dissipation employing an α-prescription. We compare the evolution of a fiducial 11 Msolar nonrotating progenitor with its evolution when including a wide range of imposed initial rotation profiles (1.25ssupernova shock. This effect yields qualitatively new dynamics in models of supernovae. We explore several potential mechanisms for viscosity in the core-collapse environment: neutrino viscosity, turbulent viscosity caused by the magnetorotational instability (MRI), and turbulent viscosity by entropy- and composition gradient-driven convection. We argue that the MRI is the most effective. We find for rotation periods in the range P0<~5 s and a range of viscous stresses that the postbounce dynamics is significantly affected by the inclusion of this extra energy deposition mechanism; in several cases we obtain strong supernova explosions.

  5. MAGNETOROTATIONAL CORE-COLLAPSE SUPERNOVAE IN THREE DIMENSIONS

    SciTech Connect

    Mösta, Philipp; Richers, Sherwood; Ott, Christian D.; Haas, Roland; Piro, Anthony L.; Boydstun, Kristen; Abdikamalov, Ernazar; Reisswig, Christian; Schnetter, Erik

    2014-04-20

    We present results of new three-dimensional (3D) general-relativistic magnetohydrodynamic simulations of rapidly rotating strongly magnetized core collapse. These simulations are the first of their kind and include a microphysical finite-temperature equation of state and a leakage scheme that captures the overall energetics and lepton number exchange due to postbounce neutrino emission. Our results show that the 3D dynamics of magnetorotational core-collapse supernovae are fundamentally different from what was anticipated on the basis of previous simulations in axisymmetry (2D). A strong bipolar jet that develops in a simulation constrained to 2D is crippled by a spiral instability and fizzles in full 3D. While multiple (magneto-)hydrodynamic instabilities may be present, our analysis suggests that the jet is disrupted by an m = 1 kink instability of the ultra-strong toroidal field near the rotation axis. Instead of an axially symmetric jet, a completely new, previously unreported flow structure develops. Highly magnetized spiral plasma funnels expelled from the core push out the shock in polar regions, creating wide secularly expanding lobes. We observe no runaway explosion by the end of the full 3D simulation 185 ms after bounce. At this time, the lobes have reached maximum radii of ∼900 km.

  6. BLACK HOLE FORMATION IN FAILING CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    O'Connor, Evan; Ott, Christian D. E-mail: cott@tapir.caltech.edu

    2011-04-01

    We present results of a systematic study of failing core-collapse supernovae and the formation of stellar-mass black holes (BHs). Using our open-source general-relativistic 1.5D code GR1D equipped with a three-species neutrino leakage/heating scheme and over 100 presupernova models, we study the effects of the choice of nuclear equation of state (EOS), zero-age main sequence (ZAMS) mass and metallicity, rotation, and mass-loss prescription on BH formation. We find that the outcome, for a given EOS, can be estimated, to first order, by a single parameter, the compactness of the stellar core at bounce. By comparing protoneutron star (PNS) structure at the onset of gravitational instability with solutions of the Tolman-Oppenheimer-Volkof equations, we find that thermal pressure support in the outer PNS core is responsible for raising the maximum PNS mass by up to 25% above the cold NS value. By artificially increasing neutrino heating, we find the critical neutrino heating efficiency required for exploding a given progenitor structure and connect these findings with ZAMS conditions, establishing, albeit approximately, for the first time based on actual collapse simulations, the mapping between ZAMS parameters and the outcome of core collapse. We also study the effect of progenitor rotation and find that the dimensionless spin of nascent BHs may be robustly limited below a* = Jc/GM{sup 2} = 1 by the appearance of nonaxisymmetric rotational instabilities.

  7. FINDING THE FIRST COSMIC EXPLOSIONS. II. CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Whalen, Daniel J.; Joggerst, Candace C.; Fryer, Chris L.; Stiavelli, Massimo; Heger, Alexander; Holz, Daniel E.

    2013-05-01

    Understanding the properties of Population III (Pop III) stars is prerequisite to elucidating the nature of primeval galaxies, the chemical enrichment and reionization of the early intergalactic medium, and the origin of supermassive black holes. While the primordial initial mass function (IMF) remains unknown, recent evidence from numerical simulations and stellar archaeology suggests that some Pop III stars may have had lower masses than previously thought, 15-50 M{sub Sun} in addition to 50-500 M{sub Sun }. The detection of Pop III supernovae (SNe) by JWST, WFIRST, or the TMT could directly probe the primordial IMF for the first time. We present numerical simulations of 15-40 M{sub Sun} Pop III core-collapse SNe performed with the Los Alamos radiation hydrodynamics code RAGE. We find that they will be visible in the earliest galaxies out to z {approx} 10-15, tracing their star formation rates and in some cases revealing their positions on the sky. Since the central engines of Pop III and solar-metallicity core-collapse SNe are quite similar, future detection of any Type II SNe by next-generation NIR instruments will in general be limited to this epoch.

  8. Supernova seismology: gravitational wave signatures of rapidly rotating core collapse

    NASA Astrophysics Data System (ADS)

    Fuller, Jim; Klion, Hannah; Abdikamalov, Ernazar; Ott, Christian D.

    2015-06-01

    Gravitational waves (GW) generated during a core-collapse supernova open a window into the heart of the explosion. At core bounce, progenitors with rapid core rotation rates exhibit a characteristic GW signal which can be used to constrain the properties of the core of the progenitor star. We investigate the dynamics of rapidly rotating core collapse, focusing on hydrodynamic waves generated by the core bounce, and the GW spectrum they produce. The centrifugal distortion of the rapidly rotating proto-neutron star (PNS) leads to the generation of axisymmetric quadrupolar oscillations within the PNS and surrounding envelope. Using linear perturbation theory, we estimate the frequencies, amplitudes, damping times, and GW spectra of the oscillations. Our analysis provides a qualitative explanation for several features of the GW spectrum and shows reasonable agreement with non-linear hydrodynamic simulations, although a few discrepancies due to non-linear/rotational effects are evident. The dominant early post-bounce GW signal is produced by the fundamental quadrupolar oscillation mode of the PNS, at a frequency 0.70 ≲ f ≲ 0.80 kHz, whose energy is largely trapped within the PNS and leaks out on a ˜10-ms time-scale. Quasi-radial oscillations are not trapped within the PNS and quickly propagate outwards until they steepen into shocks. Both the PNS structure and Coriolis/centrifugal forces have a strong impact on the GW spectrum, and a detection of the GW signal can therefore be used to constrain progenitor properties.

  9. Colloquium: Perspectives on core-collapse supernova theory

    NASA Astrophysics Data System (ADS)

    Burrows, Adam

    2013-01-01

    Core-collapse theory brings together many facets of high-energy and nuclear astrophysics and the numerical arts to present theorists with one of the most important, yet frustrating, astronomical questions: “What is the mechanism of core-collapse supernova explosions?” A review of all the physics and the 50-year history involved would soon bury the reader in minutiae that could easily obscure the essential elements of the phenomenon, as we understand it today. Moreover, much remains to be discovered and explained, and a complicated review of an unresolved subject in flux could grow stale fast. Therefore, this paper describes various important facts and perspectives that may have escaped the attention of those interested in this puzzle. Furthermore, an attempt to describe the modern theory’s physical underpinnings and a brief summary of the current state of play are given. In the process, a few myths that have crept into modern discourse are identified. However, there is much more to do and humility in the face of this age-old challenge is clearly the most prudent stance as its eventual resolution is sought.

  10. Interplay of Neutrino Opacities in Core-collapse Supernova Simulations

    SciTech Connect

    Lentz, Eric J; Mezzacappa, Anthony; Messer, Bronson; Hix, William Raphael; Bruenn, S. W.

    2012-01-01

    We have conducted a series of numerical experiments using spherically symmetric, general relativistic, neutrino radiation hydrodynamics with the code Agile-BOLTZTRAN to examine the effects of including, and improving, the calculation of neutrino opacities on the development of supernova simulations by removing, or replacing, each opacity individually, or removing opacities in groups. We find that during core collapse improvements to electron capture (EC) on nuclei, namely EC on an ensemble of nuclei based on the hybrid model, relative to the simpler independent-particle approximation (IPA) for a mean nucleus, plays the most important role of all tested neutrino opacities. Low-energy neutrinos emitted by nuclear EC preferentially escape during collapse leading to larger deleptonization of the collapsing core, without the energy downscattering via non-isoenergetic scattering (NIS) on electrons required for the models with IPA nuclear EC. During shock breakout the primary influence on the emergent neutrinos arises from NIS on electrons. For the accretion phase NIS on free nucleons and pair emission by $e^+e^-$-annihilation have the largest impact on the neutrino emission and shock evolution. Other opacities evaluated including nucleon-nucleon bremsstrahlung and especially neutrino-positron scattering have little measurable impact on neutrino emission or shock dynamics. Modern treatments of nuclear electron capture, $e^+e^-$-annihilation pair emission, and non-isoenergetic scattering on electrons and free nucleons are critical elements of core-collapse simulations of all dimensionality.

  11. INTERPLAY OF NEUTRINO OPACITIES IN CORE-COLLAPSE SUPERNOVA SIMULATIONS

    SciTech Connect

    Lentz, Eric J.; Mezzacappa, Anthony; Hix, W. Raphael; Messer, O. E. Bronson; Bruenn, Stephen W.

    2012-11-20

    We have conducted a series of numerical experiments using spherically symmetric, general relativistic, neutrino radiation hydrodynamics with the code Agile-BOLTZTRAN to examine the effects of modern neutrino opacities on the development of supernova simulations. We test the effects of opacities by removing opacities or by undoing opacity improvements for individual opacities and groups of opacities. We find that improvements to electron capture (EC) on nuclei, namely EC on an ensemble of nuclei using modern nuclear structure models rather than the simpler independent-particle approximation (IPA) for EC on a mean nucleus, plays the most important role during core collapse of all tested neutrino opacities. Low-energy neutrinos emitted by modern nuclear EC preferentially escape during collapse without the energy downscattering on electrons required to enhance neutrino escape and deleptonization for the models with IPA nuclear EC. During shock breakout the primary influence on the emergent neutrinos arises from non-isoenergetic scattering (NIS) on electrons. For the accretion phase, NIS on free nucleons and pair emission by e {sup +} e {sup -} annihilation have the largest impact on the neutrino emission and shock evolution. Other opacities evaluated, including nucleon-nucleon bremsstrahlung and especially neutrino-positron scattering, have little measurable impact on neutrino emission or shock dynamics. Modern treatments of nuclear EC, e {sup +} e {sup -}-annihilation pair emission, and NIS on electrons and free nucleons are critical elements of core-collapse simulations of all dimensionality.

  12. Dust content of core-collapse supernova hosts

    NASA Astrophysics Data System (ADS)

    Melchior, A.-L.; Combes, F.

    2008-06-01

    We study 13 core-collapse supernova (CCSN) host galaxies at z=0.1{-}0.6. Continuum observations at 250 GHz were performed using MAMBO at the IRAM-30 m telescope. No source is detected and the error-weighted mean flux is 0.25 ± 0.32 mJy. Upper limits on their dust masses are derived and the corresponding sample mean corresponds to 1.4± 2.2 × 10^8 M_⊙. These results are comparable to previous submillimetre observations of SN-Ia hosts completed by Farrah et al. and Clements et al. We conclude that CCSN hosts are not extreme sources at millimetre wavelengths, and as confirmed using the optical luminosities of a subset of our sample, they are typical of the local galaxy population.

  13. MHD Simulations of Core Collapse Supernovae with Cosmos++

    NASA Astrophysics Data System (ADS)

    Akiyama, Shizuka; Salmonson, Jay

    2010-10-01

    We performed 2D, axisymmetric, MHD simulations with Cosmos++ in order to examine the growth of the magnetorotational instability (MRI) in core-collapse supernovae. We have initialized a non-rotating 15 Msolar progenitor, infused with differential rotation and poloidal magnetic fields. The collapse of the iron core is simulated with the Shen EOS, and the parametric Ye and entropy evolution. The wavelength of the unstable mode in the post-collapse environment is expected to be only ~200 m. In order to achieve the fine spatial resolution requirement, we employed remapping technique after the iron core has collapsed and bounced. The MRI unstable region appears near the equator and angular momentum and entropy are transported outward. Higher resolution remap run display more vigorous overturns and stronger transport of angular momentum and entropy. Our results are in agreement with the earlier work by Akiyama et al. [1] and Obergaulinger et al. [2].

  14. Feedback Effects of the Magnetorotational Instability on Core Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Akiyama, S.; Wheeler, J. C.; Meier, D. L.; Lichtenstadt, I.

    2002-05-01

    We continue our investigation of the effects of the magnetorotational instability (MRI) on collapsing, rotating iron cores. A weak seed field will be exponentially amplified with a growth time t ~ 1/Ω to produce a magnetic field with strength 1014-1016 G within 300 msec after bounce. We follow the collapse with a one-dimensional flux-limited diffusion numerical code. In new work, we explore cylindrical symmetry for angular velocity profiles and invoke a centrifugal quasi-potential to allow somewhat higher initial angular rotation to be explored. We investigate the effect of convection in the core collapse environment to enhance or inhibit the growth of magnetic field, and also explore the feedback effects of the magnetic pressure and viscous drag. The rapid growth of the magnetic field may promote the formation of MHD jets up the rotation axis and, ultimately, a supernova explosion. This research is supported by NASA Grant NAG5-10766 and NSF Grant AST-0098644.

  15. Cutting-edge issues of core-collapse supernova theory

    SciTech Connect

    Kotake, Kei; Nakamura, Ko; Kuroda, Takami; Takiwaki, Tomoya

    2014-05-02

    Based on multi-dimensional neutrino-radiation hydrodynamic simulations, we report several cutting-edge issues about the long-veiled explosion mechanism of core-collapse supernovae (CCSNe). In this contribution, we pay particular attention to whether three-dimensional (3D) hydrodynamics and/or general relativity (GR) would or would not help the onset of explosions. By performing 3D simulations with spectral neutrino transport, we show that it is more difficult to obtain an explosion in 3D than in 2D. In addition, our results from the first generation of full general relativistic 3D simulations including approximate neutrino transport indicate that GR can foster the onset of neutrino-driven explosions. Based on our recent parametric studies using a light-bulb scheme, we discuss impacts of nuclear energy deposition behind the supernova shock and stellar rotation on the neutrino-driven mechanism, both of which have yet to be included in the self-consistent 3D supernova models. Finally we give an outlook with a summary of the most urgent tasks to extract the information about the explosion mechanisms from multi-messenger CCSN observables.

  16. Cutting-edge issues of core-collapse supernova theory

    NASA Astrophysics Data System (ADS)

    Kotake, Kei; Nakamura, Ko; Kuroda, Takami; Takiwaki, Tomoya

    2014-05-01

    Based on multi-dimensional neutrino-radiation hydrodynamic simulations, we report several cutting-edge issues about the long-veiled explosion mechanism of core-collapse supernovae (CCSNe). In this contribution, we pay particular attention to whether three-dimensional (3D) hydrodynamics and/or general relativity (GR) would or would not help the onset of explosions. By performing 3D simulations with spectral neutrino transport, we show that it is more difficult to obtain an explosion in 3D than in 2D. In addition, our results from the first generation of full general relativistic 3D simulations including approximate neutrino transport indicate that GR can foster the onset of neutrino-driven explosions. Based on our recent parametric studies using a light-bulb scheme, we discuss impacts of nuclear energy deposition behind the supernova shock and stellar rotation on the neutrino-driven mechanism, both of which have yet to be included in the self-consistent 3D supernova models. Finally we give an outlook with a summary of the most urgent tasks to extract the information about the explosion mechanisms from multi-messenger CCSN observables.

  17. Stellar Iron Core Collapse in 3+1 General Relativity and The Gravitational Wave Signature of Core-Collapse Supernovae.

    NASA Astrophysics Data System (ADS)

    Ott, Christian David

    2007-04-01

    I perform and analyze the first ever calculations of rotating stellar iron core collapse in {3+1} general relativity that start out with presupernova models from stellar evolutionary calculations and include a microphysical finite-temperature nuclear equation of state, an approximate scheme for electron capture during collapse and neutrino pressure effects. Based on the results of these calculations, I obtain the to-date most realistic estimates for the gravitational wave signal from collapse, bounce and the early postbounce phase of core collapse supernovae. I supplement my {3+1} GR hydrodynamic simulations with 2D Newtonian neutrino radiation-hydrodynamic supernova calculations focussing on (1) the late postbounce gravitational wave emission owing to convective overturn, anisotropic neutrino emission and protoneutron star pulsations, and (2) on the gravitational wave signature of accretion-induced collapse of white dwarfs to neutron stars.

  18. Search for core-collapse supernovae using the MiniBooNE neutrino detector

    SciTech Connect

    Aguilar-Arevalo, A. A.; Anderson, C. E.; Curioni, A.; Fleming, B. T.; Linden, S. K.; Soderberg, M.; Spitz, J.; Bazarko, A. O.; Laird, E. M.; Meyers, P. D.; Patterson, R. B.; Shoemaker, F. C.; Tanaka, H. A.; Brice, S. J.; Brown, B. C.; Finley, D. A.; Ford, R.; Garcia, F. G.; Kasper, P.; Kobilarcik, T.

    2010-02-01

    We present a search for core-collapse supernovae in the Milky Way galaxy, using the MiniBooNE neutrino detector. No evidence is found for core-collapse supernovae occurring in our Galaxy in the period from December 14, 2004 to July 31, 2008, corresponding to 98% live time for collection. We set a limit on the core-collapse supernova rate out to a distance of 13.4 kpc to be less than 0.69 supernovae per year at 90% C.L.

  19. Multimessenger signals of long-term core-collapse supernova simulations: synergetic observation strategies

    NASA Astrophysics Data System (ADS)

    Nakamura, Ko; Horiuchi, Shunsaku; Tanaka, Masaomi; Hayama, Kazuhiro; Takiwaki, Tomoya; Kotake, Kei

    2016-09-01

    The next Galactic supernova is expected to bring great opportunities for the direct detection of gravitational waves (GW), full flavour neutrinos, and multiwavelength photons. To maximize the science return from such a rare event, it is essential to have established classes of possible situations and preparations for appropriate observations. To this end, we use a long-term numerical simulation of the core-collapse supernova (CCSN) of a 17 M⊙ red supergiant progenitor to self-consistently model the multimessenger signals expected in GW, neutrino, and electromagnetic messengers. This supernova model takes into account the formation and evolution of a protoneutron star, neutrino-matter interaction, and neutrino transport, all within a two-dimensional shock hydrodynamics simulation. With this, we separately discuss three situations: (i) a CCSN at the Galactic Center, (ii) an extremely nearby CCSN within hundreds of parsecs, and (iii) a CCSN in nearby galaxies within several Mpc. These distance regimes necessitate different strategies for synergistic observations. In a Galactic CCSN, neutrinos provide strategic timing and pointing information. We explore how these in turn deliver an improvement in the sensitivity of GW analyses and help to guarantee observations of early electromagnetic signals. To facilitate the detection of multimessenger signals of CCSNe in extremely nearby and extragalactic distances, we compile a list of nearby red supergiant candidates and a list of nearby galaxies with their expected CCSN rates. By exploring the sequential multimessenger signals of a nearby CCSN, we discuss preparations for maximizing successful studies of such an unprecedented stirring event.

  20. Asymmetries in Core Collapse Supernovae Revealed by Maps of Radioactive Titanium

    NASA Technical Reports Server (NTRS)

    Grefenstette, B. W.; Harrison, F. A.; Boggs, S. E.; Reynolds, S. P.; Fryer, C. L.; Madsen, K. K.; Wik, D. R.; Zoglauer, A.; Ellinger, C. I.; Alexander, D. M.; An, H.; Barret, D.; Christensen, F. E.; Craig, W. W.; Forster, K.; Giommi, P.; Hailey, C. J.; Hornstrup, A.; Kaspi, V. M.; Kitaguchi, T.; Koglin, J. E.; Mao, P. H.; Miyasaka, H.; Mori, K.; Zhang, W. W.

    2014-01-01

    Asymmetry is required by most numerical simulations of stellar core collapse explosions, however the nature differs significantly among models. The spatial distribution of radioactive Ti-44, synthesized in an exploding star near the boundary between material falling back onto the collapsing core and that ejected into the surrounding medium, directly probes the explosion1asymmetries. Cassiopeia A is a young, nearby, core-collapse remnant from which Ti-44 emission has previously been detected, but not imaged. Asymmetries in the explosion have been indirectly inferred from a high ratio of observed Ti-44 emission to that estimated from (56)Ni9, from optical light echoes, and by jet-like features seen in the X-ray and optical ejecta. Here we report on the spatial maps and spectral properties of Ti-44 in Cassiopeia A. We find the Ti-44 to be distributed non-uniformly in the un-shocked interior of the remnant. This may explain the unexpected lack of correlation between the Ti-44 and iron X-ray emission, the latter only being visible in shock heated material. The observed spatial distribution rules out symmetric explosions even with a high level of convective mixing, as well as highly asymmetric bipolar explosions resulting from a fast rotating progenitor. Instead, these observations provide strong evidence for the development of low-mode convective instabilities in core-collapse supernovae.

  1. Asymmetries in core-collapse supernovae from maps of radioactive 44Ti in Cassiopeia A.

    PubMed

    Grefenstette, B W; Harrison, F A; Boggs, S E; Reynolds, S P; Fryer, C L; Madsen, K K; Wik, D R; Zoglauer, A; Ellinger, C I; Alexander, D M; An, H; Barret, D; Christensen, F E; Craig, W W; Forster, K; Giommi, P; Hailey, C J; Hornstrup, A; Kaspi, V M; Kitaguchi, T; Koglin, J E; Mao, P H; Miyasaka, H; Mori, K; Perri, M; Pivovaroff, M J; Puccetti, S; Rana, V; Stern, D; Westergaard, N J; Zhang, W W

    2014-02-20

    Asymmetry is required by most numerical simulations of stellar core-collapse explosions, but the form it takes differs significantly among models. The spatial distribution of radioactive (44)Ti, synthesized in an exploding star near the boundary between material falling back onto the collapsing core and that ejected into the surrounding medium, directly probes the explosion asymmetries. Cassiopeia A is a young, nearby, core-collapse remnant from which (44)Ti emission has previously been detected but not imaged. Asymmetries in the explosion have been indirectly inferred from a high ratio of observed (44)Ti emission to estimated (56)Ni emission, from optical light echoes, and from jet-like features seen in the X-ray and optical ejecta. Here we report spatial maps and spectral properties of the (44)Ti in Cassiopeia A. This may explain the unexpected lack of correlation between the (44)Ti and iron X-ray emission, the latter being visible only in shock-heated material. The observed spatial distribution rules out symmetric explosions even with a high level of convective mixing, as well as highly asymmetric bipolar explosions resulting from a fast-rotating progenitor. Instead, these observations provide strong evidence for the development of low-mode convective instabilities in core-collapse supernovae. PMID:24553239

  2. Asymmetries in Core-Collapse Supernovae from Maps of Radioactiver 44Ti in Cassiopeia A

    NASA Technical Reports Server (NTRS)

    Grefenstette, B.W.; Harrison, F. A.; Boggs, S. E.; Reynolds, S. P.; Fryer, C. L.; Madsen, K. K.; Wik, Daniel R.; Zoglauer, A.; Ellinger, C. I.; Alexander, D. M.; An, H.; Barret, D.; Christensen, F. E.; Craig, W. W.; Forster, K.; Giommi, P.; Hailey, C. J.; Hornstrup, A.; Kaspi, V. M.; Kitaguchi, T.; Koglin, J. E.; Mao, P. H.; Miyasaka, H.; Mori, K.; Perri, M.; Pivovaroff, M. J.; Puccetti, S.; Rana, V.; Stern, D.; Westergaard, N. J.; Zhang, W. W.

    2014-01-01

    Asymmetry is required by most numerical simulations of stellar core-collapse explosions, but the form it takes differs significantly among models. The spatial distribution of radioactive 44Ti, synthesized in an exploding star near the boundary between material falling back onto the collapsing core and that ejected into the surroundingmedium1, directly probes the explosion asymmetries. Cassiopeia A is a young2, nearby3, core-collapse4 remnant from which 44Ti emission has previously been detected5-8 but not imaged. Asymmetries in the explosion have been indirectly inferred from a high ratio of observed 44Ti emission to estimated 56Ni emission9, from optical light echoes10, and from jet-like features seen in the X-ray11 and optical12 ejecta. Here we report spatial maps and spectral properties of the 44Ti in Cassiopeia A. This may explain the unexpected lack of correlation between the 44Ti and iron X-ray emission, the latter being visible only in shock-heated material. The observed spatial distribution rules out symmetric explosions even with a high level of convective mixing, as well as highly asymmetric bipolar explosions resulting from a fast-rotating progenitor. Instead, these observations provide strong evidence for the development of low-mode convective instabilities in core-collapse supernovae.

  3. EFFECTS OF RESISTIVITY ON MAGNETIZED CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Sawai, H.; Suzuki, H.; Yamada, S.; Kotake, K.

    2013-02-10

    We studied the role of turbulent resistivity in the core-collapse of a strongly magnetized massive star, carrying out two-dimensional resistive-MHD simulations. Three cases with different initial strengths of magnetic field and rotation are investigated: (1) a strongly magnetized rotating core, (2) a moderately magnetized rotating core, and (3) a very strongly magnetized non-rotating core. In each case, one ideal-MHD model and two resistive-MHD models are computed. As a result of these computations, each model shows an eruption of matter assisted by magnetic acceleration (and also by centrifugal acceleration in the rotating cases). We found that resistivity attenuates the explosion in cases 1 and 2, while it enhances the explosion in case 3. We also found that in the rotating cases, the main mechanisms for the amplification of a magnetic field in the post-bounce phase are an outward advection of the magnetic field and a twisting of poloidal magnetic field lines by differential rotation, which are somewhat dampened down with the presence of resistivity. Although magnetorotational instability seems to occur in the rotating models, it plays only a minor role in magnetic field amplification. Another impact of resistivity is that on the aspect ratio. In the rotating cases, a large aspect ratio of the ejected matter, >2.5, attained in an ideal-MHD model is reduced to some extent in a resistive model. These results indicate that resistivity possibly plays an important role in the dynamics of strongly magnetized supernovae.

  4. Core-collapse and Type Ia supernovae with the SKA

    NASA Astrophysics Data System (ADS)

    Perez-Torres, M.; Alberdi, A.; Beswick, R. J.; Lundqvist, P.; Herrero-Illana, R.; Romero-Cañizales, C.; Ryder, S.; della Valle, M.; Conway, J.; Marcaide, J. M.; Mattila, S.; Murphy, T.; Ros, E.

    2015-04-01

    Core-collapse SNe (CCSNe): Systematic searches of radio emission from CCSNe are still lacking, and only targeted searches of radio emission from just some of the optically discovered CCSNe in the local universe have been carried out. Optical searches miss a significant fraction of CCSNe due to dust obscuration; CCSN radio searches are thus more promising for yielding the complete, unobscured star-formation rates in the local universe. The SKA yields the possibility to piggyback for free in this area of research by carrying out commensal, wide-field, blind transient survey observations. SKA1-SUR should be able to discover several hundreds of CCSNe in just one year, compared to about a dozen CCSNe that the VLASS would be able to detect in one year, at most. SKA, with an expected sensitivity ten times that of SKA1, is expected to detect CCSNe in the local Universe by the thousands. Therefore, commensal SKA observations could easily result in an essentially complete census of all CCSNe in the local universe, thus yielding an accurate determination of the volumetric CCSN rate. Type Ia SNe: We advocate for the use of the SKA to search for the putative prompt (~first few days after the explosion) radio emission of any nearby type Ia SN, via target-of-opportunity observations. The huge improvement in sensitivity of the SKA with respect to its predecessors will allow to unambiguously discern which progenitor scenario (single-degenerate vs. double-degenerate) applies to them.

  5. Critical surface for explosions of rotational core-collapse supernovae

    SciTech Connect

    Iwakami, Wakana; Nagakura, Hiroki; Yamada, Shoichi

    2014-09-20

    The effect of rotation on the explosion of core-collapse supernovae is investigated systematically in three-dimensional simulations. In order to obtain the critical conditions for explosion as a function of mass accretion rate, neutrino luminosity, and specific angular momentum, rigidly rotating matter was injected from the outer boundary with an angular momentum, which is increased every 500 ms. It is found that there is a critical value of the specific angular momentum, above which the standing shock wave revives, for a given combination of mass accretion rate and neutrino luminosity, i.e., an explosion can occur by rotation even if the neutrino luminosity is lower than the critical value for a given mass accretion rate in non-rotational models. The coupling of rotation and hydrodynamical instabilities plays an important role in characterizing the dynamics of shock revival for the range of specific angular momentum that are supposed to be realistic. Contrary to expectations from past studies, the most rapidly expanding direction of the shock wave is not aligned with the rotation axis. Being perpendicular to the rotation axis on average, it can be oriented in various directions. Its dispersion is small when the spiral mode of the standing accretion shock instability (SASI) governs the dynamics, while it is large when neutrino-driven convection is dominant. As a result of the comparison between two-dimensional and three-dimensional rotational models, it is found that m ≠ 0 modes of neutrino-driven convection or SASI are important for shock revival around the critical surface.

  6. The core-collapse supernova rate in Arp 299 revisited

    NASA Astrophysics Data System (ADS)

    Romero-Cañizales, C.; Mattila, S.; Alberdi, A.; Pérez-Torres, M. A.; Kankare, E.; Ryder, S. D.

    2011-08-01

    We present a study of the core-collapse supernova (CCSN) rate in nuclei A and B1, of the luminous infrared galaxy (LIRG) Arp 299, based on ˜11 yr of Very Large Array (VLA) monitoring of their radio emission at 8.4 GHz. Significant variations in the nuclear radio flux density can be used to identify the CCSN activity in the absence of high-resolution very long baseline interferometry (VLBI) observations. In the case of the B1-nucleus, the small variations in its measured diffuse (synchrotron plus free-free) radio emission are below the fluxes expected from radio supernovae (RSNe), thus making it well-suited to detect RSNe through flux density variability. In fact, we find strong evidence for at least three RSNe this way, which results in a lower limit for the CCSN rate (νSN) of >0.28+0.27-0.15 yr-1. This value agrees within the uncertainties with the infrared (IR) luminosity based SN rate estimate, and with previously reported radio estimates. In the A-nucleus, we did not detect any significant variability and found a SN detection threshold luminosity of ≈3.1 × 1028 erg s-1 Hz-1, allowing only the detection of the most luminous RSNe known. Our method is basically blind to normal CCSN explosions occurring within the A-nucleus, which result in too small variations in the nuclear flux density, remaining diluted by the strong diffuse emission of the nucleus itself. Additionally, we have attempted to find near-IR (NIR) counterparts for the earlier reported RSNe in the Arp 299 nucleus A, by comparing NIR adaptive optics images from the Gemini-N Telescope with contemporaneous observations from the European VLBI Network (EVN). However, we were not able to detect NIR counterparts for the reported radio SNe within the innermost regions of nucleus A. While our NIR observations were sensitive to typical CCSNe at ˜300 mas (or 70 pc projected distance) from the centre of the nucleus A, suffering from extinction up to AV˜ 15 mag, they were not sensitive to such highly

  7. Tomography of massive stars from core collapse to supernova shock breakout

    SciTech Connect

    Kistler, Matthew D.; Haxton, W. C.; Yüksel, Hasan

    2013-11-20

    Neutrinos and gravitational waves are the only direct probes of the inner dynamics of a stellar core collapse. They are also the first signals to arrive from a supernova (SN) and, if detected, establish the moment when the shock wave is formed that unbinds the stellar envelope and later initiates the optical display upon reaching the stellar surface with a burst of UV and X-ray photons, the shock breakout (SBO). We discuss how neutrino observations can be used to trigger searches to detect the elusive SBO event. Observation of the SBO would provide several important constraints on progenitor structure and the explosion, including the shock propagation time (the duration between the neutrino burst and SBO), an observable that is important in distinguishing progenitor types. Our estimates suggest that next-generation neutrino detectors could exploit the overdensity of nearby SNe to provide several such triggers per decade, more than an order-of-magnitude improvement over the present.

  8. On the Nature of Core-Collapse Supernova Explosions

    NASA Astrophysics Data System (ADS)

    Burrows, Adam; Hayes, John; Fryxell, Bruce A.

    1995-09-01

    We investigate in this paper the core-collapse supernova explosion mechanism in both one and two dimensions. With a radiation/hydrodynamic code based upon the PPM algorithm, we verify the usefulness of neutrino-driven overturn ("convection") between the shock and the neutrinosphere in igniting the supernova explosion. The two-dimensional simulation of the core of a 15 Msun star that we present here indicates that the breaking of spherical symmetry may be central to the explosion itself and that a multitude of bent and broken fingers is a common feature of the ejecta. As in one dimension, the explosion seems to be a mathematically critical phenomenon, evolving from a steady state to explosion after a critical mass accretion rate through the stalled shock has been reached. In the two-dimensional simulation the preexplosion convective phase lasted ˜30 overturns (˜100 ms) before exploding. The preexplosion steady state in two dimensions is similar to that achieved in one dimension, but in two dimensions, owing to the longer dwell time of matter in the overturning region, the average entropy achieved behind the stalled shock is larger. In addition, the entropy gradient in the convecting region is flatter. These effects, together with the dynamical pressure of the buoyant plumes, serve to increase the steady state shock radius (Rs) over its value in one dimension by 30%-100%. A large Rs enlarges the volume of the gain region, puts shocked matter lower in the gravitational potential well, and lowers the accretion ram pressure at the shock for a given Mdot. The critical condition for explosion is thereby relaxed. Since the "escape" temperature (Tesc) decreases with radius faster than the actual matter temperature (T) behind the shock, a larger Rs puts a larger fraction of the shocked material above its local escape temperature. T > Tesc is the condition for a thermally driven corona to lift off a star. In one, two, or three dimensions, since supernovae are driven by

  9. The core collapse supernova rate from the SDSS-II supernova survey

    SciTech Connect

    Taylor, Matt; Cinabro, David; Dilday, Ben; Galbany, Lluis; Gupta, Ravi R.; Kessler, R.; Marriner, John; Nichol, Robert C.; Richmond, Michael; Schneider, Donald P.; Sollerman, Jesper

    2014-09-10

    We use the Sloan Digital Sky Survey II Supernova Survey (SDSS-II SNS) data to measure the volumetric core collapse supernova (CCSN) rate in the redshift range (0.03 < z < 0.09). Using a sample of 89 CCSN, we find a volume-averaged rate of 1.06 ± 0.19 × 10{sup –4}((h/0.7){sup 3}/(yr Mpc{sup 3})) at a mean redshift of 0.072 ± 0.009. We measure the CCSN luminosity function from the data and consider the implications on the star formation history.

  10. iPTF Discoveries of Recent Core-Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Taddia, F.; Ferretti, R.; Papadogiannakis, S.; Petrushevska, T.; Fremling, C.; Karamehmetoglu, E.; Nyholm, A.; Roy, R.; Hangard, L.; Horesh, A.; Khazov, D.; Knezevic, S.; Johansson, J.; Leloudas, G.; Manulis, I.; Rubin, A.; Soumagnac, M.; Vreeswijk, P.; Yaron, O.; Bar, I.; Cao, Y.; Kulkarni, S.; Blagorodnova, N.

    2016-05-01

    The intermediate Palomar Transient Factory (ATel #4807) reports the discovery and classification of the following core-collapse SNe. Our automated candidate vetting to distinguish a real astrophysical source (1.0) from bogus artifacts (0.0) is powered by three generations of machine learning algorithms: RB2 (Brink et al. 2013MNRAS.435.1047B), RB4 (Rebbapragada et al. 2015AAS...22543402R) and RB5 (Wozniak et al. 2013AAS...22143105W).

  11. Neutrino Reactions on Two-Nucleon System and Core-Collapse Supernova

    NASA Astrophysics Data System (ADS)

    Nasu, Shota

    2011-10-01

    The neutrino reactions on nucleon and nucleus play important role in core-collapse supernova. Recently it is pointed that light nuclei(A = 2,3) can be abundant at the various stage of supernova environment. As an important mechanism of neutrino reaction on a few nucleon system, we study the neutrino emissivity on neutron fusion reaction nn-->de-νe.

  12. Progenitor constraints for core-collapse supernovae from Chandra X-ray observations

    NASA Astrophysics Data System (ADS)

    Heikkilä, T.; Tsygankov, S.; Mattila, S.; Eldridge, J. J.; Fraser, M.; Poutanen, J.

    2016-03-01

    The progenitors of hydrogen-poor core-collapse supernovae (SNe) of Types Ib, Ic and IIb are believed to have shed their outer hydrogen envelopes either by extremely strong stellar winds, characteristic of classical Wolf-Rayet stars, or by binary interaction with a close companion star. The exact nature of the progenitors and the relative importance of these processes are still open questions. One relatively unexplored method to constrain the progenitors is to search for high-mass X-ray binaries (HMXBs) at SN locations in pre-explosion X-ray observations. In an HMXB, one star has already exploded as a core-collapse SN, producing a neutron star or a stellar mass black hole. It is likely that the second star in the system will also explode as an SN, which should cause a detectable long-term change in the system's X-ray luminosity. In particular, a pre-explosion detection of an HMXB coincident with an SN could be informative about the progenitor's nature. In this paper, we analyse pre-explosion ACIS observations of 18 nearby Type Ib, Ic and IIb SNe from the Chandra X-ray observatory public archive. Two sources that could potentially be associated with the SN are identified in the sample. Additionally we make similar post-explosion measurements for 46 SNe. Although our modelling indicates that progenitor systems with compact binary companions are probably quite rare, studies of this type can in the future provide more stringent constraints as the number of discovered nearby SNe and suitable pre-explosion X-ray data are both increasing.

  13. Observing Gravitational Waves from Core-Collapse Supernovae in the Advanced Detector Era

    NASA Astrophysics Data System (ADS)

    Gossan, Sarah

    2016-03-01

    The next galactic core-collapse supernova (CCSN) has already exploded, and its electromagnetic (EM) waves, neutrinos, and gravitational waves (GWs) may arrive at any moment. We present an extensive study on the potential sensitivity of prospective detection scenarios for GWs from CCSN sources within 5Mpc, using realistic noise at the predicted sensitivity of the Advanced LIGO and Advanced Virgo detectors for 2015, 2017, and 2019. We make statements on the detectability of the core collapse event for sources within the galaxy and Large Magellanic Cloud, for which there will be an associated neutrino burst, and consider the exclusion of extreme post-core collapse emission models for more distant SNe with an associated EM signature. Given a detection of GW from core collapse, we discuss the potential to infer the CCSN explosion mechanism.

  14. The Explosion Mechanism of Core-Collapse Supernovae: Progress in Supernova Theory and Experiments

    SciTech Connect

    Foglizzo, Thierry; Kazeroni, Rémi; Guilet, Jérôme; Masset, Frédéric; González, Matthias; Krueger, Brendan K.; Novak, Jérôme; Faure, Julien; Martin, Noël; Blottiau, Patrick; Peres, Bruno; Durand, Gilles

    2015-01-01

    The explosion of core-collapse supernova depends on a sequence of events taking place in less than a second in a region of a few hundred kilometers at the center of a supergiant star, after the stellar core approaches the Chandrasekhar mass and collapses into a proto-neutron star, and before a shock wave is launched across the stellar envelope. Theoretical efforts to understand stellar death focus on the mechanism which transforms the collapse into an explosion. Progress in understanding this mechanism is reviewed with particular attention to its asymmetric character. We highlight a series of successful studies connecting observations of supernova remnants and pulsars properties to the theory of core-collapse using numerical simulations. The encouraging results from first principles models in axisymmetric simulations is tempered by new puzzles in 3D. The diversity of explosion paths and the dependence on the pre-collapse stellar structure is stressed, as well as the need to gain a better understanding of hydrodynamical and MHD instabilities such as SASI and neutrino-driven convection. The shallow water analogy of shock dynamics is presented as a comparative system where buoyancy effects are absent. This dynamical system can be studied numerically and also experimentally with a water fountain. Lastly, we analyse the potential of this complementary research tool for supernova theory. We also review its potential for public outreach in science museums.

  15. CORE-COLLAPSE SUPERNOVAE AND HOST GALAXY STELLAR POPULATIONS

    SciTech Connect

    Kelly, Patrick L.; Kirshner, Robert P.

    2012-11-10

    We have used images and spectra of the Sloan Digital Sky Survey to examine the host galaxies of 519 nearby supernovae (SN). The colors at the sites of the explosions, as well as chemical abundances, and specific star formation rates (SFRs) of the host galaxies provide circumstantial evidence on the origin of each SN type. We examine separately SN II, SN IIn, SN IIb, SN Ib, SN Ic, and SN Ic with broad lines (SN Ic-BL). For host galaxies that have multiple spectroscopic fibers, we select the fiber with host radial offset most similar to that of the SN. Type Ic SN explode at small host offsets, and their hosts have exceptionally strongly star-forming, metal-rich, and dusty stellar populations near their centers. The SN Ic-BL and SN IIb explode in exceptionally blue locations, and, in our sample, we find that the host spectra for SN Ic-BL show lower average oxygen abundances than those for SN Ic. SN IIb host fiber spectra are also more metal-poor than those for SN Ib, although a significant difference exists for only one of two strong-line diagnostics. SN Ic-BL host galaxy emission lines show strong central specific SFRs. In contrast, we find no strong evidence for different environments for SN IIn compared to the sites of SN II. Because our SN sample is constructed from a variety of sources, there is always a risk that sampling methods can produce misleading results. We have separated the SN discovered by targeted surveys from those discovered by galaxy-impartial searches to examine these questions and show that our results do not depend sensitively on the discovery technique.

  16. THE COSMIC CORE-COLLAPSE SUPERNOVA RATE DOES NOT MATCH THE MASSIVE-STAR FORMATION RATE

    SciTech Connect

    Horiuchi, Shunsaku; Beacom, John F.; Kochanek, Christopher S.; Stanek, K. Z.; Thompson, Todd A.; Prieto, Jose L.

    2011-09-10

    We identify a 'supernova rate problem': the measured cosmic core-collapse supernova rate is a factor of {approx}2 smaller (with significance {approx}2{sigma}) than that predicted from the measured cosmic massive-star formation rate. The comparison is critical for topics from galaxy evolution and enrichment to the abundance of neutron stars and black holes. We systematically explore possible resolutions. The accuracy and precision of the star formation rate data and conversion to the supernova rate are well supported, and proposed changes would have far-reaching consequences. The dominant effect is likely that many supernovae are missed because they are either optically dim (low-luminosity) or dark, whether intrinsically or due to obscuration. We investigate supernovae too dim to have been discovered in cosmic surveys by a detailed study of all supernova discoveries in the local volume. If possible supernova impostors are included, then dim supernovae are common enough by fraction to solve the supernova rate problem. If they are not included, then the rate of dark core collapses is likely substantial. Other alternatives are that there are surprising changes in our understanding of star formation or supernova rates, including that supernovae form differently in small galaxies than in normal galaxies. These possibilities can be distinguished by upcoming supernova surveys, star formation measurements, searches for disappearing massive stars, and measurements of supernova neutrinos.

  17. The Explosion Mechanism of Core-Collapse Supernovae: Progress in Supernova Theory and Experiments

    DOE PAGES

    Foglizzo, Thierry; Kazeroni, Rémi; Guilet, Jérôme; Masset, Frédéric; González, Matthias; Krueger, Brendan K.; Novak, Jérôme; Oertel, Micaela; Margueron, Jérôme; Faure, Julien; et al

    2015-01-01

    The explosion of core-collapse supernova depends on a sequence of events taking place in less than a second in a region of a few hundred kilometers at the center of a supergiant star, after the stellar core approaches the Chandrasekhar mass and collapses into a proto-neutron star, and before a shock wave is launched across the stellar envelope. Theoretical efforts to understand stellar death focus on the mechanism which transforms the collapse into an explosion. Progress in understanding this mechanism is reviewed with particular attention to its asymmetric character. We highlight a series of successful studies connecting observations of supernovamore » remnants and pulsars properties to the theory of core-collapse using numerical simulations. The encouraging results from first principles models in axisymmetric simulations is tempered by new puzzles in 3D. The diversity of explosion paths and the dependence on the pre-collapse stellar structure is stressed, as well as the need to gain a better understanding of hydrodynamical and MHD instabilities such as SASI and neutrino-driven convection. The shallow water analogy of shock dynamics is presented as a comparative system where buoyancy effects are absent. This dynamical system can be studied numerically and also experimentally with a water fountain. Lastly, we analyse the potential of this complementary research tool for supernova theory. We also review its potential for public outreach in science museums.« less

  18. Neutrino Reactions on Two-Nucleon System and Core-Collapse Supernova

    SciTech Connect

    Nasu, Shota

    2011-10-21

    The neutrino reactions on nucleon and nucleus play important role in core-collapse supernova. Recently it is pointed that light nuclei(A = 2,3) can be abundant at the various stage of supernova environment. As an important mechanism of neutrino reaction on a few nucleon system, we study the neutrino emissivity on neutron fusion reaction nn{yields}de{sup -}{nu}-bar{sub e}.

  19. FIRST LABORATORY OBSERVATION OF SILICA GRAINS FROM CORE COLLAPSE SUPERNOVAE

    SciTech Connect

    Haenecour, Pierre; Floss, Christine; Zinner, Ernst; Zhao Xuchao; Lin Yangting

    2013-05-01

    We report the discovery of two supernova silica (SiO{sub 2}) grains in the primitive carbonaceous chondrites LaPaZ 031117 and Grove Mountains 021710. Only five presolar silica grains have been previously reported from laboratory measurements but they all exhibit enrichments in {sup 17}O relative to solar, indicating origins in the envelopes of asymptotic giant branch stars. The two SiO{sub 2} grains identified in this study are characterized by moderate enrichments in {sup 18}O relative to solar, indicating that they originated in Type II supernova ejecta. If compared to theoretical models, the oxygen isotopic compositions of these grains can be reproduced by mixing of different supernova zones. While both theoretical models of grain condensation and recent NASA Spitzer Space Telescope observations have suggested the presence of silica in supernova ejecta, no such grains had been identified, until now, in meteorites. The discovery of these two silica grains provides definitive evidence of the condensation of silica dust in supernova ejecta.

  20. New developments in the mechanism for core-collapse supernovae

    SciTech Connect

    Guidry, M. |

    1994-12-31

    Recent results indicate that the standard type-2 supernova scenario in which the shock wave stagnates but is reenergized by neutrino heating fails to consistently produce supernova explosions having the required characteristics. The authors review the theory of convection and survey some recent calculations indicating the importance of convection operating on millisecond timescales in the protoneutron star. These calculations suggest that such convection is probably generic to the type-2 scenario, that this produces a violet overturn of material below the stalled shock, and that this overturn could lead to significant alterations in the neutrino luminosity and energy. This provides a mechanism that could be effective in reenergizing the stalled shock and producing supernovae explosions having the quantitative characteristics demands by observations. This mechanism implies, in turn, that the convection cannot be adequately described by the 1-dimensional hydrodynamics employed in most simulations. Thus, a full understanding of the supernova mechanism and the resulting heavy element production is likely to require 3-dimensional relativistic hydrodynamics and a comprehensive description of neutrino transport. The prospects for implementing such calculations using a new generation of massively parallel supercomputers and modern scalable algorithms are discussed.

  1. Neutrino nucleosynthesis in core-collapse Supernova explosions

    NASA Astrophysics Data System (ADS)

    Sieverding, A.; Huther, L.; Martínez-Pinedo, G.; Langanke, K.; Heger, A.

    2016-02-01

    The neutrino-induced nucleosynthesis (ν process) in supernova explosions of massive stars of solar metallicity with initial main sequence masses between 15 and 40 M⊙ has been studied. A new extensive set of neutrino-nucleus cross-sections for all the nuclei included in the reaction network is used and the average neutrino energies are reduced to agree with modern supernova simulations. Despite these changes the ν process is found to contribute still significantly to the production of the nuclei 7Li, 11B, 19F, 138La and 180Ta, even though the total yields for those nuclei are reduced. Furthermore we study in detail contributions of the ν process to the production of radioactive isotopes 26Al, 22Na and confirm the production of 92Nb and 98Tc.

  2. Turbulence and magnetic field amplification from spiral SASI modes in core-collapse supernovae

    SciTech Connect

    Endeve, Eirik; Cardall, Christian Y; Budiardja, Reuben D; Blondin, John; Mezzacappa, Anthony

    2013-01-01

    The stationary accretion shock instability (SASI) plays a central role in modern simulations of the explosion phase of core-collapse supernovae (CCSNe). It may be key to realizing neutrino powered explosions, and possibly links birth properties of pulsars (e.g., kick, spin, and magnetic field) to supernova dynamics. Using high-resolution magnetohydrodynamic simulations, we study the development of turbulence, and subsequent amplification of magnetic fields in a simplified model of the post-bounce core-collapse supernova environment. Turbulence develops from secondary instabilities induced by the SASI. Our simulations suggest that the development of turbulence plays an important role for the subsequent evolution of the SASI. The turbulence also acts to amplify weak magnetic fields via a small-scale dynamo.

  3. Two- and three-dimensional simulations of core-collapse supernovae with CHIMERA

    SciTech Connect

    Lentz, Eric J; Bruenn, S. W.; Harris, James A; Chertkow, Merek A; Hix, William Raphael; Mezzacappa, Anthony; Messer, Bronson; Blondin, J. M.; Marronetti, Pedro; Mauney, Christopher M; Yakunin, Konstantin

    2012-01-01

    Ascertaining the core-collapse supernova mechanism is a complex, and yet unsolved, problem dependent on the interaction of general relativity, hydrodynamics, neutrino transport, neutrino-matter interactions, and nuclear equations of state and reaction kinetics. Ab initio modeling of core-collapse supernovae and their nucleosynthetic outcomes requires care in the coupling and approximations of the physical components. We have built our multi-physics CHIMERA code for supernova modeling in 1-, 2-, and 3-D, using ray-by-ray neutrino transport, approximate general relativity, and detailed neutrino and nuclear physics. We discuss some early results from our current series of exploding 2D simulations and our work to perform computationally tractable simulations in 3D using the ``Yin--Yang'' grid.

  4. Explosive nucleosynthesis in a neutrino-driven core collapse supernova

    SciTech Connect

    Fujimoto, Shin-ichiro; Kotake, Kei; Hashimoto, Masa-aki; Ono, Masaomi; Ohnishi, Naofumi

    2010-06-01

    We investigate explosive nucleosynthesis in a delayed neutrino-driven, supernova explosion aided by standing accretion shock instability (SASI), based on two-dimensional hydrodynamic simulations of the explosion of a 15 M{sub c}entre dot star. We take into accounts neutrino heating and cooling as well as change in electron fraction due to weak interactions appropriately, in the two-dimensional simulations. We assume the isotropic emission of neutrinos from the neutrino spheres with given luminosities. and the Fermi-Dirac distribution of given temperatures. We find that the stalled shock revives due to the neutrino heating aided by SASI for cases with L{sub n}u{sub e}>=3.9x10{sup 52}ergss{sup -1} and the as-pherical shock passes through the outer layers of the star (>=10,000 km), with the explosion energies of approx10{sup 51}ergs.Next we examine abundances and masses of the supernova ejecta. We find that masses of the ejecta and {sup 56}Ni correlate with the neutrino luminosity, and {sup 56}Ni mass is comparable to that observed in SN 1987A. We also find that abundance pattern of the supernova ejecta is similar to that of the solar system, for cases with high explosion energies of >10{sup 51}ergs. We emphasize that {sup 64}Zn, which is underproduced in the spherical case, is abundantly produced in slightly neutron-rich ejecta.

  5. Supernovae. The bubble-like interior of the core-collapse supernova remnant Cassiopeia A.

    PubMed

    Milisavljevic, Dan; Fesen, Robert A

    2015-01-30

    The death of massive stars is believed to involve aspheric explosions initiated by the collapse of an iron core. The specifics of these catastrophic explosions remain uncertain, due partly to limited observational constraints on asymmetries deep inside the star. Here we present near-infrared observations of the young supernova remnant Cassiopeia A, descendant of a type IIb core-collapse explosion, and a three-dimensional map of its interior unshocked ejecta. The remnant's interior has a bubble-like morphology that smoothly connects to and helps explain the multiringed structures seen in the remnant's bright reverse-shocked main shell of expanding debris. This internal structure may originate from turbulent mixing processes that encouraged outwardly expanding plumes of radioactive (56)Ni-rich ejecta. If this is true, substantial amounts of its decay product, (56)Fe, may still reside in these interior cavities.

  6. Shock-turbulence interaction in core-collapse supernovae

    NASA Astrophysics Data System (ADS)

    Abdikamalov, Ernazar; Zhaksylykov, Azamat; Radice, David; Berdibek, Shapagat

    2016-10-01

    Nuclear shell burning in the final stages of the lives of massive stars is accompanied by strong turbulent convection. The resulting fluctuations aid supernova explosion by amplifying the non-radial flow in the post-shock region. In this work, we investigate the physical mechanism behind this amplification using a linear perturbation theory. We model the shock wave as a one-dimensional planar discontinuity and consider its interaction with vorticity and entropy perturbations in the upstream flow. We find that, as the perturbations cross the shock, their total turbulent kinetic energy is amplified by a factor of ˜2, while the average linear size of turbulent eddies decreases by about the same factor. These values are not sensitive to the parameters of the upstream turbulence and the nuclear dissociation efficiency at the shock. Finally, we discuss the implication of our results for the supernova explosion mechanism. We show that the upstream perturbations can decrease the critical neutrino luminosity for producing explosion by several per cent.

  7. Impact of sterile neutrino dark matter on core-collapse supernovae

    NASA Astrophysics Data System (ADS)

    Warren, Mackenzie L.; Mathews, Grant J.; Meixner, Matthew; Hidaka, Jun; Kajino, Toshitaka

    2016-09-01

    We summarize the impact of sterile neutrino dark matter on core-collapse supernova explosions. We explore various oscillations between electron neutrinos or mixed μ ‑ τ neutrinos and right-handed sterile neutrinos that may occur within a core-collapse supernova. In particular, we consider sterile neutrino masses and mixing angles that are consistent with sterile neutrino dark matter candidates as indicated by recent X-ray flux measurements. We find that the interpretation of the observed 3.5 keV X-ray excess as due to a decaying 7 keV sterile neutrino that comprises 100% of the dark matter would have almost no observable effect on supernova explosions. However, in the more realistic case in which the decaying sterile neutrino comprises only a small fraction of the total dark matter density due to the presence of other sterile neutrino flavors, WIMPs, etc. a larger mixing angle is allowed. In this case a 7 keV sterile neutrino could have a significant impact on core-collapse supernovae. We also consider mixing between μ ‑ τ neutrinos and sterile neutrinos. We find, however, that this mixing does not significantly alter the explosion and has no observable effect on the neutrino luminosities at early times.

  8. A low-energy core-collapse supernova without a hydrogen envelope.

    PubMed

    Valenti, S; Pastorello, A; Cappellaro, E; Benetti, S; Mazzali, P A; Manteca, J; Taubenberger, S; Elias-Rosa, N; Ferrando, R; Harutyunyan, A; Hentunen, V P; Nissinen, M; Pian, E; Turatto, M; Zampieri, L; Smartt, S J

    2009-06-01

    The final fate of massive stars depends on many factors. Theory suggests that some with initial masses greater than 25 to 30 solar masses end up as Wolf-Rayet stars, which are deficient in hydrogen in their outer layers because of mass loss through strong stellar winds. The most massive of these stars have cores which may form a black hole and theory predicts that the resulting explosion of some of them produces ejecta of low kinetic energy, a faint optical luminosity and a small mass fraction of radioactive nickel. An alternative origin for low-energy supernovae is the collapse of the oxygen-neon core of a star of 7-9 solar masses. No weak, hydrogen-deficient, core-collapse supernovae have hitherto been seen. Here we report that SN 2008ha is a faint hydrogen-poor supernova. We propose that other similar events have been observed but have been misclassified as peculiar thermonuclear supernovae (sometimes labelled SN 2002cx-like events). This discovery could link these faint supernovae to some long-duration gamma-ray bursts, because extremely faint, hydrogen-stripped core-collapse supernovae have been proposed to produce such long gamma-ray bursts, the afterglows of which do not show evidence of associated supernovae. PMID:19494909

  9. Toward connecting core-collapse supernova theory with observations

    NASA Astrophysics Data System (ADS)

    Handy, Timothy A.

    We study the evolution of the collapsing core of a 15 solar mass blue supergiant supernova progenitor from the moment shortly after core bounce until 1.5 seconds later. We present a sample of two- and three-dimensional hydrodynamic models parameterized to match the explosion energetics of supernova SN 1987A. We focus on the characteristics of the flow inside the gain region and the interplay between hydrodynamics, self-gravity, and neutrino heating, taking into account uncertainty in the nuclear equation of state. We characterize the evolution and structure of the flow behind the shock in terms the accretion flow dynamics, shock perturbations, energy transport and neutrino heating effects, and convective and turbulent motions. We also analyze information provided by particle tracers embedded in the flow. Our models are computed with a high-resolution finite volume shock capturing hydrodynamic code. The code includes source terms due to neutrino-matter interactions from a light-bulb neutrino scheme that is used to prescribe the luminosities and energies of the neutrinos emerging from the core of the proto-neutron star. The proto-neutron star is excised from the computational domain, and its contraction is modeled by a time-dependent inner boundary condition. We find the spatial dimensionality of the models to be an important contributing factor in the explosion process. Compared to two-dimensional simulations, our three-dimensional models require lower neutrino luminosities to produce equally energetic explosions. We estimate that the convective engine in our models is 4% more efficient in three dimensions than in two dimensions. We propose that this is due to the difference of morphology of convection between two- and three-dimensional models. Specifically, the greater efficiency of the convective engine found in three-dimensional simulations might be due to the larger surface-to-volume ratio of convective plumes, which aids in distributing energy deposited by

  10. Toward connecting core-collapse supernova theory with observations

    NASA Astrophysics Data System (ADS)

    Handy, Timothy A.

    We study the evolution of the collapsing core of a 15 solar mass blue supergiant supernova progenitor from the moment shortly after core bounce until 1.5 seconds later. We present a sample of two- and three-dimensional hydrodynamic models parameterized to match the explosion energetics of supernova SN 1987A. We focus on the characteristics of the flow inside the gain region and the interplay between hydrodynamics, self-gravity, and neutrino heating, taking into account uncertainty in the nuclear equation of state. We characterize the evolution and structure of the flow behind the shock in terms the accretion flow dynamics, shock perturbations, energy transport and neutrino heating effects, and convective and turbulent motions. We also analyze information provided by particle tracers embedded in the flow. Our models are computed with a high-resolution finite volume shock capturing hydrodynamic code. The code includes source terms due to neutrino-matter interactions from a light-bulb neutrino scheme that is used to prescribe the luminosities and energies of the neutrinos emerging from the core of the proto-neutron star. The proto-neutron star is excised from the computational domain, and its contraction is modeled by a time-dependent inner boundary condition. We find the spatial dimensionality of the models to be an important contributing factor in the explosion process. Compared to two-dimensional simulations, our three-dimensional models require lower neutrino luminosities to produce equally energetic explosions. We estimate that the convective engine in our models is 4% more efficient in three dimensions than in two dimensions. We propose that this is due to the difference of morphology of convection between two- and three-dimensional models. Specifically, the greater efficiency of the convective engine found in three-dimensional simulations might be due to the larger surface-to-volume ratio of convective plumes, which aids in distributing energy deposited by

  11. DAO spectroscopic classification of AT2016ccm in IC983 as a core-collapse supernova

    NASA Astrophysics Data System (ADS)

    Balam, D. D.; Graham, M. L.

    2016-05-01

    A spectrum was obtained on UT May 09.36 of AT2016ccm in IC 983 using the 1.82-m Plaskett telescope (National Research Council of Canada) covering the range 365-710 nm (resolution 0.35 nm). Cross-correlation with a template library using SNID (Blondin & Tonry 2007, ApJ, 666, 1024) shows AT2016ccm to be a core-collapse supernova approximately 1 week post maximum light.

  12. Two Dimensional Simulations of Core-Collapse Supernovae with Neutrino Transport in FLASH

    NASA Astrophysics Data System (ADS)

    O'Connor, Evan; Couch, Sean

    2016-03-01

    Core-collapse supernovae are the end stage of massive star evolution and are central to many aspects of astrophysics. They are the birth site of both neutron stars and black holes and their shocks are responsible for spreading the products of stellar evolution throughout the Galaxy and regulating star formation. Despite their importance and decades of research, the precise mechanism that converts the initial implosion of the collapsing iron core to an explosion that unbinds the majority of the star is unknown. However, we know that the majority of the energy released is ultimately radiated in neutrinos and that the physics of neutrino transport and neutrino heating-among many other aspects-must be treated carefully when modelling the core-collapse supernova central engine. In this talk, I will present recent simulations of core-collapse supernovae from the FLASH hydrodynamics code. We perform two dimensional, neutrino transport simulations using several progenitors. We test the influence of general relativity by using a pseudorelativistic potential that effectively models GR. We show that the more compact protoneutron star predicted from GR increases the neutrino heating and can lead to explosions where the corresponding Newtonian simulations fail.

  13. Experimental challenge to nucleosynthesis in core-collapse supernovae - Very early epoch of type II SNe -

    NASA Astrophysics Data System (ADS)

    Kubono, S.; Binh, Dam N.; Hayakawa, S.; Hashimoto, T.; Kahl, D. M.; Yamaguchi, H.; Wakabayashi, Y.; Teranishi, T.; Iwasa, N.; Komatsubara, T.; Kato, S.; Chen, A.; Cherubini, S.; Choi, S. H.; Hahn, I. S.; He, J. J.; Khiem, Le H.; Lee, C. S.; Kwon, Y. K.; Wanajo, S.; Janka, H.-T.

    2013-05-01

    Nucleosynthesis is one of the keys in studying the mechanism of core-collapse supernovae, which is an interesting challenge for modern science. The νp-process, which is similar to an explosive hydrogen burning process, has been proposed as the most probable process in the very early epoch of type II supernovae. Here, we discuss our experimental efforts for the νp-process, the first extensive direct measurements of the (α,p) reactions on bottle-neck proto-rich nuclei in light mass regions. Other challenges for the νp-process study are also discussed.

  14. NEW EQUATIONS OF STATE IN SIMULATIONS OF CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Hempel, M.; Liebendoerfer, M.; Fischer, T.; Schaffner-Bielich, J.

    2012-03-20

    We discuss three new equations of state (EOS) in core-collapse supernova simulations. The new EOS are based on the nuclear statistical equilibrium model of Hempel and Schaffner-Bielich (HS), which includes excluded volume effects and relativistic mean-field (RMF) interactions. We consider the RMF parameterizations TM1, TMA, and FSUgold. These EOS are implemented into our spherically symmetric core-collapse supernova model, which is based on general relativistic radiation hydrodynamics and three-flavor Boltzmann neutrino transport. The results obtained for the new EOS are compared with the widely used EOS of H. Shen et al. and Lattimer and Swesty. The systematic comparison shows that the model description of inhomogeneous nuclear matter is as important as the parameterization of the nuclear interactions for the supernova dynamics and the neutrino signal. Furthermore, several new aspects of nuclear physics are investigated: the HS EOS contains distributions of nuclei, including nuclear shell effects. The appearance of light nuclei, e.g., deuterium and tritium, is also explored, which can become as abundant as alphas and free protons. In addition, we investigate the black hole formation in failed core-collapse supernovae, which is mainly determined by the high-density EOS. We find that temperature effects lead to a systematically faster collapse for the non-relativistic LS EOS in comparison with the RMF EOS. We deduce a new correlation for the time until black hole formation, which allows the determination of the maximum mass of proto-neutron stars, if the neutrino signal from such a failed supernova would be measured in the future. This would give a constraint for the nuclear EOS at finite entropy, complementary to observations of cold neutron stars.

  15. Stellar Forensics IV: A post-explosion view of the progenitors of core-collapse supernovae

    NASA Astrophysics Data System (ADS)

    Maund, Justyn

    2012-10-01

    Recent studies have used high spatial resolution HST observations of supernova {SN} sites to directly identify the progenitors of core-collapse SNe on pre-explosion images. These studies have set constraints about the nature of massive stars and their evolution just prior to their explosion as SNe. Now, at late-times when the SNe have faded sufficiently, it is possible to return to the sites of these core-collapse supernovae to search for clues about the nature of their progenitors.We request time to conduct deep, late-time, high-resolution imaging with WFC3 UVIS of the site of the core-collapse SN 2009hd. We aim to: 1} Confirm our original identification, made in pre-explosion images, by confirming that the progenitor is now missing; 2} Apply image subtraction techniques for the pre-explosion images with this late-time imaging to determine accurate photometry of the progenitor to constrain its temperature and luminosity; and 3} use the stellar population in the immediate vicinity of the SN to determine the reddening and extinction that affected the progenitor. HST provides the unique combination of high-resolution optical/IR imaging at very faint magnitudes that will facilitate this study.

  16. A Key Role for Dimension in the Neutrino Mechanism of Core-Collapse Supernova Explosions

    SciTech Connect

    Burrows, Adam

    2008-01-23

    Core-collapse supernovae are a puzzle that has taxed theorists and computational science for half a century. Such explosions, the source of much of the heavy elements in the Universe and the birthplace of neutron stars and stellar-mass black holes, are still not understood. However, using sophisticated numerical tools and platforms, we have recently been able to demonstrate an important role for spatial dimension and instabilities in the viability of the neutrino mechanism of core-collapse explosions. In this talk, I will review the state of the field and the contending explosion models. In the process, I will highlight the computational astrophysics that has been applied to date, and that may be necessary in the future, to credibly unravel this mystery.

  17. Observational Evidence for Mixing and Dust Condensation in Core-Collapse Supernovae

    NASA Technical Reports Server (NTRS)

    Wooden, Diane; Young, Richard E. (Technical Monitor)

    1997-01-01

    Recent findings of isotopic anomalies of Ca-44 (the decay product of Ti-44) and the enhanced ratio of Si-28/Si-30 in SiC grains X, TiC subgrains, and graphite dust grains within primitive meteorites provides strong evidence that these presolar grains came from core-collapse supernovae. The chemical composition of the presolar grains requires macroscopic mixing of newly nucleo-synthesized elements from explosive silicon burning at the innermost zone of the ejects to higher velocities where C exists and where C/O > 1 in either the outer edge of the oxygen zone or in the He-C zone. To date, the only core-collapse supernova observed to form dust is the brightest supernova of the past four centuries, SN1987A in the Large Magellanic Cloud. Observations of SN1987A confirm large scale macroscopic mixing occurs in the explosions of massive stars. Rayleigh-Taylor instabilities macroscopically mix most of the ejects into regions which are still chemically homogeneous and which cool with different time scales. Only small clumps in the ejects are microscopically mixed. Observations show that dust condensed in the ejects of SN1987A after approx.500 days in the Fe-rich gas. Neither silicates nor SiC grains were seen in the dust emission spectrum of SN1987A. SN1987A, the Rosetta Stone of core-collapse supernovae, shows that while the mixing required to explain presolar grains occurs, the rapid cooling of the Fe zone and the sustained high temperatures of the O-Si, O-C, and He-C zones favor the formation of iron-rich rather than oxygen- or carbon-rich grains.

  18. Stellar Forensics III: A post-explosion view of the progenitors of core-collapse supernovae

    NASA Astrophysics Data System (ADS)

    Maund, Justyn

    2011-10-01

    Recent studies have used high spatial resolution HST observations of supernova {SN} sites to directly identify the progenitors of core-collapse SNe on pre-explosion images. These studies have set constraints about the nature of massive stars and their evolution just prior to their explosion as SNe. Now, at late-times when the SNe have faded sufficiently, it is possible to return to the sites of these core-collapse SNe to search for clues about the nature of their progenitors.We request time to conduct deep, late-time, high-resolution imaging with ACS/WFC of the sites of two core-collapse SNe 2009kr and 2009md. We aim to: 1} Confirm our original identifications, made in pre-explosion images, by confirming that the progenitors are now missing; 2} Apply image subtraction techniques for this late-time imaging with our pre-explosion images to determine accurate photometry of the progenitors to constrain their temperatures and luminosities; and 3} study the stellar populations in the immediate vicinities of these SNe, previously obscured by the progenitor and the SN, to provide a measure of the progenitor's age, as well. HST provides the unique combination of high-resolution optical/IR imaging at very faint magnitudes that will facilitate this study.

  19. Appearance of light clusters in post-bounce evolution of core-collapse supernovae

    SciTech Connect

    Sumiyoshi, Kohsuke; Roepke, Gerd

    2008-05-15

    We explore the abundance of light clusters in core-collapse supernovae at post-bounce stage in a quantum statistical approach. Adopting the profile of a supernova core from detailed numerical simulations, we study the distribution of light bound clusters up to {alpha} particles (2{<=}A{<=}4) as well as heavy nuclei (A>4) in dense matter at finite temperature. Within the frame of a cluster-mean-field approach, the abundances of light clusters are evaluated accounting for self-energy, Pauli blocking, and effects of continuum correlations. We find that deuterons and tritons, in addition to {sup 3}He and {sup 4}He, appear abundantly in a wide region from the surface of the proto-neutron star to the position of the shock wave. The appearance of light clusters may modify the neutrino emission in the cooling region and the neutrino absorption in the heating region and, thereby, influence the supernova mechanism.

  20. CORE-COLLAPSE SUPERNOVA EQUATIONS OF STATE BASED ON NEUTRON STAR OBSERVATIONS

    SciTech Connect

    Steiner, A. W.; Hempel, M.; Fischer, T.

    2013-09-01

    Many of the currently available equations of state for core-collapse supernova simulations give large neutron star radii and do not provide large enough neutron star masses, both of which are inconsistent with some recent neutron star observations. In addition, one of the critical uncertainties in the nucleon-nucleon interaction, the nuclear symmetry energy, is not fully explored by the currently available equations of state. In this article, we construct two new equations of state which match recent neutron star observations and provide more flexibility in studying the dependence on nuclear matter properties. The equations of state are also provided in tabular form, covering a wide range in density, temperature, and asymmetry, suitable for astrophysical simulations. These new equations of state are implemented into our spherically symmetric core-collapse supernova model, which is based on general relativistic radiation hydrodynamics with three-flavor Boltzmann neutrino transport. The results are compared with commonly used equations of state in supernova simulations of 11.2 and 40 M{sub Sun} progenitors. We consider only equations of state which are fitted to nuclear binding energies and other experimental and observational constraints. We find that central densities at bounce are weakly correlated with L and that there is a moderate influence of the symmetry energy on the evolution of the electron fraction. The new models also obey the previously observed correlation between the time to black hole formation and the maximum mass of an s = 4 neutron star.

  1. Analytic Closure Relations in M1 Neutrino Radiation Transport in Core-Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Murchikova, Elena; Ott, Christian D.; Abdikamalov, Ernazar; O'Connor, Evan; Wendell, John; Urbatsch, Todd

    2015-04-01

    Neutrinos play a crucial role in core-collapse supernova explosions. They deposit energy in the region behind the stalled shock and aid its revival. Moreover, together with gravitational waves, they are the only messengers that provide us with information from the supernova core. Full neutrino transport is a 6+1 dimensional problem and efficient yet accurate approximations are necessary to include neutrino transport in simulations. One approximation that has recently become popular is the M1 radiation transport scheme, which solves equations for the first two angular moments of the transport equation and closes the expansion with an analytic closure based on values of the first two moments. The quality of the M1 approximation depends on the quality of the chosen closure relation and it is not a priori clear, which closure to chose under which circumstances. We carry out an extensive study of closure relations available in the literature and compare M1 results to full Monte Carlo transport solutions in the context of spherically-symmetric core-collapse supernovae. We consider post-core-bounce configurations at multiple different times and study the dependence of the physical closure relation (obtained with Monte Carlo) on neutrino energy, species, and the background matter. This research was partially supported by the Institute of Geophysics, Planetary Physics, and Signatures at Los Alamos National Laboratory.

  2. The influence of inelastic neutrino interactions with light clusters on core-collapse supernova simulations

    NASA Astrophysics Data System (ADS)

    Furusawa, Shun; Nagakura, Hiroki; Sumiyoshi, Kohsuke; Yamada, Shoichi

    2014-12-01

    We perform numerical experiments to investigate the influence of inelastic neutrino reactions with light clusters in hot nuclear matter on core-collapse supernova simulations. These interactions have been neglected in most hydrodynamical supernova simulations. The neutrino absorptions and inelastic interactions with deuterons, tritons, helions and alpha particles are taken into account in the hydrodynamical simulations in addition to the ordinary charged- current interactions with nucleons. Axial symmetry is assumed but no equatorial symmetry is imposed. The time evolutions of shock waves are calculated with a simple light-bulb approximation for the neutrino transport and a multi-nuclei equation of state. We show that the heating rates of deuterons reach as high as ~ 10% of those of nucleons around the bottom of the gain region. On the other hand, alpha particles heat the matter near the shock wave, which is important when the shock wave expands and density and temperature of matter become low. It is also found that the models with heating by light clusters have different evolutions from those without it in non-linear evolution phase. The matter in the gain region has various densities and temperatures and there appear regions that are locally rich in deuterons and alpha particles. These results indicate that the inelastic reactions of light clusters, especially deuterons, should be incorporated in the simulations of core-collapse supernovae.

  3. The p-PROCESS in Core Collapse Supernovae:. Influence of Different Explosion Energies and Metallicities

    NASA Astrophysics Data System (ADS)

    Iwamoto, N.; Umeda, H.; Nomoto, K.

    2005-12-01

    We present results of p-process nucleosynthesis in core collapse supernovae (SNe). We focus on the influence of different explosion energies and metallicities on p-process yields. We find that overproduction factors have a strong sensitivity on peak temperatures and that the distribution of normalized mean overproduction factors is robust to changing the explosion energy and metallicity. Our results indicate that (1) the contribution to the galactic evolution of p-nuclei from stars with Z ≲ Z⊙/20 reduces significantly, and (2) more massive (M ≳ 25M⊙) and energetic SNe may be a dominant production site of the p-nuclei.

  4. Light clusters, pasta phases, and phase transitions in core-collapse supernova matter

    NASA Astrophysics Data System (ADS)

    Pais, Helena; Chiacchiera, Silvia; Providência, Constança

    2015-05-01

    The pasta phase in core-collapse supernova matter (finite temperatures and fixed proton fractions) is studied within relativistic mean-field models. Three different calculations are used for comparison: the Thomas-Fermi, the coexisting phases, and the compressible liquid drop approximations. The effects of including light clusters in nuclear matter and the densities at which the transitions between pasta configurations and to uniform matter occur are also investigated. The free energy, pressure, entropy, and chemical potentials in the range of particle number densities and temperatures expected to cover the pasta region are calculated. Finally, a comparison with a finite-temperature Skyrme-Hartree-Fock calculation is drawn.

  5. Core Collapse Supernovae Using CHIMERA: Gravitational Radiation from Non-Rotating Progenitors

    SciTech Connect

    Yakunin, Konstantin; Marronetti, Pedro; Mezzacappa, Anthony; Bruenn, S. W.; Lee, Ching-Tsai; Chertkow, Merek A; Hix, William Raphael; Blondin, J. M.; Lentz, Eric J; Messer, Bronson; Yoshida, S.

    2011-01-01

    The CHIMERA code is a multi-dimensional multi-physics engine dedicated primarily to the simulation of core collapse supernova explosions. One of the most important aspects of these explosions is their capacity to produce gravitational radiation that is detectable by earth-based laser-interferometric gravitational wave observatories such as LIGO and VIRGO. We present here preliminary gravitational signatures of two-dimensional models with non-rotating progenitors. These simulations exhibit explosions, which are followed for more than half a second after stellar core bounce.

  6. Type Ic core-collapse supernova explosions evolved from very massive stars

    NASA Astrophysics Data System (ADS)

    Yoshida, Takashi; Okita, Shinpei; Umeda, Hideyuki

    2014-03-01

    We investigate the possibility of a superluminous Type Ic core-collapse supernovae (SNe) producing a large amount of 56Ni. Very massive stars with a main-sequence mass larger than 100 M⊙ and a metallicity 0.001 < Z ≲ 0.004 are expected to explode as superluminous Type Ic SNe. Stars with ˜110-150 M⊙ and Z ≲ 0.001 would explode as Type Ic pulsational pair-instability SNe if the whole H and He layer has been lost by the mass-loss during pulsational pair instability. We evaluate the total ejecta mass and the yields of 56Ni, O and Si in core-collapse SNe evolved from very massive stars. We adopt 43.1 and 61.1 M⊙ WO stars with Z = 0.004 as SN progenitors expected to explode as Type Ic core-collapse SNe. These progenitors have masses of 110 and 250 M⊙ at the zero-age main sequence. Spherical explosions with an explosion energy larger than 2 × 1052 erg produce more than 3.5 M⊙56Ni, enough to reproduce the light curve of SN 2007bi. Asphericity of the explosion affects the total ejecta mass as well as the yields of 56Ni, O and Si. Aspherical explosions of the 110 and 250 M⊙ models reproduce the 56Ni yield of SN 2007bi. These explosions will also show large velocity dispersion. An aspherical core-collapse SN evolved from a very massive star is a possibility of the explosion of SN 2007bi.

  7. THE EXTENDED HUBBLE SPACE TELESCOPE SUPERNOVA SURVEY: THE RATE OF CORE COLLAPSE SUPERNOVAE TO z {approx} 1

    SciTech Connect

    Dahlen, Tomas; Riess, Adam G.; Strolger, Louis-Gregory; Mattila, Seppo; Kankare, Erkki; Mobasher, Bahram

    2012-09-20

    We use a sample of 45 core collapse supernovae detected with the Advanced Camera for Surveys on board the Hubble Space Telescope to derive the core collapse supernova rate in the redshift range 0.1 < z < 1.3. In redshift bins centered on (z) = 0.39, (z) = 0.73, and (z) = 1.11, we find rates of 3.00{sup +1.28}{sub -0.94} {sup +1.04}{sub -0.57}, 7.39{sup +1.86}{sub -1.52} {sup +3.20}{sub -1.60}, and 9.57{sup +3.76}{sub -2.80} {sup +4.96}{sub -2.80}, respectively, given in units of yr{sup -1} Mpc{sup -3} 10{sup -4} h {sup 3}{sub 70}. The rates have been corrected for host galaxy extinction, including supernovae missed in highly dust-enshrouded environments in infrared bright galaxies. The first errors are statistical while the second ones are the estimated systematic errors. We perform a detailed discussion of possible sources of systematic errors and note that these start to dominate over statistical errors at z > 0.5, emphasizing the need to better control the systematic effects. For example, a better understanding of the amount of dust extinction in the host galaxies and knowledge of the supernova luminosity function, in particular the fraction of faint M {approx}> -15 supernovae, is needed to better constrain the rates. When comparing our results with the core collapse supernova rate based on the star formation rate, we find a good agreement, consistent with the supernova rate following the star formation rate, as expected.

  8. Probing the metastability of a protoneutron star with hyperons in a core-collapse supernova

    NASA Astrophysics Data System (ADS)

    Banik, Sarmistha

    2014-03-01

    The role of Λ hyperons isinvestigated in the dynamical collapse of a nonrotating massive star to a black hole using a one-dimensional general-relativistic (gr1d) code. The dynamical formation and evolution of a protoneutron star (PNS) to a black hole is followed using various progenitor models, adopting a hyperonic equation of state (EoS) generated by Shen et al. [Shen, Toki, Oyamatsu, and Sumiyoshi, Astrophys. J., Suppl. Ser. 197, 20 (2011), 10.1088/0067-0049/197/2/20]. The results are compared with those of a nuclear EoS by Shen et al. [Shen, Toki, Oyamatsu, and Sumiyoshi, Nucl. Phys. A 637, 435 (1998), 10.1016/S0375-9474(98)00236-X] to understand the role of Λ hyperons in the core-collapse supernova. The neutrino signals that may be used as a probe for core collapse is also discussed. Further, an exotic EoS may support a cold neutron star with a maximum mass much lower than that of a PNS. In this regard, the metastability of a PNS in the presence of Λ hyperons is studied in the long-time evolution of the progenitors, relevant to supernova SN1987A.

  9. Exploring the nuclear pasta phase in core-collapse supernova matter.

    PubMed

    Pais, Helena; Stone, Jirina R

    2012-10-12

    The core-collapse supernova phenomenon, one of the most explosive events in the Universe, presents a challenge to theoretical astrophysics. Of the large variety of forms of matter present in core-collapse supernova, we focus on the transitional region between homogeneous (uniform) and inhomogeneous (pasta) phases. A three-dimensional, finite temperature Skyrme-Hartree-Fock (3D-SHF)+BCS calculation yields, for the first time fully self-consistently, the critical density and temperature of both the onset of the pasta in inhomogeneous matter, consisting of neutron-rich heavy nuclei and a free neutron and electron gas, and its dissolution to a homogeneous neutron, proton, and electron liquid. We also identify density regions for different pasta formations between the two limits. We employ four different forms of the Skyrme interaction, SkM*, SLy4, NRAPR, and SQMC700 and find subtle variations in the low density and high density transitions into and out of the pasta phase. One new stable pasta shape has been identified, in addition to the classic ones, on the grid of densities and temperatures used in this work. Our results are critically compared to recent calculations of pasta formation in the quantum molecular dynamics approach and Thomas-Fermi and coexisting phase approximations to relativistic mean-field models.

  10. Recombining plasma in the remnant of a core-collapsed supernova, Kes 17

    NASA Astrophysics Data System (ADS)

    Washino, Ryosaku; Uchida, Hiroyuki; Nobukawa, Masayoshi; Tsuru, Takeshi Go; Tanaka, Takaaki; Kawabata Nobukawa, Kumiko; Koyama, Katsuji

    2016-06-01

    We report on Suzaku results concerning Kes 17, a Galactic mixed-morphology supernova remnant. The X-ray spectrum of the whole Kes 17 is well explained by a pure thermal plasma, in which we found Lyα of Al XIII and Heα of Al XII, Ar XVII, and Ca XIX lines for the first time. The abundance pattern and the plasma mass suggest that Kes 17 is a remnant of a core-collapsed supernova of a 25-30 M⊙ progenitor star. The X-ray spectrum of the north region is expressed by a recombining plasma. The origin would be due to the cooling of electrons by thermal conduction to molecular clouds located near the north region.

  11. On the Requirements for Realistic Modeling of Neutrino Transport in Simulations of Core-collapse Supernovae

    SciTech Connect

    Lentz, Eric J; Mezzacappa, Anthony; Messer, Bronson; Liebendoerfer, Matthias; Hix, William Raphael; Bruenn, S. W.

    2012-01-01

    We have conducted a series of numerical experiments with the spherically-symmetric, general-relativistic neutrino radiation hydrodynamics code Agile-BOLTZTRAN to examine the effects of several approximations used in multidimensional core-collapse supernova simulations. Our code permits us to examine the effects of these approximations quantitatively by removing, or substituting for, the pieces of supernova physics of interest. These approximations include: (1) using Newtonian versus general-relativistic gravity, hydrodynamics, and transport; (2) using older weak interactions, including the omission of non-isoenergetic neutrino scattering, versus up-to-date weak interactions; and (3) omitting the velocity-dependent terms, or observer corrections, from the neutrino Boltzmann kinetic equation. We demonstrate that each of these changes has non-negligible effects on the outcomes of our simulations. Finally, we discuss the impact these results have for current, and future, multidimensional models.

  12. Multicolor Light Curve Simulations of Population III Core-Collapse Supernovae: From Shock Breakout to 56Co Decay

    NASA Astrophysics Data System (ADS)

    Tolstov, Alexey; Nomoto, Ken'ichi; Tominaga, Nozomu; Ishigaki, Miho N.; Blinnikov, Sergey; Suzuki, Tomoharu

    2016-04-01

    The properties of the first generation of stars and their supernova (SN) explosions remain unknown due to the lack of actual observations. Recently, many transient surveys have been conducted and the feasibility of detecting supernovae (SNe) of Pop III stars is growing. In this paper, we study the multicolor light curves for a number of metal-free core-collapse SN models (25-100 {M}⊙ ) to determine the indicators for the detection and identification of first generation SNe. We use mixing-fallback supernova explosion models that explain the observed abundance patterns of metal-poor stars. Numerical calculations of the multicolor light curves are performed using the multigroup radiation hydrodynamic code stella. The calculated light curves of metal-free SNe are compared with non-zero-metallicity models and several observed SNe. We have found that the shock breakout characteristics, the evolution of the photosphere’s velocity, the luminosity, and the duration and color evolution of the plateau, that is, all of the SN phases from shock breakout to 56Co decay, are helpful for estimating the parameters of the SN progenitor: the mass, the radius, the explosion energy, and the metallicity. We conclude that the multicolor light curves could potentially be used to identify first-generation SNe in current (Subaru/HSC) and future transient surveys (LSST, James Webb Space Telescope). They are also suitable for identifying low-metallicity SNe in the nearby universe (PTF, Pan-STARRS, Gaia).

  13. The IceCube data acquisition system for galactic core collapse supernova searches

    SciTech Connect

    Baum, Volker; Collaboration: IceCube Collaboration

    2014-11-18

    The IceCube Neutrino Observatory was designed to detect highly energetic neutrinos. The detector was built as a lattice of 5160 photomultiplier tubes monitoring one cubic kilometer of clear Antarctic ice. Due to low photomultiplier dark noise rates in the cold and radio-pure ice, IceCube is also able to detect bursts of O(10MeV) neutrinos expected to be emitted from core collapse supernovae. The detector will provide the world’s highest statistical precision for the lightcurves of galactic supernovae by observing an induced collective rise in all photomultiplier rates [1]. This paper presents the supernova data acquisition system, the search algorithms for galactic supernovae, as well as the recently implemented HitSpooling DAQ extension. HitSpooling will overcome the current limitation of transmitting photomultiplier rates in intervals of 1.6384 ms by storing all recorded time-stamped hits for supernova candidate triggers. From the corresponding event-based information, the average neutrino energy can be estimated and the background induced by detector noise and atmospheric muons can be reduced.

  14. Coherent network analysis of gravitational waves from three-dimensional core-collapse supernova models

    NASA Astrophysics Data System (ADS)

    Hayama, Kazuhiro; Kuroda, Takami; Kotake, Kei; Takiwaki, Tomoya

    2015-12-01

    Using predictions from three-dimensional (3D) hydrodynamics simulations of core-collapse supernovae (CCSNe), we present a coherent network analysis for the detection, reconstruction, and source localization of the gravitational-wave (GW) signals. We use the RIDGE pipeline for the analysis, in which the network of LIGO Hanford, LIGO Livingston, VIRGO, and KAGRA is considered. By combining with a GW spectrogram analysis, we show that several important hydrodynamics features in the original waveforms persist in the waveforms of the reconstructed signals. The characteristic excess in the spectrograms originates not only from the rotating core collapse, bounce, and subsequent ringdown of the proto-neutron star (PNS) as previously identified, but also from the formation of magnetohydrodynamics jets and nonaxisymmetric instabilities in the vicinity of the PNS. Regarding the GW signals emitted near the rotating core bounce, the horizon distance extends up to ˜18 kpc for the most rapidly rotating 3D model in this work. Following the rotating core bounce, the dominant source of the GW emission shifts to the nonaxisymmetric instabilities. The horizon distances extend maximally up to ˜40 kpc seen from the spin axis. With an increasing number of 3D models trending towards explosion recently, our results suggest that in addition to the best-studied GW signals due to rotating core collapse and bounce, the time is ripe to consider how we can do science from GWs of CCSNe much more seriously than before. In particular, the quasiperiodic signals due to the nonaxisymmetric instabilities and the detectability deserves further investigation to elucidate the inner workings of the rapidly rotating CCSNe.

  15. The Sensitivity of Core-collapse Supernovae to Nuclear Electron Capture

    NASA Astrophysics Data System (ADS)

    Sullivan, Chris; O'Connor, Evan; Zegers, Remco G. T.; Grubb, Thomas; Austin, Sam M.

    2016-01-01

    A weak-rate library aimed at investigating the sensitivity of astrophysical environments to variations of electron-capture rates on medium-heavy nuclei has been developed. With this library, the sensitivity of the core-collapse and early post-bounce phases of core-collapse supernovae to nuclear electron capture is examined. The rates are adjusted by factors consistent with uncertainties indicated by comparing theoretical rates to those deduced from charge-exchange and β-decay measurements. To ensure a model-independent assessment, sensitivity studies across a comprehensive set of progenitors and equations of state are performed. We find a +16/-4% range in the mass of the inner core at shock formation and a ±20% range of peak {ν }e luminosity during the deleptonization burst. These ranges are five times as large as those seen from a separate progenitor study, where we evaluate the sensitivity of these parameters to 32 presupernova models. Additionally, the simulations are found to be more sensitive to a reduction in electron-capture rates than an enhancement, and specifically to the reduction in rates for neutron-rich nuclei near the N = 50 closed neutron shell. As measurements for medium-heavy (A\\gt 65) and neutron-rich nuclei are sparse, and because accurate theoretical models that account for nuclear structure considerations of individual nuclei are not readily available, rates for these nuclei may be overestimated. If more accurate estimates confirm this, results from this study indicate that significant changes to the core-collapse trajectory are expected. For this reason, experimental and theoretical efforts should focus on this region of the nuclear chart.

  16. Stellar Forensics II: A post-explosion view of the progenitors of core-collapse supernovae

    NASA Astrophysics Data System (ADS)

    Maund, Justyn

    2010-09-01

    Recent studies have used high spatial resolution HST observations of supernova {SN} sites to directly identify the progenitors of core-collapse SNe on pre-explosion images. These studies have set constraints about the nature of massive stars and their evolution just prior to their explosion as SNe. Now, at late-times when the SNe have faded sufficiently, it is possible to return to the sites of these core-collapse SNe to search for clues about the nature of their progenitors.We request time to conduct deep, late-time, high-resolution imaging with WFC3/UVIS+IR and ACS/WFC of the sites of three core-collapse SNe 2008ax, 2008bk and 2008cn. We aim to: 1} Confirm our original identifications, made in pre-explosion images, by confirming that the progenitors are now missing; 2} Apply image subtraction techniques for this late-time imaging with our pre-explosion images to determine accurate photometry of the progenitors to constrain their temperatures and luminosities; and 3} study the stellar populations in the immediate vicinities of these SNe, previously obscured by the progenitor and the SN, to provide a measure of the progenitor's age, as well. For SN 2008ax we aim to determine the possible presence of a binary companion, as a persistent source at the SN location once the SN has faded and the progenitor has disappeared. HST provides the unique combination of high-resolution optical/IR imaging at very faint magnitudes that will facilitate this study.

  17. Observing gravitational waves from core-collapse supernovae in the advanced detector era

    NASA Astrophysics Data System (ADS)

    Gossan, S. E.; Sutton, P.; Stuver, A.; Zanolin, M.; Gill, K.; Ott, C. D.

    2016-02-01

    The next galactic core-collapse supernova (CCSN) has already exploded, and its electromagnetic (EM) waves, neutrinos, and gravitational waves (GWs) may arrive at any moment. We present an extensive study on the potential sensitivity of prospective detection scenarios for GWs from CCSNe within 5 Mpc, using realistic noise at the predicted sensitivity of the Advanced LIGO and Advanced Virgo detectors for 2015, 2017, and 2019. We quantify the detectability of GWs from CCSNe within the Milky Way and Large Magellanic Cloud, for which there will be an observed neutrino burst. We also consider extreme GW emission scenarios for more distant CCSNe with an associated EM signature. We find that a three-detector network at design sensitivity will be able to detect neutrino-driven CCSN explosions out to ˜5.5 kpc , while rapidly rotating core collapse will be detectable out to the Large Magellanic Cloud at 50 kpc. Of the phenomenological models for extreme GW emission scenarios considered in this study, such as long-lived bar-mode instabilities and disk fragmentation instabilities, all models considered will be detectable out to M31 at 0.77 Mpc, while the most extreme models will be detectable out to M82 at 3.52 Mpc and beyond.

  18. Observational upper limits on the gravitational wave production of core collapse supernovae

    NASA Astrophysics Data System (ADS)

    Zhu, Xing-Jiang; Howell, E.; Blair, D.

    2010-11-01

    The upper limit on the energy density of a stochastic gravitational wave (GW) background obtained from the 2-yr science run (S5) of the Laser Interferometer Gravitational-Wave Observatory (LIGO) is used to constrain the average GW production of core collapse supernovae (ccSNe). We assume that the ccSNe rate tracks the star formation history of the Universe and show that the stochastic background energy density depends only weakly on the assumed average source spectrum. Using the ccSNe rate for z <= 10, we scale the generic source spectrum to obtain an observation-based upper limit on the average GW emission. We show that the mean energy emitted in GWs can be constrained within < (0.49-1.98)Msolarc2 depending on the average source spectrum. While these results are higher than the total available gravitational energy in a core collapse event, second- and third-generation GW detectors will enable tighter constraints to be set on the GW emission from such systems.

  19. A kinetic theory based numerical study of core collapse supernova dynamics

    NASA Astrophysics Data System (ADS)

    Strother, Terrance T.

    The explosion mechanism of core collapse supernovae remains an unsolved problem in astrophysics after many decades of theoretical and numerical study. The complex nature of this problem forces its consideration to rely heavily upon numerical simulations. Current state-of-the-art core collapse supernova simulations typically make use of hydrodynamic codes for the modeling of baryon dynamics coupled to a Boltzmann transport simulation for the neutrinos and other leptons. The results generated by such numerical simulations have given rise to the widely accepted notion that neutrino heating and convection are crucial for the explosion mechanism. However the precise roles that some factors such as neutrinos production and propagation, rotation, three-dimensional effects, the equation of state for asymmetric nuclear matter, general relativity, instabilities, magnetic fields, as well as others play in the explosion mechanism remain to be fully determined. In this work, we review sonic of the current methods used to simulate core collapse supernovae and the various scenarios that have been developed by numerical studies are discussed. Unlike most of the numerical simulations of core collapse supernovae, we employ a kinetic theory based approach that allows us to explicitly model the propagation of neutrinos and a full ensemble of nuclei. Both of these are significant advantages. The ability to explicitly model the propagation of neutrinos puts their treatment on equal footing with the modeling of baryon dynamics. No simplifying assumptions about the nature of neutrino-matter interactions need to be made and consequently our code is capable of producing output about the flow of neutrinos that most other simulations are inherently incapable of. Furthermore, neutrino flavor oscillations are readily incorporated with our approach. The ability to model the propagation of a full ensemble of nuclei is superior to the standard tracking of free baryons, alpha particles, and a

  20. Long gamma-ray bursts and core-collapse supernovae have differentenvironments

    SciTech Connect

    Fruchter, A.S.; Levan, A.J.; Strolger, L.; Vreeswijk, P.M.; Thorsett, S.E.; Bersier, D.; Burud, I.; Castro Ceren, J.M.; Castro-Tirado, A.J.; Conselice, C.; Dahlen, T.; Ferguson, H.C.; Fynbo,J.P.U.; Garnavich, P.M.; Gibbons, R.A.; Gorosabel, J.; Gull, T.R.; Hjorth, J.; Holland, S.T.; Kouveliotou, C.; Levay, Z.; Livio, M.; Metzger, M.R.; Nugent, P.E.; Petro, L.; Pian, E.; Rhoads, J.E.; Riess,A.G.; Sahu, K.C.; Smette, A.; Tanvir, N.R.; Wijers, R.A.M.J.; Woosley, S.E.

    2006-05-01

    When massive stars exhaust their fuel they collapse andoften produce the extraordinarily bright explosions known ascore-collapse supernovae. On occasion, this stellar collapse also powersan even more brilliant relativistic explosion known as a long-durationgamma-ray burst. One would then expect that long gamma-ray bursts andcore-collapse supernovae should be found in similar galacticenvironments. Here we show that this expectation is wrong. We find thatthe long gamma-ray bursts are far more concentrated on the very brightestregions of their host galaxies than are the core-collapse supernovae.Furthermore, the host galaxies of the long gamma-ray bursts aresignificantly fainter and more irregular than the hosts of thecore-collapse supernovae. Together theseresults suggest thatlong-duration gamma-ray bursts are associated with the most massive starsand may be restricted to galaxies of limited chemical evolution. Ourresults directly imply that long gamma-ray bursts are relatively rare ingalaxies such as our own MilkyWay.

  1. The Status of Multi-Dimensional Core-Collapse Supernova Models

    NASA Astrophysics Data System (ADS)

    Müller, B.

    2016-09-01

    Models of neutrino-driven core-collapse supernova explosions have matured considerably in recent years. Explosions of low-mass progenitors can routinely be simulated in 1D, 2D, and 3D. Nucleosynthesis calculations indicate that these supernovae could be contributors of some lighter neutron-rich elements beyond iron. The explosion mechanism of more massive stars remains under investigation, although first 3D models of neutrino-driven explosions employing multi-group neutrino transport have become available. Together with earlier 2D models and more simplified 3D simulations, these have elucidated the interplay between neutrino heating and hydrodynamic instabilities in the post-shock region that is essential for shock revival. However, some physical ingredients may still need to be added/improved before simulations can robustly explain supernova explosions over a wide range of progenitors. Solutions recently suggested in the literature include uncertainties in the neutrino rates, rotation, and seed perturbations from convective shell burning. We review the implications of 3D simulations of shell burning in supernova progenitors for the `perturbations-aided neutrino-driven mechanism,' whose efficacy is illustrated by the first successful multi-group neutrino hydrodynamics simulation of an 18 solar mass progenitor with 3D initial conditions. We conclude with speculations about the impact of 3D effects on the structure of massive stars through convective boundary mixing.

  2. A NEW MULTI-DIMENSIONAL GENERAL RELATIVISTIC NEUTRINO HYDRODYNAMICS CODE FOR CORE-COLLAPSE SUPERNOVAE. II. RELATIVISTIC EXPLOSION MODELS OF CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Mueller, Bernhard; Janka, Hans-Thomas; Marek, Andreas E-mail: thj@mpa-garching.mpg.de

    2012-09-01

    We present the first two-dimensional general relativistic (GR) simulations of stellar core collapse and explosion with the COCONUT hydrodynamics code in combination with the VERTEX solver for energy-dependent, three-flavor neutrino transport, using the extended conformal flatness condition for approximating the space-time metric and a ray-by-ray-plus ansatz to tackle the multi-dimensionality of the transport. For both of the investigated 11.2 and 15 M{sub Sun} progenitors we obtain successful, though seemingly marginal, neutrino-driven supernova explosions. This outcome and the time evolution of the models basically agree with results previously obtained with the PROMETHEUS hydro solver including an approximative treatment of relativistic effects by a modified Newtonian potential. However, GR models exhibit subtle differences in the neutrinospheric conditions compared with Newtonian and pseudo-Newtonian simulations. These differences lead to significantly higher luminosities and mean energies of the radiated electron neutrinos and antineutrinos and therefore to larger energy-deposition rates and heating efficiencies in the gain layer with favorable consequences for strong nonradial mass motions and ultimately for an explosion. Moreover, energy transfer to the stellar medium around the neutrinospheres through nucleon recoil in scattering reactions of heavy-lepton neutrinos also enhances the mentioned effects. Together with previous pseudo-Newtonian models, the presented relativistic calculations suggest that the treatment of gravity and energy-exchanging neutrino interactions can make differences of even 50%-100% in some quantities and is likely to contribute to a finally successful explosion mechanism on no minor level than hydrodynamical differences between different dimensions.

  3. A New Multi-dimensional General Relativistic Neutrino Hydrodynamics Code for Core-collapse Supernovae. II. Relativistic Explosion Models of Core-collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Müller, Bernhard; Janka, Hans-Thomas; Marek, Andreas

    2012-09-01

    We present the first two-dimensional general relativistic (GR) simulations of stellar core collapse and explosion with the COCONUT hydrodynamics code in combination with the VERTEX solver for energy-dependent, three-flavor neutrino transport, using the extended conformal flatness condition for approximating the space-time metric and a ray-by-ray-plus ansatz to tackle the multi-dimensionality of the transport. For both of the investigated 11.2 and 15 M ⊙ progenitors we obtain successful, though seemingly marginal, neutrino-driven supernova explosions. This outcome and the time evolution of the models basically agree with results previously obtained with the PROMETHEUS hydro solver including an approximative treatment of relativistic effects by a modified Newtonian potential. However, GR models exhibit subtle differences in the neutrinospheric conditions compared with Newtonian and pseudo-Newtonian simulations. These differences lead to significantly higher luminosities and mean energies of the radiated electron neutrinos and antineutrinos and therefore to larger energy-deposition rates and heating efficiencies in the gain layer with favorable consequences for strong nonradial mass motions and ultimately for an explosion. Moreover, energy transfer to the stellar medium around the neutrinospheres through nucleon recoil in scattering reactions of heavy-lepton neutrinos also enhances the mentioned effects. Together with previous pseudo-Newtonian models, the presented relativistic calculations suggest that the treatment of gravity and energy-exchanging neutrino interactions can make differences of even 50%-100% in some quantities and is likely to contribute to a finally successful explosion mechanism on no minor level than hydrodynamical differences between different dimensions.

  4. The bubble-like interior of the core-collapse supernova remnant Cassiopeia A

    NASA Astrophysics Data System (ADS)

    Milisavljevic, Dan; Fesen, Robert A.

    2015-01-01

    The death of massive stars is believed to involve aspheric explosions initiated by the collapse of an iron core. The specifics of these catastrophic explosions remain uncertain, due partly to limited observational constraints on asymmetries deep inside the star. Here we present near-infrared observations of the young supernova remnant Cassiopeia A, descendant of a type IIb core-collapse explosion, and a three-dimensional map of its interior unshocked ejecta. The remnant’s interior has a bubble-like morphology that smoothly connects to and helps explain the multiringed structures seen in the remnant's bright reverse-shocked main shell of expanding debris. This internal structure may originate from turbulent mixing processes that encouraged outwardly expanding plumes of radioactive 56Ni-rich ejecta. If this is true, substantial amounts of its decay product, 56Fe, may still reside in these interior cavities.

  5. Gravitational Wave Signals from 2D and 3D Core Collapse Supernova Explosions

    NASA Astrophysics Data System (ADS)

    Yakunin, Konstantin; Mezzacappa, Anthony; Marronetti, Pedro; Bruenn, Stephen; Hix, W. Raphael; Lentz, Eric J.; Messer, O. E. Bronson; Harris, J. Austin; Endeve, Eirik; Blondin, John

    2016-03-01

    We study two- and three-dimensional (2D and 3D) core-collapse supernovae (CCSN) using our first-principles CCSN simulations performed with the neutrino hydrodynamics code CHIMERA. The following physics is included: Newtonian hydrodynamics with a nuclear equation of state capable of describing matter in both NSE and non-NSE, MGFLD neutrino transport with realistic neutrino interactions, an effective GR gravitational potential, and a nuclear reaction network. Both our 2D and 3D models achieve explosion, which in turn enables us to determine their complete gravitational wave signals. In this talk, we present them, and we analyze the similarities and differences between the 2D and 3D signals.

  6. Equation of state for nuclear matter in core-collapse supernovae by the variational method

    NASA Astrophysics Data System (ADS)

    Togashi, H.; Takehara, Y.; Yamamuro, S.; Nakazato, K.; Suzuki, H.; Sumiyoshi, K.; Takano, M.

    2014-12-01

    We construct a new nuclear equation of state (EOS) for core-collapse supernova (SN) simulations using the variational many-body theory. For uniform nuclear matter, the EOS is constructed with the cluster variational method starting from the realistic nuclear Hamiltonian composed of the Argonne v18 two-body potential and the Urbana IX three-body potential. The masses and radii of neutron stars calculated with the obtained EOS at zero temperature are consistent with recent observational data. For non-uniform nuclear matter, we construct the EOS in the Thomas-Fermi approximation. In this approximation, we assume a functional form of the density distributions of protons, neutrons, and alpha-particles, and minimize the free energy density in a Wigner-Seitz cell with respect to the parameters included in the assumed density distribution functions. The phase diagram of hot nuclear matter at a typical temperature is reasonable as compared with that of the Shen EOS.

  7. Circular Polarizations of Gravitational Waves from Core-Collapse Supernovae: A Clear Indication of Rapid Rotation.

    PubMed

    Hayama, Kazuhiro; Kuroda, Takami; Nakamura, Ko; Yamada, Shoichi

    2016-04-15

    We propose to employ the circular polarization of gravitational waves emitted by core-collapse supernovae as an unequivocal indication of rapid rotation deep in their cores just prior to collapse. It has been demonstrated by three dimensional simulations that nonaxisymmetric accretion flows may develop spontaneously via hydrodynamical instabilities in the postbounce cores. It is not surprising, then, that the gravitational waves emitted by such fluid motions are circularly polarized. We show, in this Letter, that a network of the second generation detectors of gravitational waves worldwide may be able to detect such polarizations up to the opposite side of the Galaxy as long as the rotation period of the core is shorter than a few seconds prior to collapse. PMID:27127951

  8. Near Real-time Data Analysis of Core-Collapse Supernova Simulations With Bellerophon

    SciTech Connect

    Lingerfelt, Eric J; Messer, Bronson; Desai, Sharvari S; Holt, Chastity A; Lentz, Eric J

    2014-01-01

    We present an overview of a software system, Bellerophon, built to support a production-level HPC application called CHIMERA, which simulates core-collapse supernova events at the petascale. Developed over the last four years, Bellerophon enables CHIMERA s geographically dispersed team of collaborators to perform data analysis in near real-time. Its n-tier architecture provides an encapsulated, end-to-end software solution that enables the CHIMERA team to quickly and easily access highly customizable animated and static views of results from anywhere in the world via a web-deliverable, cross-platform desktop application. In addition, Bellerophon addresses software engineering tasks for the CHIMERA team by providing an automated mechanism for performing regression testing on a variety of supercomputing platforms. Elements of the team s workflow management needs are met with software tools that dynamically generate code repository statistics, access important online resources, and monitor the current status of several supercomputing resources.

  9. Termination of the MRI via parasitic instabilities in core-collapse supernovae: influence of numerical methods

    NASA Astrophysics Data System (ADS)

    Rembiasz, T.; Obergaulinger, M.; Cerdá-Durán, P.; Aloy, M. Á.; Müller, E.

    2016-05-01

    We study the influence of numerical methods and grid resolution on the termination of the magnetorotational instability (MRI) by means of parasitic instabilities in threedimensional shearing-disc simulations reproducing typical conditions found in core-collapse supernovae. Whether or not the MRI is able to amplify weak magnetic fields in this context strongly depends, among other factors, on the amplitude at which its growth terminates. The qualitative results of our study do not depend on the numerical scheme. In all our models, MRI termination is caused by Kelvin-Helmholtz instabilities, consistent with theoretical predictions. Quantitatively, however, there are differences, but numerical convergence can be achieved even at relatively low grid resolutions if high-order reconstruction methods are used.

  10. Core collapse supernovae from blue supergiant progenitors : The evolutionary history of SN 1987A

    NASA Astrophysics Data System (ADS)

    Menon, Athira

    2015-08-01

    SN 1987A is historically one of the most remarkable supernova explosions to be seen from Earth. Due to the proximity of its location in the LMC, it remains the most well-studied object outside the solar system. It was also the only supernova whose progenitor was observed prior to its explosion.SN 1987A however, was a unique and enigmatic core collapse supernova. It was the first Type II supernova to have been observed to have exploded while its progenitor was a blue supergiant (BSG). Until then Type II supernovae were expected to originate from explosions of red supergiants (RSGs). A spectacular triple-ring nebula structure, rich in helium and nitrogen, was observed around the remnant, indicating a recent RSG phase before becoming a BSG. Even today it is not entirely understood what the evolutionary history may have been to cause a BSG to explode. The most commonly accepted hypothesis for its origin is the merger of a massive binary star system.An evolutionary scenario for such a binary system, was proposed by Podsiadlowski (1992) (P92). Through SPH simulations of the merger and the stellar evolution of the post-merger remnant, Ivanova & Podsiadlowski (2002) and (2003) (I&M) could successfully obtain the RSG to BSG transition of the progenitor.The aim of the present work is to produce the evolutionary history of the progenitor of SN 1987A and its explosion. We construct our models based on the results of P92 and I&M. Here, the secondary (less massive) star is accreted on the primary, while being simultaneously mixed in its envelope over a period of 100 years. The merged star is evolved until the onset of core collapse. For this work we use the 1-dimensional, implicit, hydrodynamical stellar evolution code, KEPLER. A large parameter space is explored, consisting of primary (16-20 Ms) and secondary masses (5-8 Ms), mixing boundaries, and accreting timescales. Those models whose end states match the observed properties of the progenitor of SN 1987A are exploded. The

  11. LOCAL SIMULATIONS OF THE MAGNETOROTATIONAL INSTABILITY IN CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Masada, Youhei; Takiwaki, Tomoya; Kotake, Kei; Sano, Takayoshi E-mail: kkotake@th.nao.ac.jp

    2012-11-10

    Bearing in mind the application of core-collapse supernovae, we study the nonlinear properties of the magnetorotational instability (MRI) by means of three-dimensional simulations in the framework of a local shearing box approximation. By systematically changing the shear rates that symbolize the degree of differential rotation in nascent proto-neutron stars (PNSs), we derive a scaling relation between the turbulent stress sustained by the MRI and the shear-vorticity ratio. Our parametric survey shows a power-law scaling between the turbulent stress (((w {sub tot}))) and the shear-vorticity ratio (g{sub q} ) as ((w {sub tot})){proportional_to}g {sup {delta}} {sub q} with an index of {delta} {approx} 0.5. The MRI-amplified magnetic energy has a similar scaling relative to the turbulent stress, while the Maxwell stress has a slightly smaller power-law index ({approx}0.36). By modeling the effect of viscous heating rates from MRI turbulence, we show that the stronger magnetic fields, or the larger shear rates initially imposed, lead to higher dissipation rates. For a rapidly rotating PNS with a spin period in milliseconds and with strong magnetic fields of 10{sup 15} G, the energy dissipation rate is estimated to exceed 10{sup 51} erg s{sup -1}. Our results suggest that the conventional magnetohydrodynamic (MHD) mechanism of core-collapse supernovae is likely to be affected by MRI-driven turbulence, which we speculate, on the one hand, could harm the MHD-driven explosions due to the dissipation of the shear rotational energy at the PNS surface; or, on the other hand, its energy deposition might be potentially favorable for the working of the neutrino-heating mechanism.

  12. Gravitational waves from core-collapse supernovae and their related compact objects

    NASA Astrophysics Data System (ADS)

    Kotake, K.; Suwa, Y.; Yasutake, N.

    Core-collapse supernovae have been supposed to be one of the most plausible sources of gravitational waves. Based on a series of our magnetohydrodynamic core-collapse simulations, we find that the gravitational amplitudes at core bounce can be within the detection limits for the currently running laser-interferometers for a galactic supernova if the central core rotates sufficiently rapidly. This is regardless of the difference of the realistic equations of state and the possible occurrence of the QCD phase transition near core bounce. Even if the core rotates slowly, we point out that the gravitational waves generated from anisotropic neutrino radiation in the postbounce phase due to the standing accretion shock instability (SASI) could be within the detection limits of the detectors in the next generation such as LCGT and the advanced LIGO for the galactic source. Since the waveforms significantly depend on the exploding scenarios, our results suggest that we can obtain the information about the long-veiled explosion mechanism from the gravitational wave signals. Furthermore we discuss the gravitational wave background (GWB) from the explosions of Pop III stars and show that the GWB from Pop III, depending on their formation rates, can be large enough to be within the detection limits of future planned interferometers such as DECIGO and BBO in the frequency interval of ~0.1-1 Hz. This means that the detections of GW background from Pop III stars can be an important tool to supply the information about the star formation history in the early universe.

  13. Local Simulations of the Magnetorotational Instability in Core-collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Masada, Youhei; Takiwaki, Tomoya; Kotake, Kei; Sano, Takayoshi

    2012-11-01

    Bearing in mind the application of core-collapse supernovae, we study the nonlinear properties of the magnetorotational instability (MRI) by means of three-dimensional simulations in the framework of a local shearing box approximation. By systematically changing the shear rates that symbolize the degree of differential rotation in nascent proto-neutron stars (PNSs), we derive a scaling relation between the turbulent stress sustained by the MRI and the shear-vorticity ratio. Our parametric survey shows a power-law scaling between the turbulent stress (langlangw totrangrang) and the shear-vorticity ratio (gq ) as langlangw totrangrangvpropg δ q with an index of δ ~ 0.5. The MRI-amplified magnetic energy has a similar scaling relative to the turbulent stress, while the Maxwell stress has a slightly smaller power-law index (~0.36). By modeling the effect of viscous heating rates from MRI turbulence, we show that the stronger magnetic fields, or the larger shear rates initially imposed, lead to higher dissipation rates. For a rapidly rotating PNS with a spin period in milliseconds and with strong magnetic fields of 1015 G, the energy dissipation rate is estimated to exceed 1051 erg s-1. Our results suggest that the conventional magnetohydrodynamic (MHD) mechanism of core-collapse supernovae is likely to be affected by MRI-driven turbulence, which we speculate, on the one hand, could harm the MHD-driven explosions due to the dissipation of the shear rotational energy at the PNS surface; or, on the other hand, its energy deposition might be potentially favorable for the working of the neutrino-heating mechanism.

  14. The Application of Bayesian Inference to Gravitational Waves from Core-Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Gossan, Sarah; Ott, Christian; Kalmus, Peter; Logue, Joshua; Heng, Siong

    2013-04-01

    The gravitational wave (GW) signature of core-collapse supernovae (CCSNe) encodes important information on the supernova explosion mechanism, the workings of which cannot be explored via observations in the electromagnetic spectrum. Recent research has shown that the CCSNe explosion mechanism can be inferred through the application of Bayesian model selection to gravitational wave signals from supernova explosions powered by the neutrino, magnetorotational and acoustic mechanisms. Extending this work, we apply Principal Component Analysis to the GW spectrograms from CCSNe to take into account also the time-frequency evolution of the emitted signals. We do so in the context of Advanced LIGO, to establish if any improvement on distinguishing between various explosion mechanisms can be obtained. Further to this, we consider a five-detector network of interferometers (comprised of the two Advanced LIGO detectors, Advanced Virgo, LIGO India and KAGRA) and generalize the aforementioned analysis for a source of known position but unknown distance, using realistic, re-colored detector data (as opposed to Gaussian noise), in order to make more reliable statements regarding our ability to distinguish between various explosion mechanisms on the basis of their GW signatures.

  15. Nuclear structure and the fate of core collapse (Type II) supernova

    NASA Astrophysics Data System (ADS)

    Gai, Moshe

    2014-08-01

    For a long time Gerry Brown and his collaborator Hans Bethe considered the question of the final fate of a core collapse (Type II) supernova. Recalling ideas from nuclear structure on Kaon condensate and a soft equation of state of the dense nuclear matter they concluded that progenitor stars with mass as low as 17-18M⊙ (including supernova 1987A) could collapse to a small mass black hole with a mass just beyond 1.5M⊙, the upper bound they derive for a neutron star. We discuss another nuclear structure effect that determines the carbon to oxygen ratio (C/O) at the end of helium burning. This ratio also determines the fate of a Type II supernova with a carbon rich progenitor star producing a neutron star and oxygen rich collapsing to a black hole. While the C/O ratio is one of the most important nuclear inputs to stellar evolution it is still not known with sufficient accuracy. We discuss future efforts to measure with gamma-beam and TPC detector of the C12(α,γ)O16 reaction that determines the C/O ratio in stellar helium burning.

  16. Three-dimensional simulations of SASI- and convection-dominated core-collapse supernovae

    NASA Astrophysics Data System (ADS)

    Fernández, Rodrigo

    2015-09-01

    We investigate the effect of dimensionality on the transition to explosion in neutrino-driven core-collapse supernovae. Using parametrized hydrodynamic simulations of the stalled supernova shock in one, two (2D), and three spatial dimensions (3D), we systematically probe the extent to which hydrodynamic instabilities alone can tip the balance in favour of explosion. In particular, we focus on systems that are well into the regimes where the standing accretion shock instability (SASI) or neutrino-driven convection dominates the dynamics. We find that SASI-dominated models can explode with up to ˜20 per cent lower neutrino luminosity in 3D than in 2D, with the magnitude of this difference decreasing with increasing resolution. This improvement in explosion conditions is related to the ability of spiral modes to generate more non-radial kinetic energy than a single sloshing mode, increasing the size of the average shock radius, and hence generating better conditions for the formation of large-scale, high-entropy bubbles. In contrast, convection-dominated explosions show a smaller difference in their critical heating rate between 2D and 3D (<8 per cent), in agreement with previous studies. The ability of our numerical implementation to maintain arbitrary symmetries is quantified with a set of SASI-based tests. We discuss implications for the diversity of explosion paths in a realistic supernova environment.

  17. Multi-D Core-Collapse Supernova Explosions and the Multi-Messenger Signatures

    NASA Astrophysics Data System (ADS)

    Kotake, Kei

    Based on multi-dimensional neutrino-radiation hydrodynamic simulations, we report several cutting-edge issues about the long-veiled explosion mechanism of core-collapse supernovae (CCSNe). In this contribution, we pay particular attention to whether three-dimensional (3D) hydrodynamics and/or general relativity (GR) would or would not help the onset of explosions. By performing 3D simulations with spectral neutrino transport, we show that it is more difficult to obtain an explosion in 3D than in 2D. In addition, our results from the first generation of full general relativistic 3D simulations including approximate neutrino transport indicate that GR can foster the onset of neutrino-driven explosions. Based on our recent parametric studies using a light-bulb scheme, we discuss impacts of nuclear energy deposition behind the supernova shock and stellar rotation on the neutrino-driven mechanism, both of which have yet to be included in the self-consistent 3D supernova models. Finally we give an outlook with a summary of the most urgent tasks to extract the information about the explosion mechanisms from multi-messenger CCSN observables.

  18. Setting the stage for circumstellar interaction in core-collapse supernovae. II. Wave-driven mass loss in supernova progenitors

    SciTech Connect

    Shiode, Joshua H.; Quataert, Eliot E-mail: eliot@berkeley.edu

    2014-01-01

    Supernovae (SNe) powered by interaction with circumstellar material provide evidence for intense stellar mass loss during the final years before core collapse. We have argued that during and after core neon burning, internal gravity waves excited by core convection can tap into the core fusion power and transport a super-Eddington energy flux out to the stellar envelope, potentially unbinding ∼1 solar mass of material. In this work, we explore the internal conditions of SN progenitors using the MESA one-dimensional stellar evolution code in search of those most susceptible to wave-driven mass loss. We focus on simple, order of magnitude considerations applicable to a wide range of progenitors. Wave-driven mass loss during core neon and oxygen fusion happens preferentially in either lower mass (∼20 solar mass zero-age main sequence) stars or massive, sub-solar metallicity stars. Roughly 20% of the SN progenitors we survey can excite 10{sup 46-48} erg of energy in waves that can potentially drive mass loss within a few months to a decade of core collapse. This energy can generate circumstellar environments with 10{sup –3}-1 solar masses reaching 100 AU before explosion. We predict a correlation between the energy associated with pre-SN mass ejection and the time to core collapse, with the most intense mass loss preferentially occurring closer to core collapse. During silicon burning, wave energy may inflate 10{sup –3}-1 solar masses of the envelope to 10-100 s of solar radii. This suggests that some nominally compact SN progenitors (Type Ibc progenitors) will have a significantly different SN shock breakout signature than traditionally assumed.

  19. Gravitational Waves from Core-collapse Supernovae and Long GRBsLong GRBs and massive stellar explosions from frame dragging around black holes

    NASA Astrophysics Data System (ADS)

    van Putten, M. H. P. M.

    2014-08-01

    The most energetic long GRBs and core-collapse supernovae may be powered by black hole inner engines. Normalized light curves of the BATSE catalogue of long GRBs are remarkably consistent with energizing an inner disk in the process of black hole spindown. A broad band chirp spectrum observed in a recent analysis of BeppoSax light curves of long GRBs may reflect the induced turbulence. Nearby CC-SNe are therefore potential sources of gravitational wave emissions with durations of tens of seconds commensurate with long GRBs.

  20. The Host Galaxies of Fast-Ejecta Core-Collapse Supernovae

    NASA Technical Reports Server (NTRS)

    Kelly, Patrick L.; Filippenko, Alexei V.; Modjaz, Maryam; Kocevski, Daniel

    2014-01-01

    Spectra of broad-lined Type Ic supernovae (SN Ic-BL), the only kind of SN observed at the locations of long-duration gamma-ray bursts (LGRBs), exhibit wide features indicative of high ejecta velocities ((is) approximately 0.1c). We study the host galaxies of a sample of 245 low-redshift (z (is) less than 0.2) core-collapse SN, including 17 SN Ic-BL, discovered by galaxy-untargeted searches, and 15 optically luminous and dust-obscured z (is) less than 1.2 LGRBs. We show that, in comparison with SDSS galaxies having similar stellar masses, the hosts of low-redshift SN Ic- BL and z (is) is less than 1.2 LGRBs have high stellar-mass and star-formation-rate densities. Core-collapse SN having typical ejecta velocities, in contrast, show no preference for such galaxies. Moreover, we find that the hosts of SN Ic-BL, unlike those of SN Ib/Ic and SN II, exhibit high gas velocity dispersions for their stellar masses. The patterns likely reflect variations among star-forming environments, and suggest that LGRBs can be used as probes of conditions in high-redshift galaxies. They may be caused by efficient formation of massive binary progenitors systems in densely star-forming regions, or, less probably, a higher fraction of stars created with the initial masses required for a SN Ic-BL or LGRB. Finally, we show that the preference of SN Ic-BL and LGRBs for galaxies with high stellar-mass and star-formation-rate densities cannot be attributed to a preference for low metal abundances but must reflect the influence of a separate environmental factor.

  1. Effects of stellar rotation on star formation rates and comparison to core-collapse supernova rates

    SciTech Connect

    Horiuchi, Shunsaku; Beacom, John F.; Bothwell, Matt S.; Thompson, Todd A.

    2013-06-01

    We investigate star formation rate (SFR) calibrations in light of recent developments in the modeling of stellar rotation. Using new published non-rotating and rotating stellar tracks, we study the integrated properties of synthetic stellar populations and find that the UV to SFR calibration for the rotating stellar population is 30% smaller than for the non-rotating stellar population, and 40% smaller for the Hα to SFR calibration. These reductions translate to smaller SFR estimates made from observed UV and Hα luminosities. Using the UV and Hα fluxes of a sample of ∼300 local galaxies, we derive a total (i.e., sky-coverage corrected) SFR within 11 Mpc of 120-170 M {sub ☉} yr{sup –1} and 80-130 M {sub ☉} yr{sup –1} for the non-rotating and rotating estimators, respectively. Independently, the number of core-collapse supernovae discovered in the same volume requires a total SFR of 270{sub −80}{sup +110} M{sub ⊙} yr{sup −1}, suggesting a tension with the SFR estimates made with rotating calibrations. More generally, when compared with the directly estimated SFR, the local supernova discoveries strongly constrain any physical effects that might increase the energy output of massive stars, including, but not limited to, stellar rotation. The cosmic SFR and cosmic supernova rate data, on the other hand, show the opposite trend, with the cosmic SFR higher than that inferred from cosmic supernovae, constraining a significant decrease in the energy output of massive stars. Together, these lines of evidence suggest that the true SFR calibration factors cannot be too far from their canonical values.

  2. A SEMI-DYNAMICAL APPROACH TO THE SHOCK REVIVAL IN CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Nagakura, Hiroki; Yamamoto, Yu; Yamada, Shoichi

    2013-03-10

    We develop a new semi-dynamical method to study shock revival by neutrino heating in core-collapse supernovae. Our new approach is an extension of the previous studies that employ spherically symmetric, steady, shocked accretion flows together with the light-bulb approximation. The latter has been widely used in the supernova community for the phenomenological investigation of the criteria for successful supernova explosions. In the present approach, we get rid of the steady-state condition and take into account shock wave motions instead. We have in mind a scenario in which it is not the critical luminosity but the critical fluctuation generated by hydrodynamical instabilities such as standing accretion shock instability and neutrino-driven convection in the post-shock region that determines the onset of shock revival. After confirming that the new approach indeed captures the dynamics of revived shock wave qualitatively, we then apply the method to various initial conditions and find that there is a critical fluctuation for shock revival, which can be well fit by the following formula: f{sub crit} {approx} 0.8 Multiplication-Sign (M{sub in}/1.4 M{sub Sun }) Multiplication-Sign {l_brace}1 - (r{sub sh}/10{sup 8} cm){r_brace}, where f{sub crit} denotes the critical pressure fluctuation normalized by the unperturbed post-shock value. M{sub in} and r{sub sh} stand for the mass of the central compact object and the shock radius, respectively. The critical fluctuation decreases with the shock radius, whereas it increases with the mass of the central object. We discuss the possible implications of our results for three-dimensional effects on shock revival, which is currently controversial in the supernova community.

  3. Should One Use the Ray-by-Ray Approximation in Core-collapse Supernova Simulations?

    NASA Astrophysics Data System (ADS)

    Skinner, M. Aaron; Burrows, Adam; Dolence, Joshua C.

    2016-11-01

    We perform the first self-consistent, time-dependent, multi-group calculations in two dimensions (2D) to address the consequences of using the ray-by-ray+ transport simplification in core-collapse supernova simulations. Such a dimensional reduction is employed by many researchers to facilitate their resource-intensive calculations. Our new code (Fornax) implements multi-D transport, and can, by zeroing out transverse flux terms, emulate the ray-by-ray+ scheme. Using the same microphysics, initial models, resolution, and code, we compare the results of simulating 12, 15, 20, and 25 M ⊙ progenitor models using these two transport methods. Our findings call into question the wisdom of the pervasive use of the ray-by-ray+ approach. Employing it leads to maximum post-bounce/pre-explosion shock radii that are almost universally larger by tens of kilometers than those derived using the more accurate scheme, typically leaving the post-bounce matter less bound and artificially more “explodable.” In fact, for our 25 M ⊙ progenitor, the ray-by-ray+ model explodes, while the corresponding multi-D transport model does not. Therefore, in two dimensions, the combination of ray-by-ray+ with the axial sloshing hydrodynamics that is a feature of 2D supernova dynamics can result in quantitatively, and perhaps qualitatively, incorrect results.

  4. ON THE REQUIREMENTS FOR REALISTIC MODELING OF NEUTRINO TRANSPORT IN SIMULATIONS OF CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Lentz, Eric J.; Mezzacappa, Anthony; Hix, W. Raphael; Messer, O. E. Bronson; Liebendoerfer, Matthias; Bruenn, Stephen W. E-mail: mezzacappaa@ornl.gov

    2012-03-01

    We have conducted a series of numerical experiments with the spherically symmetric, general relativistic, neutrino radiation hydrodynamics code AGILE-BOLTZTRAN to examine the effects of several approximations used in multidimensional core-collapse supernova simulations. Our code permits us to examine the effects of these approximations quantitatively by removing, or substituting for, the pieces of supernova physics of interest. These approximations include: (1) using Newtonian versus general relativistic gravity, hydrodynamics, and transport; (2) using a reduced set of weak interactions, including the omission of non-isoenergetic neutrino scattering, versus the current state-of-the-art; and (3) omitting the velocity-dependent terms, or observer corrections, from the neutrino Boltzmann kinetic equation. We demonstrate that each of these changes has noticeable effects on the outcomes of our simulations. Of these, we find that the omission of observer corrections is particularly detrimental to the potential for neutrino-driven explosions and exhibits a failure to conserve lepton number. Finally, we discuss the impact of these results on our understanding of current, and the requirements for future, multidimensional models.

  5. Hans A. Bethe Prize: Neutron Stars and Core-Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Lattimer, James

    2015-04-01

    Core-collapse supernovae lead to the formation of neutron stars, and both are sensitive to the dense matter equation of state. Hans Bethe first recognized that the matter in the collapsing core of a massive star has a relatively low entropy which prevents nuclear dissociation until nuclei merge near the nuclear saturation density. This recognition means that collapse continues until the core exceeds the saturation density. This prediction forms the foundation for modern simulations of supernovae. These supernovae sample matter up to about twice nuclear saturation density, but neutron stars are sensitive to the equation of state both near the saturation density and at several times higher densities. Two important recent developments are the discovery of two-solar mass neutron stars and refined experimental determinations of the behavior of the symmetry energy of nuclear matter near the saturation density. Combined with the assumption of causality, they imply that the radii of observed neutron stars are largely independent of their mass, and that this radius is in the range of 11 to 13 km. These theoretical results are not only consistent with expectations from theoretical studies of pure neutron matter, but also accumulated observations of both bursting and cooling neutron stars. In the near future, new pulsar timing data, which could lead to larger measured masses as well as measurements of moments of inertia, X-ray observations, such as from NICER, of bursting and other sources, and gravitational wave observations of neutron stars in merging compact binaries, will provide important new constraints on neutron stars and the dense matter equation of state. DOE DE-FG02-87ER-40317.

  6. Dynamics of an Alfvén Surface in Core Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Guilet, Jérôme; Foglizzo, Thierry; Fromang, Sébastien

    2011-03-01

    We investigate the dynamics of an Alfvén surface (where the Alfvén speed equals the advection velocity) in the context of core collapse supernovae during the phase of accretion on the proto-neutron star. Such a surface should exist even for weak magnetic fields because the advection velocity decreases to zero at the center of the collapsing core. In this decelerated flow, Alfvén waves created by the standing accretion shock instability or convection accumulate and amplify while approaching the Alfvén surface. We study this amplification using one-dimensional MHD simulations with explicit physical dissipation (resistivity and viscosity). In the linear regime, the amplification continues until the Alfvén wavelength becomes as small as the dissipative scale. A pressure feedback that increases the pressure in the upstream flow is created via a nonlinear coupling. We derive analytic formulae for the maximum amplification and the nonlinear coupling and check them with numerical simulations to very good accuracy. Interestingly, these quantities diverge if the dissipation is decreased to zero, scaling as the square root of the Reynolds number, suggesting large effects in weakly dissipative flows. We also characterize the nonlinear saturation of this amplification when compression effects become important, leading to either a change of the velocity gradient, or a steepening of the Alfvén wave. Applying these results to core collapse supernovae shows that the amplification can be fast enough to affect the dynamics if the magnetic field is strong enough for the Alfvén surface to lie in the region of strong velocity gradient just above the neutrinosphere. This requires the presence of a strong magnetic field in the progenitor star, which would correspond to the formation of a magnetar under the assumption of magnetic flux conservation. An extrapolation of our analytic formula (taking into account the nonlinear saturation) suggests that the Alfvén wave could reach an

  7. Implicit large eddy simulations of anisotropic weakly compressible turbulence with application to core-collapse supernovae

    NASA Astrophysics Data System (ADS)

    Radice, David; Couch, Sean M.; Ott, Christian D.

    2015-08-01

    In the implicit large eddy simulation (ILES) paradigm, the dissipative nature of high-resolution shock-capturing schemes is exploited to provide an implicit model of turbulence. The ILES approach has been applied to different contexts, with varying degrees of success. It is the de-facto standard in many astrophysical simulations and in particular in studies of core-collapse supernovae (CCSN). Recent 3D simulations suggest that turbulence might play a crucial role in core-collapse supernova explosions, however the fidelity with which turbulence is simulated in these studies is unclear. Especially considering that the accuracy of ILES for the regime of interest in CCSN, weakly compressible and strongly anisotropic, has not been systematically assessed before. Anisotropy, in particular, could impact the dissipative properties of the flow and enhance the turbulent pressure in the radial direction, favouring the explosion. In this paper we assess the accuracy of ILES using numerical methods most commonly employed in computational astrophysics by means of a number of local simulations of driven, weakly compressible, anisotropic turbulence. Our simulations employ several different methods and span a wide range of resolutions. We report a detailed analysis of the way in which the turbulent cascade is influenced by the numerics. Our results suggest that anisotropy and compressibility in CCSN turbulence have little effect on the turbulent kinetic energy spectrum and a Kolmogorov scaling is obtained in the inertial range. We find that, on the one hand, the kinetic energy dissipation rate at large scales is correctly captured even at low resolutions, suggesting that very high "effective Reynolds number" can be achieved at the largest scales of the simulation. On the other hand, the dynamics at intermediate scales appears to be completely dominated by the so-called bottleneck effect, i.e., the pile up of kinetic energy close to the dissipation range due to the partial

  8. Dense Iron Ejecta and Core-Collapse Supernova Explosion in the Young Supernova Remnant G11.2-0.3

    NASA Astrophysics Data System (ADS)

    Moon, Dae-Sik; Koo, Bon-Chul; Lee, Ho-Gyu; Matthews, Keith; Lee, Jae-Joon; Pyo, Tae-Soo; Seok, Ji Yeon; Hayashi, Masahiko

    2009-09-01

    We present the results of near-infrared spectroscopic observations of dense (gsim103 cm-3) iron ejecta in the young core-collapse supernova remnant G11.2-0.3. Five ejecta knots projected to be close to its center show a large dispersion in their Doppler shifts: two knots in the east are blueshifted by more than 1000 km s-1, while three western knots have relatively small blueshifts of 20-60 km s-1. This velocity discrepancy may indicate that the western knots have been significantly decelerated or that there exists a systematic velocity difference among the knots. One ejecta filament in the northwestern boundary, on the other hand, is redshifted by gsim200 km s-1, while opposite filament in the southeastern boundary shows a negligible radial motion. Some of the knots and filaments have secondary velocity components, and one knot shows a bow shock-like feature in the velocity structure. The iron ejecta appear to be devoid of strong emission from other heavy elements, such as S, which may attest to the α-rich freezeout process in the explosive nucleosynthesis of the core-collapse supernova explosion close to its center. The prominent bipolar distribution of the Fe ejecta in the northwestern and southeastern direction, along with the elongation of the central pulsar wind nebula in the perpendicular direction, is consistent with the interpretation that the supernova exploded primarily along the northwestern and southeastern direction. Based in part on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

  9. Constraints for the progenitor masses of 17 historic core-collapse supernovae

    SciTech Connect

    Williams, Benjamin F.; Peterson, Skyler; Gilbert, Karoline; Dalcanton, Julianne J.; Murphy, Jeremiah; Dolphin, Andrew E.; Jennings, Zachary G. E-mail: peters8@uw.edu E-mail: jeremiah@physics.fsu.edu E-mail: dolphin@raytheon.com

    2014-08-20

    Using resolved stellar photometry measured from archival Hubble Space Telescope imaging, we generate color-magnitude diagrams of the stars within 50 pc of the locations of historic core-collapse supernovae (SNe) that took place in galaxies within 8 Mpc. We fit these color-magnitude distributions with stellar evolution models to determine the best-fit age distribution of the young population. We then translate these age distributions into probability distributions for the progenitor mass of each SN. The measurements are anchored by the main-sequence stars surrounding the event, making them less sensitive to assumptions about binarity, post-main-sequence evolution, or circumstellar dust. We demonstrate that, in cases where the literature contains masses that have been measured from direct imaging, our measurements are consistent with (but less precise than) these measurements. Using this technique, we constrain the progenitor masses of 17 historic SNe, 11 of which have no previous estimates from direct imaging. Our measurements still allow the possibility that all SN progenitor masses are <20 M {sub ☉}. However, the large uncertainties for the highest-mass progenitors also allow the possibility of no upper-mass cutoff.

  10. THE DOMINANCE OF NEUTRINO-DRIVEN CONVECTION IN CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Murphy, Jeremiah W.; Dolence, Joshua C.; Burrows, Adam E-mail: jdolence@astro.princeton.edu

    2013-07-01

    Multi-dimensional instabilities have become an important ingredient in core-collapse supernova (CCSN) theory. Therefore, it is necessary to understand the driving mechanism of the dominant instability. We compare our parameterized three-dimensional CCSN simulations with other buoyancy-driven simulations and propose scaling relations for neutrino-driven convection. Through these comparisons, we infer that buoyancy-driven convection dominates post-shock turbulence in our simulations. In support of this inference, we present four major results. First, the convective fluxes and kinetic energies in the neutrino-heated region are consistent with expectations of buoyancy-driven convection. Second, the convective flux is positive where buoyancy actively drives convection, and the radial and tangential components of the kinetic energy are in rough equipartition (i.e., K{sub r} {approx} K{sub {theta}} + K{sub {phi}}). Both results are natural consequences of buoyancy-driven convection, and are commonly observed in simulations of convection. Third, buoyant driving is balanced by turbulent dissipation. Fourth, the convective luminosity and turbulent dissipation scale with the driving neutrino power. In all, these four results suggest that in neutrino-driven explosions, the multi-dimensional motions are consistent with neutrino-driven convection.

  11. Convective Properties of Rotating Two-dimensional Core-collapse Supernova Progenitors

    NASA Astrophysics Data System (ADS)

    Chatzopoulos, E.; Couch, Sean M.; Arnett, W. David; Timmes, F. X.

    2016-05-01

    We explore the effects of rotation on convective carbon, oxygen, and silicon shell burning during the late stages of evolution in a 20 M ⊙ star. Using the Modules for Experiments in Stellar Astrophysics we construct one-dimensional (1D) stellar models both with no rotation and with an initial rigid rotation of 50% of critical. At different points during the evolution, we map the 1D models into 2D and follow the multidimensional evolution using the FLASH compressible hydrodynamics code for many convective turnover times until a quasi-steady state is reached. We characterize the strength and scale of convective motions via decomposition of the momentum density into vector spherical harmonics. We find that rotation influences the total power in solenoidal modes, with a slightly larger impact for carbon and oxygen shell burning than for silicon shell burning. Including rotation in 1D stellar evolution models alters the structure of the star in a manner that has a significant impact on the character of multidimensional convection. Adding modest amounts of rotation to a stellar model that ignores rotation during the evolutionary stage, however, has little impact on the character of the resulting convection. Since the spatial scale and strength of convection present at the point of core collapse directly influence the supernova mechanism, our results suggest that rotation could play an important role in setting the stage for massive stellar explosions.

  12. Bolometric light curves and explosion parameters of 38 stripped-envelope core-collapse supernovae

    NASA Astrophysics Data System (ADS)

    Lyman, J. D.; Bersier, D.; James, P. A.; Mazzali, P. A.; Eldridge, J. J.; Fraser, M.; Pian, E.

    2016-03-01

    Literature data are collated for 38 stripped-envelope core-collapse supernovae (SE SNe; i.e. SNe IIb, Ib, Ic and Ic-BL) that have good light-curve coverage in more than one optical band. Using bolometric corrections derived in previous work, the bolometric light curve of each SN is recovered and template bolometric light curves provided. Peak light distributions and decay rates are investigated; SNe subtypes are not cleanly distinguished in this parameter space, although some grouping of types does occur and there is a suggestion of a Phillips-like relation for most SNe Ic-BL. The bolometric light curves are modelled with a simple analytical prescription and compared to results from more detailed modelling. Distributions of the explosion parameters show the extreme nature of SNe Ic-BL in terms of their 56Ni mass and the kinetic energy, however ejected masses are similar to other subtypes. SNe Ib and Ic have very similar distributions of explosion parameters, indicating a similarity in progenitors. SNe IIb are the most homogeneous subtype and have the lowest average values for 56Ni mass, ejected mass, and kinetic energy. Ejecta masses for each subtype and SE SNe as a whole are inconsistent with those expected from very massive stars. The majority of the ejecta mass distribution is well described by more moderately massive progenitors in binaries, indicating these are the dominant progenitor channel for SE SNe.

  13. THREE-DIMENSIONAL CORE-COLLAPSE SUPERNOVA SIMULATED USING A 15 M{sub ⊙} PROGENITOR

    SciTech Connect

    Lentz, Eric J.; Mezzacappa, Anthony; Harris, J. Austin; Yakunin, Konstantin N.; Bruenn, Stephen W.; Hix, W. Raphael; Messer, O. E. Bronson; Endeve, Eirik; Blondin, John M.; Marronetti, Pedro

    2015-07-10

    We have performed ab initio neutrino radiation hydrodynamics simulations in three and two spatial dimensions (3D and 2D) of core-collapse supernovae from the same 15 M{sub ☉} progenitor through 440 ms after core bounce. Both 3D and 2D models achieve explosions; however, the onset of explosion (shock revival) is delayed by ∼100 ms in 3D relative to the 2D counterpart and the growth of the diagnostic explosion energy is slower. This is consistent with previously reported 3D simulations utilizing iron-core progenitors with dense mantles. In the ∼100 ms before the onset of explosion, diagnostics of neutrino heating and turbulent kinetic energy favor earlier explosion in 2D. During the delay, the angular scale of convective plumes reaching the shock surface grows and explosion in 3D is ultimately lead by a single, large-angle plume, giving the expanding shock a directional orientation not dissimilar from those imposed by axial symmetry in 2D simulations. We posit that shock revival and explosion in the 3D simulation may be delayed until sufficiently large plumes form, whereas such plumes form more rapidly in 2D, permitting earlier explosions.

  14. Exploring the nuclear pasta phase in Core-Collapse Supernova Matter

    SciTech Connect

    Pais, Helena; Stone, Jirina R

    2012-01-01

    The core-collapse supernova (CCSN) phenomenon, one of the most explosive events in the Uni- verse, presents a challenge to theoretical astrophysics. Of the large variety of forms of matter present in CCSN, we focus on the transitional region between homogeneous and inhomogeneous phases. Traditionally, here the nuclear structures undergo a series of changes in shape from spher- ical to exotic deformed forms: rods, slabs, cylindrical holes and bubbles, termed nuclear pasta . A fully self-consistent three-dimensional, finite temperature Skyrme-Hartree-Fock + BCS (SHF) calculation yields, for the first time, the critical density and temperature of both the onset of the pasta in inhomogeneous matter, consisting of neutron heavy nuclei and a free neutron and electron gas, and its dissolution in to a homogeneous neutron, proton and electron liquid. As the nuclear matter properties depend on the effective nucleon-nucleon interaction in the SHF model, we employ four different forms of the Skyrme interaction, SkM , SLy4, NRAPR and SQMC700 and find subtle variations in the low density and high density transitions into and out of the pasta phase. Two new stable pasta shapes have been identified, in addition to the classic ones, on the grid of densities and temperatures used in this work. Detailed examination and clasification of the transitions found will form the content of a forthcoming publication.

  15. Parametric study of flow patterns behind the standing accretion shock wave for core-collapse supernovae

    SciTech Connect

    Iwakami, Wakana; Nagakura, Hiroki; Yamada, Shoichi

    2014-05-10

    In this study, we conduct three-dimensional hydrodynamic simulations systematically to investigate the flow patterns behind the accretion shock waves that are commonly formed in the post-bounce phase of core-collapse supernovae. Adding small perturbations to spherically symmetric, steady, shocked accretion flows, we compute the subsequent evolutions to find what flow pattern emerges as a consequence of hydrodynamical instabilities such as convection and standing accretion shock instability for different neutrino luminosities and mass accretion rates. Depending on these two controlling parameters, various flow patterns are indeed realized. We classify them into three basic patterns and two intermediate ones; the former includes sloshing motion (SL), spiral motion (SP), and multiple buoyant bubble formation (BB); the latter consists of spiral motion with buoyant-bubble formation (SPB) and spiral motion with pulsationally changing rotational velocities (SPP). Although the post-shock flow is highly chaotic, there is a clear trend in the pattern realization. The sloshing and spiral motions tend to be dominant for high accretion rates and low neutrino luminosities, and multiple buoyant bubbles prevail for low accretion rates and high neutrino luminosities. It is interesting that the dominant pattern is not always identical between the semi-nonlinear and nonlinear phases near the critical luminosity; the intermediate cases are realized in the latter case. Running several simulations with different random perturbations, we confirm that the realization of flow pattern is robust in most cases.

  16. NUCLEOSYNTHESIS IN CORE-COLLAPSE SUPERNOVA EXPLOSIONS TRIGGERED BY A QUARK-HADRON PHASE TRANSITION

    SciTech Connect

    Nishimura, Nobuya; Thielemann, Friedrich-Karl; Hempel, Matthias; Kaeppeli, Roger; Rauscher, Thomas; Winteler, Christian; Fischer, Tobias; Martinez-Pinedo, Gabriel; Froehlich, Carla; Sagert, Irina

    2012-10-10

    We explore heavy-element nucleosynthesis in the explosion of massive stars that are triggered by a quark-hadron phase transition during the early post-bounce phase of core-collapse supernovae. The present study is based on general-relativistic radiation hydrodynamics simulations with three-flavor Boltzmann neutrino transport in spherical symmetry, which utilize a quark-hadron hybrid equation of state based on the MIT bag model for strange quark matter. The quark-hadron phase transition inside the stellar core forms a shock wave propagating toward the surface of the proto-neutron star. This shock wave results in an explosion and ejects neutron-rich matter from the outer accreted layers of the proto-neutron star. Later, during the cooling phase, the proto-neutron star develops a proton-rich neutrino-driven wind. We present a detailed analysis of the nucleosynthesis outcome in both neutron-rich and proton-rich ejecta and compare our integrated nucleosynthesis with observations of the solar system and metal-poor stars. For our standard scenario, we find that a 'weak' r-process occurs and elements up to the second peak (A {approx} 130) are successfully synthesized. Furthermore, uncertainties in the explosion dynamics could barely allow us to obtain the strong r-process which produces heavier isotopes, including the third peak (A {approx} 195) and actinide elements.

  17. STOCHASTICITY AND EFFICIENCY IN SIMPLIFIED MODELS OF CORE-COLLAPSE SUPERNOVA EXPLOSIONS

    SciTech Connect

    Cardall, Christian Y.; Budiardja, Reuben D. E-mail: reubendb@utk.edu

    2015-11-01

    We present an initial report on 160 simulations of a highly simplified model of the post-bounce core-collapse supernova environment in three spatial dimensions (3D). We set different values of a parameter characterizing the impact of nuclear dissociation at the stalled shock in order to regulate the post-shock fluid velocity, thereby determining the relative importance of convection and the stationary accretion shock instability (SASI). While our convection-dominated runs comport with the paradigmatic notion of a “critical neutrino luminosity” for explosion at a given mass accretion rate (albeit with a nontrivial spread in explosion times just above threshold), the outcomes of our SASI-dominated runs are much more stochastic: a sharp threshold critical luminosity is “smeared out” into a rising probability of explosion over a ∼20% range of luminosity. We also find that the SASI-dominated models are able to explode with 3–4 times less efficient neutrino heating, indicating that progenitor properties, and fluid and neutrino microphysics, conducive to the SASI would make the neutrino-driven explosion mechanism more robust.

  18. Links between the Shock Instability in Core-collapse Supernovae and Asymmetric Accretions of Envelopes

    NASA Astrophysics Data System (ADS)

    Takahashi, Kazuya; Iwakami, Wakana; Yamamoto, Yu; Yamada, Shoichi

    2016-11-01

    The explosion mechanism of core-collapse supernovae (CCSNe) has not been fully understood yet, but multidimensional fluid instabilities such as standing accretion shock instability and convection are now believed to be crucial for shock revival. Another multidimensional effect that has been recently argued is the asymmetric structures in progenitors, which are induced by violent convections in silicon/oxygen layers that occur before the onset of collapse, as revealed by recent numerical simulations of the last stage of massive star evolutions. Furthermore, it has been also demonstrated numerically that accretions of such nonspherical envelopes could facilitate shock revival. These two multidimensional effects may hence hold a key to successful explosions. In this paper, we performed a linear stability analysis of the standing accretion shock in CCSNe, taking into account nonspherical, unsteady accretion flows onto the shock to clarify the possible links between the two effects. We found that such preshock perturbations can excite the fluid instabilities efficiently and hence help the shock revive in CCSNe.

  19. Three dimensional core-collapse supernova simulated using a 15 M⊙ progenitor

    DOE PAGES

    Lentz, Eric J.; Bruenn, Stephen W.; Hix, W. Raphael; Mezzacappa, Anthony; Messer, O. E. Bronson; Endeve, Eirik; Blondin, John M.; Harris, J. Austin; Marronetti, Pedro; Yakunin, Konstantin N.

    2015-07-10

    We have performed ab initio neutrino radiation hydrodynamics simulations in three and two spatial dimensions (3D and 2D) of core-collapse supernovae from the same 15 M⊙ progenitor through 440 ms after core bounce. Both 3D and 2D models achieve explosions; however, the onset of explosion (shock revival) is delayed by ~100 ms in 3D relative to the 2D counterpart and the growth of the diagnostic explosion energy is slower. This is consistent with previously reported 3D simulations utilizing iron-core progenitors with dense mantles. In the ~100 ms before the onset of explosion, diagnostics of neutrino heating and turbulent kinetic energymore » favor earlier explosion in 2D. During the delay, the angular scale of convective plumes reaching the shock surface grows and explosion in 3D is ultimately lead by a single, large-angle plume, giving the expanding shock a directional orientation not dissimilar from those imposed by axial symmetry in 2D simulations. Finally, we posit that shock revival and explosion in the 3D simulation may be delayed until sufficiently large plumes form, whereas such plumes form more rapidly in 2D, permitting earlier explosions.« less

  20. Impacts of Rotation on Three-dimensional Hydrodynamics of Core-collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Nakamura, Ko; Kuroda, Takami; Takiwaki, Tomoya; Kotake, Kei

    2014-09-01

    We perform a series of simplified numerical experiments to explore how rotation impacts the three-dimensional (3D) hydrodynamics of core-collapse supernovae. For our systematic study, we employ a light-bulb scheme to trigger explosions and a three-flavor neutrino leakage scheme to treat deleptonization effects and neutrino losses from the proto-neutron-star interior. Using a 15 M ⊙ progenitor, we compute 30 models in 3D with a wide variety of initial angular momentum and light-bulb neutrino luminosity. We find that the rotation can help the onset of neutrino-driven explosions for the models in which the initial angular momentum is matched to that obtained in recent stellar evolutionary calculations (~0.3-3 rad s-1 at the center). For the models with larger initial angular momentum, the shock surface deforms to be more oblate due to larger centrifugal force. This not only makes the gain region more concentrated around the equatorial plane, but also makes the mass larger in the gain region. As a result, buoyant bubbles tend to be coherently formed and rise in the equatorial region, which pushes the revived shock toward ever larger radii until a global explosion is triggered. We find that these are the main reasons that the preferred direction of the explosion in 3D rotating models is often perpendicular to the spin axis, which is in sharp contrast to the polar explosions around the axis that were obtained in previous two-dimensional simulations.

  1. Inelastic Neutrino Reactions with Light Nuclei and Standing Accretion Shock Instability in Core-Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Furusawa, S.; Nagakura, H.; Sumiyoshi, K.; Yamada, S.

    2016-01-01

    We perform numerical experiments to investigate the influence of inelastic neutrino reactions with light nuclei on the standing accretion shock instability. The time evolutions of shock waves are calculated with a simple light-bulb approximation for the neutrino transport and a multi-nuclei equation of state. The neutrino absorptions and inelastic interactions with deuterons, tritons, helions and alpha particles are taken into account in the hydrodynamical simulations in addition to the ordinary charged-current interactions with nucleons. Axial symmetry is assumed but no equatorial symmetry is imposed. We show that the heating rates of deuterons reach as high as ∼ 10% of those of nucleons around the bottom of the gain region. On the other hands, alpha particles heat the matter near the shock wave, which is important when the shock wave expands and density and temperature of matter become low. It is also found that the models with heating by light nuclei have different evolutions from those without it in non-linear evolution phase. The matter in the gain region has various densities and temperatures and there appear regions that are locally rich in deuterons and alpha particles. These results indicate that the inelastic reactions of light nuclei, especially deuterons, should be incorporated in the simulations of core-collapse supernovae.

  2. THE ROLE OF TURBULENCE IN NEUTRINO-DRIVEN CORE-COLLAPSE SUPERNOVA EXPLOSIONS

    SciTech Connect

    Couch, Sean M.; Ott, Christian D. E-mail: cott@tapir.caltech.edu

    2015-01-20

    The neutrino-heated ''gain layer'' immediately behind the stalled shock in a core-collapse supernova is unstable to high-Reynolds-number turbulent convection. We carry out and analyze a new set of 19 high-resolution three-dimensional (3D) simulations with a three-species neutrino leakage/heating scheme and compare with spherically symmetric (one-dimensional, 1D) and axisymmetric (two-dimensional, 2D) simulations carried out with the same methods. We study the postbounce supernova evolution in a 15 M {sub ☉} progenitor star and vary the local neutrino heating rate, the magnitude and spatial dependence of asphericity from convective burning in the Si/O shell, and spatial resolution. Our simulations suggest that there is a direct correlation between the strength of turbulence in the gain layer and the susceptibility to explosion. 2D and 3D simulations explode at much lower neutrino heating rates than 1D simulations. This is commonly explained by the fact that nonradial dynamics allows accreting material to stay longer in the gain layer. We show that this explanation is incomplete. Our results indicate that the effective turbulent ram pressure exerted on the shock plays a crucial role by allowing multi-dimensional models to explode at a lower postshock thermal pressure and thus with less neutrino heating than 1D models. We connect the turbulent ram pressure with turbulent energy at large scales and in this way explain why 2D simulations are erroneously exploding more easily than 3D simulations.

  3. The Evolution and Impacts of Magnetorotational Instability in Magnetized Core-collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Sawai, Hidetomo; Yamada, Shoichi

    2016-02-01

    We carried out two-dimensional axisymmetric MHD simulations of core-collapse supernovae for rapidly rotating magnetized progenitors. By changing both the strength of the magnetic field and the spatial resolution, the evolution of the magnetorotational instability (MRI) and its impacts upon the dynamics are investigated. We found that the MRI greatly amplifies the seed magnetic fields in the regime where the buoyant mode, not the Alfvén mode, plays a primary role in the exponential growth phase. The MRI indeed has a powerful impact on the supernova dynamics. It makes the shock expansion faster and the explosion more energetic, with some models being accompanied by the collimated jet formations. These effects, however, are not made by the magnetic pressure except for the collimated jet formations. The angular momentum transfer induced by the MRI causes the expansion of the heating region, by which the accreting matter gain additional time to be heated by neutrinos. The MRI also drifts low-Yp matter from deep inside of the core to the heating region, which makes the net neutrino heating rate larger by the reduction of the cooling due to the electron capture. These two effects enhance the efficiency of the neutrino heating, which is found to be the key to boosting the explosion. Indeed, we found that our models explode far more weakly when the net neutrino heating is switched off. The contribution of the neutrino heating to the explosion energy could reach 60% even in the case of strongest magnetic field in the current simulations.

  4. INFLUENCE OF MAGNETOROTATIONAL INSTABILITY ON NEUTRINO HEATING: A NEW MECHANISM FOR WEAKLY MAGNETIZED CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Sawai, Hidetomo; Yamada, Shoichi

    2014-03-20

    We investigated the impact of magnetorotational instability (MRI) on the dynamics of weakly magnetized, rapidly rotating core-collapse supernovae by conducting high-resolution axisymmetric MHD simulations with simplified neutrino transfer. We found that an initially sub-magnetar-class magnetic field is drastically amplified by MRI and substantially affects the dynamics thereafter. Although the magnetic pressure is not strong enough to eject matter, the amplified magnetic field efficiently transfers angular momentum from small to large radii and from higher to lower latitudes, which causes the expansion of the heating region due to the extra centrifugal force. This then enhances the efficiency of neutrino heating and eventually leads to neutrino-driven explosion. This is a new scenario of core-collapse supernovae that has never been demonstrated by past numerical simulations.

  5. The nearby supernova factory

    SciTech Connect

    Wood-Vasey, W.M.; Aldering, G.; Lee, B.C.; Loken, S.; Nugent, P.; Perlmutter, S.; Siegrist, J.; Wang, L.; Antilogus, P.; Astier, P.; Hardin, D.; Pain, R.; Copin, Y.; Smadja, G.; Gangler, E.; Castera, A.; Adam, G.; Bacon, R.; Lemonnier, J.-P.; Pecontal, A.; Pecontal, E.; Kessler, R.

    2004-01-23

    The Nearby Supernova Factory (SNfactory) is an ambitious project to find and study in detail approximately 300 nearby Type Ia supernovae (SNe Ia) at redshifts 0.03 < z < 0.08. This program will provide an exceptional data set of well-studied SNe in the nearby smooth Hubble flow that can be used as calibration for the current and future programs designed to use SNe to measure the cosmological parameters. The first key ingredient for this program is a reliable supply of Hubble-flow SNe systematically discovered in unprecedented numbers using the same techniques as those used in distant SNe searches. In 2002, 35 SNe were found using our test-bed pipeline for automated SN search and discovery. The pipeline uses images from the asteroid search conducted by the Near Earth Asteroid Tracking group at JPL. Improvements in our subtraction techniques and analysis have allowed us to increase our effective SN discovery rate to {approx}12 SNe/month in 2003.

  6. Neutrino-Induced Nucleosynthesis in Helium Shells of Early Core-Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Banerjee, Projjwal; Qian, Yong-Zhong; Heger, Alexander; Haxton, Wick

    2016-02-01

    We summarize our studies on neutrino-driven nucleosynthesis in He shells of early core-collapse supernovae with metallicities of Z ≲ 10-3 Z⊙. We find that for progenitors of ˜ 11-15 M⊙, the neutrons released by 4He(ν¯ee, e+n)3H in He shells can be captured to produce nuclei with mass numbers up to A ˜ 200. This mechanism is sensitive to neutrino emission spectra and flavor oscillations. In addition, we find two new primary mechanisms for neutrino-induced production of 9Be in He shells. The first mechanism produces 9Be via 7Li(n,γ)8Li(n,γ)9Li(e- ν¯ee)9Be and relies on a low explosion energy for its survival. The second mechanism operates in progenitors of ˜ 8 M⊙, where 9Be can be produced directly via 7Li(3H, n0)9Be during the rapid expansion of the shocked Heshell material. The light nuclei 7Li and 3H involved in these mechanisms are produced by neutrino interactions with 4He. We discuss the implications of neutrino-induced nucleosynthesis in He shells for interpreting the elemental abundances in metal-poor stars.

  7. Systematic features of axisymmetric neutrino-driven core-collapse supernova models in multiple progenitors

    NASA Astrophysics Data System (ADS)

    Nakamura, Ko; Takiwaki, Tomoya; Kuroda, Takami; Kotake, Kei

    2015-12-01

    We present an overview of two-dimensional (2D) core-collapse supernova simulations employing a neutrino transport scheme by the isotropic diffusion source approximation. We study 101 solar-metallicity, 247 ultra metal-poor, and 30 zero-metal progenitors covering zero-age main sequence mass from 10.8 M⊙ to 75.0 M⊙. Using the 378 progenitors in total, we systematically investigate how the differences in the structures of these multiple progenitors impact the hydrodynamics evolution. By following a long-term evolution over 1.0 s after bounce, most of the computed models exhibit neutrino-driven revival of the stalled bounce shock at ˜200-800 ms postbounce, leading to the possibility of explosion. Pushing the boundaries of expectations in previous one-dimensional studies, our results confirm that the compactness parameter ξ that characterizes the structure of the progenitors is also a key in 2D to diagnosing the properties of neutrino-driven explosions. Models with high ξ undergo high ram pressure from the accreting matter onto the stalled shock, which affects the subsequent evolution of the shock expansion and the mass of the protoneutron star under the influence of neutrino-driven convection and the standing accretion-shock instability. We show that the accretion luminosity becomes higher for models with high ξ, which makes the growth rate of the diagnostic explosion energy higher and the synthesized nickel mass bigger. We find that these explosion characteristics tend to show a monotonic increase as a function of the compactness parameter ξ.

  8. High-resolution three-dimensional simulations of core-collapse supernovae in multiple progenitors

    SciTech Connect

    Couch, Sean M.; O'Connor, Evan P.

    2014-04-20

    Three-dimensional (3D) simulations of core-collapse supernovae (CCSNe) are granting new insight into the as-yet-uncertain mechanism that drives successful explosions. While there is still debate about whether explosions are obtained more easily in 3D than in 2D, it is undeniable that there exist qualitative and quantitative differences between the results of 3D and 2D simulations. We present an extensive set of high-resolution 1D, 2D, and 3D CCSN simulations with multispecies neutrino leakage carried out in two different progenitors. Our simulations confirm the results of Couch indicating that 2D explodes more readily than 3D. We argue that this is due to the inadequacies of 2D to accurately capture important aspects of the 3D dynamics. We find that without artificially enhancing the neutrino heating rate, we do not obtain explosions in 3D. We examine the development of neutrino-driven convection and the standing accretion shock instability (SASI) and find that, in separate regimes, either instability can dominate. We find evidence for growth of the SASI for both 15 M {sub ☉} and 27 M {sub ☉} progenitors; however, it is weaker in 3D exploding models. The growth rate of both instabilities is artificially enhanced along the symmetry axis in 2D as compared with our axis-free 3D Cartesian simulations. Our work highlights the growing consensus that CCSNe must be studied in 3D if we hope to solve the mystery of how the explosions are powered.

  9. AN OPEN-SOURCE NEUTRINO RADIATION HYDRODYNAMICS CODE FOR CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    O’Connor, Evan

    2015-08-15

    We present an open-source update to the spherically symmetric, general-relativistic hydrodynamics, core-collapse supernova (CCSN) code GR1D. The source code is available at http://www.GR1Dcode.org. We extend its capabilities to include a general-relativistic treatment of neutrino transport based on the moment formalisms of Shibata et al. and Cardall et al. We pay special attention to implementing and testing numerical methods and approximations that lessen the computational demand of the transport scheme by removing the need to invert large matrices. This is especially important for the implementation and development of moment-like transport methods in two and three dimensions. A critical component of neutrino transport calculations is the neutrino–matter interaction coefficients that describe the production, absorption, scattering, and annihilation of neutrinos. In this article we also describe our open-source neutrino interaction library NuLib (available at http://www.nulib.org). We believe that an open-source approach to describing these interactions is one of the major steps needed to progress toward robust models of CCSNe and robust predictions of the neutrino signal. We show, via comparisons to full Boltzmann neutrino-transport simulations of CCSNe, that our neutrino transport code performs remarkably well. Furthermore, we show that the methods and approximations we employ to increase efficiency do not decrease the fidelity of our results. We also test the ability of our general-relativistic transport code to model failed CCSNe by evolving a 40-solar-mass progenitor to the onset of collapse to a black hole.

  10. Phase transitions in core-collapse supernova matter at sub-saturation densities

    NASA Astrophysics Data System (ADS)

    Pais, Helena; Newton, William G.; Stone, Jirina R.

    2014-12-01

    Phase transitions in hot, dense matter in the collapsing cores of massive stars have an important impact on the core-collapse supernova mechanism as they absorb heat, disrupt homology, and so weaken the developing shock. We perform a three-dimensional, finite temperature Skyrme-Hartree-Fock (SHF) study of inhomogeneous nuclear matter to determine the critical density and temperature for the phase transition between the pasta phase and homogeneous matter and its properties. We employ four different parametrizations of the Skyrme nuclear energy-density functional, SkM*, SLy4, NRAPR, and SQMC700, which span a range of saturation-density symmetry energy behaviors constrained by a variety of nuclear experimental probes. For each of these interactions we calculate free energy, pressure, entropy, and chemical potentials in the range of particle number densities where the nuclear pasta phases are expected to exist, 0.02-0.12 fm-3, temperatures 2-8 MeV, and a proton fraction of 0.3. We find unambiguous evidence for a first-order phase transition to uniform matter, unsoftened by the presence of the pasta phases. No conclusive signs of a first-order phase transition between the pasta phases is observed, and it is argued that the thermodynamic quantities vary continuously right up to the first-order phase transition to uniform matter. We compare our results with thermodynamic spinodals calculated using the same Skyrme parametrizations, finding that the effect of short-range Coulomb correlations and quantum shell effects included in our model leads to the pasta phases existing at densities up to 0.01 fm-3 above the spinodal boundaries, thus increasing the transition density to uniform matter by the same amount. The transition density is otherwise shown to be insensitive to the symmetry energy at saturation density within the range constrained by the concordance of a variety of experimental constraints, and can be taken to be a well determined quantity.

  11. On the maximum magnetic field amplification by the magnetorotational instability in core-collapse supernovae

    NASA Astrophysics Data System (ADS)

    Rembiasz, T.; Guilet, J.; Obergaulinger, M.; Cerdá-Durán, P.; Aloy, M. A.; Müller, E.

    2016-08-01

    Whether the magnetorotational instability (MRI) can amplify initially weak magnetic fields to dynamically relevant strengths in core-collapse supernovae is still a matter of active scientific debate. Recent numerical studies have shown that the first phase of MRI growth dominated by channel flows is terminated by parasitic instabilities of the Kelvin-Helmholtz type that disrupt MRI channel flows and quench further magnetic field growth. However, it remains to be properly assessed by what factor the initial magnetic field can be amplified and how it depends on the initial field strength and the amplitude of the perturbations. Different termination criteria leading to different estimates of the amplification factor were proposed within the parasitic model. To determine the amplification factor and test which criterion is a better predictor of the MRI termination, we perform three-dimensional shearing-disc and shearing-box simulations of a region close to the surface of a differentially rotating protoneutron star in non-ideal magnetohydrodynamics with two different numerical codes. We find that independently of the initial magnetic field strength, the MRI channel modes can amplify the magnetic field by, at most, a factor of 100. Under the conditions found in protoneutron stars, a more realistic value for the magnetic field amplification is of the order of 10. This severely limits the role of the MRI channel modes as an agent amplifying the magnetic field in protoneutron stars starting from small seed fields. A further amplification should therefore rely on other physical processes, such as for example an MRI-driven turbulent dynamo.

  12. Characteristic velocities of stripped-envelope core-collapse supernova cores

    NASA Astrophysics Data System (ADS)

    Maurer, J. I.; Mazzali, P. A.; Deng, J.; Filippenko, A. V.; Hamuy, M.; Kirshner, R. P.; Matheson, T.; Modjaz, M.; Pian, E.; Stritzinger, M.; Taubenberger, S.; Valenti, S.

    2010-02-01

    The velocity of the inner ejecta of stripped-envelope core-collapse supernovae (CC-SNe) is studied by means of an analysis of their nebular spectra. Stripped-envelope CC-SNe are the result of the explosion of bare cores of massive stars (>=8Msolar), and their late-time spectra are typically dominated by a strong [OI] λλ6300, 6363 emission line produced by the innermost, slow-moving ejecta which are not visible at earlier times as they are located below the photosphere. A characteristic velocity of the inner ejecta is obtained for a sample of 56 stripped-envelope CC-SNe of different spectral types (IIb, Ib, Ic) using direct measurements of the linewidth as well as spectral fitting. For most SNe, this value shows a small scatter around 4500kms-1. Observations (<100d) of stripped-envelope CC-SNe have revealed a subclass of very energetic SNe, termed broad-lined SNe (BL-SNe) or hypernovae, which are characterized by broad absorption lines in the early-time spectra, indicative of outer ejecta moving at very high velocity (v >= 0.1c). SNe identified as BL in the early phase show large variations of core velocities at late phases, with some having much higher and some having similar velocities with respect to regular CC-SNe. This might indicate asphericity of the inner ejecta of BL-SNe, a possibility we investigate using synthetic three-dimensional nebular spectra. Based on observations at ESO-Paranal, Prog. 081.D-0173(A), 082.D-0292(A). E-mail: maurer@mpa-garching.mpg.de

  13. POST-SHOCK-REVIVAL EVOLUTION IN THE NEUTRINO-HEATING MECHANISM OF CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Yamamoto, Yu; Yamada, Shoichi; Fujimoto, Shin-ichiro; Nagakura, Hiroki

    2013-07-01

    We perform experimental simulations with spherical symmetry and axisymmetry to understand the post-shock-revival evolution of core-collapse supernovae. Assuming that the stalled shock wave is relaunched by neutrino heating and employing the so-called light bulb approximation, we induce shock revival by raising the neutrino luminosity up to the critical value, which is determined by dynamical simulations. A 15 M{sub Sun} progenitor model is employed. We incorporate nuclear network calculations with a consistent equation of state in the simulations to account for the energy release by nuclear reactions and their feedback to hydrodynamics. Varying the shock-relaunch time rather arbitrarily, we investigate the ensuing long-term evolutions systematically, paying particular attention to the explosion energy and nucleosynthetic yields as a function of relaunch time, or equivalently, the accretion rate at shock revival. We study in detail how the diagnostic explosion energy approaches the asymptotic value and which physical processes contribute in what proportions to the explosion energy. Furthermore, we study the dependence of physical processes on the relaunch time and the dimension of dynamics. We find that the contribution of nuclear reactions to the explosion energy is comparable to or greater than that of neutrino heating. In particular, recombinations are dominant over burnings in the contributions of nuclear reactions. Interestingly, one-dimensional (1D) models studied in this paper cannot produce the appropriate explosion energy and nickel mass simultaneously; nickels are overproduced. This problem is resolved in 2D models if the shock is relaunched at 300-400 ms after the bounce.

  14. Impacts of rotation on three-dimensional hydrodynamics of core-collapse supernovae

    SciTech Connect

    Nakamura, Ko; Kuroda, Takami; Kotake, Kei; Takiwaki, Tomoya

    2014-09-20

    We perform a series of simplified numerical experiments to explore how rotation impacts the three-dimensional (3D) hydrodynamics of core-collapse supernovae. For our systematic study, we employ a light-bulb scheme to trigger explosions and a three-flavor neutrino leakage scheme to treat deleptonization effects and neutrino losses from the proto-neutron-star interior. Using a 15 M {sub ☉} progenitor, we compute 30 models in 3D with a wide variety of initial angular momentum and light-bulb neutrino luminosity. We find that the rotation can help the onset of neutrino-driven explosions for the models in which the initial angular momentum is matched to that obtained in recent stellar evolutionary calculations (∼0.3-3 rad s{sup –1} at the center). For the models with larger initial angular momentum, the shock surface deforms to be more oblate due to larger centrifugal force. This not only makes the gain region more concentrated around the equatorial plane, but also makes the mass larger in the gain region. As a result, buoyant bubbles tend to be coherently formed and rise in the equatorial region, which pushes the revived shock toward ever larger radii until a global explosion is triggered. We find that these are the main reasons that the preferred direction of the explosion in 3D rotating models is often perpendicular to the spin axis, which is in sharp contrast to the polar explosions around the axis that were obtained in previous two-dimensional simulations.

  15. Axisymmetric Ab Initio Core-Collapse Supernova Simulations of 12--25 Solar Mass Stars

    SciTech Connect

    Bruenn, S. W.; Mezzacappa, Anthony; Hix, William Raphael; Lentz, E. J.; Messer, Bronson; Lingerfelt, Eric J; Blondin, J. M.; Endeve, Eirik; Marronetti, Pedro; Yakunin, Konstantin

    2013-01-01

    We present an overview of four ab initio axisymmetric core-collapse supernova simulations employing detailed spectral neutrino transport computed with our CHIMERA code and initiated from Woosley & Heger (2007) progenitors of mass 12, 15, 20, and 25 M_sun. All four models exhibit shock revival over ~ 200 ms (leading to the possibility of explosion), driven by neutrino energy deposition. Hydrodynamic instabilities that impart substantial asymmetries to the shock aid these revivals, with convection appearing first in the 12 solar mass model and the standing accretion shock instability (SASI) appearing first in the 25 solar mass model. Three of the models have developed pronounced prolate morphologies (the 20 solar mass model has remained approximately spherical). By 500 ms after bounce the mean shock radii in all four models exceed 3,000 km and the diagnostic explosion energies are 0.33, 0.66, 0.65, and 0.70 Bethe (B=10^{51} ergs) for the 12, 15, 20, and 25 solar mass models, respectively, and are increasing. The three least massive of our models are already sufficiently energetic to completely unbind the envelopes of their progenitors (i.e., to explode), as evidenced by our best estimate of their explosion energies, which first become positive at 320, 380, and 440 ms after bounce. By 850 ms the 12 solar mass diagnostic explosion energy has saturated at 0.38 B, and our estimate for the final kinetic energy of the ejecta is ~ 0.3 B, which is comparable to observations for lower-mass progenitors.

  16. Three-Dimensional Kinematics of Core-Collapse Supernova Remnants approaching Middle Age

    NASA Astrophysics Data System (ADS)

    Winkler, P. Frank; Garber, J. H.; Plunkett, A. L. D.; Twelker, K.; Long, K. S.

    2010-03-01

    The Galactic supernova remnants (SNRs) Puppis A and G292.0+1.8 have long been known to have optical knots composed almost entirely of heavy elements (especially oxygen) with Doppler velocities 1000 km/s or higher--fragments from the progenitor core that were launched in the explosion and have only recently been excited. Both harbor young pulsars near their centers. These SNRs are similar to Cas A but larger, with less extreme velocities, and thus are presumably older. Using CCD images from epochs 1986-2008, we have measured proper motions for over 60 knots in each of these SNRs, and in both cases we find motions proportional to displacement from an expansion center, indicating free expansion. The expansion rates for both SNRs give kinematic ages 3000 yr--almost 10 times the age of Cas A. We have also obtained spectra from many of these and other knots, and have combined the radial and transverse velocities to give the first 3-dimensional models for the ejecta distribution. For G292 the ejecta are concentrated primarily in broad bi-conical jets, oriented roughly N-S in the plane of the sky. Based on its position, the pulsar should be moving nearly perpendicular to the jet axis. Puppis A shows a more complicated structure; many of its knots have strong [N II] and/or [S II] lines in addition to those from O, and with similar high velocities. The fast knots are concentrated in three complexes, all in the NE quadrant of the remnant, while the pulsar has been measured as recoiling at high velocity toward the SW. We will discuss these results and their possible implications for understanding core-collapse SNe. Supported in part by NSF grant AST-0908566.

  17. Two-dimensional Core-collapse Supernova Models with Multi-dimensional Transport

    NASA Astrophysics Data System (ADS)

    Dolence, Joshua C.; Burrows, Adam; Zhang, Weiqun

    2015-02-01

    We present new two-dimensional (2D) axisymmetric neutrino radiation/hydrodynamic models of core-collapse supernova (CCSN) cores. We use the CASTRO code, which incorporates truly multi-dimensional, multi-group, flux-limited diffusion (MGFLD) neutrino transport, including all relevant {O}(v/c) terms. Our main motivation for carrying out this study is to compare with recent 2D models produced by other groups who have obtained explosions for some progenitor stars and with recent 2D VULCAN results that did not incorporate {O}(v/c) terms. We follow the evolution of 12, 15, 20, and 25 solar-mass progenitors to approximately 600 ms after bounce and do not obtain an explosion in any of these models. Though the reason for the qualitative disagreement among the groups engaged in CCSN modeling remains unclear, we speculate that the simplifying "ray-by-ray" approach employed by all other groups may be compromising their results. We show that "ray-by-ray" calculations greatly exaggerate the angular and temporal variations of the neutrino fluxes, which we argue are better captured by our multi-dimensional MGFLD approach. On the other hand, our 2D models also make approximations, making it difficult to draw definitive conclusions concerning the root of the differences between groups. We discuss some of the diagnostics often employed in the analyses of CCSN simulations and highlight the intimate relationship between the various explosion conditions that have been proposed. Finally, we explore the ingredients that may be missing in current calculations that may be important in reproducing the properties of the average CCSNe, should the delayed neutrino-heating mechanism be the correct mechanism of explosion.

  18. TWO-DIMENSIONAL CORE-COLLAPSE SUPERNOVA MODELS WITH MULTI-DIMENSIONAL TRANSPORT

    SciTech Connect

    Dolence, Joshua C.; Burrows, Adam; Zhang, Weiqun E-mail: burrows@astro.princeton.edu

    2015-02-10

    We present new two-dimensional (2D) axisymmetric neutrino radiation/hydrodynamic models of core-collapse supernova (CCSN) cores. We use the CASTRO code, which incorporates truly multi-dimensional, multi-group, flux-limited diffusion (MGFLD) neutrino transport, including all relevant O(v/c) terms. Our main motivation for carrying out this study is to compare with recent 2D models produced by other groups who have obtained explosions for some progenitor stars and with recent 2D VULCAN results that did not incorporate O(v/c) terms. We follow the evolution of 12, 15, 20, and 25 solar-mass progenitors to approximately 600 ms after bounce and do not obtain an explosion in any of these models. Though the reason for the qualitative disagreement among the groups engaged in CCSN modeling remains unclear, we speculate that the simplifying ''ray-by-ray'' approach employed by all other groups may be compromising their results. We show that ''ray-by-ray'' calculations greatly exaggerate the angular and temporal variations of the neutrino fluxes, which we argue are better captured by our multi-dimensional MGFLD approach. On the other hand, our 2D models also make approximations, making it difficult to draw definitive conclusions concerning the root of the differences between groups. We discuss some of the diagnostics often employed in the analyses of CCSN simulations and highlight the intimate relationship between the various explosion conditions that have been proposed. Finally, we explore the ingredients that may be missing in current calculations that may be important in reproducing the properties of the average CCSNe, should the delayed neutrino-heating mechanism be the correct mechanism of explosion.

  19. Optical spectra of 73 stripped-envelope core-collapse supernovae

    SciTech Connect

    Modjaz, M.; Bianco, F. B.; Liu, Y. Q.; Blondin, S.; Kirshner, R. P.; Challis, P.; Hicken, M.; Marion, G. H.; Matheson, T.; Berlind, P.; Calkins, M. L.; Garnavich, P.; Jha, S.

    2014-05-01

    We present 645 optical spectra of 73 supernovae (SNe) of Types IIb, Ib, Ic, and broad-lined Ic. All of these types are attributed to the core collapse of massive stars, with varying degrees of intact H and He envelopes before explosion. The SNe in our sample have a mean redshift (cz) = 4200 km s{sup –1}. Most of these spectra were gathered at the Harvard-Smithsonian Center for Astrophysics (CfA) between 2004 and 2009. For 53 SNe, these are the first published spectra. The data coverage ranges from mere identification (1-3 spectra) for a few SNe to extensive series of observations (10-30 spectra) that trace the spectral evolution for others, with an average of 9 spectra per SN. For 44 SNe of the 73 SNe presented here, we have well-determined dates of maximum light to determine the phase of each spectrum. Our sample constitutes the most extensive spectral library of stripped-envelope SNe to date. We provide very early coverage (as early as 30 days before V-band max) for photospheric spectra, as well as late-time nebular coverage when the innermost regions of the SN are visible (as late as 2 yr after explosion, while for SN 1993J, we have data as late as 11.6 yr). This data set has homogeneous observations and reductions that allow us to study the spectroscopic diversity of these classes of stripped SNe and to compare these to SNe-gamma-ray bursts. We undertake these matters in follow-up papers.

  20. PROGENITOR DIAGNOSTICS FOR STRIPPED CORE-COLLAPSE SUPERNOVAE: MEASURED METALLICITIES AT EXPLOSION SITES

    SciTech Connect

    Modjaz, M.; Bloom, J. S.; Filippenko, A. V.; Perley, D.; Silverman, J. M.; Kewley, L.

    2011-04-10

    Metallicity is expected to influence not only the lives of massive stars but also the outcome of their deaths as supernovae (SNe) and gamma-ray bursts (GRBs). However, there are surprisingly few direct measurements of the local metallicities of different flavors of core-collapse SNe (CCSNe). Here, we present the largest existing set of host-galaxy spectra with H II region emission lines at the sites of 35 stripped-envelope CCSNe. We derive local oxygen abundances in a robust manner in order to constrain the SN Ib/c progenitor population. We obtain spectra at the SN sites, include SNe from targeted and untargeted surveys, and perform the abundance determinations using three different oxygen-abundance calibrations. The sites of SNe Ic (the demise of the most heavily stripped stars, having lost both H and He layers) are systematically more metal rich than those of SNe Ib (arising from stars that retained their He layer) in all calibrations. A Kolmogorov-Smirnov test yields the very low probability of 1% that SN Ib and SN Ic environment abundances, which are different on average by {approx}0.2 dex (in the Pettini and Pagel scale), are drawn from the same parent population. Broad-lined SNe Ic (without GRBs) occur at metallicities between those of SNe Ib and SNe Ic. Lastly, we find that the host-galaxy central oxygen abundance is not a good indicator of the local SN metallicity; hence, large-scale SN surveys need to obtain local abundance measurements in order to quantify the impact of metallicity on stellar death.

  1. REVIVAL OF THE STALLED CORE-COLLAPSE SUPERNOVA SHOCK TRIGGERED BY PRECOLLAPSE ASPHERICITY IN THE PROGENITOR STAR

    SciTech Connect

    Couch, Sean M.; Ott, Christian D. E-mail: cott@tapir.caltech.edu

    2013-11-20

    Multi-dimensional simulations of advanced nuclear burning stages of massive stars suggest that the Si/O layers of presupernova stars harbor large deviations from the spherical symmetry typically assumed for presupernova stellar structure. We carry out three-dimensional core-collapse supernova simulations with and without aspherical velocity perturbations to assess their potential impact on the supernova hydrodynamics in the stalled-shock phase. Our results show that realistic perturbations can qualitatively alter the postbounce evolution, triggering an explosion in a model that fails to explode without them. This finding underlines the need for a multi-dimensional treatment of the presupernova stage of stellar evolution.

  2. Long-rising Type II supernovae from Palomar Transient Factory and Caltech Core-Collapse Project

    NASA Astrophysics Data System (ADS)

    Taddia, F.; Sollerman, J.; Fremling, C.; Migotto, K.; Gal-Yam, A.; Armen, S.; Duggan, G.; Ergon, M.; Filippenko, A. V.; Fransson, C.; Hosseinzadeh, G.; Kasliwal, M. M.; Laher, R. R.; Leloudas, G.; Leonard, D. C.; Lunnan, R.; Masci, F. J.; Moon, D.-S.; Silverman, J. M.; Wozniak, P. R.

    2016-04-01

    Context. Supernova (SN) 1987A was a peculiar hydrogen-rich event with a long-rising (~84 d) light curve, stemming from the explosion of a compact blue supergiant star. Only a few similar events have been presented in the literature in recent decades. Aims: We present new data for a sample of six long-rising Type II SNe (SNe II), three of which were discovered and observed by the Palomar Transient Factory (PTF) and three observed by the Caltech Core-Collapse Project (CCCP). Our aim is to enlarge this small family of long-rising SNe II, characterizing their differences in terms of progenitor and explosion parameters. We also study the metallicity of their environments. Methods: Optical light curves, spectra, and host-galaxy properties of these SNe are presented and analyzed. Detailed comparisons with known SN 1987A-like events in the literature are shown, with particular emphasis on the absolute magnitudes, colors, expansion velocities, and host-galaxy metallicities. Bolometric properties are derived from the multiband light curves. By modeling the early-time emission with scaling relations derived from the SuperNova Explosion Code (SNEC) models of MESA progenitor stars, we estimate the progenitor radii of these transients. The modeling of the bolometric light curves also allows us to estimate other progenitor and explosion parameters, such as the ejected 56Ni mass, the explosion energy, and the ejecta mass. Results: We present PTF12kso, a long-rising SN II that is estimated to have the largest amount of ejected 56Ni mass measured for this class. PTF09gpn and PTF12kso are found at the lowest host metallicities observed for this SN group. The variety of early light-curve luminosities depends on the wide range of progenitor radii of these SNe, from a few tens of R⊙ (SN 2005ci) up to thousands (SN 2004ek) with some intermediate cases between 100 R⊙ (PTF09gpn) and 300 R⊙ (SN 2004em). Conclusions: We confirm that long-rising SNe II with light-curve shapes closely

  3. SN 2009ip and SN 2010mc: core-collapse Type IIn supernovae arising from blue supergiants

    NASA Astrophysics Data System (ADS)

    Smith, Nathan; Mauerhan, Jon C.; Prieto, Jose L.

    2014-02-01

    The recent supernova (SN) known as SN 2009ip had dramatic precursor eruptions followed by an even brighter explosion in 2012. Its pre-2012 observations make it the best documented SN progenitor in history, but have fuelled debate about the nature of its 2012 explosion - whether it was a true SN or some type of violent non-terminal event. Both could power shock interaction with circumstellar material (CSM), but only a core-collapse SN provides a self-consistent explanation. The persistent broad emission lines in the spectrum require a relatively large ejecta mass, and a corresponding kinetic energy of at least 1051 erg, while the faint 2012a event is consistent with published models of core-collapse SNe from compact (˜60 R⊙) blue supergiants. The light curves of SN 2009ip and another Type IIn, SN 2010mc, were nearly identical; we demonstrate that their spectra match as well, and that both are standard SNe IIn. Our observations contradict the recent claim that the late-time spectrum of SN 2009ip is returning to its progenitor's luminous blue variable-like state, and we show the that late-time spectra of SN 2009ip closely resemble the spectra of SN 1987A. Moreover, SN 2009ip's changing Hα equivalent width after explosion matches behaviour typically seen in core-collapse SNe IIn. Several key facts about SN 2009ip and SN 2010mc argue strongly in favour of a core-collapse interpretation, and make a non-terminal 1050 erg event implausible. The most straightforward and self-consistent interpretation is that SN 2009ip was an initially faint core-collapse explosion of a blue supergiant that produced about half as much 56Ni as SN 1987A, with most of the peak luminosity from CSM interaction.

  4. Core-collapse Supernovae from the Palomar Transient Factory: Indications for a Different Population in Dwarf Galaxies

    NASA Astrophysics Data System (ADS)

    Arcavi, Iair; Gal-Yam, Avishay; Kasliwal, Mansi M.; Quimby, Robert M.; Ofek, Eran O.; Kulkarni, Shrinivas R.; Nugent, Peter E.; Cenko, S. Bradley; Bloom, Joshua S.; Sullivan, Mark; Howell, D. Andrew; Poznanski, Dovi; Filippenko, Alexei V.; Law, Nicholas; Hook, Isobel; Jönsson, Jakob; Blake, Sarah; Cooke, Jeff; Dekany, Richard; Rahmer, Gustavo; Hale, David; Smith, Roger; Zolkower, Jeff; Velur, Viswa; Walters, Richard; Henning, John; Bui, Kahnh; McKenna, Dan; Jacobsen, Janet

    2010-09-01

    We use the first compilation of 72 core-collapse supernovae (SNe) from the Palomar Transient Factory (PTF) to study their observed subtype distribution in dwarf galaxies compared to giant galaxies. Our sample is the largest single-survey, untargeted, spectroscopically classified, homogeneous collection of core-collapse events ever assembled, spanning a wide host-galaxy luminosity range (down to Mr ≈ -14 mag) and including a substantial fraction (>20%) of dwarf (Mr >= -18 mag) hosts. We find more core-collapse SNe in dwarf galaxies than expected and several interesting trends emerge. We use detailed subclassifications of stripped-envelope core-collapse SNe and find that all Type I core-collapse events occurring in dwarf galaxies are either SNe Ib or broad-lined SNe Ic (SNe Ic-BL), while "normal" SNe Ic dominate in giant galaxies. We also see a significant excess of SNe IIb in dwarf hosts. We hypothesize that in lower metallicity hosts, metallicity-driven mass loss is reduced, allowing massive stars that would have appeared as "normal" SNe Ic in metal-rich galaxies to retain some He and H, exploding as Ib/IIb events. At the same time, another mechanism allows some stars to undergo extensive stripping and explode as SNe Ic-BL (and presumably also as long-duration gamma-ray bursts). Our results are still limited by small-number statistics, and our measurements of the observed N(Ib/c)/N(II) number ratio in dwarf and giant hosts (0.25+0.3 -0.15 and 0.23+0.11 -0.08, respectively; 1σ uncertainties) are consistent with previous studies and theoretical predictions. As additional PTF data accumulate, more robust statistical analyses will be possible, allowing the evolution of massive stars to be probed via the dwarf-galaxy SN population.

  5. Non-spherical core collapse supernovae. III. Evolution towards homology and dependence on the numerical resolution

    NASA Astrophysics Data System (ADS)

    Gawryszczak, A.; Guzman, J.; Plewa, T.; Kifonidis, K.

    2010-10-01

    Aims: We study the hydrodynamic evolution of a non-spherical core-collapse supernova in two spatial dimensions. We begin our study from the moment of shock revival - taking into account neutrino heating and cooling, nucleosynthesis, convection, and the standing accretion shock (SASI) instability of the supernova blast - and continue for the first week after the explosion when the expanding flow becomes homologous and the ejecta enter the early supernova remnant (SNR) phase. We observe the growth and interaction of Richtmyer-Meshkov, Rayleigh-Taylor, and Kelvin-Helmholtz instabilities resulting in an extensive mixing of the heavy elements throughout the ejecta. We obtain a series of models at progressively higher resolution and provide a discussion of numerical convergence. Methods: Different from previous studies, our computations are performed in a single domain. Periodic mesh mapping is avoided. This is made possible by employing cylindrical coordinates, and an adaptive mesh refinement (AMR) strategy in which the computational workload (defined as the product of the total number of computational cells and the length of the time step) is monitored and, if necessary, reduced. Results: Our results are in overall good agreement with the AMR simulations we have reported in the past. We show, however, that numerical convergence is difficult to achieve, due to the strongly non-linear nature of the problem. Even more importantly, we find that our model displays a strong tendency to expand laterally away from the equatorial plane and toward the poles. We demonstrate that this expansion is a physical property of the low-mode, SASI instability. Although the SASI operates only within about the first second of the explosion, it leaves behind a large lateral velocity gradient in the post shock layer which affects the evolution for minutes and hours later. This results in a prolate deformation of the ejecta and a fast advection of the highest-velocity 56Ni-rich material from

  6. Three-dimensional simulations of core-collapse supernovae: from shock revival to shock breakout

    NASA Astrophysics Data System (ADS)

    Wongwathanarat, A.; Müller, E.; Janka, H.-Th.

    2015-05-01

    We present three-dimensional hydrodynamic simulations of the evolution of core-collapse supernovae (SN) from blast-wave initiation by the neutrino-driven mechanism to shock breakout from the stellar surface, using an axis-free Yin-Yang grid and considering two 15 M⊙ red supergiants (RSG) and two blue supergiants (BSG) of 15 M⊙ and 20 M⊙. We demonstrate that the metal-rich ejecta in homologous expansion still carry fingerprints of asymmetries at the beginning of the explosion, but the final metal distribution is massively affected by the detailed progenitor structure. The most extended and fastest metal fingers and clumps are correlated with the biggest and fastest-rising plumes of neutrino-heated matter, because these plumes most effectively seed the growth of Rayleigh-Taylor (RT) instabilities at the C+O/He and He/H composition-shell interfaces after the passage of the SN shock. The extent of radial mixing, global asymmetry of the metal-rich ejecta, RT-induced fragmentation of initial plumes to smaller-scale fingers, and maximum Ni and minimum H velocities depend not only on the initial asphericity and explosion energy (which determine the shock and initial Ni velocities), but also on the density profiles and widths of C+O core and He shell and on the density gradient at the He/H transition, which leads to unsteady shock propagation and the formation of reverse shocks. Both RSG explosions retain a large global metal asymmetry with pronounced clumpiness and substructure, deep penetration of Ni fingers into the H-envelope (with maximum velocities of 4000-5000 km s-1 for an explosion energy around 1.5 bethe) and efficient inward H-mixing. While the 15 M⊙ BSG shares these properties (maximum Ni speeds up to ~3500 km s-1), the 20 M⊙ BSG develops a much more roundish geometry without pronounced metal fingers (maximum Ni velocities only ~2200 km s-1) because of reverse-shock deceleration and insufficient time for strong RT growth and fragmentation at the He

  7. Ozone Depletion from Nearby Supernovae

    NASA Technical Reports Server (NTRS)

    Gehrels, Neil; Laird, Claude M.; Jackman, Charles H.; Cannizzo, John K.; Mattson, Barbara J.; Chen, Wan; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    Estimates made in the 1970's indicated that a supernova occurring within tens of parsecs of Earth could have significant effects on the ozone layer. Since that time improved tools for detailed modeling of atmospheric chemistry have been developed to calculate ozone depletion, and advances have been made also in theoretical modeling of supernovae and of the resultant gamma ray spectra. In addition, one now has better knowledge of the occurrence rate of supernovae in the galaxy, and of the spatial distribution of progenitors to core-collapse supernovae. We report here the results of two-dimensional atmospheric model calculations that take as input the spectral energy distribution of a supernova, adopting various distances from Earth and various latitude impact angles. In separate simulations we calculate the ozone depletion due to both gamma rays and cosmic rays. We find that for the combined ozone depletion from these effects roughly to double the 'biologically active' UV flux received at the surface of the Earth, the supernova must occur at approximately or less than 8 parsecs.

  8. Study of the Ti44(α,p)V47 reaction and implications for core collapse supernovae

    NASA Astrophysics Data System (ADS)

    Margerin, V.; Murphy, A. St. J.; Davinson, T.; Dressler, R.; Fallis, J.; Kankainen, A.; Laird, A. M.; Lotay, G.; Mountford, D. J.; Murphy, C. D.; Seiffert, C.; Schumann, D.; Stowasser, T.; Stora, T.; Wang, C. H.-T.; Woods, P. J.

    2014-04-01

    The underlying physics triggering core collapse supernovae is not fully understood but observations of material ejected during such events helps to solve this puzzle. In particular, several satellite based γ-ray observations of the isotope 44Ti have been reported recently. Conveniently, the amount of this isotope in stellar ejecta is thought to depend critically on the explosion mechanism. The most influential reaction to the amount of 44Ti in supernovae is Ti44(α,p)V47. Here we report on a direct study of this reaction conducted at the REX-ISOLDE facility, CERN. The experiment was performed with a 44Ti beam at E=2.16 MeV/u, corresponding to an energy distribution, for reacting α-particles, centred on E=4.15 with a 1σ width of 0.23 MeV. This is, for the first time, well within the Gamow window for core collapse supernovae. The material from which the 44Ti beam was extracted originates from highly irradiated components of the SINQ spallation neutron source of the Paul Scherrer Institute. No yield above background was observed, enabling an upper limit for the rate of this reaction to be determined. This result is below expectation, suggesting that the Ti44(α,p)V47 reaction proceeds more slowly than previously thought. Implications for astrophysical events, and remnant age, are discussed.

  9. A New Multi-dimensional General Relativistic Neutrino Hydrodynamics Code for Core-collapse Supernovae. IV. The Neutrino Signal

    NASA Astrophysics Data System (ADS)

    Müller, Bernhard; Janka, Hans-Thomas

    2014-06-01

    Considering six general relativistic, two-dimensional (2D) supernova (SN) explosion models of progenitor stars between 8.1 and 27 M ⊙, we systematically analyze the properties of the neutrino emission from core collapse and bounce to the post-explosion phase. The models were computed with the VERTEX-COCONUT code, using three-flavor, energy-dependent neutrino transport in the ray-by-ray-plus approximation. Our results confirm the close similarity of the mean energies, langErang, of \\bar{\

  10. Strangeness driven phase transitions in compressed baryonic matter and their relevance for neutron stars and core collapsing supernovae

    SciTech Connect

    Raduta, Ad. R.; Gulminelli, F.; Oertel, M.

    2015-02-24

    We discuss the thermodynamics of compressed baryonic matter with strangeness within non-relativistic mean-field models with effective interactions. The phase diagram of the full baryonic octet under strangeness equilibrium is built and discussed in connection with its relevance for core-collapse supernovae and neutron stars. A simplified framework corresponding to (n, p, Λ)(+e)-mixtures is employed in order to test the sensitivity of the existence of a phase transition on the (poorely constrained) interaction coupling constants and the compatibility between important hyperonic abundances and 2M{sub ⊙} neutron stars.

  11. DAO spectroscopic classification of MASTER OT J140958.91+174549.4 as a core-collapse supernova.

    NASA Astrophysics Data System (ADS)

    Balam, D. D.; Graham, M. L.

    2016-04-01

    A spectrum was obtained on UT April 30.39 of MASTER OT J140958.91+174549.4 (CSS160427:140959+174549) using the 1.82-m Plaskett telescope (National Research Council of Canada) covering the range 365-710 nm (resolution 0.35 nm). Cross-correlation with a template library using SNID (Blondin & Tonry 2007, ApJ, 666, 1024) shows MASTER OT J140958.91+174549.4 to be a core-collapse supernova near maximum light.

  12. Progenitor mass constraints for core-collapse supernovae from correlations with host galaxy star formation

    NASA Astrophysics Data System (ADS)

    Anderson, J. P.; Habergham, S. M.; James, P. A.; Hamuy, M.

    2012-08-01

    Using Hα emission as a tracer of ongoing (<16 Myr old) and near-ultraviolet (UV) emission as a tracer of recent (16-100 Myr old) star formation, we present constraints on the properties of core-collapse (CC) supernova (SN) progenitors through the association of their explosion sites with star-forming regions. Amalgamating previous results with those gained from new data, we present statistics of a large sample of SNe; 163.5 Type II (58 IIP, 13 IIL, 13.5 IIb, 19 IIn and 12 'impostors', plus 48 with no sub-type classification) and 96.5 Type Ib/c (39.5 Ib and 52 Ic, plus five with no sub-type classification). Using pixel statistics we build distributions of associations of different SN types with host galaxy star formation. Our main findings and conclusions are as follows. An increasing progenitor mass sequence is observed, implied from an increasing association of SNe to host galaxy Hα emission. This commences with the Type Ia showing the weakest association, followed by the Type II, then the Ib, with the Type Ic showing the strongest correlation to star-forming regions. Thus, our progenitor mass sequence runs Ia-II-Ib-Ic. Overall, the Type Ibc SNe are found to occur nearer to bright H II regions than SNe of Type II. This implies that the former have shorter stellar lifetimes, thus arising from more massive progenitor stars. While Type IIP SNe do not closely follow the ongoing star formation, they accurately trace the recent formation. This implies that their progenitors arise from stars at the low end of the CC SN mass sequence, consistent with direct detections of progenitors in pre-explosion imaging. Similarly, the Type IIn SNe trace recent but not the ongoing star formation. This implies that, contrary to the general consensus, the majority of these SN do not arise from the most massive stars. Results and suggestive constraints are also presented for the

  13. Stellar Forensics: A post-explosion view of the progenitors of core-collapse supernovae

    NASA Astrophysics Data System (ADS)

    Maund, Justyn

    2009-07-01

    Recent studies have used high spatial resolution HST observations of SN sites to identify the progenitors of core-collapse SNe on pre-explosion images. These studies have set constraints about the nature of massive stars and their evolution just prior to their explosion as SNe. Now, at late-times when the SNe have faded sufficiently, it is possible to return to the sites of these core-collapse SNe to search for clues about the nature of their progenitors.We request time to conduct deep, late-time, high-resolution imaging with ACS/HRC of the sites of six core-collapse SNe. In this program we aim to: 1} confirm our identifications, that were made with HST pre-explosion images, of the red supergiant progenitors of four Type IIP SNe {1999ev, 2003gd, 2004A and 2005cs}, by observing if the objects identified as the progenitors are now missing; 2} place precise constraints on the progenitor of the Type Ic SN 2007gr by studying its host cluster; and 3} confirm our identification of an LBV-like outburst of an unstable WR star as belonging to the progenitor of a Type Ib-n core-collapse SN {2006jc}, using broad and narrow-band imaging to search for emission line stars in its locality. The deep imaging will also allow to probe the stellar populations in the immediate vicinities of these SNe, that were previously obscured by the progenitors and the bright SNe. HST provides the unique combination of high-resolution optical imaging at very faint magnitudes that will facilitate this study.

  14. An improved multipole approximation for self-gravity and its importance for core-collapse supernova simulations

    SciTech Connect

    Couch, Sean M.; Graziani, Carlo; Flocke, Norbert

    2013-12-01

    Self-gravity computation by multipole expansion is a common approach in problems such as core-collapse and Type Ia supernovae, where single large condensations of mass must be treated. The standard formulation of multipole self-gravity in arbitrary coordinate systems suffers from two significant sources of error, which we correct in the formulation presented in this article. The first source of error is due to the numerical approximation that effectively places grid cell mass at the central point of the cell, then computes the gravitational potential at that point, resulting in a convergence failure of the multipole expansion. We describe a new scheme that avoids this problem by computing gravitational potential at cell faces. The second source of error is due to sub-optimal choice of location for the expansion center, which results in angular power at high multipole l values in the gravitational field, requiring a high—and expensive—value of multipole cutoff l {sub max}. By introducing a global measure of angular power in the gravitational field, we show that the optimal coordinate for the expansion is the square-density-weighted mean location. We subject our new multipole self-gravity algorithm, implemented in the FLASH simulation framework, to two rigorous test problems: MacLaurin spheroids for which exact analytic solutions are known, and core-collapse supernovae. We show that key observables of the core-collapse simulations, particularly shock expansion, proto-neutron star motion, and momentum conservation, are extremely sensitive to the accuracy of the multipole gravity, and the accuracy of their computation is greatly improved by our reformulated solver.

  15. An Improved Multipole Approximation for Self-gravity and Its Importance for Core-collapse Supernova Simulations

    NASA Astrophysics Data System (ADS)

    Couch, Sean M.; Graziani, Carlo; Flocke, Norbert

    2013-12-01

    Self-gravity computation by multipole expansion is a common approach in problems such as core-collapse and Type Ia supernovae, where single large condensations of mass must be treated. The standard formulation of multipole self-gravity in arbitrary coordinate systems suffers from two significant sources of error, which we correct in the formulation presented in this article. The first source of error is due to the numerical approximation that effectively places grid cell mass at the central point of the cell, then computes the gravitational potential at that point, resulting in a convergence failure of the multipole expansion. We describe a new scheme that avoids this problem by computing gravitational potential at cell faces. The second source of error is due to sub-optimal choice of location for the expansion center, which results in angular power at high multipole l values in the gravitational field, requiring a high—and expensive—value of multipole cutoff l max. By introducing a global measure of angular power in the gravitational field, we show that the optimal coordinate for the expansion is the square-density-weighted mean location. We subject our new multipole self-gravity algorithm, implemented in the FLASH simulation framework, to two rigorous test problems: MacLaurin spheroids for which exact analytic solutions are known, and core-collapse supernovae. We show that key observables of the core-collapse simulations, particularly shock expansion, proto-neutron star motion, and momentum conservation, are extremely sensitive to the accuracy of the multipole gravity, and the accuracy of their computation is greatly improved by our reformulated solver.

  16. Methodology of the joint search for Gravitational Wave and Low Energy Neutrino signals from Core-Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Casentini, Claudio

    2016-05-01

    Core-Collapse Supernovae (CCSNe) have a neutrino (v) signature confirmed by SN 1987A and are potential sources of Gravitational Waves (GWs). vs and GWs coming from these sources will reach the observer almost simultaneously and without significant interaction with interstellar matter. The expected GW signals are in the range of the upcoming advanced detectors for galactic neighborhood events. However, there are still significant uncertainties on the theoretical model of the emission. A joint search of coincident vs and GWs from these sources would bring valuable information from the inner core of the collapsing star and would enhance the detection of the so-called Silent Supernovae. Recently, a project for a joint search involving GW interferometers and v detectors has started. In this paper we discuss about the principal GW theoretical models of emission, and we present a methodological study of the joint search project between GW and v.

  17. THE PROGENITOR DEPENDENCE OF THE PRE-EXPLOSION NEUTRINO EMISSION IN CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    O'Connor, Evan; Ott, Christian D. E-mail: cott@tapir.caltech.edu

    2013-01-10

    We perform spherically symmetric general-relativistic simulations of core collapse and the postbounce pre-explosion phase in 32 presupernova stellar models of solar metallicity with zero-age main-sequence masses of 12-120 M {sub Sun }. Using energy-dependent three-species neutrino transport in the two-moment approximation with an analytic closure, we show that the emitted neutrino luminosities and spectra follow very systematic trends that are correlated with the compactness ({approx}M/R) of the progenitor star's inner regions via the accretion rate in the pre-explosion phase. We find that these qualitative trends depend only weakly on the nuclear equation of state (EOS), but quantitative observational statements will require independent constraints on the EOS and the rotation rate of the core as well as a more complete understanding of neutrino oscillations. We investigate the simulated response of water Cherenkov detectors to the electron antineutrino fluxes from our models and find that the large statistics of a galactic core collapse event may allow robust conclusions on the inner structure of the progenitor star.

  18. CALTECH CORE-COLLAPSE PROJECT (CCCP) OBSERVATIONS OF TYPE II SUPERNOVAE: EVIDENCE FOR THREE DISTINCT PHOTOMETRIC SUBTYPES

    SciTech Connect

    Arcavi, Iair; Gal-Yam, Avishay; Yaron, Ofer; Cenko, S. Bradley; Becker, Adam B.; Fox, Derek B.; Leonard, Douglas C.; Moon, Dae-Sik; Sand, David J.; Soderberg, Alicia M.; Kiewe, Michael; Scheps, Raphael; Birenbaum, Gali; Chamudot, Daniel; Zhou, Jonathan

    2012-09-10

    We present R-band light curves of Type II supernovae (SNe) from the Caltech Core-Collapse Project (CCCP). With the exception of interacting (Type IIn) SNe and rare events with long rise times, we find that most light curve shapes belong to one of three apparently distinct classes: plateau, slowly declining, and rapidly declining events. The last class is composed solely of Type IIb SNe which present similar light curve shapes to those of SNe Ib, suggesting, perhaps, similar progenitor channels. We do not find any intermediate light curves, implying that these subclasses are unlikely to reflect variance of continuous parameters, but rather might result from physically distinct progenitor systems, strengthening the suggestion of a binary origin for at least some stripped SNe. We find a large plateau luminosity range for SNe IIP, while the plateau lengths seem rather uniform at approximately 100 days. As analysis of additional CCCP data goes on and larger samples are collected, demographic studies of core-collapse SNe will likely continue to provide new constraints on progenitor scenarios.

  19. CALTECH CORE-COLLAPSE PROJECT (CCCP) OBSERVATIONS OF TYPE IIn SUPERNOVAE: TYPICAL PROPERTIES AND IMPLICATIONS FOR THEIR PROGENITOR STARS

    SciTech Connect

    Kiewe, Michael; Gal-Yam, Avishay; Arcavi, Iair; Leonard, Douglas C.; Emilio Enriquez, J.; Bradley Cenko, S.; Fox, Derek B.; Moon, Dae-Sik; Sand, David J.; Soderberg, Alicia M.

    2012-01-01

    Type IIn supernovae (SNe IIn) are rare events, constituting only a few percent of all core-collapse SNe, and the current sample of well-observed SNe IIn is small. Here, we study the four SNe IIn observed by the Caltech Core-Collapse Project (CCCP). The CCCP SN sample is unbiased to the extent that object selection was not influenced by target SN properties. Therefore, these events are representative of the observed population of SNe IIn. We find that a narrow P-Cygni profile in the hydrogen Balmer lines appears to be a ubiquitous feature of SNe IIn. Our light curves show a relatively long rise time (>20 days) followed by a slow decline stage (0.01-0.15 mag day{sup -1}), and a typical V-band peak magnitude of M{sub V} = -18.4 {+-} 1.0 mag. We measure the progenitor star wind velocities (600-1400 km s{sup -1}) for the SNe in our sample and derive pre-explosion mass-loss rates (0.026-0.12 M{sub Sun} yr{sup -1}). We compile similar data for SNe IIn from the literature and discuss our results in the context of this larger sample. Our results indicate that typical SNe IIn arise from progenitor stars that undergo luminous-blue-variable-like mass loss shortly before they explode.

  20. The Gamma-Ray Bursts and Core-Collapse Supernovae - Global Star Forming Rate Peaks at Large Redshifts

    NASA Astrophysics Data System (ADS)

    Sokolov, V. V.

    2014-03-01

    This is a brief review on the first Gamma-Ray Bursts (GRB) optical identifications - GRB host galaxies and Star Forming Rate (SFR) at relatively small redshifts (z), on the metallicities of GRB hosts and the similarities and differences between GRB hosts and galaxies at larger z, and on the SFR and GRB rate (GRBR) at the high z. Evidences of a direct connection between long-duration GRBs and massive stars explosions (like Core-Collapse Super-Novae - CCSNe) are presented. Is there a fast decrease in SFR up to z ~10? Some unsolved problems related to GRBs are discussed: about the high-z GRB host galaxies, the high-z CCSN-GRB connection, and possible new crucial cosmological tests at high z.

  1. BROADBAND EXTENDED EMISSION IN GRAVITATIONAL WAVES FROM CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Levinson, Amir; Pick, Guy; Van Putten, Maurice H. P. M.

    2015-10-20

    Immediately following their formation, black holes in the core-collapse stage of massive stars are expected to surge in mass and angular momentum by hyper-accretion. Here  we describe a general framework of extended emission in gravitational waves from non-axisymmetric accretion flows from the fallback matter of the progenitor envelope. This framework shows (a) a maximum efficiency in the conversion of accretion energy into gravitational waves at hyper-accretion rates exceeding a critical value set by the ratio of the quadrupole mass inhomogeneity and viscosity, with (b) a peak characteristic strain amplitude at the frequency f{sub b} = Ω{sub b}/π, where Ω{sub b} is the Keplerian angular velocity at which viscous torques equal angular momentum loss in gravitational radiation, with h{sub char} ∝ f{sup 1/6} at f < f{sub b} and h{sub char} ∝ f{sup −1/6} at f > f{sub b}. Upcoming gravitational wave observations may probe this scaling by extracting broadband spectra using time-sliced matched filtering with chirp templates, which were recently developed for identifying turbulence in noisy time series.

  2. Broadband Extended Emission in Gravitational Waves from Core-collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Levinson, Amir; van Putten, Maurice H. P. M.; Pick, Guy

    2015-10-01

    Immediately following their formation, black holes in the core-collapse stage of massive stars are expected to surge in mass and angular momentum by hyper-accretion. Here we describe a general framework of extended emission in gravitational waves from non-axisymmetric accretion flows from the fallback matter of the progenitor envelope. This framework shows (a) a maximum efficiency in the conversion of accretion energy into gravitational waves at hyper-accretion rates exceeding a critical value set by the ratio of the quadrupole mass inhomogeneity and viscosity, with (b) a peak characteristic strain amplitude at the frequency fb = Ωb/π, where Ωb is the Keplerian angular velocity at which viscous torques equal angular momentum loss in gravitational radiation, with hchar ∝ f1/6 at f < fb and hchar ∝ f-1/6 at f > fb. Upcoming gravitational wave observations may probe this scaling by extracting broadband spectra using time-sliced matched filtering with chirp templates, which were recently developed for identifying turbulence in noisy time series.

  3. Neutrino emission from nearby supernova progenitors

    NASA Astrophysics Data System (ADS)

    Yoshida, Takashi; Takahashi, Koh; Umeda, Hideyuki

    2016-05-01

    Neutrinos have an important role for energy loss process during advanced evolution of massive stars. Although the luminosity and average energy of neutrinos during the Si burning are much smaller than those of supernova neutrinos, these neutrinos are expected to be detected by the liquid scintillation neutrino detector KamLAND if a supernova explosion occurs at the distance of ~100 parsec. We investigate the neutrino emission from massive stars during advanced evolution. We calculate the evolution of the energy spectra of neutrinos produced through electron-positron pair-annihilation in the supernova progenitors with the initial mass of 12, 15, and 20 M ⊙ during the Si burning and core-collapse stages. The neutrino emission rate increases from ~ 1050 s-1 to ~ 1052 s-1. The average energy of electron-antineutrinos is about 1.25 MeV during the Si burning and gradually increases until the core-collapse. For one week before the supernova explosion, the KamLAND detector is expected to observe 12-24 and 6-13 v¯e events in the normal and inverted mass hierarchies, respectively, if a supernova explosion of a 12-20 M ⊙ star occurs at the distance of 200 parsec, corresponding to the distance to Betelgeuse. Observations of neutrinos from SN progenitors have a possibility to constrain the core structure and the evolution just before the core collapse of massive stars.

  4. Searching for soft relativistic jets in core-collapse supernovae with the IceCube optical follow-up program

    NASA Astrophysics Data System (ADS)

    Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Allen, M. M.; Altmann, D.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Benabderrahmane, M. L.; Benzvi, S.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohm, C.; Bose, D.; Böser, S.; Botner, O.; Brown, A. M.; Buitink, S.; Caballero-Mora, K. S.; Carson, M.; Chirkin, D.; Christy, B.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D. F.; Cruz Silva, A. H.; D'Agostino, M. V.; Danninger, M.; Daughhetee, J.; Davis, J. C.; de Clercq, C.; Degner, T.; Demirörs, L.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; Deyoung, T.; Díaz-Vélez, J. C.; Dierckxsens, M.; Dreyer, J.; Dumm, J. P.; Dunkman, M.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Fedynitch, A.; Feintzeig, J.; Feusels, T.; Filimonov, K.; Finley, C.; Fischer-Wasels, T.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Goodman, J. A.; Góra, D.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gurtner, M.; Ha, C.; Haj Ismail, A.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Heinen, D.; Helbing, K.; Hellauer, R.; Herquet, P.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Hoffmann, B.; Homeier, A.; Hoshina, K.; Huelsnitz, W.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Ishihara, A.; Jacobi, E.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kenny, P.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Kroll, G.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Laihem, K.; Landsman, H.; Larson, M. J.; Lauer, R.; Lünemann, J.; Madsen, J.; Marotta, A.; Maruyama, R.; Mase, K.; Matis, H. S.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Miarecki, S.; Middell, E.; Milke, N.; Miller, J.; Montaruli, T.; Morse, R.; Movit, S. M.; Nahnhauer, R.; Nam, J. W.; Naumann, U.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; O'Murchadha, A.; Panknin, S.; Paul, L.; Pérez de Los Heros, C.; Petrovic, J.; Piegsa, A.; Pieloth, D.; Porrata, R.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Richman, M.; Rodrigues, J. P.; Rothmaier, F.; Rott, C.; Ruhe, T.; Rutledge, D.; Ruzybayev, B.; Ryckbosch, D.; Sander, H.-G.; Santander, M.; Sarkar, S.; Schatto, K.; Schmidt, T.; Schönwald, A.; Schukraft, A.; Schultes, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stezelberger, T.; Stokstad, R. G.; Stössl, A.; Strahler, E. A.; Ström, R.; Stüer, M.; Sullivan, G. W.; Swillens, Q.; Taavola, H.; Taboada, I.; Tamburro, A.; Ter-Antonyan, S.; Tilav, S.; Toale, P. A.; Toscano, S.; Tosi, D.; van Eijndhoven, N.; Vandenbroucke, J.; van Overloop, A.; van Santen, J.; Vehring, M.; Voge, M.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Weaver, Ch.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, C.; Xu, D. L.; Xu, X. W.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; Zoll, M.; IceCube Collaboration; Akerlof, C. W.; Pandey, S. B.; Yuan, F.; Zheng, W.; ROTSE Collaboration

    2012-03-01

    Context. Transient neutrino sources such as gamma-ray bursts (GRBs) and supernovae (SNe) are hypothesized to emit bursts of high-energy neutrinos on a time-scale of ≲100 s. While GRB neutrinos would be produced in high relativistic jets, core-collapse SNe might host soft-relativistic jets, which become stalled in the outer layers of the progenitor star leading to an efficient production of high-energy neutrinos. Aims: To increase the sensitivity to these neutrinos and identify their sources, a low-threshold optical follow-up program for neutrino multiplets detected with the IceCube observatory has been implemented. Methods: If a neutrino multiplet, i.e. two or more neutrinos from the same direction within 100 s, is found by IceCube a trigger is sent to the Robotic Optical Transient Search Experiment, ROTSE. The 4 ROTSE telescopes immediately start an observation program of the corresponding region of the sky in order to detect an optical counterpart to the neutrino events. Results: No statistically significant excess in the rate of neutrino multiplets has been observed and furthermore no coincidence with an optical counterpart was found. Conclusions: The search allows, for the first time, to set stringent limits on current models predicting a high-energy neutrino flux from soft relativistic hadronic jets in core-collapse SNe. We conclude that a sub-population of SNe with typical Lorentz boost factor and jet energy of 10 and 3 × 1051 erg, respectively, does not exceed 4.2% at 90% confidence.

  5. Searching for Soft Relativistic Jets in Core-Collapse Supernovae with the IceCube Optical Follow-up Program

    NASA Technical Reports Server (NTRS)

    Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Allen, M. M.; Altmann, D.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K. -H.; Benabderrahmane, M. L.; BenZvi, S.; Berdermann, J.; Stamatikos, M.

    2011-01-01

    Context. Transient neutrino sources such as Gamma-Ray Bursts (GRBs) and Supernovae (SNe) are hypothesized to emit bursts of high-energy neutrinos on a time-scale of < or approx.100 s. While GRB neutrinos would be produced in high relativistic jets, core-collapse SNe might host soft-relativistic jets, which become stalled in the outer layers of the progenitor star leading to an efficient production of high-energy neutrinos. Aims. To increase the sensitivity to these neutrinos and identify their sources, a low-threshold optical follow-up program for neutrino multiplets detected with the IceCube observatory has been implemented. Methods. If a neutrino multiplet, i.e. two or more neutrinos from the same direction within 100 s, is found by IceCube a trigger is sent to the Robotic Optical Transient Search Experiment, ROTSE. The 4 ROTSE telescopes immediately start an observation program of the corresponding region of the sky in order to detect an optical counterpart to the neutrino events. Results. No statistically significant excess in the rate of neutrino multiplets has been observed and furthermore no coincidence with an optical counterpart was found. Conclusions. The search allows, for the first time, to set stringent limits on current models predicting a high-energy neutrino flux from soft relativistic hadronic jets in core-collapse SNe. We conclude that a sub-population of SNe with typical Lorentz boost factor and jet energy of 10 and 3 x 10(exp 51) erg, respectively, does not exceed 4:2% at 90% confidence.

  6. RAY-TRACING ANALYSIS OF ANISOTROPIC NEUTRINO RADIATION FOR ESTIMATING GRAVITATIONAL WAVES IN CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Kotake, Kei; Yamada, Shoichi

    2009-10-20

    We propose a ray-tracing method to estimate gravitational waves (GWs) generated by anisotropic neutrino emission in supernova cores. To calculate the gravitational waveforms, we derive analytic formulae in a useful form, which are applicable also for three-dimensional computations. Pushed by evidence of slow rotation prior to core-collapse, we focus on asphericities in neutrino emission and matter motions outside the protoneutron star. Based on the two-dimensional models, which mimic standing accretion shock instability (SASI)-aided neutrino heating explosions, we compute the neutrino anisotropies via the ray-tracing method in a post-processing manner and calculate the resulting waveforms. For simplicity, neutrino absorption and emission by free nucleons, dominant processes outside the protoneutron stars, are only taken into account, while the neutrino scattering and the velocity-dependent terms in the transport equations are neglected. With these computations, it is found that the waveforms exhibit more variety in contrast to the ones previously estimated by the ray-by-ray analysis. In addition to a positively growing feature, which was predicted to determine the total wave amplitudes predominantly, the waveforms are shown to exhibit large negative growth for some epochs during the growth of SASI. These features are found to stem from the excess of neutrino emission in lateral directions, which can be precisely captured by the ray-tracing calculation. Reflecting the nature of SASI which grows chaotically with time, there is little systematic dependence of the input neutrino luminosities on the maximum wave amplitudes. Due to the negative contributions and the neutrino absorptions appropriately taken into account by the ray-tracing method, the wave amplitudes become more than one order of magnitude smaller than the previous estimation, thus making their detections very hard for a Galactic source. On the other hand, it is pointed out that the GW spectrum from matter

  7. Full Bayesian hierarchical light curve modeling of core-collapse supernova populations

    NASA Astrophysics Data System (ADS)

    Sanders, Nathan; Betancourt, Michael; Soderberg, Alicia Margarita

    2016-06-01

    While wide field surveys have yielded remarkable quantities of photometry of transient objects, including supernovae, light curves reconstructed from this data suffer from several characteristic problems. Because most transients are discovered near the detection limit, signal to noise is generally poor; because coverage is limited to the observing season, light curves are often incomplete; and because temporal sampling can be uneven across filters, these problems can be exacerbated at any one wavelength. While the prevailing approach of modeling individual light curves independently is successful at recovering inferences for the objects with the highest quality observations, it typically neglects a substantial portion of the data and can introduce systematic biases. Joint modeling of the light curves of transient populations enables direct inference on population-level characteristics as well as superior measurements for individual objects. We present a new hierarchical Bayesian model for supernova light curves, where information inferred from observations of every individual light curve in a sample is partially pooled across objects to constrain population-level hyperparameters. Using an efficient Hamiltonian Monte Carlo sampling technique, the model posterior can be explored to enable marginalization over weakly-identified hyperparameters through full Bayesian inference. We demonstrate our technique on the Pan-STARRS1 (PS1) Type IIP supernova light curve sample published by Sanders et al. (2015), consisting of nearly 20,000 individual photometric observations of more than 70 supernovae in five photometric filters. We discuss the Stan probabilistic programming language used to implement the model, computational challenges, and prospects for future work including generalization to multiple supernova types. We also discuss scientific results from the PS1 dataset including a new relation between the peak magnitude and decline rate of SNe IIP, a new perspective on the

  8. X-RAY EJECTA KINEMATICS OF THE GALACTIC CORE-COLLAPSE SUPERNOVA REMNANT G292.0+1.8

    SciTech Connect

    Bhalerao, Jayant; Park, Sangwook; Dewey, Daniel; Hughes, John P.; Mori, Koji; Lee, Jae-Joon

    2015-02-10

    We report on the results from the analysis of our 114 ks Chandra High Energy Transmision Grating Spectrometer observation of the Galactic core-collapse supernova remnant G292.0+1.8. To probe the three-dimensional structure of the clumpy X-ray emitting ejecta material in this remnant, we measured Doppler shifts in emission lines from metal-rich ejecta knots projected at different radial distances from the expansion center. We estimate radial velocities of ejecta knots in the range of –2300 ≲ v{sub r}  ≲ 1400 km s{sup –1}. The distribution of ejecta knots in velocity versus projected-radius space suggests an expanding ejecta shell with a projected angular thickness of ∼90'' (corresponding to ∼3 pc at d = 6 kpc). Based on this geometrical distribution of the ejecta knots, we estimate the location of the reverse shock approximately at the distance of ∼4 pc from the center of the supernova remnant, putting it in close proximity to the outer boundary of the radio pulsar wind nebula. Based on our observed remnant dynamics and the standard explosion energy of 10{sup 51} erg, we estimate the total ejecta mass to be ≲8 M {sub ☉}, and we propose an upper limit of ≲35 M {sub ☉} on the progenitor's mass.

  9. Gravitational wave signatures of ab initio two-dimensional core collapse supernova explosion models for 12 -25 M⊙ stars

    NASA Astrophysics Data System (ADS)

    Yakunin, Konstantin N.; Mezzacappa, Anthony; Marronetti, Pedro; Yoshida, Shin'ichirou; Bruenn, Stephen W.; Hix, W. Raphael; Lentz, Eric J.; Bronson Messer, O. E.; Harris, J. Austin; Endeve, Eirik; Blondin, John M.; Lingerfelt, Eric J.

    2015-10-01

    We present the gravitational waveforms computed in ab initio two-dimensional core collapse supernova models evolved with the chimera code for progenitor masses between 12 and 25 M⊙ . All models employ multifrequency neutrino transport in the ray-by-ray approximation, state-of-the-art weak interaction physics, relativistic transport corrections such as the gravitational redshift of neutrinos, two-dimensional hydrodynamics with the commensurate relativistic corrections, Newtonian self-gravity with a general-relativistic monopole correction, and the Lattimer-Swesty equation of state with 220 MeV compressibility, and begin with the most recent Woosley-Heger nonrotating progenitors in this mass range. All of our models exhibit robust explosions. Therefore, our waveforms capture all stages of supernova development: 1) a relatively short and weak prompt signal, 2) a quiescent stage, 3) a strong signal due to convection and standing accretion shock instability activity, 4) termination of active accretion onto the proto-neutron star, and 5) a slowly increasing tail that reaches a saturation value. Fourier decomposition shows that the gravitational wave signals we predict should be observable by AdvLIGO for Galactic events across the range of progenitors considered here. The fundamental limitation of these models is in their imposition of axisymmetry. Further progress will require counterpart three-dimensional models, which are underway.

  10. EFFECTS OF ROTATION ON STOCHASTICITY OF GRAVITATIONAL WAVES IN THE NONLINEAR PHASE OF CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Kotake, Kei; Iwakami-Nakano, Wakana; Ohnishi, Naofumi

    2011-08-01

    By performing three-dimensional (3D) simulations that demonstrate the neutrino-driven core-collapse supernovae aided by the standing accretion shock instability (SASI), we study how the spiral modes of the SASI can impact the properties of the gravitational-wave (GW) emission. To see the effects of rotation in the nonlinear postbounce phase, we give a uniform rotation on the flow advecting from the outer boundary of the iron core, the specific angular momentum of which is assumed to agree with recent stellar evolution models. We compute fifteen 3D models in which the initial angular momentum and the input neutrino luminosities from the protoneutron star are changed in a systematic manner. By performing a ray-tracing analysis, we accurately estimate the GW amplitudes generated by anisotropic neutrino emission. Our results show that the gravitational waveforms from neutrinos in models that include rotation exhibit a common feature; otherwise, they vary much more stochastically in the absence of rotation. The breaking of the stochasticity stems from the excess of the neutrino emission parallel to the spin axis. This is because the compression of matter is more enhanced in the vicinity of the equatorial plane due to the growth of the spiral SASI modes, leading to the formation of the spiral flows circulating around the spin axis with higher temperatures. We point out that recently proposed future space interferometers like Fabry-Perot-type DECIGO would permit the detection of these signals for a Galactic supernova.

  11. The diversity of transients from magnetar birth in core collapse supernovae

    NASA Astrophysics Data System (ADS)

    Metzger, Brian D.; Margalit, Ben; Kasen, Daniel; Quataert, Eliot

    2015-12-01

    Strongly magnetized, rapidly rotating neutron stars are contenders for the central engines of both long gamma-ray bursts (LGRBs) and hydrogen-poor superluminous supernovae (SLSNe-I). Models for typical (minute long) LGRBs invoke magnetars with high dipole magnetic fields (Bd ≳ 1015 G) and short spin-down times, SLSNe-I require neutron stars with weaker fields and longer spin-down times of weeks. Here, we identify a transition region in the space of Bd and birth period for which a magnetar can power both a LGRB and a luminous supernova. In particular, a 2 ms period magnetar with a spin-down time of ˜104 s can explain both the ultralong GRB 111209 and its associated luminous SN2011kl. For magnetars with longer spin-down times, we predict even longer duration (˜105 - 6 s) GRBs and brighter supernovae, a correlation that extends to Swift J2058+05 (commonly interpreted as a tidal disruption event). We further show that previous estimates of the maximum rotational energy of a protomagnetar were too conservative and energies up to Emax ˜ 1-2 × 1053 ergs are possible. A magnetar can therefore comfortably accommodate the extreme energy requirements recently posed by the most luminous supernova ASASSN-15lh. The luminous pulsar wind nebula powering ASASSN-15lh may lead to an `ionization breakout' X-ray burst over the coming months, accompanied by a change in the optical spectrum.

  12. Multi-Dimensional Simulations of Radiative Transfer in Aspherical Core-Collapse Supernovae

    SciTech Connect

    Tanaka, Masaomi; Maeda, Keiichi; Mazzali, Paolo A.; Nomoto, Ken'ichi

    2008-05-21

    We study optical radiation of aspherical supernovae (SNe) and present an approach to verify the asphericity of SNe with optical observations of extragalactic SNe. For this purpose, we have developed a multi-dimensional Monte-Carlo radiative transfer code, SAMURAI (SupernovA Multidimensional RAdIative transfer code). The code can compute the optical light curve and spectra both at early phases (< or approx. 40 days after the explosion) and late phases ({approx}1 year after the explosion), based on hydrodynamic and nucleosynthetic models. We show that all the optical observations of SN 1998bw (associated with GRB 980425) are consistent with polar-viewed radiation of the aspherical explosion model with kinetic energy 20x10{sup 51} ergs. Properties of off-axis hypernovae are also discussed briefly.

  13. A Newton-Krylov Solver for Implicit Solution of Hydrodynamics in Core Collapse Supernovae

    SciTech Connect

    Reynolds, D R; Swesty, F D; Woodward, C S

    2008-06-12

    This paper describes an implicit approach and nonlinear solver for solution of radiation-hydrodynamic problems in the context of supernovae and proto-neutron star cooling. The robust approach applies Newton-Krylov methods and overcomes the difficulties of discontinuous limiters in the discretized equations and scaling of the equations over wide ranges of physical behavior. We discuss these difficulties, our approach for overcoming them, and numerical results demonstrating accuracy and efficiency of the method.

  14. A large-scale dynamo and magnetoturbulence in rapidly rotating core-collapse supernovae.

    PubMed

    Mösta, Philipp; Ott, Christian D; Radice, David; Roberts, Luke F; Schnetter, Erik; Haas, Roland

    2015-12-17

    Magnetohydrodynamic turbulence is important in many high-energy astrophysical systems, where instabilities can amplify the local magnetic field over very short timescales. Specifically, the magnetorotational instability and dynamo action have been suggested as a mechanism for the growth of magnetar-strength magnetic fields (of 10(15) gauss and above) and for powering the explosion of a rotating massive star. Such stars are candidate progenitors of type Ic-bl hypernovae, which make up all supernovae that are connected to long γ-ray bursts. The magnetorotational instability has been studied with local high-resolution shearing-box simulations in three dimensions, and with global two-dimensional simulations, but it is not known whether turbulence driven by this instability can result in the creation of a large-scale, ordered and dynamically relevant field. Here we report results from global, three-dimensional, general-relativistic magnetohydrodynamic turbulence simulations. We show that hydromagnetic turbulence in rapidly rotating protoneutron stars produces an inverse cascade of energy. We find a large-scale, ordered toroidal field that is consistent with the formation of bipolar magnetorotationally driven outflows. Our results demonstrate that rapidly rotating massive stars are plausible progenitors for both type Ic-bl supernovae and long γ-ray bursts, and provide a viable mechanism for the formation of magnetars. Moreover, our findings suggest that rapidly rotating massive stars might lie behind potentially magnetar-powered superluminous supernovae. PMID:26618868

  15. A large-scale dynamo and magnetoturbulence in rapidly rotating core-collapse supernovae.

    PubMed

    Mösta, Philipp; Ott, Christian D; Radice, David; Roberts, Luke F; Schnetter, Erik; Haas, Roland

    2015-12-17

    Magnetohydrodynamic turbulence is important in many high-energy astrophysical systems, where instabilities can amplify the local magnetic field over very short timescales. Specifically, the magnetorotational instability and dynamo action have been suggested as a mechanism for the growth of magnetar-strength magnetic fields (of 10(15) gauss and above) and for powering the explosion of a rotating massive star. Such stars are candidate progenitors of type Ic-bl hypernovae, which make up all supernovae that are connected to long γ-ray bursts. The magnetorotational instability has been studied with local high-resolution shearing-box simulations in three dimensions, and with global two-dimensional simulations, but it is not known whether turbulence driven by this instability can result in the creation of a large-scale, ordered and dynamically relevant field. Here we report results from global, three-dimensional, general-relativistic magnetohydrodynamic turbulence simulations. We show that hydromagnetic turbulence in rapidly rotating protoneutron stars produces an inverse cascade of energy. We find a large-scale, ordered toroidal field that is consistent with the formation of bipolar magnetorotationally driven outflows. Our results demonstrate that rapidly rotating massive stars are plausible progenitors for both type Ic-bl supernovae and long γ-ray bursts, and provide a viable mechanism for the formation of magnetars. Moreover, our findings suggest that rapidly rotating massive stars might lie behind potentially magnetar-powered superluminous supernovae.

  16. A large-scale dynamo and magnetoturbulence in rapidly rotating core-collapse supernovae

    NASA Astrophysics Data System (ADS)

    Mösta, Philipp; Ott, Christian D.; Radice, David; Roberts, Luke F.; Schnetter, Erik; Haas, Roland

    2015-12-01

    Magnetohydrodynamic turbulence is important in many high-energy astrophysical systems, where instabilities can amplify the local magnetic field over very short timescales. Specifically, the magnetorotational instability and dynamo action have been suggested as a mechanism for the growth of magnetar-strength magnetic fields (of 1015 gauss and above) and for powering the explosion of a rotating massive star. Such stars are candidate progenitors of type Ic-bl hypernovae, which make up all supernovae that are connected to long γ-ray bursts. The magnetorotational instability has been studied with local high-resolution shearing-box simulations in three dimensions, and with global two-dimensional simulations, but it is not known whether turbulence driven by this instability can result in the creation of a large-scale, ordered and dynamically relevant field. Here we report results from global, three-dimensional, general-relativistic magnetohydrodynamic turbulence simulations. We show that hydromagnetic turbulence in rapidly rotating protoneutron stars produces an inverse cascade of energy. We find a large-scale, ordered toroidal field that is consistent with the formation of bipolar magnetorotationally driven outflows. Our results demonstrate that rapidly rotating massive stars are plausible progenitors for both type Ic-bl supernovae and long γ-ray bursts, and provide a viable mechanism for the formation of magnetars. Moreover, our findings suggest that rapidly rotating massive stars might lie behind potentially magnetar-powered superluminous supernovae.

  17. MULTI-DIMENSIONAL FEATURES OF NEUTRINO TRANSFER IN CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Sumiyoshi, K.; Takiwaki, T.; Matsufuru, H.; Yamada, S. E-mail: takiwaki.tomoya@nao.ac.jp E-mail: shoichi@heap.phys.waseda.ac.jp

    2015-01-01

    We study the multi-dimensional properties of neutrino transfer inside supernova cores by solving the Boltzmann equations for neutrino distribution functions in genuinely six-dimensional phase space. Adopting representative snapshots of the post-bounce core from other supernova simulations in three dimensions, we solve the temporal evolution to stationary states of neutrino distribution functions using our Boltzmann solver. Taking advantage of the multi-angle and multi-energy feature realized by the S {sub n} method in our code, we reveal the genuine characteristics of spatially three-dimensional neutrino transfer, such as nonradial fluxes and nondiagonal Eddington tensors. In addition, we assess the ray-by-ray approximation, turning off the lateral-transport terms in our code. We demonstrate that the ray-by-ray approximation tends to propagate fluctuations in thermodynamical states around the neutrino sphere along each radial ray and overestimate the variations between the neutrino distributions on different radial rays. We find that the difference in the densities and fluxes of neutrinos between the ray-by-ray approximation and the full Boltzmann transport becomes ∼20%, which is also the case for the local heating rate, whereas the volume-integrated heating rate in the Boltzmann transport is found to be only slightly larger (∼2%) than the counterpart in the ray-by-ray approximation due to cancellation among different rays. These results suggest that we should carefully assess the possible influences of various approximations in the neutrino transfer employed in current simulations of supernova dynamics. Detailed information on the angle and energy moments of neutrino distribution functions will be profitable for the future development of numerical methods in neutrino-radiation hydrodynamics.

  18. Nucleosynthesis in the Hot Convective Bubble in Core-Collapse Supernovae

    SciTech Connect

    Pruet, J; Woosley, S E; Buras, R; Janka, H; Hoffman, R D

    2004-09-02

    As an explosion develops in the collapsed core of a massive star, neutrino emission drives convection in a hot bubble of radiation, nucleons, and pairs just outside a proto-neutron star. Shortly thereafter, neutrinos drive a wind-like outflow from the neutron star. In both the convective bubble and the early wind, weak interactions temporarily cause a proton excess (Y{sub e} {approx}> 0.50) to develop in the ejected matter. This situation lasts for at least the first second, and the approximately 0.05-0.1 M{sub {circle_dot}} that is ejected has an unusual composition that may be important for nucleosynthesis. Using tracer particles to follow the conditions in a two-dimensional model of a successful supernova explosion calculated by Janka, Buras, and Rampp (2003), they determine the composition of this material. most of it is helium and {sup 56}Ni. The rest is relatively rare species produced by the decay of proton-rich isotopes unstable to positron emission. In the absence of pronounced charged-current neutrino capture, nuclear flow will be held up by long-lived waiting point nuclei in the vicinity of {sup 64}Ge. The resulting abundance pattern can be modestly rich in a few interesting rare isotopes like {sup 45}Sc, {sup 49}Ti, and {sup 64}Zn. The present calculations imply yields that, when compared with the production of major species in the rest of the supernova, are about those needed to account for the solar abundance of {sup 45}Sc and {sup 49}Ti. Since the synthesis will be nearly the same in stars of high and low metallicity, the primary production of these species may have discernible signatures in the abundances of low metallicity stars. They also discuss uncertainties in the nuclear physics and early supernova evolution to which abundances of interesting nuclei are sensitive.

  19. Neutrino Signal of Electron-Capture Supernovae from Core Collapse to Cooling

    SciTech Connect

    Huedepohl, L.; Mueller, B.; Janka, H.-T.; Marek, A.; Raffelt, G. G.

    2010-06-25

    An 8.8M{sub {center_dot}}electron-capture supernova was simulated in spherical symmetry consistently from collapse through explosion to essentially complete deleptonization of the forming neutron star. The evolution time ({approx}9 s) is short because high-density effects suppress our neutrino opacities. After a short phase of accretion-enhanced luminosities ({approx}200 ms), luminosity equipartition among all species becomes almost perfect and the spectra of {nu}{sub e} and {nu}{sub {mu},{tau}}very similar, ruling out the neutrino-driven wind as r-process site. We also discuss consequences for neutrino flavor oscillations.

  20. Neutrino signal of electron-capture supernovae from core collapse to cooling.

    PubMed

    Hüdepohl, L; Müller, B; Janka, H-T; Marek, A; Raffelt, G G

    2010-06-25

    An 8.8M{⊙} electron-capture supernova was simulated in spherical symmetry consistently from collapse through explosion to essentially complete deleptonization of the forming neutron star. The evolution time (∼9  s) is short because high-density effects suppress our neutrino opacities. After a short phase of accretion-enhanced luminosities (∼200  ms), luminosity equipartition among all species becomes almost perfect and the spectra of ν{e} and ν{μ,τ} very similar, ruling out the neutrino-driven wind as r-process site. We also discuss consequences for neutrino flavor oscillations.

  1. INDUCED ROTATION IN THREE-DIMENSIONAL SIMULATIONS OF CORE-COLLAPSE SUPERNOVAE: IMPLICATIONS FOR PULSAR SPINS

    SciTech Connect

    Rantsiou, Emmanouela; Burrows, Adam; Nordhaus, Jason; Almgren, Ann E-mail: burrows@astro.princeton.edu E-mail: asalmgren@lbl.gov

    2011-05-01

    It has been suggested that the observed rotation periods of radio pulsars might be induced by a non-axisymmetric spiral-mode instability in the turbulent region behind the stalled supernova bounce shock, even if the progenitor core was not initially rotating. In this paper, using the three-dimensional Adaptive Mesh Refinement code CASTRO with a realistic progenitor and equation of state and a simple neutrino heating and cooling scheme, we present a numerical study of the evolution in three dimensions of the rotational profile of a supernova core from collapse, through bounce and shock stagnation, to delayed explosion. By the end of our simulation ({approx}420 ms after core bounce), we do not witness significant spin-up of the proto-neutron star core left behind. However, we do see the development before the explosion of strong differential rotation in the turbulent gain region between the core and stalled shock. Shells in this region acquire high spin rates that reach {approx}150 Hz, but this region contains too little mass and angular momentum to translate, even if left behind, into rapid rotation for the full neutron star. We also find that much of the induced angular momentum is likely to be ejected in the explosion, and moreover that even if the optimal amount of induced angular momentum is retained in the core, the resulting spin period is likely to be quite modest. Nevertheless, induced periods of seconds are possible.

  2. THE GALACTIC SUPERNOVA REMNANT W49B LIKELY ORIGINATES FROM A JET-DRIVEN, CORE-COLLAPSE EXPLOSION

    SciTech Connect

    Lopez, Laura A.; Castro, Daniel; Ramirez-Ruiz, Enrico; Pearson, Sarah

    2013-02-10

    We present results from a 220 ks observation of the Galactic supernova remnant (SNR) W49B using the Advanced CCD Imaging Spectrometer on board the Chanrda X-ray Observatory. We exploit these data to perform detailed spatially resolved spectroscopic analyses across the SNR with the aim to investigate the thermodynamic properties and explosive origin of W49B. We find substantial variation in the electron temperature and absorbing column toward W49B, and we show that the mean metal abundances are consistent with the predicted yields in models of bipolar/jet-driven core-collapse SNe. Furthermore, we set strict upper limits on the X-ray luminosity of any undetected point sources, and we exclude the presence of a neutron star associated with W49B. We conclude that the morphological, spectral, and environmental characteristics of W49B are indicative of a bipolar Type Ib/Ic SN origin, making it the first of its kind to be discovered in the Milky Way.

  3. General-Relativistic Three-Dimensional Multi-group Neutrino Radiation-Hydrodynamics Simulations of Core-Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Roberts, Luke F.; Ott, Christian D.; Haas, Roland; O’Connor, Evan P.; Diener, Peter; Schnetter, Erik

    2016-11-01

    We report on a set of long-term general-relativistic three-dimensional (3D) multi-group (energy-dependent) neutrino radiation-hydrodynamics simulations of core-collapse supernovae. We employ a full 3D two-moment scheme with the local M1 closure, three neutrino species, and 12 energy groups per species. With this, we follow the post-core-bounce evolution of the core of a nonrotating 27 - {M}ȯ progenitor in full unconstrained 3D and in octant symmetry for ≳380 ms. We find the development of an asymmetric runaway explosion in our unconstrained simulation. We test the resolution dependence of our results and, in agreement with previous work, find that low resolution artificially aids explosion and leads to an earlier runaway expansion of the shock. At low resolution, the octant and full 3D dynamics are qualitatively very similar, but at high resolution, only the full 3D simulation exhibits the onset of explosion.

  4. Systematic Studies of Shock Revival and the Subsequent Evolutions in Core-collapse Supernovae with Parametric Progenitor Models

    NASA Astrophysics Data System (ADS)

    Yamamoto, Yu; Yamada, Shoichi

    2016-02-01

    We conducted one-dimensional and two-dimensional hydrodynamic simulations of post-shock revival evolutions in core-collapse supernovae, employing the simple neutrino light bulb approximation to produce explosions rather easily. In order to estimate the explosion energy, we took into proper account nuclear recombinations and fusions consistently with the equation of state for matter not in statistical equilibrium in general. The methodology is similar to our previous work, but is somehow improved. In this paper, we studied the influence of the progenitor structure on the dynamics systematically. In order to expedite our understanding of the systematics, we constructed six parametric progenitor models, which are different in masses of Fe iron core and Si+S layer, instead of employing realistic models provided by stellar evolution calculations, which are sometimes of stochastic nature as a function of stellar mass on the main sequence. We found that the explosion energy is tightly correlated with the mass accretion rate at shock revival irrespective of dimension and the progenitors with light iron cores but with rather high entropies, which have yet to be produced by realistic stellar evolution calculations, may reproduce the canonical values of explosion energy and nickel mass. The mass of the Si+S layer is also important in the mass accretion history after bounce, on the other hand; the higher mass accretion rates and resultant heavier cores tend to hamper strong explosions.

  5. A new equation of state with light nuclei and their weak interactions in core-collapse supernova simulations

    SciTech Connect

    Furusawa, Shun; Yamada, Shoichi; Nagakura, Hiroki; Sumiyoshi, Kohsuke; Suzuki, Hideyuki

    2014-05-02

    We perform numerical experiments to investigate the influence of inelastic neutrino reactions with light nuclei on the standing accretion shock instability. The time evolutions of shock waves are calculated with a simple light-bulb approximation for the neutrino transport and a multi-nuclei equation of state. The neutrino absorptions and inelastic interactions with deuterons, tritons, helions and alpha particles are taken into account in the hydrodynamical simulations in addition to the ordinary charged-current interactions with nucleons. Axial symmetry is assumed but no equatorial symmetry is imposed. We show that the heating rates of deuterons reach as high as ∼ 10% of those of nucleons around the bottom of the gain region. On the other hands, alpha particles heat the matter near the shock wave, which is important when the shock wave expands and density and temperature of matter become low. It is also found that the models with heating by light nuclei have different evolutions from those without it in non-linear evolution phase. The matter in the gain region has various densities and temperatures and there appear regions that are locally rich in deuterons and alpha particles. These results indicate that the inelastic reactions of light nuclei, especially deuterons, should be incorporated in the simulations of core-collapse supernovae.

  6. Three dimensional core-collapse supernova simulated using a 15 M progenitor

    SciTech Connect

    Lentz, Eric J.; Bruenn, Stephen W.; Hix, W. Raphael; Mezzacappa, Anthony; Messer, O. E. Bronson; Endeve, Eirik; Blondin, John M.; Harris, J. Austin; Marronetti, Pedro; Yakunin, Konstantin N.

    2015-07-10

    We have performed ab initio neutrino radiation hydrodynamics simulations in three and two spatial dimensions (3D and 2D) of core-collapse supernovae from the same 15 M⊙ progenitor through 440 ms after core bounce. Both 3D and 2D models achieve explosions; however, the onset of explosion (shock revival) is delayed by ~100 ms in 3D relative to the 2D counterpart and the growth of the diagnostic explosion energy is slower. This is consistent with previously reported 3D simulations utilizing iron-core progenitors with dense mantles. In the ~100 ms before the onset of explosion, diagnostics of neutrino heating and turbulent kinetic energy favor earlier explosion in 2D. During the delay, the angular scale of convective plumes reaching the shock surface grows and explosion in 3D is ultimately lead by a single, large-angle plume, giving the expanding shock a directional orientation not dissimilar from those imposed by axial symmetry in 2D simulations. Finally, we posit that shock revival and explosion in the 3D simulation may be delayed until sufficiently large plumes form, whereas such plumes form more rapidly in 2D, permitting earlier explosions.

  7. A new equation of state with light nuclei and their weak interactions in core-collapse supernova simulations

    NASA Astrophysics Data System (ADS)

    Furusawa, Shun; Nagakura, Hiroki; Sumiyoshi, Kohsuke; Yamada, Shoichi; Suzuki, Hideyuki

    2014-05-01

    We perform numerical experiments to investigate the influence of inelastic neutrino reactions with light nuclei on the standing accretion shock instability. The time evolutions of shock waves are calculated with a simple light-bulb approximation for the neutrino transport and a multi-nuclei equation of state. The neutrino absorptions and inelastic interactions with deuterons, tritons, helions and alpha particles are taken into account in the hydrodynamical simulations in addition to the ordinary charged-current interactions with nucleons. Axial symmetry is assumed but no equatorial symmetry is imposed. We show that the heating rates of deuterons reach as high as ˜ 10% of those of nucleons around the bottom of the gain region. On the other hands, alpha particles heat the matter near the shock wave, which is important when the shock wave expands and density and temperature of matter become low. It is also found that the models with heating by light nuclei have different evolutions from those without it in non-linear evolution phase. The matter in the gain region has various densities and temperatures and there appear regions that are locally rich in deuterons and alpha particles. These results indicate that the inelastic reactions of light nuclei, especially deuterons, should be incorporated in the simulations of core-collapse supernovae.

  8. Aspherical nucleosynthesis in a core-collapse supernova with 25 M {sub ☉} standard progenitor

    SciTech Connect

    Popov, M. V.; Filina, A. A.; Baranov, A. A.; Chardonnet, P.; Chechetkin, V. M.

    2014-03-01

    The problem of nucleosynthesis was studied within an aspherical supernova model. The explosive burning was computed in a star of 25 M {sub ☉} initial mass on its final stage of evolution. The chemical composition of a presupernova was taken from realistic evolutionary computations. A piecewise parabolic method on a local stencil was applied to simulate the hydrodynamics of the explosion. The gravity was recomputed by a Poisson solver on a fine grid as the explosion developed. A detailed yield of chemical elements was performed as a post-processing step using the tracer particles method. The produced nuclei formed a layer-like structure enclosing large fragments of nickel and iron-group isotopes that were pushed away from the central region by an explosion along the polar direction. The light nuclei were preferentially moving along the equatorial plane forming a torus-like structure.

  9. ON THE IMPACT OF THREE DIMENSIONS IN SIMULATIONS OF NEUTRINO-DRIVEN CORE-COLLAPSE SUPERNOVA EXPLOSIONS

    SciTech Connect

    Couch, Sean M.

    2013-09-20

    We present one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) hydrodynamical simulations of core-collapse supernovae including a parameterized neutrino heating and cooling scheme in order to investigate the critical core neutrino luminosity (L{sub crit}) required for explosion. In contrast to some previous works, we find that 3D simulations explode later than 2D simulations, and that L{sub crit} at fixed mass accretion rate is somewhat higher in three dimensions than in two dimensions. We find, however, that in two dimensions L{sub crit} increases as the numerical resolution of the simulation increases. In contrast to some previous works, we argue that the average entropy of the gain region is in fact not a good indicator of explosion but is rather a reflection of the greater mass in the gain region in two dimensions. We compare our simulations to semi-analytic explosion criteria and examine the nature of the convective motions in two dimensions and three dimensions. We discuss the balance between neutrino-driven buoyancy and drag forces. In particular, we show that the drag force will be proportional to a buoyant plume's surface area while the buoyant force is proportional to a plume's volume and, therefore, plumes with greater volume-to-surface-area ratios will rise more quickly. We show that buoyant plumes in two dimensions are inherently larger, with greater volume-to-surface-area ratios, than plumes in three dimensions. In the scenario that the supernova shock expansion is dominated by neutrino-driven buoyancy, this balance between buoyancy and drag forces may explain why 3D simulations explode later than 2D simulations and why L{sub crit} increases with resolution. Finally, we provide a comparison of our results with other calculations in the literature.

  10. Progenitor-dependent Explosion Dynamics in Self-consistent, Axisymmetric Simulations of Neutrino-driven Core-collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Summa, Alexander; Hanke, Florian; Janka, Hans-Thomas; Melson, Tobias; Marek, Andreas; Müller, Bernhard

    2016-07-01

    We present self-consistent, axisymmetric core-collapse supernova simulations performed with the Prometheus-Vertex code for 18 pre-supernova models in the range of 11–28 M ⊙, including progenitors recently investigated by other groups. All models develop explosions, but depending on the progenitor structure, they can be divided into two classes. With a steep density decline at the Si/Si–O interface, the arrival of this interface at the shock front leads to a sudden drop of the mass-accretion rate, triggering a rapid approach to explosion. With a more gradually decreasing accretion rate, it takes longer for the neutrino heating to overcome the accretion ram pressure and explosions set in later. Early explosions are facilitated by high mass-accretion rates after bounce and correspondingly high neutrino luminosities combined with a pronounced drop of the accretion rate and ram pressure at the Si/Si–O interface. Because of rapidly shrinking neutron star radii and receding shock fronts after the passage through their maxima, our models exhibit short advection timescales, which favor the efficient growth of the standing accretion-shock instability. The latter plays a supportive role at least for the initiation of the re-expansion of the stalled shock before runaway. Taking into account the effects of turbulent pressure in the gain layer, we derive a generalized condition for the critical neutrino luminosity that captures the explosion behavior of all models very well. We validate the robustness of our findings by testing the influence of stochasticity, numerical resolution, and approximations in some aspects of the microphysics.

  11. Progenitor-dependent Explosion Dynamics in Self-consistent, Axisymmetric Simulations of Neutrino-driven Core-collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Summa, Alexander; Hanke, Florian; Janka, Hans-Thomas; Melson, Tobias; Marek, Andreas; Müller, Bernhard

    2016-07-01

    We present self-consistent, axisymmetric core-collapse supernova simulations performed with the Prometheus-Vertex code for 18 pre-supernova models in the range of 11-28 M ⊙, including progenitors recently investigated by other groups. All models develop explosions, but depending on the progenitor structure, they can be divided into two classes. With a steep density decline at the Si/Si-O interface, the arrival of this interface at the shock front leads to a sudden drop of the mass-accretion rate, triggering a rapid approach to explosion. With a more gradually decreasing accretion rate, it takes longer for the neutrino heating to overcome the accretion ram pressure and explosions set in later. Early explosions are facilitated by high mass-accretion rates after bounce and correspondingly high neutrino luminosities combined with a pronounced drop of the accretion rate and ram pressure at the Si/Si-O interface. Because of rapidly shrinking neutron star radii and receding shock fronts after the passage through their maxima, our models exhibit short advection timescales, which favor the efficient growth of the standing accretion-shock instability. The latter plays a supportive role at least for the initiation of the re-expansion of the stalled shock before runaway. Taking into account the effects of turbulent pressure in the gain layer, we derive a generalized condition for the critical neutrino luminosity that captures the explosion behavior of all models very well. We validate the robustness of our findings by testing the influence of stochasticity, numerical resolution, and approximations in some aspects of the microphysics.

  12. Conditions for shock revival by neutrino heating in core-collapse supernovae

    NASA Astrophysics Data System (ADS)

    Janka, H.-Th.

    2001-03-01

    Energy deposition by neutrinos can rejuvenate the stalled bounce shock and can provide the energy for the supernova explosion of a massive star. This neutrino-heating mechanism, though investigated by numerical simulations and analytic studies, is not finally accepted or proven as the trigger of the explosion. Part of the problem is that different groups have obtained seemingly discrepant results, and the complexity of the hydrodynamic models often hampers a clear and simple interpretation of the results. This demands a deeper theoretical understanding of the requirements of a successful shock revival. A toy model is developed here for discussing the neutrino heating phase analytically. The neutron star atmosphere between the neutrinosphere and the supernova shock can well be considered to be in hydrostatic equilibrium, with a layer of net neutrino cooling below the gain radius and a layer of net neutrino heating above. Since the mass infall rate to the shock is in general different from the rate at which gas is advected into the neutron star, the mass in the gain layer varies with time. Moreover, the gain layer receives additional energy input by neutrinos emitted from the neutrinosphere and the cooling layer. Therefore the determination of the shock evolution requires a time-dependent treatment. To this end the hydrodynamical equations of continuity and energy are integrated over the volume of the gain layer to obtain conservation laws for the total mass and energy in this layer. The radius and velocity of the supernova shock can then be calculated from global properties of the gain layer as solutions of an initial value problem, which expresses the fact that the behavior of the shock is controlled by the cumulative effects of neutrino heating and mass accumulation in the gain layer. The described toy model produces steady-state accretion and mass outflow from the nascent neutron star as special cases. The approach is useful to illuminate the conditions that can

  13. THE DOUBLE PULSAR: EVIDENCE FOR NEUTRON STAR FORMATION WITHOUT AN IRON CORE-COLLAPSE SUPERNOVA

    SciTech Connect

    Ferdman, R. D.; Kramer, M.; Stappers, B. W.; Lyne, A. G.; Stairs, I. H.; Breton, R. P.; McLaughlin, M. A.; Freire, P. C. C.; Possenti, A.; Kaspi, V. M.; Manchester, R. N.

    2013-04-10

    The double pulsar system PSR J0737-3039A/B is a double neutron star binary, with a 2.4 hr orbital period, which has allowed measurement of relativistic orbital perturbations to high precision. The low mass of the second-formed neutron star, as well as the low system eccentricity and proper motion, point to a different evolutionary scenario compared to most other known double neutron star systems. We describe analysis of the pulse profile shape over 6 years of observations and present the resulting constraints on the system geometry. We find the recycled pulsar in this system, PSR J0737-3039A, to be a near-orthogonal rotator with an average separation between its spin and magnetic axes of 90 Degree-Sign {+-} 11 Degree-Sign {+-} 5 Degree-Sign . Furthermore, we find a mean 95% upper limit on the misalignment between its spin and orbital angular momentum axes of 3. Degree-Sign 2, assuming that the observed emission comes from both magnetic poles. This tight constraint lends credence to the idea that the supernova that formed the second pulsar was relatively symmetric, possibly involving electron capture onto an O-Ne-Mg core.

  14. THREE-DIMENSIONAL EXPLOSION GEOMETRY OF STRIPPED-ENVELOPE CORE-COLLAPSE SUPERNOVAE. I. SPECTROPOLARIMETRIC OBSERVATIONS

    SciTech Connect

    Tanaka, Masaomi; Iye, Masanori; Kawabata, Koji S.; Yamanaka, Masayuki; Hattori, Takashi; Aoki, Kentaro; Sasaki, Toshiyuki; Mazzali, Paolo A.; Maeda, Keiichi; Nomoto, Ken'ichi; Pian, Elena

    2012-07-20

    We study the multi-dimensional geometry of supernova (SN) explosions by means of spectropolarimetric observations of stripped-envelope SNe, i.e., SNe without a hydrogen-rich layer. We perform spectropolarimetric observations of two stripped-envelope SNe, Type Ib SN 2009jf and Type Ic SN 2009mi. Both objects show non-zero polarization at the wavelength of the strong lines. They also show a loop in the Stokes Q - U diagram, which indicates a non-axisymmetric, three-dimensional ion distribution in the ejecta. We show that five out of six stripped-envelope SNe, which have been observed spectropolarimetrically so far, show such a loop. This implies that a three-dimensional geometry is common in stripped-envelope SNe. We find that stronger lines tend to show higher polarization. This effect is not related to the geometry, and must be corrected for to compare the polarization of different lines or different objects. Even after the correction, however, there remains a dispersion of polarization degree among different objects. Such a dispersion might be caused by three-dimensional clumpy ion distributions viewed from different directions.

  15. Core-collapse Supernovae from 9 to 120 Solar Masses Based on Neutrino-powered Explosions

    NASA Astrophysics Data System (ADS)

    Sukhbold, Tuguldur; Ertl, T.; Woosley, S. E.; Brown, Justin M.; Janka, H.-T.

    2016-04-01

    Nucleosynthesis, light curves, explosion energies, and remnant masses are calculated for a grid of supernovae (SNe) resulting from massive stars with solar metallicity and masses from 9.0 to 120 {M}⊙ . The full evolution is followed using an adaptive reaction network of up to 2000 nuclei. A novel aspect of the survey is the use of a one-dimensional neutrino transport model for the explosion. This explosion model has been calibrated to give the observed energy for SN 1987A, using five standard progenitors, and for the Crab SN using a 9.6 {M}⊙ progenitor. As a result of using a calibrated central engine, the final kinetic energy of the SN is variable and sensitive to the structure of each pre-SN star. Many progenitors with extended core structures do not explode, but become black holes (BHs), and the masses of exploding stars do not form a simply connected set. The resulting nucleosynthesis agrees reasonably well with the Sun provided that a reasonable contribution from SNe Ia is also allowed, but with a deficiency of light s-process isotopes. The resulting neutron star initial mass function has a mean gravitational mass near 1.4 {M}⊙ . The average BH mass is about 9 {M}⊙ if only the helium core implodes, and 14 {M}⊙ if the entire pre-SN star collapses. Only ˜10% of SNe come from stars over 20 {M}⊙ , and some of these are Type Ib or Ic. Some useful systematics of Type IIp light curves are explored.

  16. The color-indices of early-type galaxies with core collapse supernovae

    NASA Astrophysics Data System (ADS)

    Polyakova, G. D.

    We performed least-squares fits to determine the transformation equations of the color-indices (u-g), (g-r) (SDSS photometric catalog, Release 8, 2011); (NUV-B) (GALEX ultra-violet Atlas of nearby galaxies, Gil de Paz et al, 2007); (B-Ve), (U-Be) (General photometry of galaxies, Prugniel et al, 1998) to the photometric system of catalogue RC3 (U-B)T and (B-V)T. We determined the color - indices (U-B)Tc and (B-V)Tc for the 20 galaxies with SNe of types Ibc and II. The 17 of these galaxies are seen to fall in red sequence galaxies of color- magnitude diagram for 872 of the RC3 early-type galaxies with known (U-B)T0 colors. The blue galaxies are NGC 4691, NGC 838 and NGC 7803 - the galaxies with active galaxy nuclei (AGN). The 12 host galaxies are peculiar and 13 - are members of group of galaxies.

  17. MULTI-COLOR OPTICAL AND NEAR-INFRARED LIGHT CURVES OF 64 STRIPPED-ENVELOPE CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Bianco, F. B.; Modjaz, M.; Hicken, M.; Friedman, A.; Kirshner, R. P.; Challis, P.; Marion, G. H.; Bloom, J. S.; Wood-Vasey, W. M.; Rest, A.

    2014-08-01

    We present a densely sampled, homogeneous set of light curves of 64 low-redshift (z ≲ 0.05) stripped-envelope supernovae (SNe of Type IIb, Ib, Ic, and Ic-BL). These data were obtained between 2001 and 2009 at the Fred L. Whipple Observatory (FLWO) on Mount Hopkins in Arizona, with the optical FLWO 1.2 m and the near-infrared (NIR) Peters Automated Infrared 1.3 m telescopes. Our data set consists of 4543 optical photometric measurements on 61 SNe, including a combination of U BV RI, U BV r{sup ′}i{sup ′}, and u{sup ′} BV r{sup ′}i{sup ′}, and 1919 JHK{sub s} NIR measurements on 25 SNe. This sample constitutes the most extensive multi-color data set of stripped-envelope SNe to date. Our photometry is based on template-subtracted images to eliminate any potential host-galaxy light contamination. This work presents these photometric data, compares them with data in the literature, and estimates basic statistical quantities: date of maximum, color, and photometric properties. We identify promising color trends that may permit the identification of stripped-envelope SN subtypes from their photometry alone. Many of these SNe were observed spectroscopically by the Harvard-Smithsonian Center for Astrophysics (CfA) SN group, and the spectra are presented in a companion paper. A thorough exploration that combines the CfA photometry and spectroscopy of stripped-envelope core-collapse SNe will be presented in a follow-up paper.

  18. The Development of Explosions in Axisymmetric Ab Initio Core-collapse Supernova Simulations of 12-25 M Stars

    NASA Astrophysics Data System (ADS)

    Bruenn, Stephen W.; Lentz, Eric J.; Hix, W. Raphael; Mezzacappa, Anthony; Harris, J. Austin; Messer, O. E. Bronson; Endeve, Eirik; Blondin, John M.; Chertkow, Merek Austin; Lingerfelt, Eric J.; Marronetti, Pedro; Yakunin, Konstantin N.

    2016-02-01

    We present four ab initio axisymmetric core-collapse supernova simulations initiated from 12, 15, 20, and 25 {M}⊙ zero-age main sequence progenitors. All of the simulations yield explosions and have been evolved for at least 1.2 s after core bounce and 1 s after material first becomes unbound. These simulations were computed with our Chimera code employing RbR spectral neutrino transport, special and general relativistic transport effects, and state-of-the-art neutrino interactions. Continuing the evolution beyond 1 s after core bounce allows the explosions to develop more fully and the processes involved in powering the explosions to become more clearly evident. We compute explosion energy estimates, including the negative gravitational binding energy of the stellar envelope outside the expanding shock, of 0.34, 0.88, 0.38, and 0.70 Bethe (B ≡ {10}51 erg) and increasing at 0.03, 0.15, 0.19, and 0.52 {\\text{B s}}-1, respectively, for the 12, 15, 20, and 25 {M}⊙ models at the endpoint of this report. We examine the growth of the explosion energy in our models through detailed analyses of the energy sources and flows. We discuss how the explosion energies may be subject to stochastic variations as exemplfied by the effect of the explosion geometry of the 20 {M}⊙ model in reducing its explosion energy. We compute the proto-neutron star masses and kick velocities. We compare our results for the explosion energies and ejected {}56{Ni} masses against some observational standards despite the large error bars in both models and observations.

  19. The development of explosions in axisymmetric ab initio core-collapse supernova simulations of 12–25 M⊙ stars

    DOE PAGES

    Bruenn, Stephen W.; Lentz, Eric J.; Hix, William Raphael; Mezzacappa, Anthony; Harris, James Austin; Messer, O. E. Bronson; Endeve, Eirik; Blondin, John M.; Chertkow, Merek Austin; Lingerfelt, Eric J.; et al

    2016-02-16

    We present four ab initio axisymmetric core-collapse supernova simulations initiated from 12, 15, 20, and 25 M⊙ zero-age main sequence progenitors. All of the simulations yield explosions and have been evolved for at least 1.2 s after core bounce and 1 s after material first becomes unbound. These simulations were computed with our Chimera code employing RbR spectral neutrino transport, special and general relativistic transport effects, and state-of-the-art neutrino interactions. Continuing the evolution beyond 1 s after core bounce allows the explosions to develop more fully and the processes involved in powering the explosions to become more clearly evident. Wemore » compute explosion energy estimates, including the negative gravitational binding energy of the stellar envelope outside the expanding shock, of 0.34, 0.88, 0.38, and 0.70 Bethe (B ≡ 1051 erg) and increasing at 0.03, 0.15, 0.19, and 0.52 BS–1, respectively, for the 12, 15, 20, and 25 M⊙ models at the endpoint of this report. We examine the growth of the explosion energy in our models through detailed analyses of the energy sources and flows. We discuss how the explosion energies may be subject to stochastic variations as exemplfied by the effect of the explosion geometry of the 20 M⊙ model in reducing its explosion energy. We compute the proto-neutron star masses and kick velocities. In conclusion, we compare our results for the explosion energies and ejected 56Ni masses against some observational standards despite the large error bars in both models and observations.« less

  20. NEUTRINO-DRIVEN TURBULENT CONVECTION AND STANDING ACCRETION SHOCK INSTABILITY IN THREE-DIMENSIONAL CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Abdikamalov, Ernazar; Ott, Christian D.; Radice, David; Roberts, Luke F.; Haas, Roland; Reisswig, Christian; Mösta, Philipp; Klion, Hannah; Schnetter, Erik

    2015-07-20

    We conduct a series of numerical experiments into the nature of three-dimensional (3D) hydrodynamics in the postbounce stalled-shock phase of core-collapse supernovae using 3D general-relativistic hydrodynamic simulations of a 27 M{sub ⊙} progenitor star with a neutrino leakage/heating scheme. We vary the strength of neutrino heating and find three cases of 3D dynamics: (1) neutrino-driven convection, (2) initially neutrino-driven convection and subsequent development of the standing accretion shock instability (SASI), and (3) SASI-dominated evolution. This confirms previous 3D results of Hanke et al. and Couch and Connor. We carry out simulations with resolutions differing by up to a factor of ∼4 and demonstrate that low resolution is artificially favorable for explosion in the 3D convection-dominated case since it decreases the efficiency of energy transport to small scales. Low resolution results in higher radial convective fluxes of energy and enthalpy, more fully buoyant mass, and stronger neutrino heating. In the SASI-dominated case, lower resolution damps SASI oscillations. In the convection-dominated case, a quasi-stationary angular kinetic energy spectrum E(ℓ) develops in the heating layer. Like other 3D studies, we find E(ℓ) ∝ℓ{sup −1} in the “inertial range,” while theory and local simulations argue for E(ℓ) ∝ ℓ{sup −5/3}. We argue that current 3D simulations do not resolve the inertial range of turbulence and are affected by numerical viscosity up to the energy-containing scale, creating a “bottleneck” that prevents an efficient turbulent cascade.

  1. A new multi-dimensional general relativistic neutrino hydrodynamics code for core-collapse supernovae. IV. The neutrino signal

    SciTech Connect

    Müller, Bernhard; Janka, Hans-Thomas E-mail: bjmuellr@mpa-garching.mpg.de

    2014-06-10

    Considering six general relativistic, two-dimensional (2D) supernova (SN) explosion models of progenitor stars between 8.1 and 27 M {sub ☉}, we systematically analyze the properties of the neutrino emission from core collapse and bounce to the post-explosion phase. The models were computed with the VERTEX-COCONUT code, using three-flavor, energy-dependent neutrino transport in the ray-by-ray-plus approximation. Our results confirm the close similarity of the mean energies, (E), of ν-bar {sub e} and heavy-lepton neutrinos and even their crossing during the accretion phase for stars with M ≳ 10 M {sub ☉} as observed in previous 1D and 2D simulations with state-of-the-art neutrino transport. We establish a roughly linear scaling of 〈E{sub ν-bar{sub e}}〉 with the proto-neutron star (PNS) mass, which holds in time as well as for different progenitors. Convection inside the PNS affects the neutrino emission on the 10%-20% level, and accretion continuing beyond the onset of the explosion prevents the abrupt drop of the neutrino luminosities seen in artificially exploded 1D models. We demonstrate that a wavelet-based time-frequency analysis of SN neutrino signals in IceCube will offer sensitive diagnostics for the SN core dynamics up to at least ∼10 kpc distance. Strong, narrow-band signal modulations indicate quasi-periodic shock sloshing motions due to the standing accretion shock instability (SASI), and the frequency evolution of such 'SASI neutrino chirps' reveals shock expansion or contraction. The onset of the explosion is accompanied by a shift of the modulation frequency below 40-50 Hz, and post-explosion, episodic accretion downflows will be signaled by activity intervals stretching over an extended frequency range in the wavelet spectrogram.

  2. AXISYMMETRIC AB INITIO CORE-COLLAPSE SUPERNOVA SIMULATIONS OF 12-25 M{sub Sun} STARS

    SciTech Connect

    Bruenn, Stephen W.; Yakunin, Konstantin N.; Mezzacappa, Anthony; Hix, W. Raphael; Lingerfelt, Eric J.; Lentz, Eric J.; Messer, O. E. Bronson; Blondin, John M.; Endeve, Eirik; Marronetti, Pedro

    2013-04-10

    We present an overview of four ab initio axisymmetric core-collapse supernova simulations employing detailed spectral neutrino transport computed with our CHIMERA code and initiated from Woosley and Heger progenitors of mass 12, 15, 20, and 25 M{sub Sun }. All four models exhibit shock revival over {approx}200 ms (leading to the possibility of explosion), driven by neutrino energy deposition. Hydrodynamic instabilities that impart substantial asymmetries to the shock aid these revivals, with convection appearing first in the 12 M{sub Sun} model and the standing accretion shock instability appearing first in the 25 M{sub Sun} model. Three of the models have developed pronounced prolate morphologies (the 20 M{sub Sun} model has remained approximately spherical). By 500 ms after bounce the mean shock radii in all four models exceed 3000 km and the diagnostic explosion energies are 0.33, 0.66, 0.65, and 0.70 Bethe (B = 10{sup 51} erg) for the 12, 15, 20, and 25 M{sub Sun} models, respectively, and are increasing. The three least massive of our models are already sufficiently energetic to completely unbind the envelopes of their progenitors (i.e., to explode), as evidenced by our best estimate of their explosion energies, which first become positive at 320, 380, and 440 ms after bounce. By 850 ms the 12 M{sub Sun} diagnostic explosion energy has saturated at 0.38 B, and our estimate for the final kinetic energy of the ejecta is {approx}0.3 B, which is comparable to observations for lower mass progenitors.

  3. The interplay between proto{endash}neutron star convection and neutrino transport in core-collapse supernovae

    SciTech Connect

    Mezzacappa, A.; Calder, A.C.; Guidry, M.W.; Strayer, M.R.; Guidry, M.W.; Strayer, M.R.; Umar, A.S. Bruenn, S.W. Blondin, J.M.

    1998-02-01

    We couple two-dimensional hydrodynamics to realistic one-dimensional multigroup flux-limited diffusion neutrino transport to investigate proto{endash}neutron star convection in core-collapse supernovae, and more specifically, the interplay between its development and neutrino transport. Our initial conditions, time-dependent boundary conditions, and neutrino distributions for computing neutrino heating, cooling, and deleptonization rates are obtained from one-dimensional simulations that implement multigroup flux-limited diffusion and one-dimensional hydrodynamics. The development and evolution of proto{endash}neutron star convection are investigated for both 15 and 25M{sub {circle_dot}} models, representative of the two classes of stars with compact and extended iron cores, respectively. For both models, in the absence of neutrino transport, the angle-averaged radial and angular convection velocities in the initial Ledoux unstable region below the shock after bounce achieve their peak values in {approximately}20ms, after which they decrease as the convection in this region dissipates. The dissipation occurs as the gradients are smoothed out by convection. This initial proto{endash}neutron star convection episode seeds additional convectively unstable regions farther out beneath the shock. The additional proto{endash}neutron star convection is driven by successive negative entropy gradients that develop as the shock, in propagating out after core bounce, is successively strengthened and weakened by the oscillating inner core. The convection beneath the shock distorts its sphericity, but on the average the shock radius is not boosted significantly relative to its radius in our corresponding one-dimensional models. In the presence of neutrino transport, proto{endash}neutron star convection velocities are too small relative to bulk inflow velocities to result in any significant convective transport of entropy and leptons. This is evident in our two-dimensional entropy

  4. CHARGED-PARTICLE AND NEUTRON-CAPTURE PROCESSES IN THE HIGH-ENTROPY WIND OF CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Farouqi, K.; Truran, J. W.; Kratz, K.-L.; Pfeiffer, B.; Rauscher, T.; Thielemann, F.-K. E-mail: truran@nova.uchicago.ed E-mail: k-l.Kratz@mpic.d E-mail: F-K.Thielemann@unibas.c

    2010-04-01

    The astrophysical site of the r-process is still uncertain, and a full exploration of the systematics of this process in terms of its dependence on nuclear properties from stability to the neutron drip-line within realistic stellar environments has still to be undertaken. Sufficiently high neutron-to-seed ratios can only be obtained either in very neutron-rich low-entropy environments or moderately neutron-rich high-entropy environments, related to neutron star mergers (or jets of neutron star matter) and the high-entropy wind of core-collapse supernova explosions. As chemical evolution models seem to disfavor neutron star mergers, we focus here on high-entropy environments characterized by entropy S, electron abundance Y{sub e} , and expansion velocity V{sub exp}. We investigate the termination point of charged-particle reactions, and we define a maximum entropy S{sub final} for a given V{sub exp} and Y{sub e} , beyond which the seed production of heavy elements fails due to the very small matter density. We then investigate whether an r-process subsequent to the charged-particle freeze-out can in principle be understood on the basis of the classical approach, which assumes a chemical equilibrium between neutron captures and photodisintegrations, possibly followed by a beta-flow equilibrium. In particular, we illustrate how long such a chemical equilibrium approximation holds, how the freeze-out from such conditions affects the abundance pattern, and which role the late capture of neutrons originating from beta-delayed neutron emission can play. Furthermore, we analyze the impact of nuclear properties from different theoretical mass models on the final abundances after these late freeze-out phases and beta-decays back to stability. As only a superposition of astrophysical conditions can provide a good fit to the solar r-abundances, the question remains how such superpositions are attained, resulting in the apparently robust r-process pattern observed in low

  5. Fundamental properties of core-collapse supernova and GRB progenitors: predicting the look of massive stars before death

    NASA Astrophysics Data System (ADS)

    Groh, Jose H.; Meynet, Georges; Georgy, Cyril; Ekström, Sylvia

    2013-10-01

    We investigate the fundamental properties of core-collapse supernova (SN) progenitors from single stars at solar metallicity. For this purpose, we combine Geneva stellar evolutionary models with initial masses of Mini = 20-120 M⊙ with atmospheric and wind models using the radiative transfer code CMFGEN. We provide synthetic photometry and high-resolution spectra of hot stars at the pre-SN stage. For models with Mini = 9-20 M⊙, we supplement our analysis using publicly available MARCS model atmospheres of RSGs to estimate their synthetic photometry. We employ well-established observational criteria of spectroscopic classification and find that, depending on their initial mass and rotation, massive stars end their lives as red supergiants (RSG), yellow hypergiants (YHG), luminous blue variables (LBV), and Wolf-Rayet (WR) stars of the WN and WO spectral types. For rotating models, we obtained the following types of SN progenitors: WO1-3 (Mini ≥ 32 M⊙), WN10-11 (25 < Mini < 32 M⊙), LBV (20 ≤ Mini ≤ 25 M⊙), G1 Ia+ (18 < Mini < 20 M⊙), and RSGs (9 ≤ Mini ≤ 18 M⊙). For non-rotating models, we found spectral types WO1-3 (Mini > 40 M⊙), WN7-8 (25 < Mini ≤ 40 M⊙), WN11h/LBV (20 < Mini ≤ 25 M⊙), and RSGs (9 ≤ Mini ≤ 20 M⊙). Our rotating models indicate that SN IIP progenitors are all RSG, SN IIL/b progenitors are 56% LBVs and 44% YHGs, SN Ib progenitors are 96% WN10-11 and 4% WOs, and SN Ic progenitors are all WO stars. We find that the most massive and luminous SN progenitors are not necessarily the brightest ones in a given filter, since this depends on their luminosity, temperature, wind density, and the way the spectral energy distribution compares to a filter bandpass. We find that SN IIP progenitors (RSGs) are bright in the RIJHKS filters and faint in the UB filters. SN IIL/b progenitors (LBVs and YHGs), and SN Ib progenitors (WNs) are relatively bright in optical/infrared filters, while SN Ic progenitors (WOs) are faint in all

  6. Charged-partricle and neutron-capture processes in the high-entropy wind of core-collapse supernovae.

    SciTech Connect

    Farouqi, K.; Kratz, K.-L.; Pfeiffer, B.; Rauscher, T.; Thielemann, F.-K.; Truran, J. W.; Physics; Univ. of Chicago; Joint Inst. for Nuclear Astrophysics; Univ. Mainz; Virtual Inst. for Nuclear Structure and Astrophysics; Max-Planck-Inst. fur Chemie; Univ. of Basel

    2010-04-01

    The astrophysical site of the r-process is still uncertain, and a full exploration of the systematics of this process in terms of its dependence on nuclear properties from stability to the neutron drip-line within realistic stellar environments has still to be undertaken. Sufficiently high neutron-to-seed ratios can only be obtained either in very neutron-rich low-entropy environments or moderately neutron-rich high-entropy environments, related to neutron star mergers (or jets of neutron star matter) and the high-entropy wind of core-collapse supernova explosions. As chemical evolution models seem to disfavor neutron star mergers, we focus here on high-entropy environments characterized by entropy S, electron abundance Y{sub e}, and expansion velocity V{sub exp}. We investigate the termination point of charged-particle reactions, and we define a maximum entropy S{sub final} for a given V{sub exp} and Y{sub e}, beyond which the seed production of heavy elements fails due to the very small matter density. We then investigate whether an r-process subsequent to the charged-particle freeze-out can in principle be understood on the basis of the classical approach, which assumes a chemical equilibrium between neutron captures and photodisintegrations, possibly followed by a {beta}-flow equilibrium. In particular, we illustrate how long such a chemical equilibrium approximation holds, how the freeze-out from such conditions affects the abundance pattern, and which role the late capture of neutrons originating from {beta}-delayed neutron emission can play. Furthermore, we analyze the impact of nuclear properties from different theoretical mass models on the final abundances after these late freeze-out phases and {beta}-decays back to stability. As only a superposition of astrophysical conditions can provide a good fit to the solar r-abundances, the question remains how such superpositions are attained, resulting in the apparently robust r-process pattern observed in low

  7. Charged-particle and neutron-capture processes in the high-entropy wind of core-collapse supernovae.

    SciTech Connect

    Farouqi, K.; Kratz, K.-L.; Pfeiffer, B.; Rauscher, T.; Thielemann, F.-K.; Truran, J.W.; Physics; Univ. of Chicago; Joint Inst. for Nuclear Astrophysics; Univ. Mainz; Virtual Inst. for Nuclear Structure and Astrophysics; Max-Planck-Insti. fur Chemie; Univ. of Basel

    2010-04-01

    The astrophysical site of the r-process is still uncertain, and a full exploration of the systematics of this process in terms of its dependence on nuclear properties from stability to the neutron drip-line within realistic stellar environments has still to be undertaken. Sufficiently high neutron-to-seed ratios can only be obtained either in very neutron-rich low-entropy environments or moderately neutron-rich high-entropy environments, related to neutron star mergers (or jets of neutron star matter) and the high-entropy wind of core-collapse supernova explosions. As chemical evolution models seem to disfavor neutron star mergers, we focus here on high-entropy environments characterized by entropy S, electron abundance Y{sub e}, and expansion velocity V{sub exp}. We investigate the termination point of charged-particle reactions, and we define a maximum entropy S{sub final} for a given V{sub exp} and Y{sub e}, beyond which the seed production of heavy elements fails due to the very small matter density. We then investigate whether an r-process subsequent to the charged-particle freeze-out can in principle be understood on the basis of the classical approach, which assumes a chemical equilibrium between neutron captures and photodisintegrations, possibly followed by a {beta}-flow equilibrium. In particular, we illustrate how long such a chemical equilibrium approximation holds, how the freeze-out from such conditions affects the abundance pattern, and which role the late capture of neutrons originating from {beta}-delayed neutron emission can play. Furthermore, we analyze the impact of nuclear properties from different theoretical mass models on the final abundances after these late freeze-out phases and {beta}-decays back to stability. As only a superposition of astrophysical conditions can provide a good fit to the solar r-abundances, the question remains how such superpositions are attained, resulting in the apparently robust r-process pattern observed in low

  8. THE FINAL FATE OF STARS THAT IGNITE NEON AND OXYGEN OFF-CENTER: ELECTRON CAPTURE OR IRON CORE-COLLAPSE SUPERNOVA?

    SciTech Connect

    Jones, Samuel; Hirschi, Raphael; Nomoto, Ken'ichi

    2014-12-20

    In the ONeMg cores of 8.8-9.5 M {sub ☉} stars, neon and oxygen burning is ignited off-center. Whether or not the neon-oxygen flame propagates to the center is critical for determining whether these stars undergo Fe core collapse or electron-capture-induced ONeMg core collapse. We present more details of stars that ignite neon and oxygen burning off-center. The neon flame is established in a manner similar to the carbon flame of super-AGB stars, albeit with a narrower flame width. The criteria for establishing a flame can be met if the strict Schwarzschild criterion for convective instability is adopted. Mixing across the interface of the convective shell disrupts the conditions for the propagation of the burning front, and instead the shell burns as a series of inward-moving flashes. While this may not directly affect whether or not the burning will reach the center (as in super-AGB stars), the core is allowed to contract between each shell flash. Reduction of the electron fraction in the shell reduces the Chandrasekhar mass and the center reaches the threshold density for the URCA process to activate and steer the remaining evolution of the core. This highlights the importance of a more accurate treatment of mixing in the stellar interior for yet another important question in stellar astrophysics—determining the properties of stellar evolution and supernova progenitors at the boundary between electron capture supernova and iron core-collapse supernova.

  9. Shell Model Analysis of the ^45V(p,γ) thermonuclear reaction rate relevant to ^44Ti production in core-collapse supernovae

    NASA Astrophysics Data System (ADS)

    Horoi, M.; Jora, R.; Zelevinsky, V.; Murphy, A. St. J.; Boyd, R. N.

    2001-10-01

    A reliable estimate of the ^45V(p,γ) reaction rate is necessary in order to reduce a large uncertainty in the production of ^44Ti in core collapse supernovae. We performed a theoretical analysis of the astrophysical factors and reaction rates including resonances in ^46Cr associated with the analog states in ^46Ti. Full fp shell model calculations are performed to predict positive parity states in ^46Ti situated in the Gamow window, which have a significant proton spectroscopic factor. The uncertainty of the reaction rate associated with electric dipole gamma decays to the negative parity low-lying states is also discussed.

  10. MATTER MIXING IN ASPHERICAL CORE-COLLAPSE SUPERNOVAE: A SEARCH FOR POSSIBLE CONDITIONS FOR CONVEYING {sup 56}Ni INTO HIGH VELOCITY REGIONS

    SciTech Connect

    Ono, Masaomi; Nagataki, Shigehiro; Ito, Hirotaka; Lee, Shiu-Hang; Mao, Jirong; Tolstov, Alexey; Hashimoto, Masa-aki

    2013-08-20

    We perform two-dimensional axisymmetric hydrodynamic simulations of matter mixing in aspherical core-collapse supernova explosions of a 16.3 M{sub Sun} star with a compact hydrogen envelope. Observations of SN 1987A have provided evidence that {sup 56}Ni synthesized by explosive nucleosynthesis is mixed into fast moving matter ({approx}>3500 km s{sup -1}) in the exploding star. In order to clarify the key conditions for reproducing such high velocity of {sup 56}Ni, we revisit matter mixing in aspherical core-collapse supernova explosions. Explosions are initiated artificially by injecting thermal and kinetic energies around the interface between the iron core and the silicon-rich layer. Perturbations of 5% or 30% amplitude in the radial velocities are introduced at several points in time. We find that no high velocity {sup 56}Ni can be obtained if we consider bipolar explosions with perturbations (5% amplitude) of pre-supernova origins. If large perturbations (30% amplitude) are introduced or exist due to some unknown mechanism in a later phase just before the shock wave reaches the hydrogen envelope, {sup 56}Ni with a velocity of 3000 km s{sup -1} can be obtained. Aspherical explosions that are asymmetric across the equatorial plane with clumpy structures in the initial shock waves are investigated. We find that the clump sizes affect the penetration of {sup 56}Ni. Finally, we report that an aspherical explosion model that is asymmetric across the equatorial plane with multiple perturbations of pre-supernova origins can cause the penetration of {sup 56}Ni clumps into fast moving matter of 3000 km s{sup -1}. We show that both aspherical explosions with clumpy structures and perturbations of pre-supernova origins may be necessary to reproduce the observed high velocity of {sup 56}Ni. To confirm this, more robust three-dimensional simulations are required.

  11. Convection, nucleosynthesis, and core collapse

    NASA Technical Reports Server (NTRS)

    Bazan, Grant; Arnett, David

    1994-01-01

    We use a piecewise parabolic method hydrodynamics code (PROMETHEUS) to study convective burning in two dimensions in an oxygen shell prior to core collapse. Significant mixing beyond convective boundaries determined by mixing-length theory brings fuel (C-12) into the convective regon, causing hot spots of nuclear burning. Plumes dominate the velocity structure. Finite perturbations arise in a region in which O-16 will be explosively burned to Ni-56 when the star explodes; the resulting instabilities and mixing are likely to distribute Ni-56 throughout the supernova envelope. Inhomogeneities in Y(sub e) may be large enough to affect core collapse and will affect explosive nucleosynthesis. The nature of convective burning is dramatically different from that assumed in one-dimensional simulations; quantitative estimates of nucleosynthetic yields, core masses, and the approach to core collapse will be affected.

  12. Toward Connecting Core-Collapse Supernova Theory with Observations: Nucleosynthetic Yields and Distribution of Elements in a 15 M⊙ Blue Supergiant Progenitor with SN 1987A Energetics

    NASA Astrophysics Data System (ADS)

    Plewa, Tomasz; Handy, Timothy; Odrzywolek, Andrzej

    2014-03-01

    We compute and discuss the process of nucleosynthesis in a series of core-collapse explosion models of a 15 solar mass, blue supergiant progenitor. We obtain nucleosynthetic yields and study the evolution of the chemical element distribution from the moment of core bounce until young supernova remnant phase. Our models show how the process of energy deposition due to radioactive decay modifies the dynamics and the core ejecta structure on small and intermediate scales. The results are compared against observations of young supernova remnants including Cas A and the recent data obtained for SN 1987A. The work has been supported by the NSF grant AST-1109113 and DOE grant DE-FG52-09NA29548. This research used resources of the National Energy Research Scientific Computing Center, which is supported by the U.S. DoE under Contract No. DE-AC02-05CH11231.

  13. A NEW MULTI-DIMENSIONAL GENERAL RELATIVISTIC NEUTRINO HYDRODYNAMICS CODE OF CORE-COLLAPSE SUPERNOVAE. III. GRAVITATIONAL WAVE SIGNALS FROM SUPERNOVA EXPLOSION MODELS

    SciTech Connect

    Mueller, Bernhard; Janka, Hans-Thomas; Marek, Andreas E-mail: thj@mpa-garching.mpg.de

    2013-03-20

    We present a detailed theoretical analysis of the gravitational wave (GW) signal of the post-bounce evolution of core-collapse supernovae (SNe), employing for the first time relativistic, two-dimensional explosion models with multi-group, three-flavor neutrino transport based on the ray-by-ray-plus approximation. The waveforms reflect the accelerated mass motions associated with the characteristic evolutionary stages that were also identified in previous works: a quasi-periodic modulation by prompt post-shock convection is followed by a phase of relative quiescence before growing amplitudes signal violent hydrodynamical activity due to convection and the standing accretion shock instability during the accretion period of the stalled shock. Finally, a high-frequency, low-amplitude variation from proto-neutron star (PNS) convection below the neutrinosphere appears superimposed on the low-frequency trend associated with the aspherical expansion of the SN shock after the onset of the explosion. Relativistic effects in combination with detailed neutrino transport are shown to be essential for quantitative predictions of the GW frequency evolution and energy spectrum, because they determine the structure of the PNS surface layer and its characteristic g-mode frequency. Burst-like high-frequency activity phases, correlated with sudden luminosity increase and spectral hardening of electron (anti-)neutrino emission for some 10 ms, are discovered as new features after the onset of the explosion. They correspond to intermittent episodes of anisotropic accretion by the PNS in the case of fallback SNe. We find stronger signals for more massive progenitors with large accretion rates. The typical frequencies are higher for massive PNSs, though the time-integrated spectrum also strongly depends on the model dynamics.

  14. Object classification at the Nearby Supernova Factory

    NASA Astrophysics Data System (ADS)

    Bailey, S.; Aragon, C.; Romano, R.; Thomas, R. C.; Weaver, B. A.; Wong, D.

    2008-03-01

    We present the results of applying new object classification techniques to the supernova search of the Nearby Supernova Factory. In comparison to simple threshold cuts, more sophisticated methods such as boosted decision trees, random forests, and support vector machines provide dramatically better object discrimination: we reduced the number of non-supernova candidates by a factor of 10 while increasing our supernova identification efficiency. Methods such as these will be crucial for maintaining a reasonable false positive rate in the automated transient alert pipelines of upcoming large optical surveys.

  15. A Study of SN Ejecta in the Core-Collapse Supernova Remnant G292.0+1.8: Cas A's Older Cousin

    NASA Astrophysics Data System (ADS)

    Fesen, Robert

    2006-07-01

    Recent studies of the southern oxygen-rich supernova remnant {SNR} G292.0+1.8 have shown it to be the only Galactic SNR to exhibit all the features we expect in young remnants of core-collapse supernovae: an outer shell behind an expanding primary shock, high-velocity fragments of undiluted metal-rich ejecta, and a central pulsar surrounded by a pulsar-wind nebula. G292.0+1.8's optical emission consists of numerous knots and filaments of O- and S-rich ejecta spread throughout much of the remnant shell, many with radially oriented pencil-like geometries that may trace their origins to Rayleigh-Taylor instabilities during the SN event. The evolution and fine-scale structure of SN debris in young remnants is poorly understood and largely uncharted territory. For testing models for the distribution of metal-rich ejecta from core-collapse SNe, how the ejecta evolve and clump, and how SN shocks interact with the local circumstellar medium, the 3000-yr-old G292.0+1.8 remnant rivals the 320-yr-old Cas A remnant in importance. We therefore propose the first HST images of G292.0+1.8 in order to characterize the fine-scale spatial distribution of the ejecta, their sub-arcsecond chemical make-up, and the detailed structure and scale lengths for metal-rich SN ejecta clumps. The proposed HST images of G292.0+1.8 will be used in conjunction with existing Spitzer Cycle 1 infrared data and an upcoming 0.5 Msec Chandra X-ray image. We expect to achieve the same kind of results for G292 that have already been obtained for Cas A. High-resolution HST images of this remnant, combined with Spitzer and Chandra data and contrasted with a similar data set on Cas A, will provide superb multiwavelength benchmarks for both very young and older core-collapse SNRs.

  16. Object Classification at the Nearby Supernova Factory

    SciTech Connect

    Aragon, Cecilia R.; Bailey, Stephen; Aragon, Cecilia R.; Romano, Raquel; Thomas, Rollin C.; Weaver, B. A.; Wong, D.

    2007-12-21

    We present the results of applying new object classification techniques to the supernova search of the Nearby Supernova Factory. In comparison to simple threshold cuts, more sophisticated methods such as boosted decision trees, random forests, and support vector machines provide dramatically better object discrimination: we reduced the number of nonsupernova candidates by a factor of 10 while increasing our supernova identification efficiency. Methods such as these will be crucial for maintaining a reasonable false positive rate in the automated transient alert pipelines of upcoming large optical surveys.

  17. A UNIFORM CONTRIBUTION OF CORE-COLLAPSE AND TYPE Ia SUPERNOVAE TO THE CHEMICAL ENRICHMENT PATTERN IN THE OUTSKIRTS OF THE VIRGO CLUSTER

    SciTech Connect

    Simionescu, A.; Ichinohe, Y.; Werner, N.; Urban, O.; Allen, S. W.; Zhuravleva, I.

    2015-10-01

    We present the first measurements of the abundances of α-elements (Mg, Si, and S) extending out beyond the virial radius of a cluster of galaxies. Our results, based on Suzaku Key Project observations of the Virgo Cluster, show that the chemical composition of the intracluster medium is consistent with being constant on large scales, with a flat distribution of the Si/Fe, S/Fe, and Mg/Fe ratios as a function of radius and azimuth out to 1.4 Mpc (1.3 r{sub 200}). Chemical enrichment of the intergalactic medium due solely to core-collapse supernovae (SNcc) is excluded with very high significance; instead, the measured metal abundance ratios are generally consistent with the solar value. The uniform metal abundance ratios observed today are likely the result of an early phase of enrichment and mixing, with both SNcc and SNe Ia contributing to the metal budget during the period of peak star formation activity at redshifts of 2–3. We estimate the ratio between the number of SNe Ia and the total number of supernovae enriching the intergalactic medium to be between 12% and 37%, broadly consistent with the metal abundance patterns in our own Galaxy or with the SN Ia contribution estimated for the cluster cores.

  18. A uniform contribution of core-collapse and type Ia supernovae to the chemical enrichment pattern in the outskirts of the Virgo Cluster

    DOE PAGES

    Simionescu, A.; Werner, N.; Urban, O.; Allen, S. W.; Ichinohe, Y.; Zhuravleva, I.

    2015-09-24

    We present the first measurements of the abundances of α-elements (Mg, Si, and S) extending out beyond the virial radius of a cluster of galaxies. Our results, based on Suzaku Key Project observations of the Virgo Cluster, show that the chemical composition of the intracluster medium is consistent with being constant on large scales, with a flat distribution of the Si/Fe, S/Fe, and Mg/Fe ratios as a function of radius and azimuth out to 1.4 Mpc (1.3 r200). Chemical enrichment of the intergalactic medium due solely to core-collapse supernovae (SNcc) is excluded with very high significance; instead, the measured metalmore » abundance ratios are generally consistent with the solar value. The uniform metal abundance ratios observed today are likely the result of an early phase of enrichment and mixing, with both SNcc and SNe Ia contributing to the metal budget during the period of peak star formation activity at redshifts of 2–3. Furthermore, we estimate the ratio between the number of SNe Ia and the total number of supernovae enriching the intergalactic medium to be between 12% and 37%, broadly consistent with the metal abundance patterns in our own Galaxy or with the SN Ia contribution estimated for the cluster cores.« less

  19. Gravitational wave signatures of ab initio two-dimensional core collapse supernova explosion models for 12–25M⊙ stars

    DOE PAGES

    Yakunin, Konstantin N.; Mezzacappa, Anthony; Marronetti, Pedro; Yoshida, Shin’ichirou; Bruenn, Stephen W.; Hix, W. Raphael; Lentz, Eric J.; Bronson Messer, O. E.; Harris, J. Austin; Endeve, Eirik; et al

    2015-10-19

    Here, we present the gravitational waveforms computed in ab initio two-dimensional core collapse supernova models evolved with the chimera code for progenitor masses between 12 and 25 M. For all models employ multifrequency neutrino transport in the ray-by-ray approximation, state-of-the-art weak interaction physics, relativistic transport corrections such as the gravitational redshift of neutrinos, two-dimensional hydrodynamics with the commensurate relativistic corrections, Newtonian self-gravity with a general-relativistic monopole correction, and the Lattimer-Swesty equation of state with 220 MeV compressibility, and begin with the most recent Woosley-Heger nonrotating progenitors in this mass range. All of our models exhibit robust explosions. Moreover, our waveformsmore » capture all stages of supernova development: 1) a relatively short and weak prompt signal, 2) a quiescent stage, 3) a strong signal due to convection and standing accretion shock instability activity, 4) termination of active accretion onto the proto-neutron star, and 5) a slowly increasing tail that reaches a saturation value. Fourier decomposition shows that the gravitational wave signals we predict should be observable by AdvLIGO for Galactic events across the range of progenitors considered here. The fundamental limitation of these models is in their imposition of axisymmetry. Further progress will require counterpart three-dimensional models, which are underway.« less

  20. A uniform contribution of core-collapse and type Ia supernovae to the chemical enrichment pattern in the outskirts of the Virgo Cluster

    SciTech Connect

    Simionescu, A.; Werner, N.; Urban, O.; Allen, S. W.; Ichinohe, Y.; Zhuravleva, I.

    2015-09-24

    We present the first measurements of the abundances of α-elements (Mg, Si, and S) extending out beyond the virial radius of a cluster of galaxies. Our results, based on Suzaku Key Project observations of the Virgo Cluster, show that the chemical composition of the intracluster medium is consistent with being constant on large scales, with a flat distribution of the Si/Fe, S/Fe, and Mg/Fe ratios as a function of radius and azimuth out to 1.4 Mpc (1.3 r200). Chemical enrichment of the intergalactic medium due solely to core-collapse supernovae (SNcc) is excluded with very high significance; instead, the measured metal abundance ratios are generally consistent with the solar value. The uniform metal abundance ratios observed today are likely the result of an early phase of enrichment and mixing, with both SNcc and SNe Ia contributing to the metal budget during the period of peak star formation activity at redshifts of 2–3. Furthermore, we estimate the ratio between the number of SNe Ia and the total number of supernovae enriching the intergalactic medium to be between 12% and 37%, broadly consistent with the metal abundance patterns in our own Galaxy or with the SN Ia contribution estimated for the cluster cores.

  1. Evidence for nearby supernova explosions.

    PubMed

    Benítez, Narciso; Maíz-Apellániz, Jesús; Canelles, Matilde

    2002-02-25

    Supernova (SN) explosions are one of the most energetic---and potentially lethal---phenomena in the Universe. We show that the Scorpius-Centaurus OB association, a group of young stars currently located at approximately 130 pc from the Sun, has generated 20 SN explosions during the last 11 Myr, some of them probably as close as 40 pc to our planet. The deposition on Earth of (60)Fe atoms produced by these explosions can explain the recent measurements of an excess of this isotope in deep ocean crust samples. We propose that approximately 2 Myr ago, one of the SNe exploded close enough to Earth to seriously damage the ozone layer, provoking or contributing to the Pliocene-Pleistocene boundary marine extinction.

  2. Supernova Discoveries from the Nearby Supernova Factory (SNfactory)

    DOE Data Explorer

    SNfactory International Collaboration,

    The Nearby Supernova Factory is an experiment designed to collect data on more Type Ia supernovae than have ever been studied in a single project before, and in so doing, to answer some fundamental questions about the nature of the universe. Type Ia supernovae are extraordinarily bright, remarkably uniform objects which make excellent "standard candles" for measuring the expansion rate of the universe. However, such stellar explosions are very rare, occurring only a couple of times per millenium in a typical galaxy, and remaining bright enough to detect only for a few weeks. Previous studies of Type Ia supernovae led to the discovery of the mysterious "dark energy" that is causing the universe to expand at an accelerating rate. To reduce the statistical uncertainties in previous experimental data, extensive spectral and photometric monitoring of more Type Ia supernovae is required. The SNfactory collaboration has built an automated system consisting of specialized software and custom-built hardware that systematically searches the sky for new supernovae, screens potential candidates, then performs multiple spectral and photometric observations on each supernova. These observations are stored in a database to be made available to supernova researchers world-wide for further study and analysis [copied from http://snfactory.lbl.gov/snf/snf-about.html]. Users must register and agree to the open access honor system. Finding charts are in FITS format and may not be accessible through normal browser settings.

  3. A Comparison of Boltzmann and Multigroup Flux-limited Diffusion Neutrino Transport during the Postbounce Shock Reheating Phase in Core-Collapse Supernovae

    SciTech Connect

    Messer, O.E.; Mezzacappa, A. |; Bruenn, S.W.; Guidry, M.W. |

    1998-11-01

    We compare Newtonian three-flavor multigroup Boltzmann (MGBT) and (Bruenn`s) multigroup flux-limited diffusion (MGFLD) neutrino transport in postbounce core-collapse supernova environments. We focus our study on quantities central to the postbounce neutrino heating mechanism for reviving the stalled shock. Stationary-state three-flavor neutrino distributions are developed in thermally and hydrodynamically frozen time slices obtained from core collapse and bounce simulations that implement Lagrangian hydrodynamics and MGFLD neutrino transport. We obtain distributions for time slices at 106 and 233 ms after core bounce for the core of a 15 {ital M}{sub {circle_dot}} progenitor, and at 156 ms after core bounce for a 25 {ital M}{sub {circle_dot}} progenitor. For both transport methods, the electron neutrino and antineutrino luminosities, rms energies, and mean inverse flux factors, all of which enter the neutrino heating rates, are computed as functions of radius and compared. The net neutrino heating rates are also computed as functions of radius and compared. Notably, we find significant differences in neutrino luminosities and mean inverse flux factors between the two transport methods for both precollapse models and for all three time slices. In each case, the luminosities for each transport method begin to diverge above the neutrinospheres, where the MGBT luminosities become larger than their MGFLD counterparts, finally settling to a constant difference maintained to the edge of the core. We find that the mean inverse flux factors, which describe the degree of forward peaking in the neutrino radiation field, also differ significantly between the two transport methods, with MGBT providing more isotropic radiation fields in the gain region. Most important, for a region above the gain radius we find net heating rates for MGBT that are as much as {approximately}2 times the corresponding MGFLD rates, and we find net cooling rates below the gain radius that are

  4. Overview of the nearby supernova factory

    SciTech Connect

    Aldering, Greg; Adam, Gilles; Antilogus, Pierre; Astier, Pierre; Bacon, Roland; Bongard, S.; Bonnaud, C.; Copin, Yannick; Hardin, D.; Howell, D. Andy; Lemmonnier, Jean-Pierre; Levy, J.-M.; Loken, S.; Nugent, Peter; Pain, Reynald; Pecontal, Arlette; Pecontal, Emmanuel; Perlmutter, Saul; Quimby, Robert; Schahmaneche, Kyan; Smadja, Gerard; Wood-Vasey, W. Michael

    2002-07-29

    The Nearby Supernova Factory (SNfactory) is an international experiment designed to lay the foundation for the next generation of cosmology experiments (such as CFHTLS, wP, SNAP and LSST) which will measure the expansion history of the Universe using Type Ia supernovae. The SNfactory will discover and obtain frequent lightcurve spectrophotometry covering 3200-10000 {angstrom} for roughly 300 Type Ia supernovae at the low-redshift end of the smooth Hubble flow. The quantity, quality, breadth of galactic environments, and homogeneous nature of the SNfactory dataset will make it the premier source of calibration for the Type Ia supernova width-brightness relation and the intrinsic supernova colors used for K-correction and correction for extinction by host-galaxy dust. This dataset will also allow an extensive investigation of additional parameters which possibly influence the quality of Type Ia supernovae as cosmological probes. The SNfactory search capabilities and follow-up instrumentation include wide-field CCD imagers on two 1.2-m telescopes (via collaboration with the Near Earth Asteroid Tracking team at JPL and the QUEST team at Yale), and a two-channel integral-field-unit optical spectrograph/imager being fabricated for the University of Hawaii 2.2-m telescope. In addition to ground-based follow-up, UV spectra for a subsample of these supernovae will be obtained with HST. The pipeline to obtain, transfer via wireless and standard internet, and automatically process the search images is in operation. Software and hardware development is now underway to enable the execution of follow-up spectroscopy of supernova candidates at the Hawaii 2.2-m telescope via automated remote control of the telescope and the IFU spectrograph/imager.

  5. The nuclear starburst in Arp 299-A: from the 5.0 GHz VLBI radio light-curves to its core-collapse supernova rate

    NASA Astrophysics Data System (ADS)

    Bondi, M.; Pérez-Torres, M. A.; Herrero-Illana, R.; Alberdi, A.

    2012-03-01

    Context. The nuclear region of the luminous infrared galaxy (LIRG) Arp 299-A hosts a recent ( ≃ 10 Myr) intense burst of massive star formation that is expected to lead to numerous core-collapse supernovae (CCSNe). Previous VLBI observations, carried out with the European VLBI Network (EVN) at 5.0 GHz and with the VLBA at 2.3 and 8.4 GHz, resulted in the detection of many compact, bright, non-thermal sources in a region ≲ 150 pc in size. Aims: We aim to establish the nature of all non-thermal compact components in Arp 299-A, as well as to estimate its core-collapse supernova rate. While the majority of the compact components are expected to be young radio supernovae (RSNe) and supernova remnants (SNRs), a definitive classification is still lacking. Yet, this is very relevant for eventually establishing the CCSN rate, as well as the star formation rate, for this galaxy. Methods: We used multi-epoch EVN observations taken at 5.0 GHz to image the compact radio sources in the nuclear region of Arp 299-A with milliarcsecond resolution. We also used one single-epoch 5.0 GHz Multi-Element Radio Linked Interferometer Network (MERLIN) observation to image the extended emission in which these compact radio sources are embedded. Results: We present the first 5.0 GHz radio light-curve (spanning ~2.5 yr) of all compact components in the nuclear starburst of Arp 299-A. Twenty-six compact sources are detected, eight of which are new objects. The properties of all detected objects are consistent with them being a mixed population of CCSNe and SNRs. We find clear evidence for at least two new CCSNe, implying a lower limit to the CCSN rate of νSN ≳ 0.80 SN/yr, indicating that the bulk of the current star formation in Arp 299-A is taking place in the innermost ~150 pc.A few more objects show variability consistent with them being recently exploded SNe, but only future observations will clarify this point. Our MERLIN observations trace a region of diffuse extended emission that

  6. The Tip of the Red Giant Branch Distance to the Perfect Spiral Galaxy M74 Hosting Three Core-collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Jang, In Sung; Lee, Myung Gyoon

    2014-09-01

    M74 (NGC 628) is a famous face-on spiral galaxy, hosting three core-collapse supernovae (SNe): SN Ic 2002ap, SN II-P 2003gd, and SN II-P 2013ej. However, its distance is not well known. We present a distance estimation for this galaxy based on the Tip of the Red Giant Branch (TRGB) method. We obtain photometry of the resolved stars in the arm-free region of M74 from F555W and F814W images in the Hubble Space Telescope archive. The color-magnitude diagram of the resolved stars shows a dominant red giant branch (RGB) as well as blue main sequence stars, red helium burning stars, and asymptotic giant branch stars. The I-band luminosity function of the RGB stars shows the TRGB to be at I TRGB = 26.13 ± 0.03 mag, and T RGB = 25.97 ± 0.03. From this, we derive the distance modulus to M74 to be 30.04 ± 0.04 (random) ± 0.12 (systematic) (corresponding to a linear distance of 10.19 ± 0.14 ± 0.56 Mpc). With this distance estimate, we calibrate the standardized candle method for SNe II-P. From the absolute magnitudes of SN 2003gd, we derive a value of the Hubble constant, H 0 = 72 ± 6 (random) ± 7 (systematic) km s-1 Mpc-1. It is similar to recent estimates based on the luminosity calibration of Type Ia supernovae.

  7. Analysis of fluid instabilities in core collapse supernova progenitors by a semi-analytical methodology and by two dimensional radiation-hydrodynamical simulations

    NASA Astrophysics Data System (ADS)

    Raley, Elizabeth

    2004-12-01

    We have performed an analysis of fluid instabilities below the neutrinospheres of the collapsed cores of supernova progenitors using a methodology introduced by Bruenn and Dineva [28, 29, 31]. In an extensive survey we found that the rate of lepton diffusion always exceeds the rate of thermal diffusion and as a result we do not anywhere see the neutron finger instability as described by the Livermore group [16, 17]. A new instability, lepto-entropy fingers, extending from a radius of 10 15 km out to the vicinity of the neutrinosphere, driven by the cross-response functions (i.e. the dependence of lepton transport on entropy perturbations and vice versa) was discovered. This instability has a maximum growth rate of the order of 100 s-1 with a scale of approximately 1/20 the distance of a perturbed fluid element from the core center [18]. This instability has probably already been seen in some multi-dimensional core collapse calculations. To test our results predicting the presence of doubly diffusive instabilities below the neutrinosphere of a proto-supernova, we have performed two dimensional hydrodynamic simulations with radial ray neutrino transport. This entailed rewriting RadHyd, which is the merger of EVH-1 hydrodynamics and MGFLD neutrino transport developed by Bruenn and DiNisco [43], for two dimensions. In particular, hydrodynamic evolution along angular arrays was included, as was MPI message passing capabilities, in order to utilize massively parallel computer platform such as FAU's BOCA4 Beowulf cluster. This work was partially funded by a grant from the DOE Office of Science, Scientific Discovery through Advanced Computing Program.

  8. The Tip of the red giant branch distance to the perfect spiral galaxy M74 hosting three core-collapse supernovae

    SciTech Connect

    Sung Jang, In; Gyoon Lee, Myung E-mail: mglee@astro.snu.ac.kr

    2014-09-01

    M74 (NGC 628) is a famous face-on spiral galaxy, hosting three core-collapse supernovae (SNe): SN Ic 2002ap, SN II-P 2003gd, and SN II-P 2013ej. However, its distance is not well known. We present a distance estimation for this galaxy based on the Tip of the Red Giant Branch (TRGB) method. We obtain photometry of the resolved stars in the arm-free region of M74 from F555W and F814W images in the Hubble Space Telescope archive. The color-magnitude diagram of the resolved stars shows a dominant red giant branch (RGB) as well as blue main sequence stars, red helium burning stars, and asymptotic giant branch stars. The I-band luminosity function of the RGB stars shows the TRGB to be at I {sub TRGB} = 26.13 ± 0.03 mag, and T {sub RGB} = 25.97 ± 0.03. From this, we derive the distance modulus to M74 to be 30.04 ± 0.04 (random) ± 0.12 (systematic) (corresponding to a linear distance of 10.19 ± 0.14 ± 0.56 Mpc). With this distance estimate, we calibrate the standardized candle method for SNe II-P. From the absolute magnitudes of SN 2003gd, we derive a value of the Hubble constant, H {sub 0} = 72 ± 6 (random) ± 7 (systematic) km s{sup –1} Mpc{sup –1}. It is similar to recent estimates based on the luminosity calibration of Type Ia supernovae.

  9. A New Multi-dimensional General Relativistic Neutrino Hydrodynamic Code for Core-collapse Supernovae. I. Method and Code Tests in Spherical Symmetry

    NASA Astrophysics Data System (ADS)

    Müller, Bernhard; Janka, Hans-Thomas; Dimmelmeier, Harald

    2010-07-01

    We present a new general relativistic code for hydrodynamical supernova simulations with neutrino transport in spherical and azimuthal symmetry (one dimension and two dimensions, respectively). The code is a combination of the COCONUT hydro module, which is a Riemann-solver-based, high-resolution shock-capturing method, and the three-flavor, fully energy-dependent VERTEX scheme for the transport of massless neutrinos. VERTEX integrates the coupled neutrino energy and momentum equations with a variable Eddington factor closure computed from a model Boltzmann equation and uses the "ray-by-ray plus" approximation in two dimensions, assuming the neutrino distribution to be axially symmetric around the radial direction at every point in space, and thus the neutrino flux to be radial. Our spacetime treatment employs the Arnowitt-Deser-Misner 3+1 formalism with the conformal flatness condition for the spatial three metric. This approach is exact for the one-dimensional case and has previously been shown to yield very accurate results for spherical and rotational stellar core collapse. We introduce new formulations of the energy equation to improve total energy conservation in relativistic and Newtonian hydro simulations with grid-based Eulerian finite-volume codes. Moreover, a modified version of the VERTEX scheme is developed that simultaneously conserves energy and lepton number in the neutrino transport with better accuracy and higher numerical stability in the high-energy tail of the spectrum. To verify our code, we conduct a series of tests in spherical symmetry, including a detailed comparison with published results of the collapse, shock formation, shock breakout, and accretion phases. Long-time simulations of proto-neutron star cooling until several seconds after core bounce both demonstrate the robustness of the new COCONUT-VERTEX code and show the approximate treatment of relativistic effects by means of an effective relativistic gravitational potential as in

  10. A NEW MULTI-DIMENSIONAL GENERAL RELATIVISTIC NEUTRINO HYDRODYNAMIC CODE FOR CORE-COLLAPSE SUPERNOVAE. I. METHOD AND CODE TESTS IN SPHERICAL SYMMETRY

    SciTech Connect

    Mueller, Bernhard; Janka, Hans-Thomas; Dimmelmeier, Harald E-mail: thj@mpa-garching.mpg.d

    2010-07-15

    We present a new general relativistic code for hydrodynamical supernova simulations with neutrino transport in spherical and azimuthal symmetry (one dimension and two dimensions, respectively). The code is a combination of the COCONUT hydro module, which is a Riemann-solver-based, high-resolution shock-capturing method, and the three-flavor, fully energy-dependent VERTEX scheme for the transport of massless neutrinos. VERTEX integrates the coupled neutrino energy and momentum equations with a variable Eddington factor closure computed from a model Boltzmann equation and uses the 'ray-by-ray plus' approximation in two dimensions, assuming the neutrino distribution to be axially symmetric around the radial direction at every point in space, and thus the neutrino flux to be radial. Our spacetime treatment employs the Arnowitt-Deser-Misner 3+1 formalism with the conformal flatness condition for the spatial three metric. This approach is exact for the one-dimensional case and has previously been shown to yield very accurate results for spherical and rotational stellar core collapse. We introduce new formulations of the energy equation to improve total energy conservation in relativistic and Newtonian hydro simulations with grid-based Eulerian finite-volume codes. Moreover, a modified version of the VERTEX scheme is developed that simultaneously conserves energy and lepton number in the neutrino transport with better accuracy and higher numerical stability in the high-energy tail of the spectrum. To verify our code, we conduct a series of tests in spherical symmetry, including a detailed comparison with published results of the collapse, shock formation, shock breakout, and accretion phases. Long-time simulations of proto-neutron star cooling until several seconds after core bounce both demonstrate the robustness of the new COCONUT-VERTEX code and show the approximate treatment of relativistic effects by means of an effective relativistic gravitational potential as in

  11. Simulation of the spherically symmetric stellar core collapse, bounce, and postbounce evolution of a star of 13 solar masses with boltzmann neutrino transport, and its implications for the supernova mechanism.

    PubMed

    Mezzacappa, A; Liebendörfer, M; Messer, O E; Hix, W R; Thielemann, F K; Bruenn, S W

    2001-03-01

    With exact three-flavor Boltzmann neutrino transport, we simulate the stellar core collapse, bounce, and postbounce evolution of a 13M star in spherical symmetry, the Newtonian limit, without invoking convection. In the absence of convection, prior spherically symmetric models, which implemented approximations to Boltzmann transport, failed to produce explosions. We consider exact transport to determine if these failures were due to the transport approximations made and to answer remaining fundamental questions in supernova theory. The model presented here is the first in a sequence of models beginning with different progenitors. In this model, a supernova explosion is not obtained.

  12. Powerful Nearby Supernova Caught By Web

    NASA Astrophysics Data System (ADS)

    2008-09-01

    One of the nearest supernovas in the last 25 years has been identified over a decade after it exploded. This result was made possible by combining data from the vast online archives from many of the world's premier telescopes. The supernova was first singled out in 2001 by Franz Bauer, then at Penn State and now at Columbia University, who noticed a bright, variable object in the spiral galaxy Circinus using NASA's Chandra X-ray Observatory. Though the source displayed some exceptional properties, at the time Bauer and his Penn State colleagues could not confidently identify its nature. It was not until years later that Bauer and his team were able to confirm this object was a supernova. Clues in a spectrum from the European Southern Observatory's Very Large Telescope (VLT) led the team to search through data from 18 different telescopes, both in space and on the ground, nearly all of which was from archives. Because this object was found in a nearby galaxy, making it relatively easy to study, the public archives of these telescopes contained abundant data on this galaxy. The data show that this supernova, dubbed SN 1996cr, is among the brightest supernovas ever seen in radio and X-rays. It also bears many striking similarities to the famous supernova SN 1987A, which occurred in a galaxy only 160,000 light years from Earth. "This supernova appears to be a wild cousin of SN 1987A," said Bauer. "These two look alike in many ways, except this newer supernova is intrinsically a thousand times brighter in radio and X-rays." Optical images from the archives of the Anglo-Australian Telescope in Australia show that SN 1996cr exploded between February 28, 1995 and March 15, 1996, nearly a decade after SN 1987A. SN 1996cr may not have been noticed by astronomers at the time because it was only visible in the southern hemisphere, which is not as widely monitored as the northern. Among the five nearest supernovas of the last 25 years, it is the only one that was not seen

  13. Powerful Nearby Supernova Caught By Web

    NASA Astrophysics Data System (ADS)

    2008-09-01

    One of the nearest supernovas in the last 25 years has been identified over a decade after it exploded. This result was made possible by combining data from the vast online archives from many of the world's premier telescopes. The supernova was first singled out in 2001 by Franz Bauer, then at Penn State and now at Columbia University, who noticed a bright, variable object in the spiral galaxy Circinus using NASA's Chandra X-ray Observatory. Though the source displayed some exceptional properties, at the time Bauer and his Penn State colleagues could not confidently identify its nature. It was not until years later that Bauer and his team were able to confirm this object was a supernova. Clues in a spectrum from the European Southern Observatory's Very Large Telescope (VLT) led the team to search through data from 18 different telescopes, both in space and on the ground, nearly all of which was from archives. Because this object was found in a nearby galaxy, making it relatively easy to study, the public archives of these telescopes contained abundant data on this galaxy. The data show that this supernova, dubbed SN 1996cr, is among the brightest supernovas ever seen in radio and X-rays. It also bears many striking similarities to the famous supernova SN 1987A, which occurred in a galaxy only 160,000 light years from Earth. "This supernova appears to be a wild cousin of SN 1987A," said Bauer. "These two look alike in many ways, except this newer supernova is intrinsically a thousand times brighter in radio and X-rays." Optical images from the archives of the Anglo-Australian Telescope in Australia show that SN 1996cr exploded between February 28, 1995 and March 15, 1996, nearly a decade after SN 1987A. SN 1996cr may not have been noticed by astronomers at the time because it was only visible in the southern hemisphere, which is not as widely monitored as the northern. Among the five nearest supernovas of the last 25 years, it is the only one that was not seen

  14. LIGHT CURVES OF CORE-COLLAPSE SUPERNOVAE WITH SUBSTANTIAL MASS LOSS USING THE NEW OPEN-SOURCE SUPERNOVA EXPLOSION CODE (SNEC)

    SciTech Connect

    Morozova, Viktoriya; Renzo, Mathieu; Ott, Christian D.; Clausen, Drew; Couch, Sean M.; Ellis, Justin; Roberts, Luke F.; Piro, Anthony L.

    2015-11-20

    We present the SuperNova Explosion Code (SNEC), an open-source Lagrangian code for the hydrodynamics and equilibrium-diffusion radiation transport in the expanding envelopes of supernovae. Given a model of a progenitor star, an explosion energy, and an amount and distribution of radioactive nickel, SNEC generates the bolometric light curve, as well as the light curves in different broad bands assuming blackbody emission. As a first application of SNEC, we consider the explosions of a grid of 15 M{sub ⊙} (at zero-age main sequence, ZAMS) stars whose hydrogen envelopes are stripped to different extents and at different points in their evolution. The resulting light curves exhibit plateaus with durations of ∼20–100 days if ≳1.5–2 M{sub ⊙} of hydrogen-rich material is left and no plateau if less hydrogen-rich material is left. If these shorter plateau lengths are not seen for SNe IIP in nature, it suggests that, at least for ZAMS masses ≲20 M{sub ⊙}, hydrogen mass loss occurs as an all or nothing process. This perhaps points to the important role binary interactions play in generating the observed mass-stripped supernovae (i.e., Type Ib/c events). These light curves are also unlike what is typically seen for SNe IIL, arguing that simply varying the amount of mass loss cannot explain these events. The most stripped models begin to show double-peaked light curves similar to what is often seen for SNe IIb, confirming previous work that these supernovae can come from progenitors that have a small amount of hydrogen and a radius of ∼500 R{sub ⊙}.

  15. Nearby supernova rates from the Lick Observatory Supernova Search - I. The methods and data base

    NASA Astrophysics Data System (ADS)

    Leaman, Jesse; Li, Weidong; Chornock, Ryan; Filippenko, Alexei V.

    2011-04-01

    This is the first paper of a series in which we present new measurements of the observed rates of supernovae (SNe) in the local Universe, determined from the Lick Observatory Supernova Search. We have obtained 2.3 million observations of 14 882 sample galaxies over an interval of 11 years (1998 March to 2008 December). We considered 1036 SNe detected in our sample and used an optimal subsample of 726 SNe (274 Type Ia SNe, 116 Type Ibc SNe and Type II 324 SNe) to determine our SN rates. This is the largest and most homogeneous set of nearby SNe ever assembled for this purpose, and ours is the first local SN rate analysis based on CCD imaging and modern image-subtraction techniques. In this paper, we lay the foundation of the study. We derive the recipe for the control-time calculation for SNe with a known luminosity function and provide details on the construction of the galaxy and SN samples used in the calculations. Compared with a complete volume-limited galaxy sample, our sample has a deficit of low-luminosity galaxies but still provides enough statistics for a reliable rate calculation. There is a strong Malmquist bias, so the average size (luminosity or mass) of the galaxies increases monotonically with distance, and this trend is used to showcase a correlation between SN rates and galaxy sizes. Very few core-collapse SNe are found in early-type galaxies, providing strong constraints on the amount of recent star formation within these galaxies. The small average observation interval (˜9 d) of our survey ensures that our control-time calculations can tolerate a reasonable amount of uncertainty in the luminosity functions of SNe. We perform Monte Carlo simulations to determine the limiting magnitude of each image and the SN detection efficiency as a function of galaxy Hubble type. The limiting magnitude and the detection efficiency, together with the luminosity function derived from a complete sample of very nearby SNe in Paper II, will be used to calculate the

  16. New candidate supernova remnants in nearby galaxies

    NASA Astrophysics Data System (ADS)

    Kopsacheili, Maria; Boumis, Panos; Leonidaki, Ioanna; Zezas, Andreas

    2016-06-01

    Supernova remnants (SNRs) are objects of high importance since they provide major amounts of energy to the interstellar medium (ISM), while at the same time, they depict the end-point state of massive stars (M > 8 Mo). In order to investigate the physical properties of these objects and their interplay with their environment, we have embarked in an extensive investigation of the SNR populations in nearby galaxies of different morphological types. This effort has been initiated with six galaxies, mostly irregulars,in the northern hemisphere (Leonidaki et al. 2010, 2013). Following this context, we present new candidate SNRs (down to fluxes of 10^{-16} erg sec^{-1} cm^-2) of five spiral galaxies in the southern hemisphere (NGC 45, NGC 55, NGC 1313, NGC 1672, NGC 7793), based on deep narrow-band Hα and [S II] images observed with the 4m Blanco telescope at CTIO, Chile. The new detections were achieved by calculating the [S II]/Hα flux ratio, where all sources with [S II]/ Hα > 0.4 were considered as candidate SNRs. Furthermore, we use the derived properties of the newly detected candidate SNRs ([S II]/Hα ratios, Hα fluxes) to investigate how they are distributed according to their brightness and their behavior in different environments (irregulars vs. spirals).

  17. IceCube Sensitivity for Low-Energy Neutrinos from Nearby Supernovae

    NASA Technical Reports Server (NTRS)

    Stamatikos, M.; Abbasi, R.; Berghaus, P.; Chirkin, D.; Desiati, P.; Diaz-Velez, J.; Dumm, J. P.; Eisch, J.; Feintzeig, J.; Hanson, K.; Hoshina, I.; Kurahashi, N.; Landsman, H.; Maruyama, R.; Montaruli, T.

    2012-01-01

    This paper describes the response of the IceCube neutrino telescope located at the geographic South Pole to outbursts of MeV neutrinos from the core collapse of nearby massive stars. IceCube was completed in December 2010 forming a lattice of 5160 photomultiplier tubes that monitor a volume of approx. 1 cu km in the deep Antarctic ice for particle induced photons. The telescope was designed to detect neutrinos with energies greater than 100 GeV. Owing to subfreezing ice temperatures, the photomultiplier dark noise rates are particularly low. Hence IceCube can also detect large numbers of MeV neutrinos by observing a collective rise in all photomultiplier rates on top of the dark noise. With 2 ms timing resolution, IceCube can detect subtle features in the temporal development of the supernova neutrino burst. For a supernova at the galactic center, its sensitivity matches that of a background-free megaton-scale supernova search experiment. The sensitivity decreases to 20 standard deviations at the galactic edge (30 kpc) and 6 standard deviations at the Large Magellanic Cloud (50 kpc). IceCube is sending triggers from potential supernovae to the Supernova Early Warning System. The sensitivity to neutrino properties such as the neutrino hierarchy is discussed, as well as the possibility to detect the neutronization burst, a short outbreak's released by electron capture on protons soon after collapse. Tantalizing signatures, such as the formation of a quark star or a black hole as well as the characteristics of shock waves, are investigated to illustrate IceCube's capability for supernova detection.

  18. Three-dimensional simulations of rapidly rotating core-collapse supernovae: finding a neutrino-powered explosion aided by non-axisymmetric flows

    NASA Astrophysics Data System (ADS)

    Takiwaki, Tomoya; Kotake, Kei; Suwa, Yudai

    2016-09-01

    We report results from a series of three-dimensional (3D) rotational core-collapse simulations for 11.2 and 27 M⊙ stars employing neutrino transport scheme by the isotropic diffusion source approximation. By changing the initial strength of rotation systematically, we find a rotation-assisted explosion for the 27 M⊙ progenitor , which fails in the absence of rotation. The unique feature was not captured in previous two-dimensional (2D) self-consistent rotating models because the growing non-axisymmetric instabilities play a key role. In the rapidly rotating case, strong spiral flows generated by the so-called low T/|W| instability enhance the energy transport from the proto-neutron star (PNS) to the gain region, which makes the shock expansion more energetic. The explosion occurs more strongly in the direction perpendicular to the rotational axis, which is different from previous 2D predictions.

  19. A New Empirical Model for Type Ia Supernovae Using Spectrophotometry from the Nearby Supernova Factory

    NASA Astrophysics Data System (ADS)

    Saunders, Clare; Nearby Supernova Factory

    2016-01-01

    Type Ia supernovae are currently limited in their use for cosmology by dispersion in standardized magnitudes. A large part of this dispersion is due to the fact that the current lightcurve fitters do not describe the full range of Type Ia supernova diversity. I will present an empirical model of Type Ia supernovae that captures a wider range of supernova behavior and can improve magnitude standardization. This model is constructed using over 2000 spectrophotometric observations of Type Ia supernovae from the Nearby Supernova Factory. The true spectral time series for each supernova is modeled using Gaussian Processes. The supernova model predictions are used to calculate the principal components of the full set of supernova spectral time series. K-fold cross-validation is used to determine how many components correlate to absolute magnitude. Future work will test this method on independent photometric data sets.

  20. Modeling nuclear 'pasta' and the transition to uniform nuclear matter with the 3D Skyrme-Hartree-Fock method at finite temperature: Core-collapse supernovae

    SciTech Connect

    Newton, W. G.; Stone, J. R.

    2009-05-15

    The first results of a new three-dimensional, finite temperature Skyrme-Hartree-Fock+BCS study of the properties of inhomogeneous nuclear matter at densities and temperatures leading to the transition to uniform nuclear matter are presented. Calculations are carried out in a cubic box representing a unit cell of the locally periodic structure of the matter. A constraint is placed on the two independent components of the quadrupole moment of the neutron density to investigate the dependence of the total energy density of matter on the geometry of the nuclear structure in the unit cell. This approach allows self-consistent modeling of effects such as (i) neutron drip, resulting in a neutron gas external to the nuclear structure; (ii) shell effects of bound and unbound nucleons; (iii) the variety of exotic nuclear shapes that emerge, collectively termed nuclear pasta; and (iv) the dissolution of these structures into uniform nuclear matter as density and/or temperature increase. In Part I of this work the calculation of the properties of inhomogeneous nuclear matter in the core collapse of massive stars is reported. Emphasis is on exploring the effects of the numerical method on the results obtained; notably, the influence of the finite cell size on the nuclear shapes and energy-density obtained. Results for nuclear matter in {beta} equilibrium in cold neutrons stars are the subject of Part II. The calculation of the band structure of unbound neutrons in neutron star matter, yielding thermal conductivity, specific heat, and entrainment parameters, is outlined in Part III. Calculations are performed at baryon number densities of n{sub b}=0.04-0.12 fm{sup -3}, a proton fraction of y{sub p}=0.3 and temperatures in the range 0-7.5 MeV. A wide variety of nuclear shapes are shown to emerge. It is suggested that thermodynamical properties change smoothly in the pasta regime up to the transition to uniform matter; at that transition, thermodynamic properties of the matter

  1. Probing the structure of jet-driven core-collapse supernova and long gamma-ray burst progenitors with high-energy neutrinos

    NASA Astrophysics Data System (ADS)

    Bartos, Imre; Dasgupta, Basudeb; Márka, Szabolcs

    2012-10-01

    Times of arrival of high-energy neutrinos encode information about their sources. We demonstrate that the energy-dependence of the onset time of neutrino emission in advancing relativistic jets can be used to extract important information about the supernova/gamma-ray burst progenitor structure. We examine this energy and time dependence for different supernova and gamma-ray burst progenitors, including red and blue supergiants, helium cores, Wolf-Rayet stars, and chemically homogeneous stars, with a variety of masses and metallicities. For choked jets, we calculate the cutoff of observable neutrino energies depending on the radius at which the jet is stalled. Further, we exhibit how such energy and time dependence may be used to identify and differentiate between progenitors, with as few as one or two observed events, under favorable conditions.

  2. XRF 100316D/SN 2010bh: CLUE TO THE DIVERSE ORIGIN OF NEARBY SUPERNOVA-ASSOCIATED GAMMA-RAY BURSTS

    SciTech Connect

    Fan Yizhong; Zhang Bibbin; Liang Enwei; Zhang Bing; Xu Dong E-mail: zhang@physics.unlv.edu

    2011-01-01

    X-ray Flash (XRF) 100316D, a nearby super-long underluminous burst with a peak energy E{sub p} {approx} 20 keV, was detected by Swift and was found to be associated with an energetic supernova SN 2010bh. Both the spectral and the temporal behavior are rather similar to XRF 060218, except that the latter was associated with a 'less energetic' SN 2006aj and had a prominent soft thermal emission component in the spectrum. We analyze the spectral and temporal properties of this burst and interpret the prompt gamma-ray emission and the early X-ray plateau emission as synchrotron emission from a dissipating Poynting flux dominated outflow, probably powered by a magnetar with a spin period of P {approx} 10 ms and the polar cap magnetic field B{sub p} {approx} 3 x 10{sup 15} G. The energetic supernova SN 2010bh associated with this burst is, however, difficult to interpret within the slow magnetar model, and we suspect that the nascent magnetar may spin much faster with an initial rotation period {approx}1 ms. It suggests a delay between the core collapse and the emergence of the relativistic magnetar wind from the star. The diverse behaviors of low-luminosity gamma-ray bursts and their associated supernovae may be understood within a unified picture that invokes different initial powers of the central engine and different delay times between the core collapse and the emergence of the relativistic jet from the star.

  3. Studies of Nearby Supernovae with the Katzman Automatic Imaging Telescope

    NASA Astrophysics Data System (ADS)

    Filippenko, A. V.

    2000-05-01

    The Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory is a fully robotic 0.75-m reflector equipped with a CCD imaging camera. Its telescope control system checks the weather, opens the dome, points to the desired objects, finds and acquires guide stars, exposes, stores the data, and manipulates the data without human intervention. There is a filter wheel with 20 slots, including UBVRI. Five-minute guided exposures yield R ~ 20 mag. One of our main goals is to discover nearby supernovae (with redshifts generally less than 5000 km/s), to be used for a variety of studies. Special emphasis is placed on finding them well before maximum brightness. A limit of ~ 19 mag (4σ ) is reached in the 25-second unfiltered, unguided exposures of our Lick Observatory Supernova Search (LOSS). We observe up to ~ 1000 galaxies per night, and try to cycle back to the same galaxies after 3-4 nights. Our software automatically subtracts new images from old ones and identifies supernova candidates that are subsequently examined by undergraduate research assistants. LOSS found 19 supernovae in 1998 and 40 in 1999, making KAIT the world's most successful search engine for nearby supernovae. We also find novae in the Local Group, comets, asteroids, and cataclysmic variables. Multi-filter follow-up photometry is conducted of the most important supernovae, and all objects are monitored in unfiltered mode. A Web page describing LOSS is at http://astro.berkeley.edu/ ~bait/kait.html . KAIT and its associated science have been made possible with funding or donations from NSF, NASA, the Sylvia and Jim Katzman Foundation, Sun Microsystems Inc., the Hewlett-Packard Company, Photometrics Ltd., AutoScope Corporation, and the University of California. Many people contributed to KAIT and LOSS over the past decade, especially R. R. Treffers, W. D. Li, and M. W. Richmond.

  4. Toward connecting core-collapse supernova theory with observations. I. Shock revival in a 15 M {sub ☉} blue supergiant progenitor with SN 1987A energetics

    SciTech Connect

    Handy, Timothy; Plewa, Tomasz; Odrzywołek, Andrzej

    2014-03-10

    We study the evolution of the collapsing core of a 15 M {sub ☉} blue supergiant supernova progenitor from the core bounce until 1.5 s later. We present a sample of hydrodynamic models parameterized to match the explosion energetics of SN 1987A. We find the spatial model dimensionality to be an important contributing factor in the explosion process. Compared to two-dimensional (2D) simulations, our three-dimensional (3D) models require lower neutrino luminosities to produce equally energetic explosions. We estimate that the convective engine in our models is 4% more efficient in 3D than in 2D. We propose that the greater efficiency of the convective engine found in 3D simulations might be due to the larger surface-to-volume ratio of convective plumes, which aids in distributing energy deposited by neutrinos. We do not find evidence of the standing accretion shock instability or turbulence being a key factor in powering the explosion in our models. Instead, the analysis of the energy transport in the post-shock region reveals characteristics of penetrative convection. The explosion energy decreases dramatically once the resolution is inadequate to capture the morphology of convection on large scales. This shows that the role of dimensionality is secondary to correctly accounting for the basic physics of the explosion. We also analyze information provided by particle tracers embedded in the flow and find that the unbound material has relatively long residency times in 2D models, while in 3D a significant fraction of the explosion energy is carried by particles with relatively short residency times.

  5. Quasithermal neutrinos from rotating protoneutron stars born during core collapse of massive stars

    NASA Astrophysics Data System (ADS)

    Murase, Kohta; Dasgupta, Basudeb; Thompson, Todd A.

    2014-02-01

    Rotating and magnetized protoneutron stars may drive relativistic magnetocentrifugally accelerated winds as they cool immediately after core collapse. The wind fluid near the star is composed of neutrons and protons, and the neutrons become relativistic while collisionally coupled with the ions. Here, we argue that the neutrons in the flow eventually undergo inelastic collisions around the termination shock inside the stellar material, producing ˜0.1-1 GeV neutrinos, without relying on cosmic-ray acceleration mechanisms. Even higher-energy neutrinos may be produced via particle acceleration mechanisms. We show that Precision IceCube Next Generation Upgrade and Hyper-Kamiokande can detect such neutrinos from nearby core-collapse supernovae, by reducing the atmospheric neutrino background via coincident detection of MeV neutrinos or gravitational waves and optical observations. Detection of these GeV and/or higher-energy neutrinos would provide important clues to the physics of magnetic acceleration, nucleosynthesis, the relation between supernovae and gamma-ray bursts, and the properties of newly born neutron stars.

  6. A Snapshot Survey of the Sites of Recent, Nearby Supernovae

    NASA Astrophysics Data System (ADS)

    Filippenko, Alex

    2012-10-01

    During the past few years, robotic {or nearly robotic} searches for supernovae {SNe}, most notably our Lick Observatory Supernova Search {LOSS}, have found hundreds of SNe, many of them in quite nearby galaxies {cz < 4000 km/s}. Most of the objects were discovered before maximum brightness, and have follow-up photometry and spectroscopy; they include some of the best-studied SNe to date. We propose to conduct a survey program to image the sites of some of these nearby objects, to obtain late-time photometry that will help reveal the origin of their lingering energy. The images will also provide high-resolution information on the local environments of SNe that are far superior to what we can procure from the ground. For example, we will obtain color-magnitude diagrams of stars in these SN sites, to constrain the reddening and SN progenitor masses. We will provide statistics on the light echoes around SNe, an important clue to their progenitor systems. We also propose to image several "SN impostors" - faint SNe IIn with massive progenitors - to verify whether they are indeed superoutbursts of luminous blue variables and survived the explosions, or a new/weak class of massive star explosions. Finally, the data will add multi-filter, deep images of many nearby galaxies to the HST archive for future studies such as galaxy morphology, stellar populations, SN progenitors, and variable stars.

  7. Could a nearby supernova explosion have caused a mass extinction?

    PubMed

    Ellis, J; Schramm, D N

    1995-01-01

    We examine the possibility that a nearby supernova explosion could have caused one or more of the mass extinctions identified by paleontologists. We discuss the possible rate of such events in the light of the recent suggested identification of Geminga as a supernova remnant less than 100 parsec (pc) away and the discovery of a millisecond pulsar about 150 pc away and observations of SN 1987A. The fluxes of gamma-radiation and charged cosmic rays on the Earth are estimated, and their effects on the Earth's ozone layer are discussed. A supernova explosion of the order of 10 pc away could be expected as often as every few hundred million years and could destroy the ozone layer for hundreds of years, letting in potentially lethal solar ultraviolet radiation. In addition to effects on land ecology, this could entail mass destruction of plankton and reef communities, with disastrous consequences for marine life as well. A supernova extinction should be distinguishable from a meteorite impact such as the one that presumably killed the dinosaurs at the "KT boundary." The recent argument that the KT event was exceedingly large and thus quite rare supports the need for other catastrophic events.

  8. Could a nearby supernova explosion have caused a mass extinction?

    PubMed Central

    Ellis, J; Schramm, D N

    1995-01-01

    We examine the possibility that a nearby supernova explosion could have caused one or more of the mass extinctions identified by paleontologists. We discuss the possible rate of such events in the light of the recent suggested identification of Geminga as a supernova remnant less than 100 parsec (pc) away and the discovery of a millisecond pulsar about 150 pc away and observations of SN 1987A. The fluxes of gamma-radiation and charged cosmic rays on the Earth are estimated, and their effects on the Earth's ozone layer are discussed. A supernova explosion of the order of 10 pc away could be expected as often as every few hundred million years and could destroy the ozone layer for hundreds of years, letting in potentially lethal solar ultraviolet radiation. In addition to effects on land ecology, this could entail mass destruction of plankton and reef communities, with disastrous consequences for marine life as well. A supernova extinction should be distinguishable from a meteorite impact such as the one that presumably killed the dinosaurs at the "KT boundary." The recent argument that the KT event was exceedingly large and thus quite rare supports the need for other catastrophic events. PMID:11607506

  9. Could a nearby supernova explosion have caused a mass extinction?

    SciTech Connect

    Ellis, J.; Schramm, D.N. |

    1995-01-03

    We examine the possibility that a nearby supernova explosion could have caused one or more of the mass extinctions identified by paleontologists. We discuss the possible rate of such events in the light of the recent suggested identification of Geminga as a supernova remnant less than 100 parsec (pc) away and the discovery of a millisecond pulsar about 150 pc away and observations of SN 1987A. The fluxes of {gamma}-radiation and charged cosmic rays on the Earth are estimated, and their effects on the Earth`s ozone layer are discussed. A supernova explosion of the order of 10 pc away could be expected as often as every few hundred million years and could destroy the ozone layer for hundreds of years, letting in potentially lethal solar ultraviolet radiation. In addition to effects on land ecology, this could entail mass destruction of plankton and reef communities, with disastrous consequences for marine life as well. A supernova extinction should be distinguishable from a meteorite impact such as the one that presumably killed the dinosaurs at the {open_quotes}KT boundary.{close_quotes} The recent argument that the KT event was exceedingly large and thus quite rare supports the need for other catastrophic events. 24 refs.

  10. Core-collapse supernovae and nucleosynthesis

    SciTech Connect

    Haxton, W.C.

    1994-12-01

    I discuss some of the physics that governs the collapse and explosion of a massive star, including issues such as lepton number losses in the infall stage and neutrino heating and convection following the core bounce. I review recent work on the neutrino process and the r-process, describing how the nucleosynthesis depends on the explosion mechanism. Some of the interesting possibilities for oscillations of closure mass {nu}{sub {tau}}s are discussed, along with their signatures in terrestrial detectors and in nucleosynthesis.

  11. A young supernova remnant illuminating nearby molecular clouds with cosmic rays

    NASA Astrophysics Data System (ADS)

    Cui, Y.; Pühlhofer, G.; Santangelo, A.

    2016-06-01

    The supernova remnant (SNR) HESS J1731-347 displays strong nonthermal TeV γ-ray and X-ray emission, thus the object is presently accelerating particles to very high energies. A distinctive feature of this young SNR is the nearby (~30 pc in projection) extended source HESS J1729-345, which is currently unidentified but is in spatial projection coinciding with known molecular clouds (MC). We model the SNR evolution to explore whether the TeV emission from HESS J1729-345 can be explained as emission from runaway hadronic cosmic rays (CRs) that are illuminating these MCs. The observational data of HESS J1729-345 and HESS J1731-347 can be reproduced using core-collapse SN models for HESS J1731-347. Starting with different progenitor stars and their presupernova environment, we model potential SNR evolution histories along with the CR acceleration in the SNR and the diffusion of the CRs. A simplified three-dimensional structure of the MCs is introduced based on data of that region, adopting a distance of 3.2 kpc to the source. A Monte Carlo based diffusion model for the escaping CRs is developed to deal with the inhomogeneous environment. The fast SNR forward shock speed, as implied from the X-ray data, can easily be explained when employing scenarios with progenitor star masses between 20 M⊙ and 25 M⊙, where the SNR shock is still expanding inside the main-sequence (MS) bubble at present time. The TeV spectrum of HESS J1729-345 is satisfactorily fitted by the emission from the highest energy CRs that have escaped the SNR, using a standard Galactic CR diffusion coefficient in the interclump medium. The TeV image of HESS J1729-345 can be explained with a reasonable three-dimensional structure of MCs. The TeV emission from the SNR itself is dominated by leptonic emission in this model. We also explore scenarios where the shock is starting to encounter the dense MS progenitor wind bubble shell. The escaping hadronic CR hypothesis for the γ-ray emission of HESS J1729

  12. Evidence of nearby supernovae affecting life on Earth

    NASA Astrophysics Data System (ADS)

    Svensmark, Henrik

    2012-06-01

    Observations of open star clusters in the solar neighbourhood are used to calculate local supernova (SN) rates for the past 510 Myr. Peaks in the SN rates match passages of the Sun through periods of locally increased cluster formation which could be caused by spiral arms of the Galaxy. A statistical analysis indicates that the Solar system has experienced many large short-term increases in the flux of Galactic cosmic rays (GCR) from nearby SNe. The hypothesis that a high GCR flux should coincide with cold conditions on the Earth is borne out by comparing the general geological record of climate over the past 510 Myr with the fluctuating local SN rates. Surprisingly, a simple combination of tectonics (long-term changes in sea level) and astrophysical activity (SN rates) largely accounts for the observed variations in marine biodiversity over the past 510 Myr. An inverse correspondence between SN rates and carbon dioxide (CO2) levels is discussed in terms of a possible drawdown of CO2 by enhanced bio-productivity in oceans that are better fertilized in cold conditions - a hypothesis that is not contradicted by data on the relative abundance of the heavy isotope of carbon, 13C.

  13. Measuring cosmic bulk flows with Type Ia supernovae from the Nearby Supernova Factory

    NASA Astrophysics Data System (ADS)

    Feindt, U.; Kerschhaggl, M.; Kowalski, M.; Aldering, G.; Antilogus, P.; Aragon, C.; Bailey, S.; Baltay, C.; Bongard, S.; Buton, C.; Canto, A.; Cellier-Holzem, F.; Childress, M.; Chotard, N.; Copin, Y.; Fakhouri, H. K.; Gangler, E.; Guy, J.; Kim, A.; Nugent, P.; Nordin, J.; Paech, K.; Pain, R.; Pecontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigault, M.; Runge, K.; Saunders, C.; Scalzo, R.; Smadja, G.; Tao, C.; Thomas, R. C.; Weaver, B. A.; Wu, C.

    2013-12-01

    Context. Our Local Group of galaxies appears to be moving relative to the cosmic microwave background with the source of the peculiar motion still uncertain. While in the past this has been studied mostly using galaxies as distance indicators, the weight of Type Ia supernovae (SNe Ia) has increased recently with the continuously improving statistics of available low-redshift supernovae. Aims: We measured the bulk flow in the nearby universe (0.015 < z < 0.1) using 117 SNe Ia observed by the Nearby Supernova Factory, as well as the Union2 compilation of SN Ia data already in the literature. Methods: The bulk flow velocity was determined from SN data binned in redshift shells by including a coherent motion (dipole) in a cosmological fit. Additionally, a method of spatially smoothing the Hubble residuals was used to verify the results of the dipole fit. To constrain the location and mass of a potential mass concentration (e.g., the Shapley supercluster) responsible for the peculiar motion, we fit a Hubble law modified by adding an additional mass concentration. Results: The analysis shows a bulk flow that is consistent with the direction of the CMB dipole up to z ~ 0.06, thereby doubling the volume over which conventional distance measures are sensitive to a bulk flow. We see no significant turnover behind the center of the Shapley supercluster. A simple attractor model in the proximity of the Shapley supercluster is only marginally consistent with our data, suggesting the need for another, more distant source. In the redshift shell 0.06 < z < 0.1, we constrain the bulk flow velocity to ≤240 km s-1 (68% confidence level) for the direction of the CMB dipole, in contradiction to recent claims of the existence of a large-amplitude dark flow.

  14. Intracluster Supernovae in the Multi-epoch Nearby Cluster Survey

    NASA Astrophysics Data System (ADS)

    Sand, David J.; Graham, Melissa L.; Bildfell, Chris; Foley, Ryan J.; Pritchet, Chris; Zaritsky, Dennis; Hoekstra, Henk; Just, Dennis W.; Herbert-Fort, Stéphane; Sivanandam, Suresh

    2011-03-01

    The Multi-Epoch Nearby Cluster Survey has discovered 23 cluster Type Ia supernovae (SNe Ia) in the 58 X-ray-selected galaxy clusters (0.05 lsimzlsim 0.15) surveyed. Four of our SN Ia events have no host galaxy on close inspection, and are likely intracluster SNe. Although one of the candidates, Abell399_3_14_0, appears to be associated in projection with the outskirts of a nearby red sequence galaxy, its velocity offset of ~1000 km s-1 indicates that it is unbound and therefore an intracluster SN. Another of our candidates, Abell85_6_08_0, has a spectrum consistent with an SN1991bg-like object, suggesting that at least some portion of intracluster stars belong to an old stellar population. Deep image stacks at the location of the candidate intracluster SNe put upper limits on the luminosities of faint hosts, with Mr >~ -13.0 mag and Mg >~ -12.5 mag in all cases. For such limits, the fraction of the cluster luminosity in faint dwarfs below our detection limit is lsim0.1%, assuming a standard cluster luminosity function. All four events occurred within ~600 kpc of the cluster center (projected), as defined by the position of the brightest cluster galaxy, and are more centrally concentrated than the cluster SN Ia population as a whole. After accounting for several observational biases that make intracluster SNe easier to discover and spectroscopically confirm, we calculate an intracluster stellar mass fraction of 0.16+0.13 -0.09 (68% confidence limit) for all objects within R 200. If we assume that the intracluster stellar population is exclusively old, and the cluster galaxies themselves have a mix of stellar ages, we derive an upper limit on the intracluster stellar mass fraction of <0.47 (84% one-sided confidence limit). When combined with the intragroup SNe results of McGee & Balogh, we confirm the declining intracluster stellar mass fraction as a function of halo mass reported by Gonzalez and collaborators.

  15. HOST GALAXIES OF TYPE Ia SUPERNOVAE FROM THE NEARBY SUPERNOVA FACTORY

    SciTech Connect

    Childress, M.; Aldering, G.; Aragon, C.; Bailey, S.; Fakhouri, H. K.; Hsiao, E. Y.; Kim, A. G.; Loken, S.; Antilogus, P.; Bongard, S.; Canto, A.; Cellier-Holzem, F.; Guy, J.; Baltay, C.; Buton, C.; Kerschhaggl, M.; Kowalski, M.; Chotard, N.; Copin, Y.; Gangler, E. [Universite de Lyon, F-69622, Lyon; Universite de Lyon 1, Villeurbanne; CNRS and others

    2013-06-20

    We present photometric and spectroscopic observations of galaxies hosting Type Ia supernovae (SNe Ia) observed by the Nearby Supernova Factory. Combining Galaxy Evolution Explorer (GALEX) UV data with optical and near-infrared photometry, we employ stellar population synthesis techniques to measure SN Ia host galaxy stellar masses, star formation rates (SFRs), and reddening due to dust. We reinforce the key role of GALEX UV data in deriving accurate estimates of galaxy SFRs and dust extinction. Optical spectra of SN Ia host galaxies are fitted simultaneously for their stellar continua and emission lines fluxes, from which we derive high-precision redshifts, gas-phase metallicities, and H{alpha}-based SFRs. With these data we show that SN Ia host galaxies present tight agreement with the fiducial galaxy mass-metallicity relation from Sloan Digital Sky Survey (SDSS) for stellar masses log(M{sub *}/M{sub Sun }) > 8.5 where the relation is well defined. The star formation activity of SN Ia host galaxies is consistent with a sample of comparable SDSS field galaxies, though this comparison is limited by systematic uncertainties in SFR measurements. Our analysis indicates that SN Ia host galaxies are, on average, typical representatives of normal field galaxies.

  16. Host Galaxies of Type Ia Supernovae from the Nearby Supernova Factory

    NASA Astrophysics Data System (ADS)

    Childress, M.; Aldering, G.; Antilogus, P.; Aragon, C.; Bailey, S.; Baltay, C.; Bongard, S.; Buton, C.; Canto, A.; Cellier-Holzem, F.; Chotard, N.; Copin, Y.; Fakhouri, H. K.; Gangler, E.; Guy, J.; Hsiao, E. Y.; Kerschhaggl, M.; Kim, A. G.; Kowalski, M.; Loken, S.; Nugent, P.; Paech, K.; Pain, R.; Pecontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigault, M.; Runge, K.; Scalzo, R.; Smadja, G.; Tao, C.; Thomas, R. C.; Weaver, B. A.; Wu, C.

    2013-06-01

    We present photometric and spectroscopic observations of galaxies hosting Type Ia supernovae (SNe Ia) observed by the Nearby Supernova Factory. Combining Galaxy Evolution Explorer (GALEX) UV data with optical and near-infrared photometry, we employ stellar population synthesis techniques to measure SN Ia host galaxy stellar masses, star formation rates (SFRs), and reddening due to dust. We reinforce the key role of GALEX UV data in deriving accurate estimates of galaxy SFRs and dust extinction. Optical spectra of SN Ia host galaxies are fitted simultaneously for their stellar continua and emission lines fluxes, from which we derive high-precision redshifts, gas-phase metallicities, and Hα-based SFRs. With these data we show that SN Ia host galaxies present tight agreement with the fiducial galaxy mass-metallicity relation from Sloan Digital Sky Survey (SDSS) for stellar masses log(M */M ⊙) > 8.5 where the relation is well defined. The star formation activity of SN Ia host galaxies is consistent with a sample of comparable SDSS field galaxies, though this comparison is limited by systematic uncertainties in SFR measurements. Our analysis indicates that SN Ia host galaxies are, on average, typical representatives of normal field galaxies.

  17. HOST GALAXY PROPERTIES AND HUBBLE RESIDUALS OF TYPE Ia SUPERNOVAE FROM THE NEARBY SUPERNOVA FACTORY

    SciTech Connect

    Childress, M.; Aldering, G.; Aragon, C.; Bailey, S.; Fakhouri, H. K.; Hsiao, E. Y.; Kim, A. G.; Loken, S.; Antilogus, P.; Bongard, S.; Canto, A.; Cellier-Holzem, F.; Guy, J.; Baltay, C.; Buton, C.; Kerschhaggl, M.; Kowalski, M.; Chotard, N.; Copin, Y.; Gangler, E. [Universite de Lyon, F-69622, Lyon; Universite de Lyon 1, Villeurbanne; CNRS and others

    2013-06-20

    We examine the relationship between Type Ia supernova (SN Ia) Hubble residuals and the properties of their host galaxies using a sample of 115 SNe Ia from the Nearby Supernova Factory. We use host galaxy stellar masses and specific star formation rates fitted from photometry for all hosts, as well as gas-phase metallicities for a subset of 69 star-forming (non-active galactic nucleus) hosts, to show that the SN Ia Hubble residuals correlate with each of these host properties. With these data we find new evidence for a correlation between SN Ia intrinsic color and host metallicity. When we combine our data with those of other published SN Ia surveys, we find the difference between mean SN Ia brightnesses in low- and high-mass hosts is 0.077 {+-} 0.014 mag. When viewed in narrow (0.2 dex) bins of host stellar mass, the data reveal apparent plateaus of Hubble residuals at high and low host masses with a rapid transition over a short mass range (9.8 {<=} log (M{sub *}/M{sub Sun }) {<=} 10.4). Although metallicity has been a favored interpretation for the origin of the Hubble residual trend with host mass, we illustrate how dust in star-forming galaxies and mean SN Ia progenitor age both evolve along the galaxy mass sequence, thereby presenting equally viable explanations for some or all of the observed SN Ia host bias.

  18. Terrestrial Effects of Nearby Supernovae in the Early Pleistocene

    NASA Astrophysics Data System (ADS)

    Thomas, B. C.; Engler, E. E.; Kachelrieß, M.; Melott, A. L.; Overholt, A. C.; Semikoz, D. V.

    2016-07-01

    Recent results have strongly confirmed that multiple supernovae happened at distances of ˜100 pc, consisting of two main events: one at 1.7-3.2 million years ago, and the other at 6.5-8.7 million years ago. These events are said to be responsible for excavating the Local Bubble in the interstellar medium and depositing 60Fe on Earth and the Moon. Other events are indicated by effects in the local cosmic ray (CR) spectrum. Given this updated and refined picture, we ask whether such supernovae are expected to have had substantial effects on the terrestrial atmosphere and biota. In a first look at the most probable cases, combining photon and CR effects, we find that a supernova at 100 pc can have only a small effect on terrestrial organisms from visible light and that chemical changes such as ozone depletion are weak. However, tropospheric ionization right down to the ground, due to the penetration of ≥TeV CRs, will increase by nearly an order of magnitude for thousands of years, and irradiation by muons on the ground and in the upper ocean will increase twentyfold, which will approximately triple the overall radiation load on terrestrial organisms. Such irradiation has been linked to possible changes in climate and increased cancer and mutation rates. This may be related to a minor mass extinction around the Pliocene-Pleistocene boundary, and further research on the effects is needed.

  19. Terrestrial Effects of Nearby Supernovae in the Early Pleistocene

    NASA Astrophysics Data System (ADS)

    Thomas, B. C.; Engler, E. E.; Kachelrieß, M.; Melott, A. L.; Overholt, A. C.; Semikoz, D. V.

    2016-07-01

    Recent results have strongly confirmed that multiple supernovae happened at distances of ˜100 pc, consisting of two main events: one at 1.7–3.2 million years ago, and the other at 6.5–8.7 million years ago. These events are said to be responsible for excavating the Local Bubble in the interstellar medium and depositing 60Fe on Earth and the Moon. Other events are indicated by effects in the local cosmic ray (CR) spectrum. Given this updated and refined picture, we ask whether such supernovae are expected to have had substantial effects on the terrestrial atmosphere and biota. In a first look at the most probable cases, combining photon and CR effects, we find that a supernova at 100 pc can have only a small effect on terrestrial organisms from visible light and that chemical changes such as ozone depletion are weak. However, tropospheric ionization right down to the ground, due to the penetration of ≥TeV CRs, will increase by nearly an order of magnitude for thousands of years, and irradiation by muons on the ground and in the upper ocean will increase twentyfold, which will approximately triple the overall radiation load on terrestrial organisms. Such irradiation has been linked to possible changes in climate and increased cancer and mutation rates. This may be related to a minor mass extinction around the Pliocene-Pleistocene boundary, and further research on the effects is needed.

  20. Gravitational wave signatures of ab initio two-dimensional core collapse supernova explosion models for 1225M stars

    SciTech Connect

    Yakunin, Konstantin N.; Mezzacappa, Anthony; Marronetti, Pedro; Yoshida, Shin’ichirou; Bruenn, Stephen W.; Hix, W. Raphael; Lentz, Eric J.; Bronson Messer, O. E.; Harris, J. Austin; Endeve, Eirik; Blondin, John M.; Lingerfelt, Eric J.

    2015-10-19

    Here, we present the gravitational waveforms computed in ab initio two-dimensional core collapse supernova models evolved with the chimera code for progenitor masses between 12 and 25 M. For all models employ multifrequency neutrino transport in the ray-by-ray approximation, state-of-the-art weak interaction physics, relativistic transport corrections such as the gravitational redshift of neutrinos, two-dimensional hydrodynamics with the commensurate relativistic corrections, Newtonian self-gravity with a general-relativistic monopole correction, and the Lattimer-Swesty equation of state with 220 MeV compressibility, and begin with the most recent Woosley-Heger nonrotating progenitors in this mass range. All of our models exhibit robust explosions. Moreover, our waveforms capture all stages of supernova development: 1) a relatively short and weak prompt signal, 2) a quiescent stage, 3) a strong signal due to convection and standing accretion shock instability activity, 4) termination of active accretion onto the proto-neutron star, and 5) a slowly increasing tail that reaches a saturation value. Fourier decomposition shows that the gravitational wave signals we predict should be observable by AdvLIGO for Galactic events across the range of progenitors considered here. The fundamental limitation of these models is in their imposition of axisymmetry. Further progress will require counterpart three-dimensional models, which are underway.

  1. Deciphering the Encoded Debris of Supernovae

    NASA Astrophysics Data System (ADS)

    Milisavljevic, Dan

    2016-06-01

    Theory and observation strongly favor the notion that asymmetric explosions drive core-collapse supernovae. Where and how this asymmetry is introduced is uncertain, in part because of limited constraints on various dynamical processes that may take place deep inside the star prior to and during core collapse. Fortunately, the debris fields of supernovae encode valuable information about these processes in their three-dimensional kinematics and chemical abundances. Accessing that information accurately, however, is not straightforward since observed properties may have multiple origins; e.g., asymmetries in both the explosion mechanism and/or turbulent stellar interior, and nonuniform circumstellar environments. I argue that the key to deciphering supernova debris fields is via end-toend investigations that connect extragalactic events with young, nearby supernova remnants. This approach has the unique ability to trace the sources of mixing and clumping at large and small scales back to the time of explosion. I will emphasize how a holistic SN-SNR methodology is necessary for the next generation of three-dimensional core-collapse simulations seeking to robustly model and interpret the gravitational wave, neutrino, and EM signatures of supernovae.

  2. The explosion sites of nearby supernovae seen with integral field spectroscopy

    NASA Astrophysics Data System (ADS)

    Kuncarayakti, Hanindyo

    2015-08-01

    The progenitor stars of supernovae are still not very well constrained, despite numerous efforts in studying these objects directly or indirectly. There have been detections of the progenitor candidates in pre-explosion Hubble Space Telescope images, but these are rare and it is difficult to increase the statistics due to the limited availability of usable pre-explosion images. Alternatively, one may perform statistical studies on the supernova environments to derive useful constraints on the SN progenitor star. Integral field spectroscopy of nearby supernova sites within ~30 Mpc have been obtained using multiple IFU spectrographs in Hawaii and Chile. This technique enables both spatial and spectral information of the explosion sites to be acquired simultaneously, thus providing the identification of the parent stellar population of the supernova progenitor and the estimates for its physical parameters including age and metallicity. While this work has mainly been done in the optical wavelengths using instruments such as VIMOS, GMOS, and MUSE, a near-infrared approach has also been carried out using the AO-assisted SINFONI. By studying the supernova parent stellar population, we aim to characterize the mass and metallicity of the progenitors of different types of supernovae.

  3. Supernova neutrino detection

    SciTech Connect

    Scholberg, K.

    2015-07-15

    In this presentation I summarize the main detection channels for neutrinos from core-collapse supernovae, and describe current status of and future prospects for supernova-neutrino-sensitive detectors worldwide.

  4. THREE-DIMENSIONAL BOLTZMANN HYDRO CODE FOR CORE COLLAPSE IN MASSIVE STARS. I. SPECIAL RELATIVISTIC TREATMENTS

    SciTech Connect

    Nagakura, Hiroki; Sumiyoshi, Kohsuke; Yamada, Shoichi

    2014-10-01

    We propose a novel numerical method for solving multi-dimensional, special relativistic Boltzmann equations for neutrinos coupled with hydrodynamics equations. This method is meant to be applied to simulations of core-collapse supernovae. We handle special relativity in a non-conventional way, taking account of all orders of v/c. Consistent treatment of the advection and collision terms in the Boltzmann equations has been a challenge, which we overcome by employing two different energy grids: Lagrangian remapped and laboratory fixed grids. We conduct a series of basic tests and perform a one-dimensional simulation of core-collapse, bounce, and shock-stall for a 15 M {sub ☉} progenitor model with a minimum but essential set of microphysics. We demonstrate in the latter simulation that our new code is capable of handling all phases in core-collapse supernova. For comparison, a non-relativistic simulation is also conducted with the same code, and we show that they produce qualitatively wrong results in neutrino transfer. Finally, we discuss a possible incorporation of general relativistic effects into our method.

  5. Nearby Supernova Factory Observations of SN 2005gj: Another TypeIa Supernova in a Massive Circumstellar Envelope

    SciTech Connect

    Aldering, G.; Antilogus, P.; Bailey, S.; Baltay, C.; Bauer, A.; Blanc, N.; Bongard, S.; Copin, Y.; Gangler, E.; Gilles, S.; Kessler, R.; Kocevski, D.; Lee, B.C.; Loken, S.; Nugent, P.; Pain, R.; Pecontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigaudier, G.; Scalzo, R.; Smadja, G.; Thomas, R.C.; Wang, L.; Weaver, B.A.; Rabinowitz, D.; Bauer, A.

    2006-06-01

    We report the independent discovery and follow-up observations of supernova 2005gj by the Nearby Supernova Factory. This is the second confirmed case of a ''hybrid'' Type Ia/IIn supernova, which like the prototype SN 2002ic, we interpret as the explosion of a white dwarf interacting with a circumstellar medium. Our early-phase photometry of SN 2005gj shows that the strength of the interaction between the supernova ejecta and circumstellar material is much stronger than for SN 2002ic. Our .rst spectrum shows a hot continuum with broad and narrow H{alpha} emission. Later spectra, spanning over 4 months from outburst, show clear Type Ia features combined with broad and narrow H{gamma}, H{beta},H{alpha} and He I {lambda}{lambda}5876,7065 in emission. At higher resolution, P Cygni profiles are apparent. Surprisingly, we also observe an inverted P Cygni profile for [O III] {lambda}5007. We find that the lightcurve and measured velocity of the unshocked circumstellar material imply mass loss as recently as 8 years ago. This is in contrast to SN 2002ic, for which an inner cavity in the circumstellar material was inferred. Within the context of the thin-shell approximation, the early lightcurve is well-described by a flat radial density profile for the circumstellar material. However, our decomposition of the spectra into Type Ia and shock emission components allows for little obscuration of the supernova, suggesting an aspherical or clumpy distribution for the circumstellar material. We suggest that the emission line velocity profiles arise from electron scattering rather than the kinematics of the shock. This is supported by the inferred high densities, and the lack of evidence for evolution in the line widths. Ground- and space-based photometry, and Keck spectroscopy, of the host galaxy are used to ascertain that the host galaxy has low metallicity (Z/Z{sub {circle_dot}} < 0.3; 95% confidence) and that this galaxy is undergoing a significant star formation event that

  6. Three-dimensional hydrodynamic instabilities in stellar core collapses

    NASA Astrophysics Data System (ADS)

    Lou, Yu-Qing; Lian, Biao

    2012-03-01

    A spherically symmetric hydrodynamic stellar core collapse process under gravity is time-dependent and may become unstable once disturbed. Subsequent non-linear evolutions of such growth of hydrodynamic instabilities may lead to various physical consequences. Specifically for a homologous collapse of a stellar core characterized by a polytropic exponent Γ= 4/3, we examine oscillations and/or instabilities of three-dimensional (3D) general polytropic perturbations. Being incompressible, the radial component of vorticity perturbation always grows unstably during the same homologous core collapse. For compressible 3D perturbations, the polytropic index γ of perturbations can differ from Γ= 4/3 of the general polytropic hydrodynamic background flow, where the background specific entropy is conserved along streamlines and can vary in radius and time. Our model formulation here is more general than previous ones. The Brunt-Väisälä buoyancy frequency ? does not vanish, allowing for the existence of internal gravity g- modes and/or g+ modes, depending on the sign of ? respectively. Eigenvalues and eigenfunctions of various oscillatory and unstable perturbation modes are computed, given asymptotic boundary conditions. As studied in several specialized cases of Goldreich & Weber and of Lou & Cao and Cao & Lou, we further confirm that acoustic p modes and surface f modes remain stable in the current more general situations. In comparison, g- modes and sufficiently high radial order g+ modes are unstable, leading to inevitable convective motions within the collapsing stellar interior; meanwhile, sufficiently low radial order g+ modes remain stably trapped in the collapsing core. Unstable growths of 3D g-mode disturbances are governed dominantly by the angular momentum conservation and modified by the gas pressure restoring force. We note in particular that unstable temporal growths of 3D vortical perturbations exist even when the specific entropy distribution becomes

  7. VizieR Online Data Catalog: Optical supernova remnants in nearby galaxies (Vucetic+, 2015)

    NASA Astrophysics Data System (ADS)

    Vucetic, M. M.; Arbutina, B.; Urosevic, D.

    2015-09-01

    To estimate the contribution from SNRs to the total Hα emission used to determine SFRs in a galaxy, we searched the literature for all galaxies that have optically identified SNRs. In total, there are 25 of them (excluding the Milky Way). In following tables we give data for 18 nearby galaxies which have been surveyed for optical supernova remnants (SNRs). In each table we give coordinates, Hα fluxes, diameters and [SII]/Hα emission line ratios for detected SNRs, found in literature. (19 data files).

  8. Supernovae and mass extinctions

    NASA Technical Reports Server (NTRS)

    Vandenbergh, S.

    1994-01-01

    Shklovsky and others have suggested that some of the major extinctions in the geological record might have been triggered by explosions of nearby supernovae. The frequency of such extinction events will depend on the galactic supernova frequency and on the distance up to which a supernova explosion will produce lethal effects upon terrestrial life. In the present note it will be assumed that a killer supernova has to occur so close to Earth that it will be embedded in a young, active, supernova remnant. Such young remnants typically have radii approximately less than 3 pc (1 x 10(exp 19) cm). Larger (more pessimistic?) killer radii have been adopted by Ruderman, Romig, and by Ellis and Schramm. From observations of historical supernovae, van den Bergh finds that core-collapse (types Ib and II) supernovae occur within 4 kpc of the Sun at a rate of 0.2 plus or minus 0.1 per century. Adopting a layer thickness of 0.3 kpc for the galacitc disk, this corresponds to a rate of approximately 1.3 x 10(exp -4) supernovae pc(exp -3) g.y.(exp -1). Including supernovae of type Ia will increase the total supernovae rate to approximately 1.5 x 10(exp -4) supernovae pc(exp -3) g.y.(exp -1). For a lethal radius of R pc the rate of killer events will therefore be 1.7 (R/3)(exp 3) x 10(exp -2) supernovae per g.y. However, a frequency of a few extinctions per g.y. is required to account for the extinctions observed during the phanerozoic. With R (extinction) approximately 3 pc, the galactic supernova frequency is therefore too low by 2 orders of magnitude to account for the major extinctions in the geological record.

  9. Surprises in the Theory of Core-Collapse Supernova Explosions

    NASA Astrophysics Data System (ADS)

    Burrows, Adam; Dessart, Luc; Livne, Eli; Ott, Christian D.

    2007-08-01

    We summarize some provocative new ideas that have emerged from our multidimensional radiation hydrodynamic simulations of the explosions of the cores of massive stars. We see the excitation of core g-modes that emit sufficient acoustic power to energize an anisotropic blast. The core continues to radiate sound as long as it is needed. There is simultaneously accretion on one side and explosion from another. However, the acoustic-powered mechanism requires a significant delay and will be aborted if another mechanism, such as the neutrino-driven mechanism, succeeds earlier. Whether that happens is the subject of vigorous research. Here, first we discuss the current status of the neutrino mechanism and then follow with a summary of the main features of the acoustic mechanism.

  10. A Search for New Candidate Super-Chandrasekhar-mass Type Ia Supernovae in the Nearby Supernova Factory Data Set

    NASA Astrophysics Data System (ADS)

    Scalzo, R.; Aldering, G.; Antilogus, P.; Aragon, C.; Bailey, S.; Baltay, C.; Bongard, S.; Buton, C.; Canto, A.; Cellier-Holzem, F.; Childress, M.; Chotard, N.; Copin, Y.; Fakhouri, H. K.; Gangler, E.; Guy, J.; Hsiao, E. Y.; Kerschhaggl, M.; Kowalski, M.; Nugent, P.; Paech, K.; Pain, R.; Pecontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigault, M.; Runge, K.; Smadja, G.; Tao, C.; Thomas, R. C.; Weaver, B. A.; Wu, C.; Nearby Supernova Factory, The

    2012-09-01

    We present optical photometry and spectroscopy of five Type Ia supernovae discovered by the Nearby Supernova Factory selected to be spectroscopic analogs of the candidate super-Chandrasekhar-mass events SN 2003fg and SN 2007if. Their spectra are characterized by hot, highly ionized photospheres near maximum light, for which SN 1991T supplies the best phase coverage among available close spectral templates. Like SN 2007if, these supernovae are overluminous (-19.5 < MV < -20) and the velocity of the Si II λ6355 absorption minimum is consistent with being constant in time from phases as early as a week before, and up to two weeks after, B-band maximum light. We interpret the velocity plateaus as evidence for a reverse-shock shell in the ejecta formed by interaction at early times with a compact envelope of surrounding material, as might be expected for SNe resulting from the mergers of two white dwarfs. We use the bolometric light curves and line velocity evolution of these SNe to estimate important parameters of the progenitor systems, including 56Ni mass, total progenitor mass, and masses of shells and surrounding carbon/oxygen envelopes. We find that the reconstructed total progenitor mass distribution of the events (including SN 2007if) is bounded from below by the Chandrasekhar mass, with SN 2007if being the most massive. We discuss the relationship of these events to the emerging class of super-Chandrasekhar-mass SNe Ia, estimate the relative rates, compare the mass distribution to that expected for double-degenerate SN Ia progenitors from population synthesis, and consider implications for future cosmological Hubble diagrams.

  11. A SEARCH FOR NEW CANDIDATE SUPER-CHANDRASEKHAR-MASS TYPE Ia SUPERNOVAE IN THE NEARBY SUPERNOVA FACTORY DATA SET

    SciTech Connect

    Scalzo, R.; Aldering, G.; Aragon, C.; Bailey, S.; Childress, M.; Fakhouri, H. K.; Hsiao, E. Y.; Antilogus, P.; Bongard, S.; Canto, A.; Cellier-Holzem, F.; Guy, J.; Baltay, C.; Buton, C.; Kerschhaggl, M.; Kowalski, M.; Chotard, N.; Copin, Y.; Gangler, E.; Nugent, P.; Collaboration: Nearby Supernova Factory; and others

    2012-09-20

    We present optical photometry and spectroscopy of five Type Ia supernovae discovered by the Nearby Supernova Factory selected to be spectroscopic analogs of the candidate super-Chandrasekhar-mass events SN 2003fg and SN 2007if. Their spectra are characterized by hot, highly ionized photospheres near maximum light, for which SN 1991T supplies the best phase coverage among available close spectral templates. Like SN 2007if, these supernovae are overluminous (-19.5 < M{sub V} < -20) and the velocity of the Si II {lambda}6355 absorption minimum is consistent with being constant in time from phases as early as a week before, and up to two weeks after, B-band maximum light. We interpret the velocity plateaus as evidence for a reverse-shock shell in the ejecta formed by interaction at early times with a compact envelope of surrounding material, as might be expected for SNe resulting from the mergers of two white dwarfs. We use the bolometric light curves and line velocity evolution of these SNe to estimate important parameters of the progenitor systems, including {sup 56}Ni mass, total progenitor mass, and masses of shells and surrounding carbon/oxygen envelopes. We find that the reconstructed total progenitor mass distribution of the events (including SN 2007if) is bounded from below by the Chandrasekhar mass, with SN 2007if being the most massive. We discuss the relationship of these events to the emerging class of super-Chandrasekhar-mass SNe Ia, estimate the relative rates, compare the mass distribution to that expected for double-degenerate SN Ia progenitors from population synthesis, and consider implications for future cosmological Hubble diagrams.

  12. Spectrophotometric time series of SN 2011fe from the Nearby Supernova Factory

    NASA Astrophysics Data System (ADS)

    Pereira, R.; Thomas, R. C.; Aldering, G.; Antilogus, P.; Baltay, C.; Benitez-Herrera, S.; Bongard, S.; Buton, C.; Canto, A.; Cellier-Holzem, F.; Chen, J.; Childress, M.; Chotard, N.; Copin, Y.; Fakhouri, H. K.; Fink, M.; Fouchez, D.; Gangler, E.; Guy, J.; Hillebrandt, W.; Hsiao, E. Y.; Kerschhaggl, M.; Kowalski, M.; Kromer, M.; Nordin, J.; Nugent, P.; Paech, K.; Pain, R.; Pécontal, E.; Perlmutter, S.; Rabinowitz, D.; Rigault, M.; Runge, K.; Saunders, C.; Smadja, G.; Tao, C.; Taubenberger, S.; Tilquin, A.; Wu, C.

    2013-06-01

    We present 32 epochs of optical (3300-9700 Å) spectrophotometric observations of the nearby quintessential "normal" type Ia supernova (SN Ia) SN 2011fe in the galaxy M101, extending from -15 to +97 d with respect to B-band maximum, obtained by the Nearby Supernova Factory collaboration. SN 2011fe is the closest (μ = 29.04) and brightest (Bmax = 9.94 mag) SN Ia observed since the advent of modern large scale programs for the intensive periodic followup of supernovae. Both synthetic light curve measurements and spectral feature analysis attest to the normality of SN 2011fe. There is very little evidence for reddening in its host galaxy. The homogeneous calibration, intensive time sampling, and high signal-to-noise ratio of the data set make it unique. Thus it is ideal for studying the physics of SN Ia explosions in detail, and for furthering the use of SNe Ia as standardizable candles for cosmology. Several such applications are shown, from the creation of a bolometric light curve and measurement of the 56Ni mass, to the simulation ofdetection thresholds for unburned carbon, direct comparisons with other SNe Ia, and existing spectral templates. A movie is available in electronic form at http://www.aanda.orgAll the reduced spectra are available as FITS files in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5">130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/554/A27

  13. Improved models of stellar core collapse and still no explosions: what is missing?

    PubMed

    Buras, R; Rampp, M; Janka, H-Th; Kifonidis, K

    2003-06-20

    Two-dimensional hydrodynamic simulations of stellar core collapse are presented which for the first time were performed by solving the Boltzmann equation for the neutrino transport including a state-of-the-art description of neutrino interactions. Stellar rotation is also taken into account. Although convection develops below the neutrinosphere and in the neutrino-heated region behind the supernova shock, the models do not explode. This suggests missing physics, possibly with respect to the nuclear equation of state and weak interactions in the subnuclear regime. However, it might also indicate a fundamental problem with the neutrino-driven explosion mechanism.

  14. When Stars Attack! Live Radioactivities as Geological Signatures of Nearby Supernova Explosions

    NASA Astrophysics Data System (ADS)

    Fields, Brian D.

    2007-05-01

    The lifespans of the most massive stars are a symphony of the fundamental forces, culminating in a spectacular and violent supernova explosion. While these events are awesome to observe, they can take a more sinister shade when they occur closer to home, because an explosion inside a certain "minimum safe distance" would pose a grave threat to life on Earth. We will discuss these cosmic insults to life, and ways to determine whether a supernova occurred nearby over the course of the Earth's existence. We will then present recent evidence that a star exploded near the Earth about 3 million years ago. Radioactive iron-60 atoms have been found in ancient samples of deep-ocean material, and are likely to be debris from this explosion. Recent data confirm this radioactive signal, and for the first time allow sea sediments to be used as a telescope, probing the nuclear reactions that power exploding stars. Furthermore, an explosion so close to Earth was probably a "near-miss," which emitted intense and possibly harmful radiation. The resulting environmental damage may even have led to extinction of species which were the most vulnerable to this radiation.

  15. Two paths of cluster evolution: global expansion versus core collapse

    NASA Astrophysics Data System (ADS)

    O'Leary, Ryan M.; Stahler, Steven W.; Ma, Chung-Pei

    2014-10-01

    All gravitationally bound clusters expand, due to both gas loss from their most massive members and binary heating. All are eventually disrupted tidally, either by passing molecular clouds or the gravitational potential of their host galaxies. However, their interior evolution can follow two very different paths. Only clusters of sufficiently large initial population and size undergo the combined interior contraction and exterior expansion that leads eventually to core collapse. In all other systems, core collapse is frustrated by binary heating. These clusters globally expand for their entire lives, up to the point of tidal disruption. Using a suite of direct N-body calculations, we trace the `collapse line' in rv-N space that separates these two paths. Here, rv and N are the cluster's initial virial radius and population, respectively. For realistic starting radii, the dividing N-value is from 104 to over 105. We also show that there exists a minimum population, Nmin, for core collapse. Clusters with N < Nmin tidally disrupt before core collapse occurs. At the Sun's Galactocentric radius, RG = 8.5 kpc, we find Nmin ≳ 300. The minimum population scales with Galactocentric radius as R_G^{-9/8}. The position of an observed cluster relative to the collapse line can be used to predict its future evolution. Using a small sample of open clusters, we find that most lie below the collapse line, and thus will never undergo core collapse. Most globular clusters, on the other hand, lie well above the line. In such a case, the cluster may or may not go through core collapse, depending on its initial size. We show how an accurate age determination can help settle this issue.

  16. Near-extremal Black Holes as Initial Conditions of Long GRB Supernovae and Probes of Their Gravitational Wave Emission

    NASA Astrophysics Data System (ADS)

    van Putten, Maurice H. P. M.

    2015-09-01

    Long gamma-ray bursts (GRBs) associated with supernovae and short GRBs with extended emission (SGRBEE) from mergers are probably powered by black holes as a common inner engine, as their prompt GRB emission satisfies the same Amati correlation in the Ep,i-Eiso plane. We introduce modified Bardeen equations to identify hyper-accretion driving newly formed black holes in core-collapse supernovae to near-extremal spin as a precursor to prompt GRB emission. Subsequent spin-down is observed in the BATSE catalog of long GRBs. Spin-down provides a natural unification of long durations associated with the lifetime of black hole spin for normal long GRBs and SGRBEEs, given the absence of major fallback matter in mergers. The results point to major emissions unseen in high frequency gravitational waves. A novel matched filtering method is described for LIGO-Virgo and KAGRA broadband probes of nearby core-collapse supernovae at essentially maximal sensitivity.

  17. Discovery of the nearby long, soft GRB 100316D with an associated supernova

    NASA Astrophysics Data System (ADS)

    Starling, R. L. C.; Wiersema, K.; Levan, A. J.; Sakamoto, T.; Bersier, D.; Goldoni, P.; Oates, S. R.; Rowlinson, A.; Campana, S.; Sollerman, J.; Tanvir, N. R.; Malesani, D.; Fynbo, J. P. U.; Covino, S.; D'Avanzo, P.; O'Brien, P. T.; Page, K. L.; Osborne, J. P.; Vergani, S. D.; Barthelmy, S.; Burrows, D. N.; Cano, Z.; Curran, P. A.; de Pasquale, M.; D'Elia, V.; Evans, P. A.; Flores, H.; Fruchter, A. S.; Garnavich, P.; Gehrels, N.; Gorosabel, J.; Hjorth, J.; Holland, S. T.; van der Horst, A. J.; Hurkett, C. P.; Jakobsson, P.; Kamble, A. P.; Kouveliotou, C.; Kuin, N. P. M.; Kaper, L.; Mazzali, P. A.; Nugent, P. E.; Pian, E.; Stamatikos, M.; Thöne, C. C.; Woosley, S. E.

    2011-03-01

    We report the Swift discovery of the nearby long, soft gamma-ray burst GRB 100316D, and the subsequent unveiling of its low-redshift host galaxy and associated supernova. We derive the redshift of the event to be z= 0.0591 ± 0.0001 and provide accurate astrometry for the gamma-ray burst (GRB) supernova (SN). We study the extremely unusual prompt emission with time-resolved γ-ray to X-ray spectroscopy and find that the spectrum is best modelled with a thermal component in addition to a synchrotron emission component with a low peak energy. The X-ray light curve has a remarkably shallow decay out to at least 800 s. The host is a bright, blue galaxy with a highly disturbed morphology and we use Gemini-South, Very Large Telescope and Hubble Space Telescope observations to measure some of the basic host galaxy properties. We compare and contrast the X-ray emission and host galaxy of GRB 100316D to a subsample of GRB-SNe. GRB 100316D is unlike the majority of GRB-SNe in its X-ray evolution, but resembles rather GRB 060218, and we find that these two events have remarkably similar high energy prompt emission properties. Comparison of the host galaxies of GRB-SNe demonstrates, however, that there is a great diversity in the environments in which GRB-SNe can be found. GRB 100316D is an important addition to the currently sparse sample of spectroscopically confirmed GRB-SNe, from which a better understanding of long GRB progenitors and the GRB-SN connection can be gleaned.

  18. Characterizing mid-ultraviolet to optical light curves of nearby type IIn supernovae

    DOE PAGES

    de la Rosa, Janie; Roming, Pete; Pritchard, Tyler; Fryer, Chris

    2016-03-21

    Here, we present early mid-ultraviolet and optical observations of Type IIn supernovae (SNe IIn) observed from 2007 to 2013. Our results focus on the properties of UV light curves: peak absolute magnitudes, temporal decay, and color evolution. During early times, this sample demonstrates that UV light decays faster than optical, and each event transitions from a predominantly UV-bright phase to an optically bright phase. In order to understand early UV behavior, we generate and analyze the sample's blackbody luminosity, temperature, and radius as the SN ejecta expand and cool. Since most of our observations were detected post maximum luminosity, wemore » introduce a method for estimating the date of peak magnitude. When our observations are compared based on filter, we find that even though these SNe IIn vary in peak magnitudes, there are similarities in UV decay rates. We use a simple semi-analytical SN model in order to understand the effects of the explosion environment on our UV observations. Understanding the UV characteristics of nearby SNe IIn during an early phase can provide valuable information about the environment surrounding these explosions, leading us to evaluating the diversity of observational properties in this subclass.« less

  19. A faint type of supernova from a white dwarf with a helium-rich companion.

    PubMed

    Perets, H B; Gal-Yam, A; Mazzali, P A; Arnett, D; Kagan, D; Filippenko, A V; Li, W; Arcavi, I; Cenko, S B; Fox, D B; Leonard, D C; Moon, D-S; Sand, D J; Soderberg, A M; Anderson, J P; James, P A; Foley, R J; Ganeshalingam, M; Ofek, E O; Bildsten, L; Nelemans, G; Shen, K J; Weinberg, N N; Metzger, B D; Piro, A L; Quataert, E; Kiewe, M; Poznanski, D

    2010-05-20

    Supernovae are thought to arise from two different physical processes. The cores of massive, short-lived stars undergo gravitational core collapse and typically eject a few solar masses during their explosion. These are thought to appear as type Ib/c and type II supernovae, and are associated with young stellar populations. In contrast, the thermonuclear detonation of a carbon-oxygen white dwarf, whose mass approaches the Chandrasekhar limit, is thought to produce type Ia supernovae. Such supernovae are observed in both young and old stellar environments. Here we report a faint type Ib supernova, SN 2005E, in the halo of the nearby isolated galaxy, NGC 1032. The 'old' environment near the supernova location, and the very low derived ejected mass ( approximately 0.3 solar masses), argue strongly against a core-collapse origin. Spectroscopic observations and analysis reveal high ejecta velocities, dominated by helium-burning products, probably excluding this as a subluminous or a regular type Ia supernova. We conclude that it arises from a low-mass, old progenitor, likely to have been a helium-accreting white dwarf in a binary. The ejecta contain more calcium than observed in other types of supernovae and probably large amounts of radioactive (44)Ti. PMID:20485429

  20. A faint type of supernova from a white dwarf with a helium-rich companion.

    PubMed

    Perets, H B; Gal-Yam, A; Mazzali, P A; Arnett, D; Kagan, D; Filippenko, A V; Li, W; Arcavi, I; Cenko, S B; Fox, D B; Leonard, D C; Moon, D-S; Sand, D J; Soderberg, A M; Anderson, J P; James, P A; Foley, R J; Ganeshalingam, M; Ofek, E O; Bildsten, L; Nelemans, G; Shen, K J; Weinberg, N N; Metzger, B D; Piro, A L; Quataert, E; Kiewe, M; Poznanski, D

    2010-05-20

    Supernovae are thought to arise from two different physical processes. The cores of massive, short-lived stars undergo gravitational core collapse and typically eject a few solar masses during their explosion. These are thought to appear as type Ib/c and type II supernovae, and are associated with young stellar populations. In contrast, the thermonuclear detonation of a carbon-oxygen white dwarf, whose mass approaches the Chandrasekhar limit, is thought to produce type Ia supernovae. Such supernovae are observed in both young and old stellar environments. Here we report a faint type Ib supernova, SN 2005E, in the halo of the nearby isolated galaxy, NGC 1032. The 'old' environment near the supernova location, and the very low derived ejected mass ( approximately 0.3 solar masses), argue strongly against a core-collapse origin. Spectroscopic observations and analysis reveal high ejecta velocities, dominated by helium-burning products, probably excluding this as a subluminous or a regular type Ia supernova. We conclude that it arises from a low-mass, old progenitor, likely to have been a helium-accreting white dwarf in a binary. The ejecta contain more calcium than observed in other types of supernovae and probably large amounts of radioactive (44)Ti.

  1. Gravitational wave extraction in simulations of rotating stellar core collapse

    SciTech Connect

    Reisswig, C.; Ott, C. D.; Sperhake, U.; Schnetter, E.

    2011-03-15

    We perform simulations of general relativistic rotating stellar core collapse and compute the gravitational waves (GWs) emitted in the core-bounce phase of three representative models via multiple techniques. The simplest technique, the quadrupole formula (QF), estimates the GW content in the spacetime from the mass-quadrupole tensor only. It is strictly valid only in the weak-field and slow-motion approximation. For the first time, we apply GW extraction methods in core collapse that are fully curvature based and valid for strongly radiating and highly relativistic sources. These techniques are not restricted to weak-field and slow-motion assumptions. We employ three extraction methods computing (i) the Newman-Penrose (NP) scalar {Psi}{sub 4}, (ii) Regge-Wheeler-Zerilli-Moncrief master functions, and (iii) Cauchy-characteristic extraction (CCE) allowing for the extraction of GWs at future null infinity, where the spacetime is asymptotically flat and the GW content is unambiguously defined. The latter technique is the only one not suffering from residual gauge and finite-radius effects. All curvature-based methods suffer from strong nonlinear drifts. We employ the fixed-frequency integration technique as a high-pass waveform filter. Using the CCE results as a benchmark, we find that finite-radius NP extraction yields results that agree nearly perfectly in phase, but differ in amplitude by {approx}1%-7% at core bounce, depending on the model. Regge-Wheeler-Zerilli-Moncrief waveforms, while, in general, agreeing in phase, contain spurious high-frequency noise of comparable amplitudes to those of the relatively weak GWs emitted in core collapse. We also find remarkably good agreement of the waveforms obtained from the QF with those obtained from CCE. The results from QF agree very well in phase and systematically underpredict peak amplitudes by {approx}5%-11%, which is comparable to the NP results and is certainly within the uncertainties associated with core collapse

  2. Radio evolution of the remnant of Supernova 1987A

    NASA Astrophysics Data System (ADS)

    Zanardo, Giovanna

    Radio supernovae result from the collision between a supernova (SN) shock and the progenitor's circumstellar medium (CSM). Supernova 1987A in the Large Magellanic Cloud, as the only nearby core-collapse supernova observed with a telescope since its early stages, has allowed unique studies of the SN-CSM interaction and the complex structure of the resulting emission. This thesis investigates the evolution of the remnant of SN 1987A, as the shock wave impacts the dense CSM in the equatorial ring, and the possible presence of a compact object in the remnant interior, using new data from the Australia Telescope Compact Array, the Atacama Large Millimeter/submillimeter Array, the Australian Long Baseline Array, and the Parkes telescope.

  3. ASASSN-16at: Discovery of A Probable Nearby Supernova in UGC 08041

    NASA Astrophysics Data System (ADS)

    Bock, G.; Shappee, B. J.; Stanek, K. Z.; Prieto, J. L.; Kochanek, C. S.; Holoien, T. W.-S.; Brown, J. S.; Godoy-Rivera, D.; Basu, U.; Bersier, D.; Dong, Subo; Chen, Ping; Brimacombe, J.; Masi, G.; Kiyota, S.

    2016-01-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy UGC 8041.

  4. SweetSpot Data Release 1: 70 Type Ia Supernovae in the Near Infrared in the Nearby Hubble Flow

    NASA Astrophysics Data System (ADS)

    Wood-Vasey, W. Michael; Weyant, Anja; Allen, Lori; Trevino Barton, Nathan; Garnavich, Peter M.; Farhin Jahan, Nabila; Jha, Saurabh; Kroboth, Jessica Rose; Ponder, Kara Ann; Joyce, Richard R.; Matheson, Thomas; Rest, Armin

    2015-01-01

    SweetSpot is an NOAO Survey program from 2012B-2015A that is observing 150 Type Ia supernovae (SNeIa) in the Hubble flow to obtain reliable NIR luminosities free from peculiar-velocity confusion and the uncertainties of dust.Our full SweetSpot program will (1) extend the NIR Hubble diagram past currently available samples; (2) quantitatively demonstrate the degree to which SNeIa are robust standard candles in the NIR; (3) provide key insights about the color evolution and intrinsic properties of SNeIa and their host galaxies; and (4) establish a well-calibrated low-redshift anchor for future NIR supernova surveys from JWST, Euclid, and WFIRST/NEW. By the end of the survey we will have measured the relative distance to a redshift of z~0.05 to 1%. Nearby Type Ia supernova (SN Ia) observations such as these will test the standard nature of SNeIa in the restframe NIR, allow insight into the nature of dust, and provide a critical anchor for future cosmological SN Ia surveys at higher redshift.We here present our Data Release 1 which includes 70 supernovae observed from 2011B-2013B. Along with an updated NIR Hubble diagram combining these SNeIa with those from the literature, we explore the relationships between SNIa NIR luminosity and properties of the host galaxy.

  5. Relativistic MHD simulations of stellar core collapse and magnetars

    NASA Astrophysics Data System (ADS)

    Font, José A.; Cerdá-Durán, Pablo; Gabler, Michael; Müller, Ewald; Stergioulas, Nikolaos

    2011-02-01

    We present results from simulations of magneto-rotational stellar core collapse along with Alfvén oscillations in magnetars. These simulations are performed with the CoCoA/CoCoNuT code, which is able to handle ideal MHD flows in dynamical spacetimes in general relativity. Our core collapse simulations highlight the importance of genuine magnetic effects, like the magneto-rotational instability, for the dynamics of the flow. For the modelling of magnetars we use the anelastic approximation to general relativistic MHD, which allows for an effective suppression of fluid modes and an accurate description of Alfvén waves. We further compute Alfvén oscillation frequencies along individual magnetic field lines with a semi-analytic approach. Our work confirms previous results based on perturbative approaches regarding the existence of two families of quasi-periodic oscillations (QPOs), with harmonics at integer multiples of the fundamental frequency. Additional material is presented in the accompanying contribution by Gabler et al (2010b) in these proceedings.

  6. Atmospheric extinction properties above Mauna Kea from the Nearby SuperNova Factory spectro-photometric data set

    NASA Astrophysics Data System (ADS)

    Buton, C.; Copin, Y.; Aldering, G.; Antilogus, P.; Aragon, C.; Bailey, S.; Baltay, C.; Bongard, S.; Canto, A.; Cellier-Holzem, F.; Childress, M.; Chotard, N.; Fakhouri, H. K.; Gangler, E.; Guy, J.; Hsiao, E. Y.; Kerschhaggl, M.; Kowalski, M.; Loken, S.; Nugent, P.; Paech, K.; Pain, R.; Pécontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigault, M.; Runge, K.; Scalzo, R.; Smadja, G.; Tao, C.; Thomas, R. C.; Weaver, B. A.; Wu, C.; Nearby SuperNova Factory

    2013-01-01

    We present a new atmospheric extinction curve for Mauna Kea spanning 3200-9700 Å. It is the most comprehensive to date, being based on some 4285 standard star spectra obtained on 478 nights spread over a period of 7 years obtained by the Nearby SuperNova Factory using the SuperNova Integral Field Spectrograph. This mean curve and its dispersion can be used as an aid in calibrating spectroscopic or imaging data from Mauna Kea, and in estimating the calibration uncertainty associated with the use of a mean extinction curve. Our method for decomposing the extinction curve into physical components, and the ability to determine the chromatic portion of the extinction even on cloudy nights, is described and verified over the wide range of conditions sampled by our large dataset. We demonstrate good agreement with atmospheric science data obtain at nearby Mauna Loa Observatory, and with previously published measurements of the extinction above Mauna Kea. Extinction tables are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/549/A8

  7. Early Radio and X-Ray Observations of the Youngest Nearby Type Ia Supernova PTF 11kly (SN 2011fe)

    NASA Technical Reports Server (NTRS)

    Horesh, Assaf; Kulkarni, S. R.; Fox, Derek B.; Carpenter, John; Kasliwal, Mansi M.; Ofek, Eran O.; Quimby, Robert; Gal-Yam, Avishay; Cenko, S. Bradley; deBruyn, A. G.; Kamble, Atish; Wijers, Ralph A. M. J.; vanderHorst, Alexander J.; Kouveliotou, Chryssa; Podsiadlowski, Philipp; Sullivan, Mark; Maguire, Kate; Howell, D. Andrew; Nugent, Peter E.; Gehrels, Neil; Law, Nicolas M.; Poznanski, Dovi; Shara, Michael

    2012-01-01

    On August 24 (UT) the Palomar Transient Factory (PTF) discovered PTF11kly (SN 2011fe), the youngest and most nearby type Ia supernova (SN Ia) in decades. We followed this event up in the radio (centimeter and millimeter bands) and X-ray bands, starting about a day after the estimated explosion time. We present our analysis of the radio and X-ray observations, yielding the tightest constraints yet placed on the pre-explosion mass-loss rate from the progenitor system of this supernova. We find a robust limit of M(raised dot) less than or equal to 10(exp -8) (w /100 kilometers per second ) solar mass yr(exp -1) from sensitive X-ray non-detections, as well as a similar limit from radio data, which depends, however, on assumptions about microphysical parameters. We discuss our results in the context of single-degenerate models for SNe Ia and find that our observations modestly disfavor symbiotic progenitor models involving a red giant donor, but cannot constrain systems accreting from main sequence or sub-giant stars, including the popular supersoft channel. In view of the proximity of PTF11kly and the sensitivity of our prompt observations we would have to wait for a long time (decade or longer) in order to more meaningfully probe the circumstellar matter of Ia supernovae.

  8. Nucleosynthesis in jets from rotating magnetized stars during core collapse

    SciTech Connect

    Fujimoto, Shin-ichirou; Nishimura, Nobuya; Hashimoto, Masa-aki

    2008-05-12

    We investigate nucleosynthesis inside magnetically driven jets ejected from rotating, magnetized massive stars, or collapsars, based on long-term, magnetohydrodynamic simulations of the core collapse of six collapsars with the various distributions of magnetic fields and angular momentum before the collapse. We follow the evolution of the abundances of about 4000 nuclides from the collapse phase to the ejection phase and through the jet generation phase using a large nuclear reaction network. We find that the r-process successfully operates in the jets from three collapsars, so that U and Th are synthesized abundantly, even when the collapsar have a relatively small magnetic field (10{sup 10} G) and a moderately rotating core before the collapse. The abundance patterns inside the jets are similar to that of the r-elements in the solar system.

  9. Nearby Supernova Factory Observations of SN 2006D: On SporadicCarbon Signatures in Early Type Ia Supernova Spectra

    SciTech Connect

    Thomas, R.C.; Aldering, G.; Antilogus, P.; Aragon, C.; Bailey,S.; Baltay, C.; Baron, E.; Bauer, A.; Buton, C.; Bongard, S.; Copin, Y.; Gangler, E.; Gilles, S.; Kessler, R.; Loken, S.; Nugent, P.; Pain, R.; Parrent, J.; Pecontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigaudier, G.; Runge, K.; Scalzo, R.; Smadja, G.; Wang, L.; Weaver, B.A.

    2006-10-12

    We present four spectra of the Type Ia supernova SN Ia 2006Dextending from -7 to +13 days with respect to B-band maximum. The spectrainclude the strongest signature of unburned material at photosphericvelocities observed in a SN Ia to date. The earliest spectrum exhibits CII absorption features below 14,000 km/s, including a distinctive C IIlambda 6580 absorption feature. The carbon signatures dissipate as the SNapproaches peak brightness. In addition to discussing implications ofphotospheric-velocity carbon for white dwarf explosion models, we outlinesome factors that may influence the frequency of its detection before andaround peak brightness. Two effects are explored in this regard,including depopulation of the C II optical levels by non-LTE effects, andline-of-sight effects resulting from a clumpy distribution of unburnedmaterial with low volume-filling factor.

  10. WHO PULLED THE TRIGGER: A SUPERNOVA OR AN ASYMPTOTIC GIANT BRANCH STAR?

    SciTech Connect

    Boss, Alan P.; Keiser, Sandra A. E-mail: keiser@dtm.ciw.ed

    2010-07-01

    The short-lived radioisotope (SLRI) {sup 60}Fe requires production in a core collapse supernova or asymptotic giant branch (AGB) star immediately before its incorporation into the earliest solar system solids. Shock waves from a somewhat distant supernova, or a relatively nearby AGB star, have the right speeds to simultaneously trigger the collapse of a dense molecular cloud core and to inject shock wave material into the resulting protostar. A new set of FLASH2.5 adaptive mesh refinement hydrodynamic models shows that the injection efficiency depends sensitively on the assumed shock thickness and density. Supernova shock waves appear to be thin enough to inject the amount of shock wave material necessary to match the SLRI abundances measured for primitive meteorites. Planetary nebula shock waves from AGB stars, however, appear to be too thick to achieve the required injection efficiencies. These models imply that a supernova pulled the trigger that led to the formation of our solar system.

  11. Early Radio and X-Ray Observations of the Youngest nearby Type Ia Supernova PTF 11kly (SN 2011fe)

    NASA Astrophysics Data System (ADS)

    Horesh, Assaf; Kulkarni, S. R.; Fox, Derek B.; Carpenter, John; Kasliwal, Mansi M.; Ofek, Eran O.; Quimby, Robert; Gal-Yam, Avishay; Cenko, S. Bradley; de Bruyn, A. G.; Kamble, Atish; Wijers, Ralph A. M. J.; van der Horst, Alexander J.; Kouveliotou, Chryssa; Podsiadlowski, Philipp; Sullivan, Mark; Maguire, Kate; Howell, D. Andrew; Nugent, Peter E.; Gehrels, Neil; Law, Nicholas M.; Poznanski, Dovi; Shara, Michael

    2012-02-01

    On 2011 August 24 (UT) the Palomar Transient Factory (PTF) discovered PTF11kly (SN 2011fe), the youngest and most nearby Type Ia supernova (SN Ia) in decades. We followed this event up in the radio (centimeter and millimeter bands) and X-ray bands, starting about a day after the estimated explosion time. We present our analysis of the radio and X-ray observations, yielding the tightest constraints yet placed on the pre-explosion mass-loss rate from the progenitor system of this supernova. We find a robust limit of \\dot{M}\\lesssim 10^{-8}(w/100\\,km\\,s^{-1})\\,M_{\\odot }\\,yr^{-1} from sensitive X-ray non-detections, as well as a similar limit from radio data, which depends, however, on assumptions about microphysical parameters. We discuss our results in the context of single-degenerate models for SNe Ia and find that our observations modestly disfavor symbiotic progenitor models involving a red giant donor, but cannot constrain systems accreting from main-sequence or sub-giant stars, including the popular supersoft channel. In view of the proximity of PTF11kly and the sensitivity of our prompt observations, we would have to wait for a long time (a decade or longer) in order to more meaningfully probe the circumstellar matter of SNe Ia.

  12. THE THREE-DIMENSIONAL EVOLUTION TO CORE COLLAPSE OF A MASSIVE STAR

    SciTech Connect

    Couch, Sean M.; Chatzopoulos, Emmanouil; Arnett, W. David; Timmes, F. X.

    2015-07-20

    We present the first three-dimensional (3D) simulation of the final minutes of iron core growth in a massive star, up to and including the point of core gravitational instability and collapse. We capture the development of strong convection driven by violent Si burning in the shell surrounding the iron core. This convective burning builds the iron core to its critical mass and collapse ensues, driven by electron capture and photodisintegration. The non-spherical structure and motion generated by 3D convection is substantial at the point of collapse, with convective speeds of several hundreds of km s{sup −1}. We examine the impact of such physically realistic 3D initial conditions on the core-collapse supernova mechanism using 3D simulations including multispecies neutrino leakage and find that the enhanced post-shock turbulence resulting from 3D progenitor structure aids successful explosions. We conclude that non-spherical progenitor structure should not be ignored, and should have a significant and favorable impact on the likelihood for neutrino-driven explosions. In order to make simulating the 3D collapse of an iron core feasible, we were forced to make approximations to the nuclear network making this effort only a first step toward accurate, self-consistent 3D stellar evolution models of the end states of massive stars.

  13. Gamma and neutrino radiation dose from gamma ray bursts and nearby supernovae.

    PubMed

    Karam, P Andrew

    2002-04-01

    Supernovae and gamma ray bursts are exceptionally powerful cosmic events that occur randomly in space and time in our galaxy. Their potential to produce very high radiation levels has been discussed, along with speculation that they may have caused mass extinctions noted from the fossil record. It is far more likely that they have produced radiation levels that, while not lethal, are genetically significant, and these events may have influenced the course of evolution and the manner in which organisms respond to radiation insult. Finally, intense gamma radiation exposure from these events may influence the ability of living organisms to travel through space. Calculations presented in this paper suggest that supernovae and gamma ray bursts are likely to produce sea-level radiation exposures of about I Gy with a mean interval of about five million years and sea-level radiation exposures of about 0.2 Gy every million years. Comets and meteors traveling through space would receive doses in excess of 10 Gy at a depth of 0.02 m at mean intervals of 4 and 156 million years, respectively. This may place some constraints on the ability of life to travel through space either between planets or between planetary systems. Calculations of radiation dose from neutrino radiation are presented and indicate that this is not a significant source of radiation exposure for even extremely close events for the expected neutrino spectrum from these events.

  14. Collective neutrino oscillations in supernovae

    SciTech Connect

    Duan, Huaiyu

    2014-06-24

    In a dense neutrino medium neutrinos can experience collective flavor transformation through the neutrino-neutrino forward scattering. In this talk we present some basic features of collective neutrino flavor transformation in the context in core-collapse supernovae. We also give some qualitative arguments for why and when this interesting phenomenon may occur and how it may affect supernova nucleosynthesis.

  15. Reconstructing the supernova bounce time with neutrinos in IceCube

    SciTech Connect

    Halzen, Francis; Raffelt, Georg G.

    2009-10-15

    Generic model predictions for the early neutrino signal of a core-collapse supernova (SN) imply that IceCube can reconstruct the bounce to within about {+-}3.5 ms at 95% C.L. (assumed SN distance 10 kpc), relevant for coincidence with gravitational-wave detectors. The timing uncertainty scales approximately with the distance squared. The offset between true and reconstructed bounce time of up to several ms depends on the neutrino flavor oscillation scenario. Our work extends the recent study of Pagliaroli et al.[Phys. Rev. Lett. 103, 031102 (2009)] and demonstrates IceCube's superb timing capabilities for neutrinos from the next nearby SN.

  16. PTF discovers and follows-up nearby, young, Type II supernova

    NASA Astrophysics Data System (ADS)

    Kasliwal, M. M.; Quimby, R. M.; Ofek, E. O.; Kulkarni, S. R.; Gal-Yam, A.; Arcavi, I.; Green, Y.; Walker, E.; Mazzali, P.; Nugent, P. E.; Poznanski, D.; Howell, D. A.; Dilday, B.; Fox, D. B.

    2010-09-01

    On UT 2010 Sep 15.243, the Palomar Transient Factory discovered an optical transient, PTF10vdl at RA(J2000) = 23:05:49.001 and DEC(J2000)=03:31:20.50 near NGC 7483. We obtained Target Of Opportunity spectra with Gemini-S/GMOS (PI Kasliwal) on Sep 16.29. The spectrum was extremely blue (f_nu proportional to nu^4.5) and nearly featureless. We further obtained a spectrum with the TNG/DOLORES (PI Walker) on Sep 17.40 and P-Cygni profiles of four Balmer lines were clearly visible, consistent with the redshift of NGC 7483, suggesting this is a Type II supernova.

  17. Supernova 2007bi as a pair-instability explosion.

    PubMed

    Gal-Yam, A; Mazzali, P; Ofek, E O; Nugent, P E; Kulkarni, S R; Kasliwal, M M; Quimby, R M; Filippenko, A V; Cenko, S B; Chornock, R; Waldman, R; Kasen, D; Sullivan, M; Beshore, E C; Drake, A J; Thomas, R C; Bloom, J S; Poznanski, D; Miller, A A; Foley, R J; Silverman, J M; Arcavi, I; Ellis, R S; Deng, J

    2009-12-01

    Stars with initial masses such that 10M[symbol: see text] core-collapse supernova. By contrast, extremely massive stars with M(initial) >or= 140M[symbol: see text] (if such exist) develop oxygen cores with masses, M(core), that exceed 50M[symbol: see text], where high temperatures are reached at relatively low densities. Conversion of energetic, pressure-supporting photons into electron-positron pairs occurs before oxygen ignition and leads to a violent contraction which triggers a nuclear explosion that unbinds the star in a pair-instability supernova. Transitional objects with 100M[symbol: see text] < M(initial) < 140M[symbol: see text] may end up as iron-core-collapse supernovae following violent mass ejections, perhaps as a result of brief episodes of pair instability, and may already have been identified. Here we report observations of supernova SN 2007bi, a luminous, slowly evolving object located within a dwarf galaxy. We estimate the exploding core mass to be M(core) approximately 100M[symbol: see text], in which case theory unambiguously predicts a pair-instability supernova. We show that >3M[symbol: see text] of radioactive (56)Ni was synthesized during the explosion and that our observations are well fitted by models of pair-instability supernovae. This indicates that nearby dwarf galaxies probably host extremely massive stars, above the apparent Galactic stellar mass limit, which perhaps result from processes similar to those that created the first stars in the Universe. PMID:19956255

  18. Supernova 2007bi as a pair-instability explosion.

    PubMed

    Gal-Yam, A; Mazzali, P; Ofek, E O; Nugent, P E; Kulkarni, S R; Kasliwal, M M; Quimby, R M; Filippenko, A V; Cenko, S B; Chornock, R; Waldman, R; Kasen, D; Sullivan, M; Beshore, E C; Drake, A J; Thomas, R C; Bloom, J S; Poznanski, D; Miller, A A; Foley, R J; Silverman, J M; Arcavi, I; Ellis, R S; Deng, J

    2009-12-01

    Stars with initial masses such that 10M[symbol: see text] core-collapse supernova. By contrast, extremely massive stars with M(initial) >or= 140M[symbol: see text] (if such exist) develop oxygen cores with masses, M(core), that exceed 50M[symbol: see text], where high temperatures are reached at relatively low densities. Conversion of energetic, pressure-supporting photons into electron-positron pairs occurs before oxygen ignition and leads to a violent contraction which triggers a nuclear explosion that unbinds the star in a pair-instability supernova. Transitional objects with 100M[symbol: see text] < M(initial) < 140M[symbol: see text] may end up as iron-core-collapse supernovae following violent mass ejections, perhaps as a result of brief episodes of pair instability, and may already have been identified. Here we report observations of supernova SN 2007bi, a luminous, slowly evolving object located within a dwarf galaxy. We estimate the exploding core mass to be M(core) approximately 100M[symbol: see text], in which case theory unambiguously predicts a pair-instability supernova. We show that >3M[symbol: see text] of radioactive (56)Ni was synthesized during the explosion and that our observations are well fitted by models of pair-instability supernovae. This indicates that nearby dwarf galaxies probably host extremely massive stars, above the apparent Galactic stellar mass limit, which perhaps result from processes similar to those that created the first stars in the Universe.

  19. Mapping X-Ray Ejecta Distribution in the Galactic Core-Collapse SNR G292.0+1.8

    NASA Astrophysics Data System (ADS)

    Park, Sangwook; Bhalerao, Jayant; Schenck, Andrew

    2015-08-01

    Based on our deep Chandra ACIS observation, we present the spatial distributions of individual elements of the shocked metal-rich ejecta in the textbook-type Galactic core-collapse supernova remnant G292.0+1.8 (G292). To separate the complex network of overabundant ejecta-dominated regions from low-abundant circumstellar regions, we apply our adaptive-mesh grid method to extract X-ray spectra from over 3000 sub-regions across G292, and perform various spectral model fits to individual regional spectra. Our initial results show highly asymmetric, differential spatial distributions for individual ejecta elements O, Ne, Mg, and Si. Gas temperature, pressure, and density also show substantially non-uniform distributions in G292. Implications from our initial results on the explosion asymmetry and the progenitor’s nature are briefly discussed.

  20. COSMIC-RAY STREAMING FROM SUPERNOVA REMNANTS AND GAMMA-RAY EMISSION FROM NEARBY MOLECULAR CLOUDS

    SciTech Connect

    Yan Huirong; Lazarian, A.; Schlickeiser, R.

    2012-02-01

    High-energy gamma-ray emission has been detected recently from supernova remnants (SNRs) and their surroundings. The existence of molecular clouds near some of the SNRs suggests that the gamma rays originate predominantly from p-p interactions with cosmic rays (CRs) accelerated at a closeby SNR shock wave. Here we investigate the acceleration of CRs and the gamma-ray production in the cloud self-consistently by taking into account the interactions of the streaming instability and the background turbulence both at the shock front and in the ensuing propagation to the clouds. We focus on the later evolution of SNRs, when the conventional treatment of the streaming instability is valid but the magnetic field is enhanced due to Bell's current instability and/or the dynamo generation of magnetic field in the precursor region. We calculate the time dependence of the maximum energy of the accelerated particles. This result is then used to determine the diffusive flux of the runaway particles escaping the shock region, from which we obtain the gamma spectrum consistent with observations. Finally, we check the self-consistency of our results by comparing the required level of diffusion with the level of the streaming instability attainable in the presence of turbulence damping. The energy range of CRs subject to the streaming instability is able to produce the observed energy spectrum of gamma rays.

  1. Radio spectral characteristics of the supernova remnant Puppis A and nearby sources

    NASA Astrophysics Data System (ADS)

    Reynoso, E. M.; Walsh, A. J.

    2015-08-01

    This paper presents a new study of the spectral index distribution of the supernova remnant (SNR) Puppis A. The nature of field compact sources is also investigated according to the measured spectral indices. This work is based on new observations of Puppis A and its surroundings performed with the Australia Telescope Compact Array in two configurations using the Compact Array Broad-band Backend centred at 1.75 GHz. We find that the global spectral index of Puppis A is α = -0.563 ± 0.013. Local variations have been detected, however this global index represents well the bulk of the SNR. At the SE, we found a pattern of parallel strips with a flat spectrum compatible with small-scale filaments, although not correlated in detail. The easternmost filament agrees with the idea that the SNR shock front is interacting with an external cloud. There is no evidence of the previously suggested correlation between emissivity and spectral index. A number of compact features are proposed to be evolved clumps of ejecta based on their spectral indices, although dynamic measurements are needed to confirm this hypothesis. We estimate precise spectral indices for the five previously known field sources, two of which are found to be double (one of them, probably triple), and catalogue 40 new sources. In the light of these new determinations, the extragalactic nature previously accepted for some compact sources is now in doubt.

  2. On relative supernova rates and nucleosynthesis roles

    NASA Technical Reports Server (NTRS)

    Arnett, W. David; Schramm, David N.; Truran, James W.

    1989-01-01

    It is shown that the Ni-56-Fe-56 observed in SN 1987A argues that core collapse supernovae may be responsible for more than 50 percent of the iron in the galaxy. Furthermore it is argued that the time averaged rate of thermonuclear driven Type I supernovae may be at least an order of magnitude lower than the average rate of core collapse supernovae. The present low rate of Type II supernovae (below their time averaged rate of approx. 1/10 yr) is either because the past rate was much higher because many core collapse supernovae are dim like SN 1987A. However, even in this latter case they are only an order of magnitude dimmer that normal Type II's due to the contribution of Ni-56 decay to the light curve.

  3. On relative supernova rates and nucleosynthesis roles

    NASA Technical Reports Server (NTRS)

    Arnett, W. David; Schramm, David N.; Truran, James W.

    1988-01-01

    It is shown that the Ni-56-Fe-56 observed in SN 1987A argues that core collapse supernovae may be responsible for more that 50 percent of the iron in the galaxy. Furthermore it is argued that the time averaged rate of thermonuclear driven Type I supernovae may be at least an order of magnitude lower than the average rate of core collapse supernovae. The present low rate of Type II supernovae (below their time averaged rate of approx. 1/10 yr) is either because the past rate was much higher because many core collapse supernovae are dim like SN 1987A. However, even in this latter case they are only an order of magnitude dimmer that normal Type II's due to the contribution of Ni-56 decay to the light curve.

  4. SN 2015BN: A Detailed Multi-wavelength View of a Nearby Superluminous Supernova

    NASA Astrophysics Data System (ADS)

    Nicholl, M.; Berger, E.; Smartt, S. J.; Margutti, R.; Kamble, A.; Alexander, K. D.; Chen, T.-W.; Inserra, C.; Arcavi, I.; Blanchard, P. K.; Cartier, R.; Chambers, K. C.; Childress, M. J.; Chornock, R.; Cowperthwaite, P. S.; Drout, M.; Flewelling, H. A.; Fraser, M.; Gal-Yam, A.; Galbany, L.; Harmanen, J.; Holoien, T. W.-S.; Hosseinzadeh, G.; Howell, D. A.; Huber, M. E.; Jerkstrand, A.; Kankare, E.; Kochanek, C. S.; Lin, Z.-Y.; Lunnan, R.; Magnier, E. A.; Maguire, K.; McCully, C.; McDonald, M.; Metzger, B. D.; Milisavljevic, D.; Mitra, A.; Reynolds, T.; Saario, J.; Shappee, B. J.; Smith, K. W.; Valenti, S.; Villar, V. A.; Waters, C.; Young, D. R.

    2016-07-01

    We present observations of SN 2015bn (=PS15ae = CSS141223-113342+004332 = MLS150211-113342+004333), a Type I superluminous supernova (SLSN) at redshift z = 0.1136. As well as being one of the closest SLSNe I yet discovered, it is intrinsically brighter ({M}U≈ -23.1) and in a fainter galaxy ({M}B≈ -16.0) than other SLSNe at z˜ 0.1. We used this opportunity to collect the most extensive data set for any SLSN I to date, including densely sampled spectroscopy and photometry, from the UV to the NIR, spanning ‑50 to +250 days from optical maximum. SN 2015bn fades slowly, but exhibits surprising undulations in the light curve on a timescale of 30–50 days, especially in the UV. The spectrum shows extraordinarily slow evolution except for a rapid transformation between +7 and +20–30 days. No narrow emission lines from slow-moving material are observed at any phase. We derive physical properties including the bolometric luminosity, and find slow velocity evolution and non-monotonic temperature and radial evolution. A deep radio limit rules out a healthy off-axis gamma-ray burst, and places constraints on the pre-explosion mass loss. The data can be consistently explained by a ≳ 10 M {}ȯ stripped progenitor exploding with ˜ {10}51 erg kinetic energy, forming a magnetar with a spin-down timescale of ˜20 days (thus avoiding a gamma-ray burst) that reheats the ejecta and drives ionization fronts. The most likely alternative scenario—interaction with ˜20 M {}ȯ of dense, inhomogeneous circumstellar material—can be tested with continuing radio follow-up.

  5. SN 2015BN: A Detailed Multi-wavelength View of a Nearby Superluminous Supernova

    NASA Astrophysics Data System (ADS)

    Nicholl, M.; Berger, E.; Smartt, S. J.; Margutti, R.; Kamble, A.; Alexander, K. D.; Chen, T.-W.; Inserra, C.; Arcavi, I.; Blanchard, P. K.; Cartier, R.; Chambers, K. C.; Childress, M. J.; Chornock, R.; Cowperthwaite, P. S.; Drout, M.; Flewelling, H. A.; Fraser, M.; Gal-Yam, A.; Galbany, L.; Harmanen, J.; Holoien, T. W.-S.; Hosseinzadeh, G.; Howell, D. A.; Huber, M. E.; Jerkstrand, A.; Kankare, E.; Kochanek, C. S.; Lin, Z.-Y.; Lunnan, R.; Magnier, E. A.; Maguire, K.; McCully, C.; McDonald, M.; Metzger, B. D.; Milisavljevic, D.; Mitra, A.; Reynolds, T.; Saario, J.; Shappee, B. J.; Smith, K. W.; Valenti, S.; Villar, V. A.; Waters, C.; Young, D. R.

    2016-07-01

    We present observations of SN 2015bn (=PS15ae = CSS141223-113342+004332 = MLS150211-113342+004333), a Type I superluminous supernova (SLSN) at redshift z = 0.1136. As well as being one of the closest SLSNe I yet discovered, it is intrinsically brighter ({M}U≈ -23.1) and in a fainter galaxy ({M}B≈ -16.0) than other SLSNe at z˜ 0.1. We used this opportunity to collect the most extensive data set for any SLSN I to date, including densely sampled spectroscopy and photometry, from the UV to the NIR, spanning -50 to +250 days from optical maximum. SN 2015bn fades slowly, but exhibits surprising undulations in the light curve on a timescale of 30-50 days, especially in the UV. The spectrum shows extraordinarily slow evolution except for a rapid transformation between +7 and +20-30 days. No narrow emission lines from slow-moving material are observed at any phase. We derive physical properties including the bolometric luminosity, and find slow velocity evolution and non-monotonic temperature and radial evolution. A deep radio limit rules out a healthy off-axis gamma-ray burst, and places constraints on the pre-explosion mass loss. The data can be consistently explained by a ≳ 10 M {}⊙ stripped progenitor exploding with ˜ {10}51 erg kinetic energy, forming a magnetar with a spin-down timescale of ˜20 days (thus avoiding a gamma-ray burst) that reheats the ejecta and drives ionization fronts. The most likely alternative scenario—interaction with ˜20 M {}⊙ of dense, inhomogeneous circumstellar material—can be tested with continuing radio follow-up.

  6. The Nonlinear Evolution of Massive Stellar Core Collapses That ``Fizzle''

    NASA Astrophysics Data System (ADS)

    Imamura, James N.; Pickett, Brian K.; Durisen, Richard H.

    2003-04-01

    Core collapse in a massive rotating star may pause before nuclear density is reached, if the core contains total angular momentum J>~1049 g cm2 s-1. In such aborted or ``fizzled'' collapses, temporary equilibrium objects form that, although rapidly rotating, are secularly and dynamically stable because of the high electron fraction per baryon Ye>0.3 and the high entropy per baryon Sb/k~1-2 of the core material at neutrino trapping. These fizzled collapses are called ``fizzlers.'' In the absence of prolonged infall from the surrounding star, the evolution of fizzlers is driven by deleptonization, which causes them to contract and spin up until they either become stable neutron stars or reach the dynamic instability point for barlike modes. The barlike instability case is of current interest because the bars would be sources of gravitational wave (GW) radiation. In this paper, we use linear and nonlinear techniques, including three-dimensional hydrodynamic simulations, to study the behavior of fizzlers that have deleptonized to the point of reaching dynamic bar instability. The simulations show that the GW emission produced by bar-unstable fizzlers has rms strain amplitude r15h=10-23 to 10-22 for an observer on the rotation axis, with wave frequency of roughly 60-600 Hz. Here h is the strain and r15= (r/15 Mpc) is the distance to the fizzler in units of 15 Mpc. If the bars that form by dynamic instability can maintain GW emission at this level for 100 periods or more, they may be detectable by the Laser Interferometer Gravitational-Wave Observatory at the distance of the Virgo Cluster. They would be detectable as burst sources, defined as sources that persist for ~10 cycles or less, if they occurred in the Local Group of galaxies. The long-term behavior of the bars is the crucial issue for the detection of fizzler events. The bars present at the end of our simulations are dynamically stable but will evolve on longer timescales because of a variety of effects, such as

  7. The X-ray properties of supernova remnants in nearby galaxies

    NASA Astrophysics Data System (ADS)

    Long, Knox S.; Blair, William P.; Kuntz, Kip D.; Winkler, P. Frank

    2016-06-01

    More extragalactic SNRs have been detected in X-rays in nearby galaxies than in the Milky Way. Most of the X-ray detected SNRs were first identified optically, and then detected as soft X-ray sources in deep imaging observations with Chandra and in some cases XMM. Here, we discuss the large X-ray samples of SNRs in M51, M83, and M101, with the goal of understanding which SNRs are detected in X-rays and which are not. Not surprisingly perhaps, most of the SNRs in these galaxies are middle-aged SNRs; very few analogs of Cas A or other young objects have been found. Trends of X-ray luminosity with diameter are absent, probably because the total amount of swept up material is the dominant factor in determining the X-ray luminosity of a SNR at a particular time. SNR expanding into high density media evolve rapidly and have X-ray luminosities that peak at small diameters, whereas those expanding into lower density media evolve more slowly and have luminosities that peak later.

  8. X-ray Properties of Supernova Remnants in Nearby Spiral Galaxies

    NASA Astrophysics Data System (ADS)

    Long, Knox S.; Blair, William P.; Kuntz, K. D.; Winkler, P. Frank

    2016-04-01

    More extragalactic SNRs have been detected in X-rays in nearby galaxies than in the Milky Way. Most of the X-ray detected SNRs were first identified optically, and then detected as soft X-ray sources in deep imaging observations with Chandra and in some cases XMM. Here, we discuss the large X-ray samples of SNRs in M33, M51, M83, and M101, with the goal of understanding which SNRs are detected in X-rays and which are not. Not surprisingly perhaps, most of the SNRs in these galaxies are middle-aged ones very few analogs of Cas A, the Crab or other young objects have been found. Trends of X-ray luminosity with diameter are absent, probably because the total amount of swept up material is the dominant factor in determining the X-ray luminosity of a SNR at a particular time. SNRs expanding into high density media evolve rapidly and have X-ray luminosities that peak at small diameters, whereas those expanding into lower density media evolve more slowly and have luminosities that peak later.

  9. An X-Ray, Optical, and Radio Search for Supernova Remnants in the Nearby Sculptor Group Sd Galaxy NGC 7793

    NASA Astrophysics Data System (ADS)

    Pannuti, Thomas G.; Duric, Nebojsa; Lacey, Christina K.; Ferguson, Annette M. N.; Magnor, Marcus A.; Mendelowitz, Caylin

    2002-02-01

    This paper is the second in a series devoted to examining the multiwavelength properties of supernova remnants (SNRs) located in nearby galaxies. We consider here the resident SNRs in the nearby Sculptor group Sd galaxy NGC 7793. Using our own Very Large Array (VLA) radio observations at 6 and 20 cm, as well as archived ROSAT X-ray data, previously published optical results, and our own Hα image, we have searched for X-ray and radio counterparts to previously known optically identified SNRs and for new previously unidentified SNRs at these two wavelength regimes. Consistent with our prior results for NGC 300, only a tiny minority of the optically identified SNRs have been found at another wavelength. The most noteworthy source in our study is N7793-S26, which is the only SNR in this galaxy that is detected at all three wavelengths (X-ray, optical, and radio). It features a long (~450 pc) filamentary morphology that is clearly seen in both the optical and the radio images. N7793-S26's radio luminosity exceeds that of the Galactic SNR Cas A, and based on equipartition calculations we determine that an energy of at least 1052 ergs is required to maintain this source. Such a result argues for the source being created by multiple supernova explosions rather than by a single supernova event. A second optically identified SNR, N7793-S11, has detectable radio emission but no detectable X-ray emission. A radio-selected sample of candidate SNRs has also been prepared by searching for coincidences between nonthermal radio sources and regions of Hα emission in this galaxy. This search has produced five new candidate radio SNRs to be added to the 28 SNRs that have already been detected by optical methods. A complementary search for new candidate X-ray SNRs has also been conducted by searching for soft-spectrum sources (kT<1 keV) that are coincident with regions of Hα emission. That search has yielded a candidate X-ray SNR that is coincident with one (and possibly two) of the

  10. The Shape of Superluminous Supernovae

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-11-01

    emit an unpolarized spectrum. Otherwise, the polarization of an objects spectrum reveals information about its geometry.Modeling EjectaThe authors best model of the geometry of SN 2015bn 24 days before (top) and 28 days after (bottom) peak flux. The model consists of two ellipsoidal layers of ejecta material. [Inserra et al. 2016]Based on their observations, Inserra and collaborators find that SN 2015bn is not spherically symmetric but it does appear to be axisymmetric around a single dominant axis. They also find that the polarization level of the object changes both with wavelength and over time.To explain these dependencies, the authors produce a simple toy model of SN 2015bn. In the best-fitting model, the supernova has a two-layered ellipsoidal or bipolar geometry. The inner region becomes more and more aspherical as time passes.What does this model tell us about the physical cause of this superluminous supernova? Inserra and collaborators argue that the axisymmetric shape favors a core-collapse explosion. A central inner engine of a spinning magnetar (a highly magnetized neutron star) or black hole then remains at the center of this explosion, pumping energy into it and causing the increase of the inner asymmetry over time.The authors caution that their models are very preliminary but these observations should drive future, more detailed modeling, as well as further spectropolarimetric observations of future nearby superluminous supernovae. With luck, we will soon better understand what drives these unusual explosions.CitationC. Inserra et al 2016 ApJ 831 79. doi:10.3847/0004-637X/831/1/79

  11. Results from Core-collapse Simulations with Multi-dimensional, Multi-angle Neutrino Transport

    NASA Astrophysics Data System (ADS)

    Brandt, Timothy D.; Burrows, Adam; Ott, Christian D.; Livne, Eli

    2011-02-01

    We present new results from the only two-dimensional multi-group, multi-angle calculations of core-collapse supernova evolution. The first set of results from these calculations was published in 2008 by Ott et al. We have followed a nonrotating and a rapidly rotating 20 M sun model for ~400 ms after bounce. We show that the radiation fields vary much less with angle than the matter quantities in the region of net neutrino heating. This happens because most neutrinos are emitted from inner radiative regions and because the specific intensity is an integral over sources from many angles at depth. The latter effect can only be captured by multi-angle transport. We then compute the phase relationship between dipolar oscillations in the shock radius and in matter and radiation quantities throughout the post-shock region. We demonstrate a connection between variations in neutrino flux and the hydrodynamical shock oscillations, and use a variant of the Rayleigh test to estimate the detectability of these neutrino fluctuations in IceCube and Super-Kamiokande. Neglecting flavor oscillations, fluctuations in our nonrotating model would be detectable to ~10 kpc in IceCube, and a detailed power spectrum could be measured out to ~5 kpc. These distances are considerably lower in our rapidly rotating model or with significant flavor oscillations. Finally, we measure the impact of rapid rotation on detectable neutrino signals. Our rapidly rotating model has strong, species-dependent asymmetries in both its peak neutrino flux and its light curves. The peak flux and decline rate show pole-equator ratios of up to ~3 and ~2, respectively.

  12. Gamma line radiation from supernovae. [nucleosynthesis

    NASA Technical Reports Server (NTRS)

    Arnett, W. D.

    1978-01-01

    Recent calculations of core collapse or massive stars result in explosive ejection of the mantle by a reflected shock. These hydrodynamic results are important for predictions of explosive nucleosynthesis and gamma-ray line emission from supernovae. Previous estimates, based on simple parameterized models or the nucleosynthesis in an average supernova, are compared with these latest results.

  13. A mildly relativistic radio jet from the otherwise normal type Ic supernova 2007gr.

    PubMed

    Paragi, Z; Taylor, G B; Kouveliotou, C; Granot, J; Ramirez-Ruiz, E; Bietenholz, M; van der Horst, A J; Pidopryhora, Y; van Langevelde, H J; Garrett, M A; Szomoru, A; Argo, M K; Bourke, S; Paczyński, B

    2010-01-28

    The class of type Ic supernovae have drawn increasing attention since 1998 owing to their sparse association (only four so far) with long duration gamma-ray bursts (GRBs). Although both phenomena originate from the core collapse of a massive star, supernovae emit mostly at optical wavelengths, whereas GRBs emit mostly in soft gamma-rays or hard X-rays. Though the GRB central engine generates ultra-relativistic jets, which beam the early emission into a narrow cone, no relativistic outflows have hitherto been found in type Ib/c supernovae explosions, despite theoretical expectations and searches. Here we report radio (interferometric) observations that reveal a mildly relativistic expansion in a nearby type Ic supernova, SN 2007gr. Using two observational epochs 60 days apart, we detect expansion of the source and establish a conservative lower limit for the average apparent expansion velocity of 0.6c. Independently, a second mildly relativistic supernova has been reported. Contrary to the radio data, optical observations of SN 2007gr indicate a typical type Ic supernova with ejecta velocities approximately 6,000 km s(-1), much lower than in GRB-associated supernovae. We conclude that in SN 2007gr a small fraction of the ejecta produced a low-energy mildly relativistic bipolar radio jet, while the bulk of the ejecta were slower and, as shown by optical spectropolarimetry, mildly aspherical.

  14. A mildly relativistic radio jet from the otherwise normal type Ic supernova 2007gr

    NASA Astrophysics Data System (ADS)

    Paragi, Z.; Taylor, G. B.; Kouveliotou, C.; Granot, J.; Ramirez-Ruiz, E.; Bietenholz, M.; van der Horst, A. J.; Pidopryhora, Y.; van Langevelde, H. J.; Garrett, M. A.; Szomoru, A.; Argo, M. K.; Bourke, S.; Paczyński, B.

    2010-01-01

    The class of type Ic supernovae have drawn increasing attention since 1998 owing to their sparse association (only four so far) with long duration γ-ray bursts (GRBs). Although both phenomena originate from the core collapse of a massive star, supernovae emit mostly at optical wavelengths, whereas GRBs emit mostly in soft γ-rays or hard X-rays. Though the GRB central engine generates ultra-relativistic jets, which beam the early emission into a narrow cone, no relativistic outflows have hitherto been found in type Ib/c supernovae explosions, despite theoretical expectations and searches. Here we report radio (interferometric) observations that reveal a mildly relativistic expansion in a nearby type Ic supernova, SN 2007gr. Using two observational epochs 60days apart, we detect expansion of the source and establish a conservative lower limit for the average apparent expansion velocity of 0.6c. Independently, a second mildly relativistic supernova has been reported. Contrary to the radio data, optical observations of SN 2007gr indicate a typical type Ic supernova with ejecta velocities ~6,000kms-1, much lower than in GRB-associated supernovae. We conclude that in SN 2007gr a small fraction of the ejecta produced a low-energy mildly relativistic bipolar radio jet, while the bulk of the ejecta were slower and, as shown by optical spectropolarimetry, mildly aspherical.

  15. Time-Dependent Collective Neutrino Oscillations in Supernovae

    NASA Astrophysics Data System (ADS)

    Abbar, Sajad; Duan, Huaiyu

    2015-10-01

    Neutrinos can experience self-induced flavor conversion in core-collapse supernovae due to neutrino-neutrino forward scattering. Previously a stationary supernova model, the so called ``neutrino bulb model,'' was used exclusively to study collective neutrino oscillations in the core-collapse supernova. We show that even a small time-dependent perturbation in neutrino fluxes on the surface of the proto-neutron star can lead to fast varying collective oscillations at large radii. This result calls for time-dependent supernova models for the study of collective neutrino oscillations. This work was supported by DOE EPSCoR Grant DE-SC0008142 at UNM.

  16. VizieR Online Data Catalog: Core collapse supernovae (type Ibc) (Eldridge+, 2013)

    NASA Astrophysics Data System (ADS)

    Eldridge, J. J.; Fraser, M.; Smartt, S. J.; Maund, J. R.; Crockett, R. M.

    2014-10-01

    We have followed the methodology of Paper I (Smartt et al., 2009MNRAS.395.1409S) in sample selection. The list of SNe maintained by the International Astronomical Union (IAU) Central Bureau for Astronomical Telegrams (CBET) was searched for all SNe with a named host galaxy discovered in the 14yr period from 1998 January 1 to 2012 March 30. This sample was then cross-matched against the HyperLEDA galaxy data base to identify all SNe for which the host galaxy had a recessional velocity (corrected for Local Group infall on Virgo) of 2000km/s or less, corresponding to a distance limit of 28Mpc for H0=72km/s/Mpc. For SNe where there was not a named host in the IAU catalogue, HyperLEDA was searched for any galaxy within 1.5-arcmin of the SN position. Finally, the coordinates of any SNe which did not have a named host or a galaxy within 1.5-arcmin and was brighter than magnitude 16 were queried via the NASA Extragalactic Database (NED). (2 data files).

  17. GENERAL-RELATIVISTIC SIMULATIONS OF THREE-DIMENSIONAL CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Ott, Christian D.; Abdikamalov, Ernazar; Moesta, Philipp; Haas, Roland; Drasco, Steve; O'Connor, Evan P.; Reisswig, Christian; Meakin, Casey A.; Schnetter, Erik

    2013-05-10

    We study the three-dimensional (3D) hydrodynamics of the post-core-bounce phase of the collapse of a 27 M{sub Sun} star and pay special attention to the development of the standing accretion shock instability (SASI) and neutrino-driven convection. To this end, we perform 3D general-relativistic simulations with a three-species neutrino leakage scheme. The leakage scheme captures the essential aspects of neutrino cooling, heating, and lepton number exchange as predicted by radiation-hydrodynamics simulations. The 27 M{sub Sun} progenitor was studied in 2D by Mueller et al., who observed strong growth of the SASI while neutrino-driven convection was suppressed. In our 3D simulations, neutrino-driven convection grows from numerical perturbations imposed by our Cartesian grid. It becomes the dominant instability and leads to large-scale non-oscillatory deformations of the shock front. These will result in strongly aspherical explosions without the need for large-scale SASI shock oscillations. Low-l-mode SASI oscillations are present in our models, but saturate at small amplitudes that decrease with increasing neutrino heating and vigor of convection. Our results, in agreement with simpler 3D Newtonian simulations, suggest that once neutrino-driven convection is started, it is likely to become the dominant instability in 3D. Whether it is the primary instability after bounce will ultimately depend on the physical seed perturbations present in the cores of massive stars. The gravitational wave signal, which we extract and analyze for the first time from 3D general-relativistic models, will serve as an observational probe of the postbounce dynamics and, in combination with neutrinos, may allow us to determine the primary hydrodynamic instability.

  18. Photoneutron Cross Sections for 9Be and the α-PROCESS in Core-Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Utsunomiya, H.; Yonezawa, Y.; Akimune, H.; Yamagata, T.; Ohta, M.; Fujishiro, M.; Toyokawa, H.; Ohgaki, H.

    2003-04-01

    Photoneutron cross sections were measured for 9Be in the energy range from 1.78 to 6.11 MeV with laser-induced Compton backscattered γ rays. The data are compared with those from the Bremsstrahlung and the radioactive isotope measurements. γ-decay widths for the 1/2+ and 5/2- states were deduced from the least-squares fit to the data as well as the energy-integrated cross section. Astro-physical implications are discussed.

  19. NEAR-EXTREMAL BLACK HOLES AS INITIAL CONDITIONS OF LONG GRB SUPERNOVAE AND PROBES OF THEIR GRAVITATIONAL WAVE EMISSION

    SciTech Connect

    Van Putten, Maurice H. P. M.

    2015-09-01

    Long gamma-ray bursts (GRBs) associated with supernovae and short GRBs with extended emission (SGRBEE) from mergers are probably powered by black holes as a common inner engine, as their prompt GRB emission satisfies the same Amati correlation in the E{sub p,i}–E{sub iso} plane. We introduce modified Bardeen equations to identify hyper-accretion driving newly formed black holes in core-collapse supernovae to near-extremal spin as a precursor to prompt GRB emission. Subsequent spin-down is observed in the BATSE catalog of long GRBs. Spin-down provides a natural unification of long durations associated with the lifetime of black hole spin for normal long GRBs and SGRBEEs, given the absence of major fallback matter in mergers. The results point to major emissions unseen in high frequency gravitational waves. A novel matched filtering method is described for LIGO–Virgo and KAGRA broadband probes of nearby core-collapse supernovae at essentially maximal sensitivity.

  20. Modification of magicity toward the dripline and its impact on electron-capture rates for stellar core collapse

    NASA Astrophysics Data System (ADS)

    Raduta, Ad. R.; Gulminelli, F.; Oertel, M.

    2016-02-01

    The importance of microphysical inputs from laboratory nuclear experiments and theoretical nuclear structure calculations in the understanding of core-collapse dynamics and the subsequent supernova explosion is largely recognized in the recent literature. In this work, we analyze the impact of the masses of very neutron-rich nuclei on the matter composition during collapse and the corresponding electron-capture rate. To this end, we introduce an empirical modification of the popular Duflo-Zuker mass model to account for possible shell quenching far from stability. We study the effect of this quenching on the average electron-capture rate. We show that the pre-eminence of the closed shells with N =50 and N =82 in the collapse dynamics is considerably decreased if the shell gaps are reduced in the region of 78Ni and beyond. As a consequence, local modifications of the overall electron-capture rate of up to 30% can be expected, depending on the strength of magicity quenching. This finding has potentially important consequences on the entropy generation, the neutrino emissivity, and the mass of the core at bounce. Our work underlines the importance of new experimental measurements in this region of the nuclear chart, the most crucial information being the nuclear mass and the Gamow-Teller strength. Reliable microscopic calculations of the associated elementary rate, in a wide range of temperatures and electron densities, optimized on these new empirical information, will be additionally needed to get quantitative predictions of the collapse dynamics.

  1. Neutrino Scattering and Flavor Transformation in Supernovae

    NASA Astrophysics Data System (ADS)

    Cherry, John F.; Carlson, J.; Friedland, Alexander; Fuller, George M.; Vlasenko, Alexey

    2012-06-01

    We argue that the small fraction of neutrinos that undergo direction-changing scattering outside of the neutrinosphere could have significant influence on neutrino flavor transformation in core-collapse supernova environments. We show that the standard treatment for collective neutrino flavor transformation is adequate at late times but could be inadequate in early epochs of core-collapse supernovae, where the potentials that govern neutrino flavor evolution are affected by the scattered neutrinos. Taking account of this effect, and the way it couples to entropy and composition, will require a new approach in neutrino flavor transformation modeling.

  2. The Search for Supernova Grains in an Ice Core

    NASA Astrophysics Data System (ADS)

    Cole, A. L.; Boyd, R. N.; Davis, M. E.; Thompson, L. G.; Davis, A. M.; Lewis, R. S.; Zinner, E.

    2006-12-01

    A search was conducted for grains of the potential core-collapse supernova (SN) condensate minerals corundum (Al2O3), hibonite (CaAl12O19), and spinel (MgAl2O4) among grains filtered from the 308.6 m Guliya ice core recovered from the Qinghai-Tibetan plateau in China. Simple models are developed and calculations are presented to estimate the number of Al2O3 grains that would be deposited per cm2 on the Earth by a nearby core-collapse SN and to estimate the number of presolar oxide grains that could be contained in micrometeorite (MM) grains that are accreted by the Earth. A total of 698 candidate SN condensate grains were identified in six Guliya ice core grain samples from the following time periods: ~2-10, ~25-27, ~34-36, ~53-57, ~59-62, and ~68-72 kyr. A procedure developed at the University of Chicago to identify presolar grains in meteoric samples was used to find these candidate grains. Nanometer-scale secondary ion mass spectrometry (NanoSIMS) analysis, performed at Washington University on 37 grains from the ~34-36, ~53-57, and ~59-62 kyr samples, indicated that none possessed the extreme oxygen-16 enhancements expected from a SN source. However, nine of the 37 grains did possess the oxygen-16 enhancements consistent with calcium-aluminum-rich inclusions (CAIs).

  3. Dust production in supernovae and AGB stars

    NASA Astrophysics Data System (ADS)

    Matsuura, Mikako

    2015-08-01

    In the last decade, the role of supernovae on dust has changed; it has been long proposed that supernovae are dust destroyers, but now recent observations show that core-collapse supernovae can become dust factories. Theoretical models of dust evolution in galaxies have predicted that core-collapse supernovae can be an important source of dust in galaxies, if these supernovae can form a significant mass of dust (0.1-1 solar masses). The Herschel Space Observatory and ALMA detected dust in the ejecta of Supernova 1987A. They revealed an estimated 0.5 solar masses of dust. Herschel also found nearly 0.1 solar masses of dust in historical supernovae remnants, namely Cassiopeia A and the Crab Nebula. If dust grains can survive future interaction with the supernova winds and ambient interstellar medium, core-collapse supernovae can be an important source of dust in the interstellar media of galaxies. We further discuss the total dust mass injected by AGB stars and SNe into the interstellar medium of the Magellanic Clouds.

  4. High Statistics Study of Nearby Type 1a Supernovae. QUEST Camera Short Term Maintenance: Final Technical Report

    SciTech Connect

    Baltay, Charles

    2012-10-16

    The Quest Camera was installed at the Palomar Obervatory in California. The camera was used to carry out a survey of low redshift Type 1a supernovae.The purpose of this DOE grant was to perform short term maintenance on the QUEST camera.

  5. Supernova shock breakout from a red supergiant.

    PubMed

    Schawinski, Kevin; Justham, Stephen; Wolf, Christian; Podsiadlowski, Philipp; Sullivan, Mark; Steenbrugge, Katrien C; Bell, Tony; Röser, Hermann-Josef; Walker, Emma S; Astier, Pierre; Balam, Dave; Balland, Christophe; Carlberg, Ray; Conley, Alex; Fouchez, Dominique; Guy, Julien; Hardin, Delphine; Hook, Isobel; Howell, D Andrew; Pain, Reynald; Perrett, Kathy; Pritchet, Chris; Regnault, Nicolas; Yi, Sukyoung K

    2008-07-11

    Massive stars undergo a violent death when the supply of nuclear fuel in their cores is exhausted, resulting in a catastrophic "core-collapse" supernova. Such events are usually only detected at least a few days after the star has exploded. Observations of the supernova SNLS-04D2dc with the Galaxy Evolution Explorer space telescope reveal a radiative precursor from the supernova shock before the shock reached the surface of the star and show the initial expansion of the star at the beginning of the explosion. Theoretical models of the ultraviolet light curve confirm that the progenitor was a red supergiant, as expected for this type of supernova. These observations provide a way to probe the physics of core-collapse supernovae and the internal structures of their progenitor stars.

  6. Reassessment of True Core Collapse Differential Pressure Values for Filter Elements in Safety Critical Environments - 13076

    SciTech Connect

    Swain, Adam

    2013-07-01

    As the areas of application for diverse filter types increases, the mechanics and material sciences associated with the hardware and its relationship with more and more arduous process environments becomes critical to the successful and reliable operation of the filtration equipment. Where the filter is the last safe barrier between the process and the life environment, structural integrity and reliability is paramount in both the validation and the ethical acceptability of the designed equipment. Core collapse is a key factor influencing filter element selection, and is an extremely complex issue with a number of variables and failure mechanisms. It is becoming clear that the theory behind core collapse calculations is not always supported with real tested data. In exploring this issue we have found that the calculation method is not always reflective of the true as tested collapse value, with the calculated values being typically in excess or even an order of magnitude higher than the tested values. The above claim is supported by a case study performed by the author, which disproves most of what was previously understood to be true. This paper also aims to explore the various failure mechanisms of different configurations of filter core, comparing calculated collapse values against real tested values, with a view to understanding a method of calculating their true collapse value. As the technology is advancing, and filter elements are being used in higher temperature, higher pressure, more radioactive and more chemically aggressive environments, confidence in core collapse values and data is crucial. (authors)

  7. Bayesian reconstruction of gravitational wave burst signals from simulations of rotating stellar core collapse and bounce

    SciTech Connect

    Roever, Christian; Bizouard, Marie-Anne; Christensen, Nelson; Dimmelmeier, Harald; Heng, Ik Siong; Meyer, Renate

    2009-11-15

    Presented in this paper is a technique that we propose for extracting the physical parameters of a rotating stellar core collapse from the observation of the associated gravitational wave signal from the collapse and core bounce. Data from interferometric gravitational wave detectors can be used to provide information on the mass of the progenitor model, precollapse rotation, and the nuclear equation of state. We use waveform libraries provided by the latest numerical simulations of rotating stellar core collapse models in general relativity, and from them create an orthogonal set of eigenvectors using principal component analysis. Bayesian inference techniques are then used to reconstruct the associated gravitational wave signal that is assumed to be detected by an interferometric detector. Posterior probability distribution functions are derived for the amplitudes of the principal component analysis eigenvectors, and the pulse arrival time. We show how the reconstructed signal and the principal component analysis eigenvector amplitude estimates may provide information on the physical parameters associated with the core collapse event.

  8. Optical Observations of the Nearby Galaxy IC342 With Narrow Band [S II] and Hα Filters. II - Detection of 16 Optically-Identified Supernova Remnant Candidates

    NASA Astrophysics Data System (ADS)

    Vučetić, M. M.; Ćiprijanović, A.; Pavlović, M. Z.; Pannuti, T. G.; Petrov, N.; Göker, Ü. D.; Ercan, E. N.

    2015-12-01

    We present the detection of 16 optical supernova remnant (SNR) candidates in the nearby spiral galaxy IC342. The candidates were detected by applying [S II]/Hα ratio criterion on observations made with the 2 m RCC telescope at Rozhen National Astronomical Observatory in Bulgaria. In this paper, we report the coordinates, diameters, Hα and [S II] fluxes for 16 SNRs detected in two fields of view in the IC342 galaxy. Also, we estimate that the contamination of total Hα flux from SNRs in the observed portion of IC342 is 1.4 percent. This would represent the fractional error when the star formation rate (SFR) for this galaxy is derived from the total galaxy's Hα emission.

  9. What Shapes Supernova Remnants?

    NASA Astrophysics Data System (ADS)

    Lopez, Laura A.

    2014-01-01

    Evidence has mounted that Type Ia and core-collapse (CC) supernovae (SNe) can have substantial deviations from spherical symmetry; one such piece of evidence is the complex morphologies of supernova remnants (SNRs). However, the relative role of the explosion geometry and the environment in shaping SNRs remains an outstanding question. Recently, we have developed techniques to quantify the morphologies of SNRs, and we have applied these methods to the extensive X-ray and infrared archival images available of Milky Way and Magellanic Cloud SNRs. In this proceeding, we highlight some results from these studies, with particular emphasis on SNR asymmetries and whether they arise from ``nature'' or ``nurture''.

  10. Sweetspot: Near-infrared observations of 13 type Ia supernovae from a new NOAO survey probing the nearby smooth Hubble flow

    SciTech Connect

    Weyant, Anja; Wood-Vasey, W. Michael; Allen, Lori; Joyce, Richard; Matheson, Thomas; Garnavich, Peter M.; Jha, Saurabh W.

    2014-04-01

    We present 13 Type Ia supernovae (SNe Ia) observed in the rest-frame near-infrared (NIR) from 0.02 < z < 0.09 with the WIYN High-resolution Infrared Camera on the WIYN 3.5 m telescope. With only one to three points per light curve and a prior on the time of maximum from the spectrum used to type the object, we measure an H-band dispersion of spectroscopically normal SNe Ia of 0.164 mag. These observations continue to demonstrate the improved standard brightness of SNe Ia in an H band, even with limited data. Our sample includes two SNe Ia at z ∼ 0.09, which represent the most distant rest-frame NIR H-band observations published to date. This modest sample of 13 NIR SNe Ia represent the pilot sample for {sup S}weetSpot{sup —}a 3 yr NOAO Survey program that will observe 144 SNe Ia in the smooth Hubble flow. By the end of the survey we will have measured the relative distance to a redshift of z ∼ 0.05%-1%. Nearby Type Ia supernova (SN Ia) observations such as these will test the standard nature of SNe Ia in the rest-frame NIR, allow insight into the nature of dust, and provide a critical anchor for future cosmological SN Ia surveys at higher redshift.

  11. Supernovae

    NASA Astrophysics Data System (ADS)

    March, Marisa

    2014-03-01

    We live in a Universe that is getting bigger faster. This astonishing discovery of Universal acceleration was made in the late 1990s by two teams who made observations of a special type of exploded star known as a `Supernova Type Ia'. (SNeIa) Since the discovery of the accelerating Universe, one of the biggest questions in modern cosmology has been to determine the cause of that acceleration - the answer to this question will have far reaching implications for our theories of cosmology and fundamental physics more broadly. The two main competing explanations for this apparent late time acceleration of the Universe are modified gravity and dark energy. The Dark Energy Survey (DES) has been designed and commissioned to find to find answers to these questions about the nature of dark energy and modified gravity. The new 570 megapixel Dark Energy Camera is currently operating with the Cerro-Tololo Inter American Observatory's 4m Blanco teleccope, carrying out a systematic search for SNeIa, and mapping out the large scale structure of the Universe by making observations of galaxies. The DES science program program which saw first light in September 2013 will run for five years in total. DES SNeIa data in combination with the other DES observations of large scale structure will enable us to put increasingly accurate constraints on the expansion history of the Universe and will help us distinguish between competing theories of dark energy and modified gravity. As we draw to the close of the first observing season of DES in March 2014, we will report on the current status of the DES supernova survey, presenting first year supernovae data, preliminary results, survey strategy, discovery pipeline, spectroscopic target selection and data quality. This talk will give the first glimpse of the DES SN first year data and initial results as we begin our five year survey in search of dark energy. On behalf of the Dark Energy Survey collaboration.

  12. AN XMM-NEWTON STUDY OF THE BRIGHT, NEARBY SUPERNOVA REMNANT G296.1-0.5

    SciTech Connect

    Castro, D.; Slane, P. O.; Patnaude, D. J.; Gaensler, B. M.; Hughes, J. P.

    2011-06-20

    We present a detailed study of the supernova remnant (SNR) G296.1-0.5, performed using observations with the European Photon Imaging Camera (EPIC) and Reflection Grating Spectrometer instruments of the XMM-Newton satellite. G296.1-0.5 is a bright remnant that displays an incomplete multiple-shell morphology in both its radio and X-ray images. We use a set of observations toward G296.1-0.5, from three distinct pointings of EPIC, in order to perform a thorough spatial and spectral analysis of this remnant, and hence determine what type of progenitor gave rise to the supernova explosion, and describe the evolutionary state of the SNR. Our XMM-Newton observations establish that the spectral characteristics are consistent across the X-ray bright regions of the object and are best described by a model of the emission from a nonequilibrium ionization collisional plasma. The study reveals that the emission from the shell is characterized by an excess of N and an underabundance of O, which is typical of wind material from red supergiant and Wolf-Rayet stars. Additionally, we have detected transient X-ray source 2XMMi J115004.8-622442 at the edge of the SNR whose properties suggest that it is the result of stellar flare, and we discuss its nature in more detail.

  13. Non-cosmological FRBs from young supernova remnant pulsars

    NASA Astrophysics Data System (ADS)

    Connor, Liam; Sievers, Jonathan; Pen, Ue-Li

    2016-05-01

    We propose a new extra but non-cosmological explanation for fast radio bursts (FRBs) based on very young pulsars in supernova remnants. Within a few hundred years of a core-collapse supernova, the ejecta is confined within ˜1 pc, providing a high enough column density of free electrons for the observed 375-1600 pc cm-3 of dispersion measure (DM). By extrapolating a Crab-like pulsar to its infancy in an environment like that of SN 1987A, we hypothesize such an object could emit supergiant pulses sporadically which would be bright enough to be seen at a few hundred megaparsecs. We hypothesize that such supergiant pulses would preferentially occur early in the pulsar's life when the free electron density is still high, which is why we do not see large numbers of moderate DM FRBs (≲300 pc cm-3). In this scenario, Faraday rotation at the source gives rotation measures (RMs) much larger than the expected cosmological contribution. If the emission were pulsar-like, then the polarization vector could swing over the duration of the burst, which is not expected from non-rotating objects. In this model, the scattering, large DM, and commensurate RM all come from one place which is not the case for the cosmological interpretation. The model also provides testable predictions of the flux distribution and repeat rate of FRBs, and could be furthermore verified by spatial coincidence with optical supernovae of the past several decades and cross-correlation with nearby galaxy maps.

  14. Core collapse and horizontal-branch morphology in Galactic globular clusters

    NASA Astrophysics Data System (ADS)

    Pasquato, M.; Raimondo, G.; Brocato, E.; Chung, C.; Moraghan, A.; Lee, Y.-W.

    2013-06-01

    Context. Stellar collision rates in globular clusters (GCs) do not appear to correlate with horizontal branch (HB) morphology, suggesting that dynamics does not play a role in the second-parameter problem. However, core densities and collision rates derived from surface-brightness may be significantly underestimated as the surface-brightness profile of GCs is not necessarily a good indicator of the dynamical state of GC cores. Core-collapse may go unnoticed if high central densities of dark remnants are present. Aims: We test whether GC HB morphology data supports a dynamical contribution to the so-called second-parameter effect. Methods: To remove first-parameter dependence we fitted the maximum effective temperature along the HB as a function of metallicity in a sample of 54 Milky Way GCs. We plotted the residuals to the fit as a function of second-parameter candidates, namely dynamical age and total luminosity. We considered dynamical age (i.e. the ratio between age and half-light relaxation time) among possible second-parameters. We used a set of direct N-body simulations, including ones with dark remnants to illustrate how core density peaks, due to core collapse, in a dynamical-age range similar to that in which blue HBs are overabundant with respect to the metallicity expectation, especially for low-concentration initial conditions. Results: GC total luminosity shows nonlinear behavior compatible with the self-enrichment picture. However, the data are amenable to a different interpretation based on a dynamical origin of the second-parameter effect. Enhanced mass-stripping in the late red-giant-branch phase due to stellar interactions in collapsing cores is a viable candidate mechanism. In this picture, GCs with HBs bluer than expected based on metallicity are those undergoing core-collapse.

  15. Detection of Radio Transients from Supernovae

    NASA Astrophysics Data System (ADS)

    Schmitt, Christian

    2011-05-01

    A core-collapse supernova (SN) would produce an expanding shell of charged particles which interact with the surrounding magnetic field of the progenitor star producing a transient radio pulse. Approximately one supernova event per century is expected in a galaxy. The radio waves emitted are detectable by a new generation of low-frequency radio telescope arrays. We present details of an ongoing search for such events by the Eight-meter-wavelength Transient Array (ETA) and the Long Wavelength Array (LWA).

  16. The locations of recent supernovae near the Sun from modelling (60)Fe transport.

    PubMed

    Breitschwerdt, D; Feige, J; Schulreich, M M; de Avillez, M A; Dettbarn, C; Fuchs, B

    2016-04-01

    The signature of (60)Fe in deep-sea crusts indicates that one or more supernovae exploded in the solar neighbourhood about 2.2 million years ago. Recent isotopic analysis is consistent with a core-collapse or electron-capture supernova that occurred 60 to 130 parsecs from the Sun. Moreover, peculiarities in the cosmic ray spectrum point to a nearby supernova about two million years ago. The Local Bubble of hot, diffuse plasma, in which the Solar System is embedded, originated from 14 to 20 supernovae within a moving group, whose surviving members are now in the Scorpius-Centaurus stellar association. Here we report calculations of the most probable trajectories and masses of the supernova progenitors, and hence their explosion times and sites. The (60)Fe signal arises from two supernovae at distances between 90 and 100 parsecs. The closest occurred 2.3 million years ago at present-day galactic coordinates l = 327°, b = 11°, and the second-closest exploded about 1.5 million years ago at l = 343°, b = 25°, with masses of 9.2 and 8.8 times the solar mass, respectively. The remaining supernovae, which formed the Local Bubble, contribute to a smaller extent because they happened at larger distances and longer ago ((60)Fe has a half-life of 2.6 million years). There are uncertainties relating to the nucleosynthesis yields and the loss of (60)Fe during transport, but they do not influence the relative distribution of (60)Fe in the crust layers, and therefore our model reproduces the measured relative abundances very well.

  17. Slowly fading super-luminous supernovae that are not pair-instability explosions.

    PubMed

    Nicholl, M; Smartt, S J; Jerkstrand, A; Inserra, C; McCrum, M; Kotak, R; Fraser, M; Wright, D; Chen, T-W; Smith, K; Young, D R; Sim, S A; Valenti, S; Howell, D A; Bresolin, F; Kudritzki, R P; Tonry, J L; Huber, M E; Rest, A; Pastorello, A; Tomasella, L; Cappellaro, E; Benetti, S; Mattila, S; Kankare, E; Kangas, T; Leloudas, G; Sollerman, J; Taddia, F; Berger, E; Chornock, R; Narayan, G; Stubbs, C W; Foley, R J; Lunnan, R; Soderberg, A; Sanders, N; Milisavljevic, D; Margutti, R; Kirshner, R P; Elias-Rosa, N; Morales-Garoffolo, A; Taubenberger, S; Botticella, M T; Gezari, S; Urata, Y; Rodney, S; Riess, A G; Scolnic, D; Wood-Vasey, W M; Burgett, W S; Chambers, K; Flewelling, H A; Magnier, E A; Kaiser, N; Metcalfe, N; Morgan, J; Price, P A; Sweeney, W; Waters, C

    2013-10-17

    Super-luminous supernovae that radiate more than 10(44) ergs per second at their peak luminosity have recently been discovered in faint galaxies at redshifts of 0.1-4. Some evolve slowly, resembling models of 'pair-instability' supernovae. Such models involve stars with original masses 140-260 times that of the Sun that now have carbon-oxygen cores of 65-130 solar masses. In these stars, the photons that prevent gravitational collapse are converted to electron-positron pairs, causing rapid contraction and thermonuclear explosions. Many solar masses of (56)Ni are synthesized; this isotope decays to (56)Fe via (56)Co, powering bright light curves. Such massive progenitors are expected to have formed from metal-poor gas in the early Universe. Recently, supernova 2007bi in a galaxy at redshift 0.127 (about 12 billion years after the Big Bang) with a metallicity one-third that of the Sun was observed to look like a fading pair-instability supernova. Here we report observations of two slow-to-fade super-luminous supernovae that show relatively fast rise times and blue colours, which are incompatible with pair-instability models. Their late-time light-curve and spectral similarities to supernova 2007bi call the nature of that event into question. Our early spectra closely resemble typical fast-declining super-luminous supernovae, which are not powered by radioactivity. Modelling our observations with 10-16 solar masses of magnetar-energized ejecta demonstrates the possibility of a common explosion mechanism. The lack of unambiguous nearby pair-instability events suggests that their local rate of occurrence is less than 6 × 10(-6) times that of the core-collapse rate. PMID:24132291

  18. The locations of recent supernovae near the Sun from modelling 60Fe transport

    NASA Astrophysics Data System (ADS)

    Breitschwerdt, D.; Feige, J.; Schulreich, M. M.; Avillez, M. A. De.; Dettbarn, C.; Fuchs, B.

    2016-04-01

    The signature of 60Fe in deep-sea crusts indicates that one or more supernovae exploded in the solar neighbourhood about 2.2 million years ago. Recent isotopic analysis is consistent with a core-collapse or electron-capture supernova that occurred 60 to 130 parsecs from the Sun. Moreover, peculiarities in the cosmic ray spectrum point to a nearby supernova about two million years ago. The Local Bubble of hot, diffuse plasma, in which the Solar System is embedded, originated from 14 to 20 supernovae within a moving group, whose surviving members are now in the Scorpius-Centaurus stellar association. Here we report calculations of the most probable trajectories and masses of the supernova progenitors, and hence their explosion times and sites. The 60Fe signal arises from two supernovae at distances between 90 and 100 parsecs. The closest occurred 2.3 million years ago at present-day galactic coordinates l = 327°, b = 11°, and the second-closest exploded about 1.5 million years ago at l = 343°, b = 25°, with masses of 9.2 and 8.8 times the solar mass, respectively. The remaining supernovae, which formed the Local Bubble, contribute to a smaller extent because they happened at larger distances and longer ago (60Fe has a half-life of 2.6 million years). There are uncertainties relating to the nucleosynthesis yields and the loss of 60Fe during transport, but they do not influence the relative distribution of 60Fe in the crust layers, and therefore our model reproduces the measured relative abundances very well.

  19. Slowly fading super-luminous supernovae that are not pair-instability explosions

    NASA Astrophysics Data System (ADS)

    Nicholl, M.; Smartt, S. J.; Jerkstrand, A.; Inserra, C.; McCrum, M.; Kotak, R.; Fraser, M.; Wright, D.; Chen, T.-W.; Smith, K.; Young, D. R.; Sim, S. A.; Valenti, S.; Howell, D. A.; Bresolin, F.; Kudritzki, R. P.; Tonry, J. L.; Huber, M. E.; Rest, A.; Pastorello, A.; Tomasella, L.; Cappellaro, E.; Benetti, S.; Mattila, S.; Kankare, E.; Kangas, T.; Leloudas, G.; Sollerman, J.; Taddia, F.; Berger, E.; Chornock, R.; Narayan, G.; Stubbs, C. W.; Foley, R. J.; Lunnan, R.; Soderberg, A.; Sanders, N.; Milisavljevic, D.; Margutti, R.; Kirshner, R. P.; Elias-Rosa, N.; Morales-Garoffolo, A.; Taubenberger, S.; Botticella, M. T.; Gezari, S.; Urata, Y.; Rodney, S.; Riess, A. G.; Scolnic, D.; Wood-Vasey, W. M.; Burgett, W. S.; Chambers, K.; Flewelling, H. A.; Magnier, E. A.; Kaiser, N.; Metcalfe, N.; Morgan, J.; Price, P. A.; Sweeney, W.; Waters, C.

    2013-10-01

    Super-luminous supernovae that radiate more than 1044 ergs per second at their peak luminosity have recently been discovered in faint galaxies at redshifts of 0.1-4. Some evolve slowly, resembling models of `pair-instability' supernovae. Such models involve stars with original masses 140-260 times that of the Sun that now have carbon-oxygen cores of 65-130 solar masses. In these stars, the photons that prevent gravitational collapse are converted to electron-positron pairs, causing rapid contraction and thermonuclear explosions. Many solar masses of 56Ni are synthesized; this isotope decays to 56Fe via 56Co, powering bright light curves. Such massive progenitors are expected to have formed from metal-poor gas in the early Universe. Recently, supernova 2007bi in a galaxy at redshift 0.127 (about 12 billion years after the Big Bang) with a metallicity one-third that of the Sun was observed to look like a fading pair-instability supernova. Here we report observations of two slow-to-fade super-luminous supernovae that show relatively fast rise times and blue colours, which are incompatible with pair-instability models. Their late-time light-curve and spectral similarities to supernova 2007bi call the nature of that event into question. Our early spectra closely resemble typical fast-declining super-luminous supernovae, which are not powered by radioactivity. Modelling our observations with 10-16 solar masses of magnetar-energized ejecta demonstrates the possibility of a common explosion mechanism. The lack of unambiguous nearby pair-instability events suggests that their local rate of occurrence is less than 6 × 10-6 times that of the core-collapse rate.

  20. The locations of recent supernovae near the Sun from modelling (60)Fe transport.

    PubMed

    Breitschwerdt, D; Feige, J; Schulreich, M M; de Avillez, M A; Dettbarn, C; Fuchs, B

    2016-04-01

    The signature of (60)Fe in deep-sea crusts indicates that one or more supernovae exploded in the solar neighbourhood about 2.2 million years ago. Recent isotopic analysis is consistent with a core-collapse or electron-capture supernova that occurred 60 to 130 parsecs from the Sun. Moreover, peculiarities in the cosmic ray spectrum point to a nearby supernova about two million years ago. The Local Bubble of hot, diffuse plasma, in which the Solar System is embedded, originated from 14 to 20 supernovae within a moving group, whose surviving members are now in the Scorpius-Centaurus stellar association. Here we report calculations of the most probable trajectories and masses of the supernova progenitors, and hence their explosion times and sites. The (60)Fe signal arises from two supernovae at distances between 90 and 100 parsecs. The closest occurred 2.3 million years ago at present-day galactic coordinates l = 327°, b = 11°, and the second-closest exploded about 1.5 million years ago at l = 343°, b = 25°, with masses of 9.2 and 8.8 times the solar mass, respectively. The remaining supernovae, which formed the Local Bubble, contribute to a smaller extent because they happened at larger distances and longer ago ((60)Fe has a half-life of 2.6 million years). There are uncertainties relating to the nucleosynthesis yields and the loss of (60)Fe during transport, but they do not influence the relative distribution of (60)Fe in the crust layers, and therefore our model reproduces the measured relative abundances very well. PMID:27078566

  1. Slowly fading super-luminous supernovae that are not pair-instability explosions.

    PubMed

    Nicholl, M; Smartt, S J; Jerkstrand, A; Inserra, C; McCrum, M; Kotak, R; Fraser, M; Wright, D; Chen, T-W; Smith, K; Young, D R; Sim, S A; Valenti, S; Howell, D A; Bresolin, F; Kudritzki, R P; Tonry, J L; Huber, M E; Rest, A; Pastorello, A; Tomasella, L; Cappellaro, E; Benetti, S; Mattila, S; Kankare, E; Kangas, T; Leloudas, G; Sollerman, J; Taddia, F; Berger, E; Chornock, R; Narayan, G; Stubbs, C W; Foley, R J; Lunnan, R; Soderberg, A; Sanders, N; Milisavljevic, D; Margutti, R; Kirshner, R P; Elias-Rosa, N; Morales-Garoffolo, A; Taubenberger, S; Botticella, M T; Gezari, S; Urata, Y; Rodney, S; Riess, A G; Scolnic, D; Wood-Vasey, W M; Burgett, W S; Chambers, K; Flewelling, H A; Magnier, E A; Kaiser, N; Metcalfe, N; Morgan, J; Price, P A; Sweeney, W; Waters, C

    2013-10-17

    Super-luminous supernovae that radiate more than 10(44) ergs per second at their peak luminosity have recently been discovered in faint galaxies at redshifts of 0.1-4. Some evolve slowly, resembling models of 'pair-instability' supernovae. Such models involve stars with original masses 140-260 times that of the Sun that now have carbon-oxygen cores of 65-130 solar masses. In these stars, the photons that prevent gravitational collapse are converted to electron-positron pairs, causing rapid contraction and thermonuclear explosions. Many solar masses of (56)Ni are synthesized; this isotope decays to (56)Fe via (56)Co, powering bright light curves. Such massive progenitors are expected to have formed from metal-poor gas in the early Universe. Recently, supernova 2007bi in a galaxy at redshift 0.127 (about 12 billion years after the Big Bang) with a metallicity one-third that of the Sun was observed to look like a fading pair-instability supernova. Here we report observations of two slow-to-fade super-luminous supernovae that show relatively fast rise times and blue colours, which are incompatible with pair-instability models. Their late-time light-curve and spectral similarities to supernova 2007bi call the nature of that event into question. Our early spectra closely resemble typical fast-declining super-luminous supernovae, which are not powered by radioactivity. Modelling our observations with 10-16 solar masses of magnetar-energized ejecta demonstrates the possibility of a common explosion mechanism. The lack of unambiguous nearby pair-instability events suggests that their local rate of occurrence is less than 6 × 10(-6) times that of the core-collapse rate.

  2. Equation of State Dependence of Gravitational Waves from Rapidly Rotating Core-Collapse

    NASA Astrophysics Data System (ADS)

    Richers, Sherwood; Ott, Christian D.; Abdikamalov, Ernazar

    2016-03-01

    We carry out axisymmetric simulations of rotating core-collapse, exploring over 92 precollapse rotational configurations and 18 different finite-temperature microphysical equations of state (EOS) using the general-relativistic hydrodynamical code CoCoNuT. Our focus is on gravitational wave (GW) emission. We find that the GW wave signature depends systematically on the rotation rate of the inner core at bounce and the compactness of the protoneutron star (PNS), set by the EOS and rotation. The GW signal from core bounce is almost independent of the EOS. However, the frequency of the post-bounce ring down signal from the fundamental quadrupole oscillation mode of the PNS is dependent on both rotation and the EOS, increasing with rotation rate and compactness. We will discuss the origin of the EOS-dependent f-mode frequency variation and its potential observability with Advanced LIGO.

  3. COSMIC-LAB: Double BSS sequences as signatures of the Core Collapse phenomenon in star clusters.

    NASA Astrophysics Data System (ADS)

    Ferraro, Francesco

    2011-10-01

    Globular Clusters {GCs} are old stellar systems tracing key stages of the star formation and chemical enrichment history of the early Universe and the galaxy assembly phase. As part of a project {COSMIC-LAB} aimed at using GCs as natural laboratories to study the complex interplay between dynamics and stellar evolution, here we present a proposal dealing with the role of Blue Straggler Stars {BSS}.BSS are core-hydrogen burning stars more massive than the main-sequence turnoff population. The canonical scenarios for BSS formation are either the mass transfer between binary companions, or stellar mergers induced by collisions. We have recently discovered two distinct and parallel sequences of BSS in the core of M30 {Ferraro et al. 2009, Nature 462, 1082}. We suggested that each of the two sequences is populated by BSS formed by one of the two processes, both triggered by the cluster core collapse, that, based on the observed BSS properties, must have occurred 1-2 Gyr ago. Following this scenario, we have identified a powerful "clock" to date the occurrence of this key event in the GC history.Here we propose to secure WFC3 images of 4 post-core collapse GCs, reaching S/N=200 at the BSS magnitude level, in order to determine the ubiquity of the BSS double sequence and calibrate the "dynamical clock". This requires very high spatial resolution and very high precision photometry capabilities that are unique to the HST. The modest amount of requested time will have a deep impact on the current and future generations of dynamical evolutionary models of collisional stellar systems.

  4. Properties of optically selected supernova remnant candidates in M33

    SciTech Connect

    Lee, Jong Hwan; Lee, Myung Gyoon E-mail: mglee@astro.snu.ac.kr

    2014-10-01

    Narrowband images covering strong emission lines are efficient for surveying supernova remnants (SNRs) in nearby galaxies. Using the narrowband images provided by the Local Group Galaxy Survey, we searched for SNRs in M33. Culling the objects with enhanced [S II]/Hα and round morphology in the continuum-subtracted Hα and [S II] images, we produced a list of 199 sources. Among them, 79 are previously unknown. Their progenitor and morphology types were classified. A majority of the sample (170 objects) are likely remnants of core-collapse supernovae (SNe), and 29 are remnants of Type Ia SNe. The cumulative size distribution of these objects is found to be similar to that of the M31 remnants derived in a similar way. We obtain a power-law slope, α = 2.38 ± 0.05. Thus, a majority of the sources are considered to be in the Sedov-Taylor phase, consistent with previous findings. The histogram of the emission-line ratio ([S II]/Hα) of the remnants has two concentrations at [S II]/Hα ∼ 0.55 and ∼0.8, as in M31. Interestingly, L {sub X} (and L {sub 20cm}) of the compact center-bright objects are correlated with their optical luminosity. The remnants with X-ray emission have brighter optical surface brightnesses and smaller diameters than those without X-ray emission.

  5. Properties of Optically Selected Supernova Remnant Candidates in M33

    NASA Astrophysics Data System (ADS)

    Lee, Jong Hwan; Lee, Myung Gyoon

    2014-10-01

    Narrowband images covering strong emission lines are efficient for surveying supernova remnants (SNRs) in nearby galaxies. Using the narrowband images provided by the Local Group Galaxy Survey, we searched for SNRs in M33. Culling the objects with enhanced [S II]/Hα and round morphology in the continuum-subtracted Hα and [S II] images, we produced a list of 199 sources. Among them, 79 are previously unknown. Their progenitor and morphology types were classified. A majority of the sample (170 objects) are likely remnants of core-collapse supernovae (SNe), and 29 are remnants of Type Ia SNe. The cumulative size distribution of these objects is found to be similar to that of the M31 remnants derived in a similar way. We obtain a power-law slope, α = 2.38 ± 0.05. Thus, a majority of the sources are considered to be in the Sedov-Taylor phase, consistent with previous findings. The histogram of the emission-line ratio ([S II]/Hα) of the remnants has two concentrations at [S II]/Hα ~ 0.55 and ~0.8, as in M31. Interestingly, L X (and L 20 cm) of the compact center-bright objects are correlated with their optical luminosity. The remnants with X-ray emission have brighter optical surface brightnesses and smaller diameters than those without X-ray emission.

  6. Assessing the link between recent supernovae near Earth and the iron-60 anomaly in a deep-sea crust

    NASA Astrophysics Data System (ADS)

    Schulreich, Michael M.; Breitschwerdt, Dieter

    2016-06-01

    Some time ago, an enhanced concentration of the radionuclide 60Fe was discovered in a deep-sea ferromanganese crust, isolated in layers dating from about 2.2, Myr ago. Since 60Fe (half-life of 2.6, Myr) is not naturally produced on Earth, such an excess can only be attributed to extraterrestrial sources, particularly one or several nearby supernovae in the recent past. It has been speculated that these supernovae might have been involved in the formation of the Local Superbubble, our Galactic habitat. The aim of this talk is to provide a quantitative evidence for this scenario. For that purpose, I will present results from high-resolution hydrodynamical simulations of the Local Superbubble and its neighbour Loop I in different environments, including a self-consistently evolved supernova-driven interstellar medium. For the superbubble modelling, the time sequence and locations of the generating core-collapse supernova explosions are taken into account, which are derived from the mass spectrum of the perished members of certain, carefully preselected stellar moving groups. The release and turbulent mixing of 60Fe is followed via passive scalars, where the yields of the decaying radioisotope were adjusted according to recent stellar evolution calculations. The models are able to reproduce both the timing and the intensity of the 60Fe excess observed with rather high precision.

  7. Extragalactic Transients Discovered by the All-Sky Automated Survey for SuperNovae

    NASA Astrophysics Data System (ADS)

    Warren-Son Holoien, Thomas; ASAS-SN Team

    2015-01-01

    Even in the modern era, only human eyes scan the entire optical sky for the violent, variable, and transient events that shape our universe. The "All Sky Automated Survey for SuperNovae" (ASAS-SN or "Assassin") is changing this by monitoring the extra-galactic sky down to V~17 mag every 2-3 days using multiple telescopes in the northern and southern hemispheres, hosted by Las Cumbres Observatory Global Telescope Network. The primary goal of ASAS-SN is a complete survey of bright, nearby supernovae (SNe), and since April 2013 ASAS-SN has discovered over 40 new Type-Ia SNe and over 15 new core collapse SNe, including roughly half of all the SNe currently visible with V<17 mag. ASAS-SN also discovers many other interesting extragalactic transients, the most exciting of which was the recent tidal disruption event (TDE) ASASSN-14ae at ~200 Mpc, the closest TDE ever discovered at optical wavelengths. The brightness of these nearby events allows detailed follow-up at many wavelengths. Here we present some of these data on recent ASAS-SN extragalactic transients.

  8. Aspherical supernovae

    SciTech Connect

    Kasen, Daniel Nathan

    2004-05-21

    Although we know that many supernovae are aspherical, the exact nature of their geometry is undetermined. Because all the supernovae we observe are too distant to be resolved, the ejecta structure can't be directly imaged, and asymmetry must be inferred from signatures in the spectral features and polarization of the supernova light. The empirical interpretation of this data, however, is rather limited--to learn more about the detailed supernova geometry, theoretical modeling must been undertaken. One expects the geometry to be closely tied to the explosion mechanism and the progenitor star system, both of which are still under debate. Studying the 3-dimensional structure of supernovae should therefore provide new break throughs in our understanding. The goal of this thesis is to advance new techniques for calculating radiative transfer in 3-dimensional expanding atmospheres, and use them to study the flux and polarization signatures of aspherical supernovae. We develop a 3-D Monte Carlo transfer code and use it to directly fit recent spectropolarimetric observations, as well as calculate the observable properties of detailed multi-dimensional hydrodynamical explosion simulations. While previous theoretical efforts have been restricted to ellipsoidal models, we study several more complicated configurations that are tied to specific physical scenarios. We explore clumpy and toroidal geometries in fitting the spectropolarimetry of the Type Ia supernova SN 2001el. We then calculate the observable consequences of a supernova that has been rendered asymmetric by crashing into a nearby companion star. Finally, we fit the spectrum of a peculiar and extraordinarily luminous Type Ic supernova. The results are brought to bear on three broader astrophysical questions: (1) What are the progenitors and the explosion processes of Type Ia supernovae? (2) What effect does asymmetry have on the observational diversity of Type Ia supernovae, and hence their use in cosmology? (3) And

  9. Aspherical supernovae

    NASA Astrophysics Data System (ADS)

    Kasen, Daniel Nathan

    Although we know that many supernovae are aspherical, the exact nature of their geometry is undetermined. Because all the supernovae we observe are too distant to be resolved, the ejecta structure can't be directly imaged, and asymmetry must be inferred from signatures in the spectral features and polarization of the supernova light. The empirical interpretation of this data, however, is rather limited--to learn more about the detailed supernova geometry, theoretical modeling must be undertaken. One expects the geometry to be closely tied to the explosion mechanism and the progenitor star system, both of which are still under debate. Studying the 3-dimensional structure of supernovae should therefore provide new breakthroughs in our understanding. The goal of this thesis is to advance new techniques for calculating radiative transfer in 3-dimensional expanding atmospheres, and use them to study the flux and polarization signatures of aspherical supernovae. We develop a 3-D Monte Carlo transfer code and use it to directly fit recent spectropolarimetric observations, as well as calculate the observable properties of detailed multi- dimensional hydrodynamical explosion simulations. While previous theoretical efforts have been restricted to ellipsoidal models, we study several more complicated configurations that are tied to specific physical scenarios. We explore clumpy and toroidal geometries in fitting the spectropolarimetry of the Type Ia supernova SN 2001el. We then calculate the observable consequences of a supernova that has been rendered asymmetric by crashing into a nearby companion star. Finally we fit the spectrum of a peculiar and extraordinarily luminous Type Ic supernova. The results are brought to bear on three broader astrophysical questions: (1) What are the progenitors and the explosion processes of Type Ia supernovae? (2) What effect does asymmetry have on the observational diversity of Type Ia supernovae, and hence their use in cosmology? (3) And

  10. MIXING OF CLUMPY SUPERNOVA EJECTA INTO MOLECULAR CLOUDS

    SciTech Connect

    Pan Liubin; Desch, Steven J.; Scannapieco, Evan; Timmes, F. X.

    2012-09-01

    Several lines of evidence, from isotopic analyses of meteorites to studies of the Sun's elemental and isotopic composition, indicate that the solar system was contaminated early in its evolution by ejecta from a nearby supernova. Previous models have invoked supernova material being injected into an extant protoplanetary disk, or isotropically expanding ejecta sweeping over a distant (>10 pc) cloud core, simultaneously enriching it and triggering its collapse. Here, we consider a new astrophysical setting: the injection of clumpy supernova ejecta, as observed in the Cassiopeia A supernova remnant, into the molecular gas at the periphery of an H II region created by the supernova's progenitor star. To track these interactions, we have conducted a suite of high-resolution (1500{sup 3} effective) three-dimensional numerical hydrodynamic simulations that follow the evolution of individual clumps as they move into molecular gas. Even at these high resolutions, our simulations do not quite achieve numerical convergence, due to the challenge of properly resolving the small-scale mixing of ejecta and molecular gas, although they do allow some robust conclusions to be drawn. Isotropically exploding ejecta do not penetrate into the molecular cloud or mix with it, but, if cooling is properly accounted for, clumpy ejecta penetrate to distances {approx}10{sup 18} cm and mix effectively with large regions of star-forming molecular gas. In fact, the {approx}2 M{sub Sun} of high-metallicity ejecta from a single core-collapse supernova is likely to mix with {approx}2 Multiplication-Sign 10{sup 4} M{sub Sun} of molecular gas material as it is collapsing. Thus, all stars forming late ( Almost-Equal-To 5 Myr) in the evolution of an H II region may be contaminated by supernova ejecta at the level {approx}10{sup -4}. This level of contamination is consistent with the abundances of short-lived radionuclides and possibly some stable isotopic shifts in the early solar system and is

  11. Detecting the QCD phase transition in the next Galactic supernova neutrino burst

    SciTech Connect

    Dasgupta, Basudeb; Fischer, Tobias; Liebendoerfer, Matthias; Horiuchi, Shunsaku; Mirizzi, Alessandro; Sagert, Irina; Schaffner-Bielich, Juergen

    2010-05-15

    Predictions of the thermodynamic conditions for phase transitions at high baryon densities and large chemical potentials are currently uncertain and largely phenomenological. Neutrino observations of core-collapse supernovae can be used to constrain the situation. Recent simulations of stellar core collapse that include a description of quark matter predict a sharp burst of {nu}{sub e} several hundred milliseconds after the prompt {nu}{sub e} neutronization burst. We study the observational signatures of that {nu}{sub e} burst at current neutrino detectors--IceCube and Super-Kamiokande. For a Galactic core-collapse supernova, we find that signatures of the QCD phase transition can be detected, regardless of the neutrino oscillation scenario. The detection would constitute strong evidence of a phase transition in the stellar core, with implications for the equation of state at high matter density and the supernova explosion mechanism.

  12. ON THE INJECTION OF SHORT-LIVED RADIONUCLIDES FROM A SUPERNOVA INTO THE SOLAR NEBULA: CONSTRAINTS FROM THE OXYGEN ISOTOPES

    SciTech Connect

    Liu, Ming-Chang

    2014-02-01

    Injection of short-lived radionuclides from a nearby core-collapse Type II supernova into the already-formed solar protoplanetary disk was proposed to account for the former presence of {sup 26}Al, {sup 41}Ca, and {sup 60}Fe in the early solar system inferred from isotopic analysis of meteoritic samples. One potential corollary of this ''late-injection'' scenario is that the disk's initial (pre-injection) oxygen isotopic composition could be significantly altered, as supernova material that carried the short-lived radionuclides would also deliver oxygen components synthesized in that given star. Therefore, the change in the oxygen isotopic composition of the disk caused by injection could in principle be used to constrain the supernova injection models. Previous studies showed that although supernova oxygen could result in a wide range of shifts in {sup 17}O/{sup 16}O and {sup 18}O/{sup 16}O of the disk, a couple of cases existed where the calculated oxygen changes in the disk would be compatible with the meteoritic and solar wind data. Recently, the initial abundances of {sup 41}Ca and {sup 60}Fe in the solar system were revised to lower values, and the feasibility of supernova injection as a source for the three radionuclides was called into question. In this study, supernova parameters needed for matching {sup 26}Al, {sup 41}Ca, and {sup 60}Fe to their early solar system abundances were reinvestigated and then were used to infer the pre-injection O-isotope composition of the disk. The result suggested that a supernova undergoing mixing fallback might be a viable source for the three radionuclides.

  13. On the Injection of Short-lived Radionuclides from a Supernova into the Solar Nebula: Constraints from the Oxygen Isotopes

    NASA Astrophysics Data System (ADS)

    Liu, Ming-Chang

    2014-02-01

    Injection of short-lived radionuclides from a nearby core-collapse Type II supernova into the already-formed solar protoplanetary disk was proposed to account for the former presence of 26Al, 41Ca, and 60Fe in the early solar system inferred from isotopic analysis of meteoritic samples. One potential corollary of this "late-injection" scenario is that the disk's initial (pre-injection) oxygen isotopic composition could be significantly altered, as supernova material that carried the short-lived radionuclides would also deliver oxygen components synthesized in that given star. Therefore, the change in the oxygen isotopic composition of the disk caused by injection could in principle be used to constrain the supernova injection models. Previous studies showed that although supernova oxygen could result in a wide range of shifts in 17O/16O and 18O/16O of the disk, a couple of cases existed where the calculated oxygen changes in the disk would be compatible with the meteoritic and solar wind data. Recently, the initial abundances of 41Ca and 60Fe in the solar system were revised to lower values, and the feasibility of supernova injection as a source for the three radionuclides was called into question. In this study, supernova parameters needed for matching 26Al, 41Ca, and 60Fe to their early solar system abundances were reinvestigated and then were used to infer the pre-injection O-isotope composition of the disk. The result suggested that a supernova undergoing mixing fallback might be a viable source for the three radionuclides.

  14. THE ENGINES BEHIND SUPERNOVAE AND GAMMA-RAY BURSTS

    SciTech Connect

    FRYER, CHRISTOPHER LEE

    2007-01-23

    The authors review the different engines behind supernova (SNe) and gamma-ray bursts (GRBs), focusing on those engines driving explosions in massive stars: core-collapse SNe and long-duration GRBs. Convection and rotation play important roles in the engines of both these explosions. They outline the basic physics and discuss the wide variety of ways scientists have proposed that this physics can affect the supernova explosion mechanism, concluding with a review of the current status in these fields.

  15. A giant outburst two years before the core-collapse of a massive star.

    PubMed

    Pastorello, A; Smartt, S J; Mattila, S; Eldridge, J J; Young, D; Itagaki, K; Yamaoka, H; Navasardyan, H; Valenti, S; Patat, F; Agnoletto, I; Augusteijn, T; Benetti, S; Cappellaro, E; Boles, T; Bonnet-Bidaud, J-M; Botticella, M T; Bufano, F; Cao, C; Deng, J; Dennefeld, M; Elias-Rosa, N; Harutyunyan, A; Keenan, F P; Iijima, T; Lorenzi, V; Mazzali, P A; Meng, X; Nakano, S; Nielsen, T B; Smoker, J V; Stanishev, V; Turatto, M; Xu, D; Zampieri, L

    2007-06-14

    The death of massive stars produces a variety of supernovae, which are linked to the structure of the exploding stars. The detection of several precursor stars of type II supernovae has been reported (see, for example, ref. 3), but we do not yet have direct information on the progenitors of the hydrogen-deficient type Ib and Ic supernovae. Here we report that the peculiar type Ib supernova SN 2006jc is spatially coincident with a bright optical transient that occurred in 2004. Spectroscopic and photometric monitoring of the supernova leads us to suggest that the progenitor was a carbon-oxygen Wolf-Rayet star embedded within a helium-rich circumstellar medium. There are different possible explanations for this pre-explosion transient. It appears similar to the giant outbursts of luminous blue variable stars (LBVs) of 60-100 solar masses, but the progenitor of SN 2006jc was helium- and hydrogen-deficient (unlike LBVs). An LBV-like outburst of a Wolf-Rayet star could be invoked, but this would be the first observational evidence of such a phenomenon. Alternatively, a massive binary system composed of an LBV that erupted in 2004, and a Wolf-Rayet star exploding as SN 2006jc, could explain the observations. PMID:17568740

  16. A giant outburst two years before the core-collapse of a massive star.

    PubMed

    Pastorello, A; Smartt, S J; Mattila, S; Eldridge, J J; Young, D; Itagaki, K; Yamaoka, H; Navasardyan, H; Valenti, S; Patat, F; Agnoletto, I; Augusteijn, T; Benetti, S; Cappellaro, E; Boles, T; Bonnet-Bidaud, J-M; Botticella, M T; Bufano, F; Cao, C; Deng, J; Dennefeld, M; Elias-Rosa, N; Harutyunyan, A; Keenan, F P; Iijima, T; Lorenzi, V; Mazzali, P A; Meng, X; Nakano, S; Nielsen, T B; Smoker, J V; Stanishev, V; Turatto, M; Xu, D; Zampieri, L

    2007-06-14

    The death of massive stars produces a variety of supernovae, which are linked to the structure of the exploding stars. The detection of several precursor stars of type II supernovae has been reported (see, for example, ref. 3), but we do not yet have direct information on the progenitors of the hydrogen-deficient type Ib and Ic supernovae. Here we report that the peculiar type Ib supernova SN 2006jc is spatially coincident with a bright optical transient that occurred in 2004. Spectroscopic and photometric monitoring of the supernova leads us to suggest that the progenitor was a carbon-oxygen Wolf-Rayet star embedded within a helium-rich circumstellar medium. There are different possible explanations for this pre-explosion transient. It appears similar to the giant outbursts of luminous blue variable stars (LBVs) of 60-100 solar masses, but the progenitor of SN 2006jc was helium- and hydrogen-deficient (unlike LBVs). An LBV-like outburst of a Wolf-Rayet star could be invoked, but this would be the first observational evidence of such a phenomenon. Alternatively, a massive binary system composed of an LBV that erupted in 2004, and a Wolf-Rayet star exploding as SN 2006jc, could explain the observations.

  17. Presupernova models and supernovae

    NASA Technical Reports Server (NTRS)

    Sugimoto, D.; Nomoto, K.

    1980-01-01

    The present status of theories of presupernova stellar evolution and the triggering mechanisms of supernova explosions are reviewed. The validity of the single-star approximation for stellar core evolution is considered, and the central density and temperature of the stellar core are discussed. Attention is then given to the results of numerical models of supernova explosions by carbon deflagration of an intermediate mass star, resulting in the total disruption of the star; the photodissociation of iron nuclei in a massive star, resulting in neutron star or black hole formation; and stellar core collapse triggered by electron capture in stars of mass ranging between those of the intermediate mass and massive stars, resulting in neutron star formation despite oxygen deflagration. Helium and carbon combustion and detonation in accreting white dwarfs and the gravitational collapse triggered by electron-pair creation in supermassive stars are also discussed, and problems requiring future investigation are indicated.

  18. THE INFLUENCE OF INELASTIC NEUTRINO REACTIONS WITH LIGHT NUCLEI ON THE STANDING ACCRETION SHOCK INSTABILITY IN CORE-COLLAPSE SUPERNOVAE

    SciTech Connect

    Furusawa, Shun; Nagakura, Hiroki; Yamada, Shoichi; Sumiyoshi, Kohsuke

    2013-09-01

    We perform numerical experiments to investigate the influence of inelastic neutrino reactions with light nuclei on the standing accretion shock instability (SASI). The time evolution of shock waves is calculated with a simple light-bulb approximation for the neutrino transport and a multi-nuclei equation of state. The neutrino absorptions and inelastic interactions with deuterons, tritons, helions, and alpha particles are taken into account in the hydrodynamical simulations. In addition, the effects of ordinary charged-current interactions with nucleons is addressed in the simulations. Axial symmetry is assumed but no equatorial symmetry is imposed. We show that the heating rates of deuterons reach as high as {approx}10% of those of nucleons around the bottom of the gain region. On the other hand, alpha particles are heated near the shock wave, which is important when the shock wave expands and the density and temperature of matter become low. It is also found that the models with heating by light nuclei evolve differently in the non-linear phase of SASI than do models that lack heating by light nuclei. This result is because matter in the gain region has a varying density and temperature and therefore sub-regions appear that are locally rich in deuterons and alpha particles. Although the light nuclei are never dominant heating sources and they work favorably for shock revival in some cases and unfavorably in other cases, they are non-negligible and warrant further investigation.

  19. Nucleosynthesis in O-Ne-Mg Supernovae

    SciTech Connect

    Hoffman, R D; Janka, H; Muller, B

    2007-12-18

    We have studied detailed nucleosynthesis in the shocked surface layers of an oxygen-neon-magnesium core collapse supernova with an eye to determining whether the conditions are suitable for r-process nucleosynthesis. We find no such conditions in an unmodified model, but do find overproduction of N=50 nuclei (previously seen in early neutron-rich neutrino winds) in amounts that, if ejected, would pose serious problems for Galactic chemical evolution.

  20. Relativistic MHD simulations of core-collapse GRB jets: 3D instabilities and magnetic dissipation

    NASA Astrophysics Data System (ADS)

    Bromberg, Omer; Tchekhovskoy, Alexander

    2016-02-01

    Relativistic jets are associated with extreme astrophysical phenomena, like the core collapse of massive stars in gamma-ray bursts (GRBs) and the accretion on to supermassive black holes in active galactic nuclei. It is generally accepted that these jets are powered electromagnetically, by the magnetized rotation of a central compact object (black hole or neutron star). However, how the jets produce the observed emission and survive the propagation for many orders of magnitude in distance without being disrupted by current-driven instabilities is the subject of active debate. We carry out time-dependent 3D relativistic magnetohydrodynamic (MHD) simulations of relativistic, Poynting-flux-dominated jets. The jets are launched self-consistently by the rotation of a strongly magnetized central object. This determines the natural degree of azimuthal magnetic field winding, a crucial factor that controls jet stability. We find that the jets are susceptible to two types of instability: (i) a global, external kink mode that grows on long time-scales. It bodily twists the jet, reducing its propagation velocity. We show analytically that in flat density profiles, like the ones associated with galactic cores, the external mode grows and may stall the jet. In the steep profiles of stellar envelopes the external kink weakens as the jet propagates outward. (ii) a local, internal kink mode that grows over short time-scales and causes small-angle magnetic reconnection and conversion of about half of the jet electromagnetic energy flux into heat. We suggest that internal kink instability is the main dissipation mechanism responsible for powering GRB prompt emission.

  1. DISCOVERY OF FIVE CANDIDATE ANALOGS FOR η CARINAE IN NEARBY GALAXIES

    SciTech Connect

    Khan, Rubab; Adams, Scott M.; Stanek, K. Z.; Kochanek, C. S.; and others

    2015-12-20

    The late-stage evolution of very massive stars such as η Carinae may be dominated by episodic mass ejections that may later lead to Type II superluminous supernova (SLSN-II; e.g., SN 2006gy). However, as long as η Car is one of a kind, it is nearly impossible to quantitatively evaluate these possibilities. Here, we announce the discovery of five objects in the nearby (∼4–8 Mpc) massive star-forming galaxies M51, M83, M101, and NGC 6946 that have optical through mid-infrared (mid-IR) photometric properties consistent with the hitherto unique η Car. The Spitzer mid-IR spectral energy distributions of these L{sub bol} ≃ 3–8 × 10{sup 6} L{sub ⊙} objects rise steeply in the 3.6–8 μm bands and then turn over between 8 and 24 μm, indicating the presence of warm (∼400–600 K) circumstellar dust. Their optical counterparts in HST images are ∼1.5–2 dex fainter than their mid-IR peaks and require the presence of ∼5–10 M{sub ⊙} of obscuring material. Our finding implies that the rate of η Car–like events is a fraction f = 0.094 (0.040 < f < 0.21 at 90% confidence) of the core-collapse supernova (ccSN) rate. If there is only one eruption mechanism and Type II superluminous supernovae are due to ccSNe occurring inside these dense shells, then the ejection mechanism is likely associated with the onset of carbon burning (∼10{sup 3}–10{sup 4} years), which is also consistent with the apparent ages of massive Galactic shells.

  2. Discovery of Five Candidate Analogs for η Carinae in Nearby Galaxies

    NASA Astrophysics Data System (ADS)

    Khan, Rubab; Adams, Scott M.; Stanek, K. Z.; Kochanek, C. S.; Sonneborn, G.

    2015-12-01

    The late-stage evolution of very massive stars such as η Carinae may be dominated by episodic mass ejections that may later lead to Type II superluminous supernova (SLSN-II; e.g., SN 2006gy). However, as long as η Car is one of a kind, it is nearly impossible to quantitatively evaluate these possibilities. Here, we announce the discovery of five objects in the nearby (∼4–8 Mpc) massive star-forming galaxies M51, M83, M101, and NGC 6946 that have optical through mid-infrared (mid-IR) photometric properties consistent with the hitherto unique η Car. The Spitzer mid-IR spectral energy distributions of these Lbol ≃ 3–8 × 106 L⊙ objects rise steeply in the 3.6–8 μm bands and then turn over between 8 and 24 μm, indicating the presence of warm (∼400–600 K) circumstellar dust. Their optical counterparts in HST images are ∼1.5–2 dex fainter than their mid-IR peaks and require the presence of ∼5–10 M⊙ of obscuring material. Our finding implies that the rate of η Car–like events is a fraction f = 0.094 (0.040 < f < 0.21 at 90% confidence) of the core-collapse supernova (ccSN) rate. If there is only one eruption mechanism and Type II superluminous supernovae are due to ccSNe occurring inside these dense shells, then the ejection mechanism is likely associated with the onset of carbon burning (∼103–104 years), which is also consistent with the apparent ages of massive Galactic shells.

  3. THE BLUE STRAGGLER STAR POPULATION IN NGC 1261: EVIDENCE FOR A POST-CORE-COLLAPSE BOUNCE STATE

    SciTech Connect

    Simunovic, Mirko; Puzia, Thomas H.; Sills, Alison E-mail: tpuzia@astro.puc.cl

    2014-11-01

    We present a multi-passband photometric study of the Blue Straggler Star (BSS) population in the Galactic globular cluster (GC) NGC 1261, using available space- and ground-based survey data. The inner BSS population is found to have two distinct sequences in the color-magnitude diagram (CMD), similar to double BSS sequences detected in other GCs. These well defined sequences are presumably linked to single short-lived events such as core collapse, which are expected to boost the formation of BSSs. In agreement with this, we find a BSS sequence in NGC 1261 which can be well reproduced individually by a theoretical model prediction of a 2 Gyr old population of stellar collision products, which are expected to form in the denser inner regions during short-lived core contraction phases. Additionally, we report the occurrence of a group of BSSs with unusually blue colors in the CMD, which are consistent with a corresponding model of a 200 Myr old population of stellar collision products. The properties of the NGC 1261 BSS populations, including their spatial distributions, suggest an advanced dynamical evolutionary state of the cluster, but the core of this GC does not show the classical signatures of core collapse. We argue that these apparent contradictions provide evidence for a post-core-collapse bounce state seen in dynamical simulations of old GCs.

  4. Petascale Supernova Simulation with CHIMERA

    SciTech Connect

    Messer, Bronson; Bruenn, S. W.; Blondin, J. M.; Mezzacappa, Anthony; Hix, William Raphael; Dirk, Charlotte

    2007-01-01

    CHIMERA is a multi-dimensional radiation hydrodynamics code designed to study core-collapse supernovae. The code is made up of three essentially independent parts: a hydrodynamics module, a nuclear burning module, and a neutrino transport solver combined within an operator-split approach. We describe some ma jor algorithmic facets of the code and briefly discuss some recent results. The multi-physics nature of the problem, and the specific implementation of that physics in CHIMERA, provide a rather straightforward path to effective use of multi-core platforms in the near future.

  5. Gamma-Ray Burst Associated Supernovae: Outliers Become Mainstream

    NASA Technical Reports Server (NTRS)

    Pian, E.; Mazzali, P.; Masetti, N.; Ferrero, P.; Klose, S.; Palazzi, E.; Ramirez-Ruiz, E.; Woosley, S. E.; Kouveliotou, C.; Deng, J.

    2006-01-01

    During the last eight years a clear connection has been established-between the two most powerful explosions in our Universe: core-collapse supernovae (SNe) and long gamma ray bursts (GRBs). Theory suggests4 that every GRB is simultaneously accompanied by a SN, but in only a few nearby cases have these two phenomena been observed together. We report the discovery and daily monitoring of SN 2006aj associated with the GRB 060218. Because the event was the second closest GRB, both explosions could be examined in detail. GRB 060218 had an unusually soft spectrum, long duration, and a total energy 100 to 1000 times less than most other GRBs. Yet SN 2006aj was similar to those in other GRBs, aside from rising more rapidly and being approximately 40% fainter. Taken together, these observations suggest that GRBs have two components: a broad, energetic, but only mildly relativistic outflow that makes a SN, and a more narrowly focused, highly relativistic jet responsible for the GRB. The properties of the GRB jet apparently vary greatly from event to event, while the broad SN outflow varies much less. Low energy transients like GRB 060218 may be the most common events in the Universe.

  6. Probing the physics of bright supernovae with high-cadence photometry

    NASA Astrophysics Data System (ADS)

    Bonanos, Alceste; Boumis, Panos

    2016-06-01

    We propose high-cadence photometry as a tool to probe the physics of both thermonuclear and core-collapse supernova explosions. We demonstrate the idea by conducting high-cadence monitoring of theoptical light curve of the nearby, Type Ia SN 2014J in M82. B and V-band photometry on days 15‑18 after tmax(B) was obtained with a cadence of 2 min per band, using the 2.3 m Aristarchos telescope, at Helmos Observatory, Greece. The data reveal evidence for rapid variability at the 0.02‑0.05 mag level on timescales of 15‑60 min on all four nights. The rapid variability could be due to one or a combination of the following scenarios: the clumpiness of the ejecta, their interaction with circumstellar material, the asymmetry of the explosion, or the mechanism causing the secondary maximum in the near-infrared lightcurve. We present our plans to use the new Prime Focus Instrument with its fast-frame sCMOS cameras on the Kryoneri 1.2 m telescope in Greece, constructed as part of ESA's lunar monitoring project NELIOTA, to systematically monitor bright supernovae for rapid variability.

  7. The LCOGT Supernova Key Project

    NASA Astrophysics Data System (ADS)

    Howell, Dale Andrew; Arcavi, Iair; Hosseinzadeh, Griffin; McCully, Curtis; Valenti, Stefano; Lcogt Supernova Key Project

    2015-01-01

    I present first results from the Las Cumbres Observatory Global Telescope Network (LCOGT) Supernova Key Project. LCOGT is a network of 11 robotic one and two meter telescopes spaced around the globe with imaging and spectroscopic capabilities. The supernova key project is a 3 year program to obtain lightcurves and spectra of at least 450 supernovae. About half are expected to be core-collapse supernovae, and half thermonuclear. We will start light curves and spectroscopy within hours of discovery, and focus on those SNe caught soon after explosion. The goals are fivefold: (1) observe supernovae soon after explosion to search for signs of their progenitors, (2) obtain a large homogeneous sample of supernovae for next generation cosmological studies, (3) obtain a large sample of supernovae for statistical studies comparing groups that are split into different populations, (4) obtain some of the first large samples of the recently discovered classes of rare and exotic explosions, (5) obtain the optical light curves and spectroscopy in support of studies at other wavelengths and using other facilities including UV observations, IR imaging and spectroscopy, host galaxy studies, high resolution spectroscopy, and late-time spectroscopy with large telescopes.

  8. Theoretical models for supernovae

    SciTech Connect

    Woosley, S.E.; Weaver, T.A.

    1981-09-21

    The results of recent numerical simulations of supernova explosions are presented and a variety of topics discussed. Particular emphasis is given to (i) the nucleosynthesis expected from intermediate mass (10sub solar less than or equal to M less than or equal to 100 Msub solar) Type II supernovae and detonating white dwarf models for Type I supernovae, (ii) a realistic estimate of the ..gamma..-line fluxes expected from this nucleosynthesis, (iii) the continued evolution, in one and two dimensions, of intermediate mass stars wherein iron core collapse does not lead to a strong, mass-ejecting shock wave, and (iv) the evolution and explosion of vary massive stars (M greater than or equal to 100 Msub solar of both Population I and III. In one dimension, nuclear burning following a failed core bounce does not appear likely to lead to a supernova explosion although, in two dimensions, a combination of rotation and nuclear burning may do so. Near solar proportions of elements from neon to calcium and very brilliant optical displays may be created by hypernovae, the explosions of stars in the mass range 100 M/sub solar/ to 300 M/sub solar/. Above approx. 300 M/sub solar/ a black hole is created by stellar collapse following carbon ignition. Still more massive stars may be copious producers of /sup 4/He and /sup 14/N prior to their collapse on the pair instability.

  9. Red-Supergiant and Supernova Rate Problems: Implication for the Relic Supernova Neutrino Spectrum

    NASA Astrophysics Data System (ADS)

    Hidaka, J.; Kajino, T.; Mathews, G. J.

    2016-08-01

    Direct observations of core-collapse supernovae (SNe) and their red supergiant (RSG) progenitors suggest that the upper mass limit of RSGs may be only about 16.5{--}18{M}ȯ , while the standard theoretical value is as much as 25{M}ȯ . We investigate the possibility that RSGs with m\\gt 16.5{--}18{M}ȯ end their lives as failed supernovae (fSNe) and analyze their contribution to the relic supernova neutrino spectrum. We show that adopting this mass limit simultaneously solves both the RSG problem and the supernova rate problem. In addition, energetic neutrinos that originated from fSNe are sensitive to the explosion mechanism, and in particular, to the nuclear equation of state (EOS). We show that this solution to the RSG problem might also be used to constrain the EOS for failed supernovae.

  10. How Bright Can Supernovae Get?

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-04-01

    Supernovae enormous explosions associated with the end of a stars life come in a variety of types with different origins. A new study has examined how the brightest supernovae in the Universe are produced, and what limits might be set on their brightness.Ultra-Luminous ObservationsRecent observations have revealed many ultra-luminous supernovae, which haveenergies that challenge our abilities to explain them usingcurrent supernova models. An especially extreme example is the 2015 discovery of the supernova ASASSN-15lh, which shone with a peak luminosity of ~2*1045 erg/s, nearly a trillion times brighter than the Sun. ASASSN-15lh radiated a whopping ~2*1052 erg in the first four months after its detection.How could a supernova that bright be produced? To explore the answer to that question, Tuguldur Sukhbold and Stan Woosley at University of California, Santa Cruz, have examined the different sources that could produce supernovae and calculated upper limits on the potential luminosities ofeach of these supernova varieties.Explosive ModelsSukhbold and Woosley explore multiple different models for core-collapse supernova explosions, including:Prompt explosionA stars core collapses and immediately explodes.Pair instabilityElectron/positron pair production at a massive stars center leads to core collapse. For high masses, radioactivity can contribute to delayed energy output.Colliding shellsPreviously expelled shells of material around a star collide after the initial explosion, providing additional energy release.MagnetarThe collapsing star forms a magnetar a rapidly rotating neutron star with an incredibly strong magnetic field at its core, which then dumps energy into the supernova ejecta, further brightening the explosion.They then apply these models to different types of stars.Setting the LimitThe authors show that the light curve of ASASSN-15lh (plotted in orange) can be described by a model (black curve) in which a magnetar with an initial spin period of 0.7 ms

  11. CHEMICAL ENRICHMENT IN THE CARBON-ENHANCED DAMPED Ly{alpha} SYSTEM BY POPULATION III SUPERNOVAE

    SciTech Connect

    Kobayashi, Chiaki; Tominaga, Nozomu; Nomoto, Ken'ichi

    2011-04-01

    We show that the recently observed elemental abundance pattern of the carbon-rich metal-poor damped Ly{alpha} (DLA) system is in excellent agreement with the nucleosynthesis yields of faint core-collapse supernovae of primordial stars. The observed abundance pattern is not consistent with the nucleosynthesis yields of pair-instability supernovae. The DLA abundance pattern is very similar to that of carbon-rich extremely metal-poor (EMP) stars, and the contributions from low-mass stars and/or binary effects should be very small in DLAs. This suggests that chemical enrichment by the first stars in the first galaxies is driven by core-collapse supernovae from {approx}20 to 50 M{sub sun} stars and also supports the supernova scenario as the enrichment source of EMP stars in the Milky Way Galaxy.

  12. Intense Magnetism in Supernovae

    NASA Astrophysics Data System (ADS)

    Thompson, C.

    2002-05-01

    Observations of the Soft Gamma Repeaters and Anomalous X-ray Pulsars have provided strong evidence for a class of neutron stars with magnetic fields exceeding 1015 G. This talk will overview the excellent prospects for generating such intense fields in a core-collapse supernova, with a focus on the violent convective motions believed to occur both inside and outside the neutrinosphere of the forming neutron star. I will also examine the effects of late fallback, and the role of (electron-type) neutrinos in aiding buoyant motions of the magnetic field. The case will be made that the SGRs and AXPs are distinguished from classical radio pulsars by a very rapid initial rotation of the neutron star.

  13. Type Ibn Supernovae: Not a Single Class

    NASA Astrophysics Data System (ADS)

    Hosseinzadeh, Griffin; Arcavi, Iair; Howell, Dale Andrew; McCully, Curtis; Valenti, Stefano

    2016-01-01

    Type Ibn supernovae are a small yet diverse class of explosions whose spectra are characterized by low-velocity helium emission lines. The prevailing theory has been that these are the core-collapse explosions of very massive stars embedded in helium-rich circumstellar material. However, unlike the more common Type IIn supernovae, whose interaction with hydrogen-rich circumstellar material has been shown to generate a wide variety of light curve shapes, we find that light curves of Type Ibn supernovae are more homogeneous and faster evolving. Spectroscopically, we find that Type Ibn supernovae divide cleanly into two classes, only one of which resembles the archetypal Type Ibn SN 2006jc. We explore various photometric and spectroscopic parameter spaces in order to characterize these two classes. We consider the possibility that not all objects classified as Type Ibn have the same physical origin.

  14. Are 44Ti-producing supernovae exceptional?

    NASA Astrophysics Data System (ADS)

    The, L.-S.; Clayton, D. D.; Diehl, R.; Hartmann, D. H.; Iyudin, A. F.; Leising, M. D.; Meyer, B. S.; Motizuki, Y.; Schönfelder, V.

    2006-05-01

    According to standard models supernovae produce radioactive 44Ti, which should be visible in gamma-rays following decay to 44Ca for a few centuries. 44Ti production is believed to be the source of cosmic 44Ca, whose abundance is well established. Yet, gamma-ray telescopes have not seen the expected young remnants of core collapse events. The 44Ti mean life of τ ≃ 89 y and the Galactic supernova rate of ≃3/100 y imply ≃several detectable 44Ti gamma-ray sources, but only one is clearly seen, the 340-year-old Cas A SNR. Furthermore, supernovae which produce much 44Ti are expected to occur primarily in the inner part of the Galaxy, where young massive stars are most abundant. Because the Galaxy is transparent to gamma-rays, this should be the dominant location of expected gamma-ray sources. Yet the Cas A SNR as the only one source is located far from the inner Galaxy (at longitude 112°). We evaluate the surprising absence of detectable supernovae from the past three centuries. We discuss whether our understanding of SN explosions, their 44Ti yields, their spatial distributions, and statistical arguments can be stretched so that this apparent disagreement may be accommodated within reasonable expectations, or if we have to revise some or all of the above aspects to bring expectations in agreement with the observations. We conclude that either core collapse supernovae have been improbably rare in the Galaxy during the past few centuries, or 44Ti-producing supernovae are atypical supernovae. We also present a new argument based on 44Ca/40Ca ratios in mainstream SiC stardust grains that may cast doubt on massive-He-cap type I supernovae as the source of most galactic 44Ca.

  15. The first ten years of Swift supernovae

    NASA Astrophysics Data System (ADS)

    Brown, Peter J.; Roming, Peter W. A.; Milne, Peter A.

    2015-09-01

    The Swift Gamma Ray Burst Explorer has proven to be an incredible platform for studying the multiwavelength properties of supernova explosions. In its first ten years, Swift has observed over three hundred supernovae. The ultraviolet observations reveal a complex diversity of behavior across supernova types and classes. Even amongst the standard candle type Ia supernovae, ultraviolet observations reveal distinct groups. When the UVOT data is combined with higher redshift optical data, the relative populations of these groups appear to change with redshift. Among core-collapse supernovae, Swift discovered the shock breakout of two supernovae and the Swift data show a diversity in the cooling phase of the shock breakout of supernovae discovered from the ground and promptly followed up with Swift. Swift observations have resulted in an incredible dataset of UV and X-ray data for comparison with high-redshift supernova observations and theoretical models. Swift's supernova program has the potential to dramatically improve our understanding of stellar life and death as well as the history of our universe.

  16. Spectropolarimetry of the Type Ib Supernova iPTF 13bvn: revealing the complex explosion geometry of a stripped-envelope core-collapse supernova

    NASA Astrophysics Data System (ADS)

    Reilly, Emma; Maund, Justyn R.; Baade, Dietrich; Wheeler, J. Craig; Silverman, Jeffrey M.; Clocchiatti, Alejandro; Patat, Ferdinando; Höflich, Peter; Spyromilio, Jason; Wang, Lifan; Zelaya, Paula

    2016-03-01

    We present six epochs of spectropolarimetric observations and one epoch of spectroscopy of the Type Ib SN iPTF 13bvn. The epochs of these observations correspond to -10 to +61 d with respect to the r-band light-curve maximum. The continuum is intrinsically polarized to the 0.2-0.4 per cent level throughout the observations, implying asphericities of ˜10 per cent in the shape of the photosphere. We observe significant line polarization associated with the spectral features of Ca II IR3, He I/Na I D, He I λλ6678, 7065, Fe II λ4924 and O I λ7774. We propose that an absorption feature at ˜6200 Å, usually identified as Si II λ6355, is most likely to be high-velocity H α at -16 400 km s-1. Two distinctly polarized components, separated in velocity, are detected for both He I/Na I D and Ca II IR3 , indicating the presence of two discrete line-forming regions in the ejecta in both radial velocity space and in the plane of the sky. We use the polarization of He I λ5876 as a tracer of sources of non-thermal excitation in the ejecta; finding that the bulk of the radioactive nickel was constrained to lie interior to ˜50-65 per cent of the ejecta radius. The observed polarization is also discussed in the context of the possible progenitor system of iPTF 13bvn, with our observations favouring the explosion of a star with an extended, distorted envelope rather than a compact Wolf-Rayet star.

  17. Asteroseismology of the nearby SN-II Progenitor: Rigel. I. The MOST High-precision Photometry and Radial Velocity Monitoring

    NASA Astrophysics Data System (ADS)

    Moravveji, Ehsan; Guinan, Edward F.; Shultz, Matt; Williamson, Michael H.; Moya, Andres

    2012-03-01

    Rigel (β Ori, B8 Ia) is a nearby blue supergiant displaying α Cyg type variability, and is one of the nearest Type II supernova progenitors. As such it is an excellent test bed to study the internal structure of pre-core-collapse stars. In this study, for the first time, we present 28 days of high-precision MOST photometry and over six years of spectroscopic monitoring. We report 19 significant pulsation modes of signal-to-noise ratio, S/N >~ 4.6 from radial velocities, with variability timescales ranging from 1.21 to 74.7 days, which are associated with high-order low-degree gravity modes. While the radial velocity variations show a degree of correlation with the flux changes, there is no clear interplay between the equivalent widths of different metallic and Hα lines. Based on data from the MOST satellite, a Canadian Space Agency mission, operated jointly by Dynacon, Inc., the University of Toronto Institute of Aerospace Studies, and the University of British Columbia, with the assistance of the University of Vienna.

  18. Supernova Simulations from the T-6 Group at Los Alamos National Laboratory (LANL)

    DOE Data Explorer

    Woosley, Stanford

    LANL's primary effort to numerically model supernova explosions is based in the Theoretical Astrophysics Group (T-6). Both thermonuclear supernovae and core- collapse supernovae are studied, with special emphasis placed on multi-dimensional simulations. Both types of supernova require a wide range of input physics, which is provided by research efforts throughout the lab. In particular this research benefits from other LANL efforts studying massive star evolution, equations of state and aspects of neutrino physics. [From http://laastro.lanl.gov/science/computation.html

  19. Searching for Low-Frequency Radio Transients from Supernovae

    NASA Astrophysics Data System (ADS)

    Tsai-Wei, Jr.; Cutchin, Sean; Kothari, Manthan; Schmitt, Christian; Kavic, Michael; Simonetti, John

    2011-10-01

    Supernovae events may be accompanied by prompt emission of a low-frequency electromagnetic transient. These transient events are created by the interaction of a shock wave of charged particles created by SN core-collapse with a stars ambient magnetic field. Such events can be detected in low-frequency radio array. Here we discuss an ongoing search for such events using two radio arrays: the Long Wavelength Array (LWA) and Eight-meter-wavelength Transient Array (ETA).

  20. Three-Dimensional Magnetic Fields in Realistic Simulations of Stellar Core Collapse and Bounce

    NASA Astrophysics Data System (ADS)

    Liebendoerfer, Matthias

    2005-08-01

    The evolution of massive stars ends with an inner iron core that is unstable to gravitational collapse. Its dynamics is determined by electron capture on nuclei in the condensing matter. When the energydependent neutrino mean free path becomes short, emitted neutrinos escape in a competition between thermalization and diffusion. This process is accurately captured in spherically symmetric simulations with Boltzmann neutrino transport (e.g. Liebendoerfer et al. 2005, ApJ, 620, 840). Here, I present a simple parameterization of the comprehensive treatment of neutrino physics so that multi-dimensional simulations {of the collapse phase} can include the results of stateof- the-art neutrino transport in an efficient and accurate way (Liebendoerfer, astro-ph/0504072). With the application to the 3-D MHD simulations of Liebendoerfer, Pen, & Thompson (2005, to be published in Nucl. Phys. A), realistic three-dimensional simulations of slowly rotating collapse with magnetic fields become feasible to narrow the configuration space at bounce, i.e. at the onset of the not fully understood supernova explosion. The evolution of the magnetic field is followed for different choices of the uncertain initial values at the onset of collapse. Until a few milliseconds after bounce, a mainly compression-induced field amplification of about two orders of magnitude is found in the hot material layered around the protoneutron star. Larger magnetic fields are trapped within the protoneutron star. After bounce, the magnetic field lines entangle in the layers where convection is driven by entropy gradients. Cross-view stereograms are shown to visualize their evolution in 3-D.

  1. Chemical solver to compute molecule and grain abundances and non-ideal MHD resistivities in prestellar core-collapse calculations

    NASA Astrophysics Data System (ADS)

    Marchand, P.; Masson, J.; Chabrier, G.; Hennebelle, P.; Commerçon, B.; Vaytet, N.

    2016-07-01

    We develop a detailed chemical network relevant to calculate the conditions that are characteristic of prestellar core collapse. We solve the system of time-dependent differential equations to calculate the equilibrium abundances of molecules and dust grains, with a size distribution given by size-bins for these latter. These abundances are used to compute the different non-ideal magneto-hydrodynamics resistivities (ambipolar, Ohmic and Hall), needed to carry out simulations of protostellar collapse. For the first time in this context, we take into account the evaporation of the grains, the thermal ionisation of potassium, sodium, and hydrogen at high temperature, and the thermionic emission of grains in the chemical network, and we explore the impact of various cosmic ray ionisation rates. All these processes significantly affect the non-ideal magneto-hydrodynamics resistivities, which will modify the dynamics of the collapse. Ambipolar diffusion and Hall effect dominate at low densities, up to nH = 1012 cm-3, after which Ohmic diffusion takes over. We find that the time-scale needed to reach chemical equilibrium is always shorter than the typical dynamical (free fall) one. This allows us to build a large, multi-dimensional multi-species equilibrium abundance table over a large temperature, density and ionisation rate ranges. This table, which we make accessible to the community, is used during first and second prestellar core collapse calculations to compute the non-ideal magneto-hydrodynamics resistivities, yielding a consistent dynamical-chemical description of this process. The multi-dimensional multi-species equilibrium abundance table and a copy of the code are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A18

  2. Very Low Energy Supernovae From Neutrino Mass Loss

    NASA Astrophysics Data System (ADS)

    Lovegrove, Elizabeth; Woosley, S. E.

    2013-01-01

    The continuing difficulty of achieving a reliable core-collapse supernova in simulation has led many to speculate about what transients might be visible if a core-collapse supernova fails. If some percentage of such supernovae fail, there may be many more types of transients occurring than are currently being detected and catalogued as supernovae. Even if the original outgoing shock in a collapsing presupernova star fails, one must still consider the hydrodynamic response of the star to the abrupt loss of a small amount of mass via neutrinos as the core forms a protoneutron star. Following a suggestion by Nadezhin (1980), we use the Kepler and CASTRO codes to model the hydrodynamical responses of typical supernova progenitor stars to the loss of approximately 0.2 - 0.5 solar masses of gravitational mass from their centers. In a red supergiant star, a very weak supernova with total kinetic energy ~1047 ergs results. The binding energy of the hydrogen envelope before the explosion is of the same order and, depending upon assumptions regarding the neutrino loss rates, most of it is ejected. Ejection speeds are ~50 km/s and luminosities ~1039 ergs/s are maintained for about a year. A significant part of the energy comes from the recombination of hydrogen. The color of the explosion is extremely red and the events bear some similarity to the detected transients catalogued as "luminous red novae."

  3. Interacting supernovae and supernova impostors. LSQ13zm: an outburst heralds the death of a massive star

    NASA Astrophysics Data System (ADS)

    Tartaglia, L.; Pastorello, A.; Sullivan, M.; Baltay, C.; Rabinowitz, D.; Nugent, P.; Drake, A. J.; Djorgovski, S. G.; Gal-Yam, A.; Fabrika, S.; Barsukova, E. A.; Goranskij, V. P.; Valeev, A. F.; Fatkhullin, T.; Schulze, S.; Mehner, A.; Bauer, F. E.; Taubenberger, S.; Nordin, J.; Valenti, S.; Howell, D. A.; Benetti, S.; Cappellaro, E.; Fasano, G.; Elias-Rosa, N.; Barbieri, M.; Bettoni, D.; Harutyunyan, A.; Kangas, T.; Kankare, E.; Martin, J. C.; Mattila, S.; Morales-Garoffolo, A.; Ochner, P.; Rebbapragada, Umaa D.; Terreran, G.; Tomasella, L.; Turatto, M.; Verroi, E.; Woźniak, P. R.

    2016-06-01

    We report photometric and spectroscopic observations of the optical transient LSQ13zm. Historical data reveal the presence of an eruptive episode (that we label as `2013a') followed by a much brighter outburst (`2013b') three weeks later, that we argue to be the genuine supernova explosion. This sequence of events closely resemble those observed for SN 2010mc and (in 2012) SN 2009ip. The absolute magnitude reached by LSQ13zm during 2013a (MR = -14.87 ± 0.25 mag) is comparable with those of supernova impostors, while that of the 2013b event (MR = -18.46 ± 0.21 mag) is consistent with those of interacting supernovae. Our spectra reveal the presence of a dense and structured circumstellar medium, probably produced through numerous pre-supernova mass-loss events. In addition, we find evidence for high-velocity ejecta, with a fraction of gas expelled at more than 20 000 km s-1. The spectra of LSQ13zm show remarkable similarity with those of well-studied core-collapse supernovae. From the analysis of the available photometric and spectroscopic data, we conclude that we first observed the last event of an eruptive sequence from a massive star, likely a Luminous Blue Variable, which a short time later exploded as a core-collapse supernova. The detailed analysis of archival images suggest that the host galaxy is a star-forming Blue Dwarf Compact Galaxy.

  4. Methodological studies on the search for Gravitational Waves and Neutrinos from Type II Supernovae

    NASA Astrophysics Data System (ADS)

    Casentini, Claudio

    2016-02-01

    Type II SNe, also called Core-collapse SuperNovae have a neutrino (v) emission, as confirmed by SN 1987A, and are also potential sources of gravitational waves. Neutrinos and gravitational waves from these sources reach Earth almost contemporaneously and without relevant interaction with stellar matter and interstellar medium. The upcoming advanced gravitational interferometers would be sensitive enough to detect gravitational waves signals from close galactic Core-collapse SuperNovae events. Nevertheless, significant uncertainties on theoretical models of emission remain. A joint search of coincident low energy neutrinos and gravitational waves events from these sources would bring valuable information from the inner core of the collapsing star and would enhance the detection of the so-called Silent SuperNovae. Recently a project for a joint search involving gravitational wave interferometers and neutrino detectors has started. We discuss the benefits of a joint search and the status of the search project.

  5. Electromagnetic priors for black hole spindown in searches for gravitational waves from supernovae and long GRBs

    NASA Astrophysics Data System (ADS)

    van Putten, M. H. P. M.; Della Valle, M.; Levinson, A.

    2011-11-01

    Context. Some core-collapse supernovae appear to be hyper-energetic, and a subset of these are aspherical and associated with long GRBs. Aims: We use observations of electromagnetic emission from core-collapse supernovae and GRBs to impose constraints on their free energy source as a prior to searches for their gravitational wave emission. Methods: We review these events based on a finite efficiency for the conversion of spin energy to magnetic winds powering supernovae. Results: We find that some of the hyper-energetic events cannot be powered by the spindown of rapidly rotating proto-neutron stars by virtue of their limited rotational energy. They can, instead, be produced by the spindown of black holes providing a distinct prospect for gravitational-wave emission of interest to LIGO, Virgo, and the LCGT. Figure 1 is available in electronic form at http://www.aanda.org

  6. Electron capture in carbon dwarf supernovae

    NASA Technical Reports Server (NTRS)

    Mazurek, T. J.; Truran, J. W.; Cameron, A. G. W.

    1974-01-01

    The rates of electron capture on heavier elements under the extreme conditions predicted for dwarf star supernovae have been computed, incorporating modifications that seem to be indicated by present experimental results. An estimate of the maximum possible value of such rates is also given. The distribution of nuclei in nuclear statistical equilibrium has been calculated for the range of expected supernovae conditions, including the effects of the temperature dependence of nuclear partition functions. These nuclide abundance distributions are then used to compute nuclear equilibrium thermodynamic properties. The effects of the electron capture on such equilibrium matter are discussed. In the context of the 'carbon detonation' supernova model, the dwarf central density required to ensure core collapse to a neutron star configuration is found to be slightly higher than that obtained by Bruenn (1972) with the electron capture rates of Hansen (1966).-

  7. Probing Exotic Physics With Supernova Neutrinos

    SciTech Connect

    Kelso, Chris; Hooper, Dan

    2010-09-01

    Future galactic supernovae will provide an extremely long baseline for studying the properties and interactions of neutrinos. In this paper, we discuss the possibility of using such an event to constrain (or discover) the effects of exotic physics in scenarios that are not currently constrained and are not accessible with reactor or solar neutrino experiments. In particular, we focus on the cases of neutrino decay and quantum decoherence. We calculate the expected signal from a core-collapse supernova in both current and future water Cerenkov, scintillating, and liquid argon detectors, and find that such observations will be capable of distinguishing between many of these scenarios. Additionally, future detectors will be capable of making strong, model-independent conclusions by examining events associated with a galactic supernova's neutronization burst.

  8. Stellar Evolution/Supernova Research Data Archives from the SciDAC Computational Astrophysics Consortium

    DOE Data Explorer

    Woosley, Stan [University of California, Santa Cruz

    Theoretical high-energy astrophysics studies the most violent explosions in the universe - supernovae (the massive explosions of dying stars) and gamma ray bursts (mysterious blasts of intense radiation). The evolution of massive stars and their explosion as supernovae and/or gamma ray bursts describes how the "heavy" elements needed for life, such as oxygen and iron, are forged (nucleosynthesis) and ejected to later form new stars and planets. The Computational Astrophysics Consortium's project includes a Science Application Partnership on Adaptive Algorithms that develops software involved. The principal science topics are - in order of priority - 1) models for Type Ia supernovae, 2) radiation transport, spectrum formation, and nucleosynthesis in model supernovae of all types; 3) the observational implications of these results for experiments in which DOE has an interest, especially the Joint Dark Energy Mission, Supernova/Acceleration Probe (SNAP) satellite observatory, the Large Synoptic Survey Telescope (LSST), and ground based supernova searches; 4) core collapse supernovae; 5) gamma-ray bursts; 6) hypernovae from Population III stars; and 7) x-ray bursts. Models of these phenomena share a common need for nuclear reactions and radiation transport coupled to multi-dimensional fluid flow. The team has developed and used supernovae simulation codes to study Type 1A and core-collapse supernovae. (Taken from http://www.scidac.gov/physics/grb.html) The Stellar Evolution Data Archives contains more than 225 Pre-SN models that can be freely accessed.

  9. Supernova hydrodynamics experiments using the Nova laser

    SciTech Connect

    Remington, B.A.; Glendinning, S.G.; Estabrook, K.; Wallace, R.J.; Rubenchik, A.; Kane, J.; Arnett, D.; Drake, R.P.; McCray, R.

    1997-04-01

    We are developing experiments using the Nova laser to investigate two areas of physics relevant to core-collapse supernovae (SN): (1) compressible nonlinear hydrodynamic mixing and (2) radiative shock hydrodynamics. In the former, we are examining the differences between the 2D and 3D evolution of the Rayleigh-Taylor instability, an issue critical to the observables emerging from SN in the first year after exploding. In the latter, we are investigating the evolution of a colliding plasma system relevant to the ejecta-stellar wind interactions of the early stages of SN remnant formation. The experiments and astrophysical implications are discussed.

  10. Supernovae. ⁴⁴Ti gamma-ray emission lines from SN1987A reveal an asymmetric explosion.

    PubMed

    Boggs, S E; Harrison, F A; Miyasaka, H; Grefenstette, B W; Zoglauer, A; Fryer, C L; Reynolds, S P; Alexander, D M; An, H; Barret, D; Christensen, F E; Craig, W W; Forster, K; Giommi, P; Hailey, C J; Hornstrup, A; Kitaguchi, T; Koglin, J E; Madsen, K K; Mao, P H; Mori, K; Perri, M; Pivovaroff, M J; Puccetti, S; Rana, V; Stern, D; Westergaard, N J; Zhang, W W

    2015-05-01

    In core-collapse supernovae, titanium-44 ((44)Ti) is produced in the innermost ejecta, in the layer of material directly on top of the newly formed compact object. As such, it provides a direct probe of the supernova engine. Observations of supernova 1987A (SN1987A) have resolved the 67.87- and 78.32-kilo-electron volt emission lines from decay of (44)Ti produced in the supernova explosion. These lines are narrow and redshifted with a Doppler velocity of ~700 kilometers per second, direct evidence of large-scale asymmetry in the explosion. PMID:25954004

  11. Supernovae. ⁴⁴Ti gamma-ray emission lines from SN1987A reveal an asymmetric explosion.

    PubMed

    Boggs, S E; Harrison, F A; Miyasaka, H; Grefenstette, B W; Zoglauer, A; Fryer, C L; Reynolds, S P; Alexander, D M; An, H; Barret, D; Christensen, F E; Craig, W W; Forster, K; Giommi, P; Hailey, C J; Hornstrup, A; Kitaguchi, T; Koglin, J E; Madsen, K K; Mao, P H; Mori, K; Perri, M; Pivovaroff, M J; Puccetti, S; Rana, V; Stern, D; Westergaard, N J; Zhang, W W

    2015-05-01

    In core-collapse supernovae, titanium-44 ((44)Ti) is produced in the innermost ejecta, in the layer of material directly on top of the newly formed compact object. As such, it provides a direct probe of the supernova engine. Observations of supernova 1987A (SN1987A) have resolved the 67.87- and 78.32-kilo-electron volt emission lines from decay of (44)Ti produced in the supernova explosion. These lines are narrow and redshifted with a Doppler velocity of ~700 kilometers per second, direct evidence of large-scale asymmetry in the explosion.

  12. Energetic Supernovae from the Cosmic Dawn

    NASA Astrophysics Data System (ADS)

    Chen, Ke-Jung

    2013-04-01

    We present the results from our 3D supernova simulations by using CASTRO, a new radiation-hydrodynamics code. The first generation of stars in the universe ended the cosmic dark age by shining the first light. But what was the fate of these stars? Based on the stellar evolution models, the fate of stars depends on their masses. Modern cosmological simulations suggest that the first stars could be very massive, with a typical mass scale over 50 solar masses. We look for the possible supernovae from the death of the first stars with masses over 50 solar masses. Besides the iron-core collapse supernovae, we find energetic thermonuclear supernovae, including two types of pair-instability supernovae and one type of general-relativity instability supernovae. Our models capture all explosive burning and follow the explosion until the shock breaks out from the stellar surface. We will discuss the energetics, nucleosynthesis, and possible observational signatures for these primordial supernovae that will be the prime targets for future large telescopes such as the James Webb Space Telescope (JWST).

  13. Supernova neutrinos and explosive nucleosynthesis

    SciTech Connect

    Kajino, T.; Aoki, W.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Shibagaki, S.; Mathews, G. J.; Nakamura, K.; Suzuki, T.

    2014-05-09

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos. We studied the explosive nucleosyn-thesis in supernovae and found that several isotopes {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta as well as r-process nuclei are affected by the neutrino interactions. The abundance of these isotopes therefore depends strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We discuss first how to determine the neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the effects of neutrino oscillation on their abundances, and propose a novel method to determine the still unknown neutrino oscillation parameters, mass hierarchy and θ{sub 13}, simultaneously. There is recent evidence that SiC X grains from the Murchison meteorite may contain supernova-produced light elements {sup 11}B and {sup 7}Li encapsulated in the presolar grains. Combining the recent experimental constraints on θ{sub 13}, we show that our method sug-gests at a marginal preference for an inverted neutrino mass hierarchy. Finally, we discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  14. Gamma-ray constraints on supernova nucleosynthesis

    NASA Technical Reports Server (NTRS)

    Leising, Mark D.

    1994-01-01

    Gamma-ray spectroscopy holds great promise for probing nucleosynthesis in individual supernova explosions via short-lived radioactivity, and for measuring current global Galactic supernova nucleosynthesis with longer-lived radioactivity. It was somewhat surprising that the former case was realized first for a Type II supernova, when both Co-56 and Co-57 were detected in SN 1987A. These provide unprecedented constraints on models of Type II explosions and nucleosynthesis. Live Al-26 in the Galaxy might come from Type II supernovae, and if it is eventually shown to be so, can constrain massive star evolution, supernova nucleosynthesis, and the Galactic Type II supernova rate. Type Ia supernovae, thought to be thermonuclear explosions, have not yet been detected in gamma-rays. This is somewhat surprising given current models and recent Co-56 detection attempts. Ultimately, gamma-ray measurements can confirm their thermonuclear nature, probe the nuclear burning conditions, and help evaluate their contributions to Galactic nucleosynthesis. Type Ib/c supernovae are poorly understood. Whether they are core collapse or thermonuclear events might be ultimately settled by gamma-ray observations. Depending on details of the nuclear processing, any of these supernova types might contribute to a detectable diffuse glow of Fe-60 gamma-ray lines. Previous attempts at detection have come very close to expected emission levels. Remnants of any type of age less that a few centuries might be detectable as individual spots of Ti-44 gamma-ray line emission. It is in fact quite surprising that previous surveys have not discovered such spots, and the constraints on the combination of nucleosynthesis yields and supernova rates are very interesting. All of these interesting limits and possibilities mean that the next mission, International Gamma-Ray Astrophysics Laboratory (INTEGRAL), if it has sufficient sensitivity, is very likely to lead to the realization of much of the great potential

  15. FINDING {eta} CAR ANALOGS IN NEARBY GALAXIES USING SPITZER. I. CANDIDATE SELECTION

    SciTech Connect

    Khan, Rubab; Stanek, K. Z.; Kochanek, C. S. E-mail: kstanek@astronomy.ohio-state.edu

    2013-04-10

    The late-stage evolution of the most massive stars such as {eta} Carinae is controlled by the effects of mass loss, which may be dominated by poorly understood eruptive mass ejections. Understanding this population is challenging because no true analogs of {eta} Car have been clearly identified in the Milky Way or other galaxies. We utilize Spitzer IRAC images of seven nearby ({approx}< 4 Mpc) galaxies to search for such analogs. We find 34 candidates with a flat or rising mid-IR spectral energy distributions toward longer mid-infrared wavelengths that emit >10{sup 5} L{sub Sun} in the IRAC bands (3.6 to 8.0 {mu}m) and are not known to be background sources. Based on our estimates for the expected number of background sources, we expect that follow-up observations will show that most of these candidates are not dust enshrouded massive stars, with an expectation of only 6 {+-} 6 surviving candidates. Since we would detect true analogs of {eta} Car for roughly 200 years post-eruption, this implies that the rate of eruptions like {eta} Car is less than the core-collapse supernova rate. It is possible, however, that every M > 40 M{sub Sun} star undergoes such eruptions given our initial results. In Paper II we will characterize the candidates through further analysis and follow-up observations, and there is no barrier to increasing the galaxy sample by an order of magnitude. The primary limitation of the present search is that Spitzer's resolution limits us to the shorter wavelength IRAC bands. With the James Webb Space Telescope, such surveys can be carried out at the far more optimal wavelengths of 10-30 {mu}m, allowing identification of {eta} Car analogs for millennia rather than centuries post-eruption.

  16. A search for giant flares from soft gamma-ray repeaters in nearby galaxies in the Konus-WIND short burst sample

    NASA Astrophysics Data System (ADS)

    Svinkin, D. S.; Hurley, K.; Aptekar, R. L.; Golenetskii, S. V.; Frederiks, D. D.

    2015-02-01

    The knowledge of the rate of soft gamma-ray repeater (SGR) giant flares (GFs) is important for understanding the GF mechanism and the SGR energy budget in the framework of the magnetar model. We estimate the upper limit to the rate using the results of an extensive search for extragalactic SGR GFs among 140 short gamma-ray bursts detected between 1994 and 2010 by Konus-WIND using Interplanetary Network (IPN) localizations and temporal parameters. We show that Konus-WIND and the IPN are capable of detecting GFs with energies of 2.3 × 1046 erg (which is the energy of the GF from SGR 1806-20 assuming a distance of 15 kpc) at distances of up to ˜30 Mpc and GFs with energies of ≲ 1045 erg (which is the energy of the GF from SGR 0526-66) at distances of up to ≈6 Mpc. Using a sample of 1896 nearby galaxies, we found that only two bursts, GRB 051103 and GRB 070201, have a low chance coincidence probability between an IPN localization and a nearby galaxy. We found the upper limit to the fraction of GFs among short gamma-ray bursts with fluence above ˜5 × 10-7 erg cm-2 to be <8 per cent (95 per cent confidence level). Assuming that the number of active SGRs in nearby galaxies is proportional to their core-collapse supernova rate, we derived the one-sided 95 per cent upper limit to the rate of GFs with energy output similar to the GF from SGR 1806-20 to be (0.6-1.2)× 10^{-4} Q_{46}^{-1.5} yr-1 per SGR, where Q46 is the GF energy output in 1046 erg.

  17. Supernovae from yellow, blue supergiants: origin and consequences for stellar evolution

    NASA Astrophysics Data System (ADS)

    Meynet, Georges; Georgy, Cyril; Saio, Hideyuki; Kudritzki, Rolf-Peter; Groh, Jose

    2015-08-01

    A few core collapse supernovae progenitors have been found to be yellow or blue supergiants. We shall discuss possible scenarios involving single and close binary evolution allowing to explain this kind of core collapse supernova progenitors. According to stellar models for both single and close binaries, blue supergiants, at the end of their nuclear lifetimes and thus progenitors of core collapse supernovae, present very different characteristics for what concerns their surface compositions, rotational surface velocities and pulsational properties with respect to blue supergiants in their core helium burning phase. We discuss how the small observed scatter of the flux-weighted gravity-luminosity (FWGL) relation of blue supergiants constrains the evolution of massive stars after the Main-Sequence phase and the nature of the progenitors of supernovae in the mass range between 12 and 40 solar masses. The present day observed surface abundances of blue supergiants, of their pulsational properties, as well as the small scatter of the FWGL relation provide strong constraints on both internal mixing and mass loss in massive stars and therefore on the end point of their evolution.

  18. Probing Dark Energy via Neutrino and Supernova Observatories

    SciTech Connect

    Hall, Lawrence; Hall, Lawrence J.; Murayama, Hitoshi; Papucci, Michele; Perez, Gilad

    2006-07-10

    A novel method for extracting cosmological evolution parameters is proposed, using a probe other than light: future observations of the diffuse anti-neutrino flux emitted from core-collapse supernovae (SNe), combined with the SN rate extracted from future SN surveys. The relic SN neutrino differential flux can be extracted by using future neutrino detectors such as Gadolinium-enriched, megaton, water detectors or 100-kiloton detectors of liquid Argon or liquid scintillator. The core-collapse SN rate can be reconstructed from direct observation of SN explosions using future precision observatories. Our method, by itself, cannot compete with the accuracy of the optical-based measurements but may serve as an important consistency check as well as a source of complementary information. The proposal does not require construction of a dedicated experiment, but rather relies on future experiments proposed for other purposes.

  19. Cosmological and supernova neutrinos

    NASA Astrophysics Data System (ADS)

    Kajino, T.; Aoki, W.; Balantekin, A. B.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Kusakabe, M.; Mathews, G. J.; Nakamura, K.; Pehlivan, Y.; Shibagaki, S.; Suzuki, T.

    2014-06-01

    The Big Bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) anisotropies are the pillars of modern cosmology. It has recently been suggested that axion which is a dark matter candidate in the framework of the standard model could condensate in the early universe and induce photon cooling before the epoch of the photon last scattering. Although this may render a solution to the overproduction problem of primordial 7Li abundance, there arises another serious difficulty of overproducing D abundance. We propose a hybrid dark matter model with both axions and relic supersymmetric (SUSY) particles to solve both overproduction problems of the primordial D and 7Li abundances simultaneously. The BBN also serves to constrain the nature of neutrinos. Considering non-thermal photons produced in the decay of the heavy sterile neutrinos due to the magnetic moment, we explore the cosmological constraint on the strength of neutrino magnetic moment consistent with the observed light element abundances. Core-collapse supernovae eject huge flux of energetic neutrinos which affect explosive nucleosynthesis of rare isotopes like 7Li, 11B, 92Nb, 138La and 180Ta and r-process elements. Several isotopes depend strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. Combining the recent experimental constraints on θ13 with predicted and observed supernova-produced abundance ratio 11B/7Li encapsulated in the presolar grains from the Murchison meteorite, we show a marginal preference for an inverted neutrino mass hierarchy. We also discuss supernova relic neutrinos (SRN) that may indicate the softness of the equation of state (EoS) of nuclear matter and adiabatic conditions of the neutrino oscillation.

  20. Cosmological and supernova neutrinos

    SciTech Connect

    Kajino, T.; Aoki, W.; Balantekin, A. B.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Shibagaki, S.; Kusakabe, M.; Mathews, G. J.; Nakamura, K.; Pehlivan, Y.; Suzuki, T.

    2014-06-24

    The Big Bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) anisotropies are the pillars of modern cosmology. It has recently been suggested that axion which is a dark matter candidate in the framework of the standard model could condensate in the early universe and induce photon cooling before the epoch of the photon last scattering. Although this may render a solution to the overproduction problem of primordial {sup 7}Li abundance, there arises another serious difficulty of overproducing D abundance. We propose a hybrid dark matter model with both axions and relic supersymmetric (SUSY) particles to solve both overproduction problems of the primordial D and {sup 7}Li abundances simultaneously. The BBN also serves to constrain the nature of neutrinos. Considering non-thermal photons produced in the decay of the heavy sterile neutrinos due to the magnetic moment, we explore the cosmological constraint on the strength of neutrino magnetic moment consistent with the observed light element abundances. Core-collapse supernovae eject huge flux of energetic neutrinos which affect explosive nucleosynthesis of rare isotopes like {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta and r-process elements. Several isotopes depend strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. Combining the recent experimental constraints on θ{sub 13} with predicted and observed supernova-produced abundance ratio {sup 11}B/{sup 7}Li encapsulated in the presolar grains from the Murchison meteorite, we show a marginal preference for an inverted neutrino mass hierarchy. We also discuss supernova relic neutrinos (SRN) that may indicate the softness of the equation of state (EoS) of nuclear matter and adiabatic conditions of the neutrino oscillation.

  1. The Multiply Imaged Strongly Lensed Supernova Refsdal

    NASA Astrophysics Data System (ADS)

    Kelly, Patrick

    2016-01-01

    In 1964, Sjur Refsdal first considered the possibility that the light from a background supernova could traverse multiple paths around a strong gravitational lens towards us. He showed that the arrival times of the supernova's light would depend on the cosmic expansion rate, as well as the distribution of matter in the lens. I will discuss the discovery of the first such multiply imaged supernova, which exploded behind the MACS J1149.6+2223 galaxy cluster. We have obtained Hubble Space Telescope grism and ground-based spectra of the four images of the supernova, which form an Einstein Cross configuration around an elliptical cluster member. These spectra as well as rest-frame optical light curves have allowed us to learn about the properties of the peculiar core-collapse supernova explosion, and contain information about the lenses' matter distribution as well as their stellar populations. A delayed image of the supernova is expected close to the galaxy cluster center as early as Fall 2015, and will serve as an unprecedented probe of the potential of a massive galaxy cluster.

  2. Photometric Selection of High-Redshift Type Ia Supernova Candidates

    NASA Astrophysics Data System (ADS)

    Sullivan, M.; Howell, D. A.; Perrett, K.; Nugent, P. E.; Astier, P.; Aubourg, E.; Balam, D.; Basa, S.; Carlberg, R. G.; Conley, A.; Fabbro, S.; Fouchez, D.; Guy, J.; Hook, I.; Lafoux, H.; Neill, J. D.; Pain, R.; Palanque-Delabrouille, N.; Pritchet, C. J.; Regnault, N.; Rich, J.; Taillet, R.; Aldering, G.; Baumont, S.; Bronder, J.; Filiol, M.; Knop, R. A.; Perlmutter, S.; Tao, C.

    2006-02-01

    We present a method for selecting high-redshift Type Ia supernovae (SNe Ia) located via rolling SN searches. The technique, using both color and magnitude information of events from only two to three epochs of multiband real-time photometry, is able to discriminate between SNe Ia and core-collapse SNe. Furthermore, for SNe Ia the method accurately predicts the redshift, phase, and light-curve parameterization of these events based only on pre-maximum-light data. We demonstrate the effectiveness of the technique on a simulated survey of SNe Ia and core-collapse SNe, where the selection method effectively rejects most core-collapse SNe while retaining SNe Ia. We also apply the selection code to real-time data acquired as part of the Canada-France-Hawaii Telescope Supernova Legacy Survey (SNLS). During the period 2004 May to 2005 January in the SNLS, 440 SN candidates were discovered, of which 70 were confirmed spectroscopically as SNe Ia and 15 as core-collapse events. For this test data set, the selection technique correctly identifies 100% of the identified SNe II as non-SNe Ia with only a 1%-2% false rejection rate. The predicted parameterization of the SNe Ia has a precision of Δz/(1+zspec)<0.09 in redshift and +/-2-3 rest-frame days in phase, providing invaluable information for planning spectroscopic follow-up observations. We also investigate any bias introduced by this selection method on the ability of surveys such as SNLS to measure cosmological parameters (e.g., w and ΩM) and find any effect to be negligible.

  3. Supernovae and Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Mathews, Grant J.

    2014-09-01

    Nucleosynthesis by rapid neutron capture (the r-process) could be an important diagnostic of the explosive deep interiors of supernovae. The early appearance of r-process elements in the Galaxy, along with energetic requirements, strongly argues in favor of a supernova origin for r-process isotopes. However there is a current conundrum as to the relative contributions from various supernovae environments, e.g. MHD jets or neutrino energized winds. There are also possible contributions from failed supernovae (collapsars) leading to a black hole (BH), or the ejection of material during the mergers of neutron stars in binary systems, i.e. NS+NS or NS+BH systems. In this talk we will review the theoretical underpinnings of each possibility in the quest to deduce the relative contribution of each process. In particular, each model for r-process nucleosynthesis invariably leads to systematic discrepancies with the observed solar-system r-process abundances. For example, although the location of the abundance peaks near nuclear mass numbers A = 130 and 195 identify an environment of rapid neutron capture near closed nuclear shells, the abundances of elements just above and below those peaks are often underproduced by more than an order of magnitude in model calculations. Similarly, most recent neutrino-driven wind simulations produce only the lighter r-process elements, while neutron-star mergers may miss the r-process peaks due to fission recycling. In this talk we demonstrate that the underproduction of elements above and below the r-process peaks can be supplemented via fission fragment distributions from the recycling of material synthesized during neutron star mergers, while the abundance peaks themselves are well reproduced in MHD jets in supernovae and collapsars. Moreover, we show that the relative contributions to the solar-system r-process yields from core-collapse supernovae and neutron star mergers required by this proposal are consistent with estimates of the

  4. Nuclear quests for supernova dynamics and nucleosynthesis

    SciTech Connect

    Langanke, K.; Martinez-Pinedo, G.

    2011-10-28

    Nuclear physics plays a crucial role in various aspects of core collapse supernovae. The collapse dynamics is strongly influenced by electron captures. Using modern many-body theory improved capture rates have been derived recently with the important result that the process is dominated by capture on nuclei until neutrino trapping is achieved. Following the core bounce the ejected matter is the site of interesting nucleosynthesis. The early ejecta are proton-rich and give rise to the recently discovered {nu}p-process. Later ejecta might be neutron-rich and can be one site of the r-process. The manuscript discusses recent progress in describing nuclear input relevant for the supernova dynamics and nucleosynthesis.

  5. FUZZY SUPERNOVA TEMPLATES. I. CLASSIFICATION

    SciTech Connect

    Rodney, Steven A.; Tonry, John L. E-mail: jt@ifa.hawaii.ed

    2009-12-20

    Modern supernova (SN) surveys are now uncovering stellar explosions at rates that far surpass what the world's spectroscopic resources can handle. In order to make full use of these SN data sets, it is necessary to use analysis methods that depend only on the survey photometry. This paper presents two methods for utilizing a set of SN light-curve templates to classify SN objects. In the first case, we present an updated version of the Bayesian Adaptive Template Matching program (BATM). To address some shortcomings of that strictly Bayesian approach, we introduce a method for Supernova Ontology with Fuzzy Templates (SOFT), which utilizes fuzzy set theory for the definition and combination of SN light-curve models. For well-sampled light curves with a modest signal-to-noise ratio (S/N >10), the SOFT method can correctly separate thermonuclear (Type Ia) SNe from core collapse SNe with >=98% accuracy. In addition, the SOFT method has the potential to classify SNe into sub-types, providing photometric identification of very rare or peculiar explosions. The accuracy and precision of the SOFT method are verified using Monte Carlo simulations as well as real SN light curves from the Sloan Digital Sky Survey and the SuperNova Legacy Survey. In a subsequent paper, the SOFT method is extended to address the problem of parameter estimation, providing estimates of redshift, distance, and host galaxy extinction without any spectroscopy.

  6. Discovery and Observations of the Unusually Luminous Type-Defying II-P/II-L Supernova ASASSN-13co

    NASA Astrophysics Data System (ADS)

    Holoien, T. W.-S.; Prieto, J. L.; Pejcha, O.; Stanek, K. Z.; Kochanek, C. S.; Shappee, B. J.; Grupe, D.; Morrell, N.; Thorstensen, J. R.; Basu, U.; Beacom, J. F.; Bersier, D.; Brimacombe, J.; Davis, A. B.; Pojmański, G.; Skowron, D. M.

    2016-06-01

    We present photometric and spectroscopic observations of ASASSN-13co, an unusually luminous Type II supernova and the first core-collapse supernova discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN). First detection of the supernova was on UT 2013 August 29 and the data presented span roughly 3.5 months after discovery. We use the recently developed model by Pejcha and Prieto to model the multi-band light curves of ASASSN-13co and derive the bolometric luminosity curve. We compare ASASSN-13co to other Type II supernovae to show that it was unusually luminous for a Type II supernova and that it exhibited an atypical light curve shape that does not cleanly match that of either a standard Type II-L or Type II-P supernova.

  7. The Dominance of Dynamic Barlike Instabilities in the Evolution of a Massive Stellar Core Collapse That ``Fizzles''

    NASA Astrophysics Data System (ADS)

    Imamura, James N.; Durisen, Richard H.

    2001-03-01

    Core collapse in a massive rotating star may halt at subnuclear density if the core contains angular momentum J>~1049 g cm2 s-1. An aborted collapse can lead to the formation of a rapidly rotating equilibrium object, which, because of its high electron fraction, Ye>0.4, and high entropy per baryon, Sb/k~1-2, is secularly and dynamically stable. The further evolution of such a ``fizzler'' is driven by deleptonization and cooling of the hot, dense material. These processes cause the fizzler both to contract toward neutron star densities and to spin up, driving it toward instability points of the barlike modes. Using linear stability analyses to study the latter case, we find that the stability properties of fizzlers are similar to those of Maclaurin spheroids and polytropes despite the nonpolytropic nature and extreme compressibility of the fizzler equation of state. For fizzlers with the specific angular momentum distribution of the Maclaurin spheroids, secular and dynamic barlike instabilities set in at T/|W|~0.14 and 0.27, respectively, where T is the rotational kinetic energy and W is the gravitational energy of the fizzler, the same limits as found for Maclaurin spheroids. For fizzlers in which angular momentum is more concentrated toward the equator, the secular stability limits drop dramatically. For the most extreme angular momentum distribution we consider, the secular stability limit for the barlike modes falls to T/|W|~0.038, compared with T/|W|~0.09-0.10 for the most extreme polytropic cases known previously (Imamura et al.). For fixed equation-of-state parameters, the secular and dynamic stability limits occur at roughly constant mass over the range of typical fizzler central densities. Deleptonization and cooling decrease the limiting masses on timescales shorter than the growth time for secular instability. Consequently, unless an evolving fizzler reaches neutron star densities first, it will always encounter dynamic barlike instabilities before

  8. Automated search for supernovae

    SciTech Connect

    Kare, J.T.

    1984-11-15

    This thesis describes the design, development, and testing of a search system for supernovae, based on the use of current computer and detector technology. This search uses a computer-controlled telescope and charge coupled device (CCD) detector to collect images of hundreds of galaxies per night of observation, and a dedicated minicomputer to process these images in real time. The system is now collecting test images of up to several hundred fields per night, with a sensitivity corresponding to a limiting magnitude (visual) of 17. At full speed and sensitivity, the search will examine some 6000 galaxies every three nights, with a limiting magnitude of 18 or fainter, yielding roughly two supernovae per week (assuming one supernova per galaxy per 50 years) at 5 to 50 percent of maximum light. An additional 500 nearby galaxies will be searched every night, to locate about 10 supernovae per year at one or two percent of maximum light, within hours of the initial explosion.

  9. The CoCoNuT code: from neutron star oscillations to supernova explosions

    NASA Astrophysics Data System (ADS)

    Cerdá-Durán, P.; Gabler, M.; Müller, E.; Font, J. A.; Stergioulas, N.; Obergaulinger, M.; Aloy, M. A.; DeBrye, N.; Cordero-Carrión, I.; Ibáñez, J. M.

    2013-05-01

    CoCoNuT is a numerical code, that evolves the General relativistic magneto-hydrodynamics equations coupled to the Einstein equations in the CFC approximation. Its main purpose is to simulate astrophysical scenarios in which strong gravity is important such as the collapse of massive stars and the evolution of neutron stars. I review recent results of the numerical code regarding neutron star oscillations and core collapse supernova and its observational consequences.

  10. The convective engine paradigm for the supernova explosion mechanism and its consequences.

    NASA Astrophysics Data System (ADS)

    Herant, M.

    1995-05-01

    The convective engine paradigm for the explosion mechanism in core collapse supernovae is presented in a pedagogical manner. A candid evaluation of its strengths and weaknesses is attempted. The case where the convective mode corresponds to l=1, m=0 (one inflow, one outflow) is explored in more detail. The author also discusses the potential importance of such a convective pattern for neutron star kicks.

  11. Accelerating Our Understanding of Supernova Explosion Mechanism via Simulations and Visualizations with GenASiS

    SciTech Connect

    Budiardja, R. D.; Cardall, Christian Y; Endeve, Eirik

    2015-01-01

    Core-collapse supernovae are among the most powerful explosions in the Universe, releasing about 1053 erg of energy on timescales of a few tens of seconds. These explosion events are also responsible for the production and dissemination of most of the heavy elements, making life as we know it possible. Yet exactly how they work is still unresolved. One reason for this is the sheer complexity and cost of a self-consistent, multi-physics, and multi-dimensional core-collapse supernova simulation, which is impractical, and often impossible, even on the largest supercomputers we have available today. To advance our understanding we instead must often use simplified models, teasing out the most important ingredients for successful explosions, while helping us to interpret results from higher fidelity multi-physics models. In this paper we investigate the role of instabilities in the core-collapse supernova environment. We present here simulation and visualization results produced by our code GenASiS.

  12. DISCRIMINATING THE PROGENITOR TYPE OF SUPERNOVA REMNANTS WITH IRON K-SHELL EMISSION

    SciTech Connect

    Yamaguchi, Hiroya; Petre, Robert; Enoto, Teruaki; Badenes, Carles; Nakano, Toshio; Hiraga, Junko S.; Castro, Daniel; Hughes, John P.; Maeda, Yoshitomo; Nobukawa, Masayoshi; Uchida, Hiroyuki; Safi-Harb, Samar; Slane, Patrick O.; Smith, Randall K.

    2014-04-20

    Supernova remnants (SNRs) retain crucial information about both their parent explosion and circumstellar material left behind by their progenitor. However, the complexity of the interaction between supernova ejecta and ambient medium often blurs this information, and it is not uncommon for the basic progenitor type (Ia or core-collapse) of well-studied remnants to remain uncertain. Here we present a powerful new observational diagnostic to discriminate between progenitor types and constrain the ambient medium density of SNRs using solely Fe K-shell X-ray emission. We analyze all extant Suzaku observations of SNRs and detect Fe Kα emission from 23 young or middle-aged remnants, including five first detections (IC 443, G292.0+1.8, G337.2-0.7, N49, and N63A). The Fe Kα centroids clearly separate progenitor types, with the Fe-rich ejecta in Type Ia remnants being significantly less ionized than in core-collapse SNRs. Within each progenitor group, the Fe Kα luminosity and centroid are well correlated, with more luminous objects having more highly ionized Fe. Our results indicate that there is a strong connection between explosion type and ambient medium density, and suggest that Type Ia supernova progenitors do not substantially modify their surroundings at radii of up to several parsecs. We also detect a K-shell radiative recombination continuum of Fe in W49B and IC 443, implying a strong circumstellar interaction in the early evolutionary phases of these core-collapse remnants.

  13. Supernova relic neutrinos and the supernova rate problem: Analysis of uncertainties and detectability of ONeMg and failed supernovae

    SciTech Connect

    Mathews, Grant J.; Hidaka, Jun; Kajino, Toshitaka; Suzuki, Jyutaro

    2014-08-01

    Direct measurements of the core collapse supernova rate (R{sub SN}) in the redshift range 0 ≤ z ≤ 1 appear to be about a factor of two smaller than the rate inferred from the measured cosmic massive star formation rate (SFR). This discrepancy would imply that about one-half of the massive stars that have been born in the local observed comoving volume did not explode as luminous supernovae. In this work, we explore the possibility that one could clarify the source of this 'supernova rate problem' by detecting the energy spectrum of supernova relic neutrinos with a next generation 10{sup 6} ton water Čerenkov detector like Hyper-Kamiokande. First, we re-examine the supernova rate problem. We make a conservative alternative compilation of the measured SFR data over the redshift range 0 ≤z ≤ 7. We show that by only including published SFR data for which the dust obscuration has been directly determined, the ratio of the observed massive SFR to the observed supernova rate R{sub SN} has large uncertainties ∼1.8{sub −0.6}{sup +1.6} and is statistically consistent with no supernova rate problem. If we further consider that a significant fraction of massive stars will end their lives as faint ONeMg SNe or as failed SNe leading to a black hole remnant, then the ratio reduces to ∼1.1{sub −0.4}{sup +1.0} and the rate problem is essentially solved. We next examine the prospects for detecting this solution to the supernova rate problem. We first study the sources of uncertainty involved in the theoretical estimates of the neutrino detection rate and analyze whether the spectrum of relic neutrinos can be used to independently identify the existence of a supernova rate problem and its source. We consider an ensemble of published and unpublished core collapse supernova simulation models to estimate the uncertainties in the anticipated neutrino luminosities and temperatures. We illustrate how the spectrum of detector events might be used to establish the average

  14. Snapping Supernovae at z>1.7

    SciTech Connect

    Aldering, Greg; Kim, Alex G.; Kowalski, Marek; Linder, Eric V.; Perlmutter, Saul

    2006-07-03

    We examine the utility of very high redshift Type Ia supernovae for cosmology and systematic uncertainty control. Next generation space surveys such as the Supernova/Acceleration Probe (SNAP) will obtain thousands of supernovae at z>1.7, beyond the design redshift for which the supernovae will be exquisitely characterized. We find that any z gtrsim 2 standard candles' use for cosmological parameter estimation is quite modest and subject to pitfalls; we examine gravitational lensing, redshift calibration, and contamination effects in some detail. The very high redshift supernovae - both thermonuclear and core collapse - will provide copious interesting information on star formation, environment, and evolution. However, the new observational systematics that must be faced, as well as the limited expansion of SN-parameter space afforded, does not point to high value for 1.7

  15. Possible Nearby Transient discovered by PSST

    NASA Astrophysics Data System (ADS)

    Wright, D.; Smith, K. W.; Smartt, S. J.; Huber, M.; Chambers, K. C.; Flewelling, H.; Willman, M.; Primak, N.; Schultz, A.; Gibson, B.; Magnier, E.; Waters, C.; Tonry, J.; Wainscoat, R. J.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-01-01

    A transient, which is a possible nearby supernova, has been discovered as part of the Pan-STARRS Survey for Transients (PSST). Information on all objects discovered by the Pan-STARRS Survey for Transients is available at http://star.pst.qub.ac.uk/ps1threepi/ (see Huber et al. ATel #7153).

  16. Multi-Dimensional Full Boltzmann-Neutrino-Radiation Hydrodynamic Simulations and Their Detailed Comparisons with Monte-Carlo Methods in Core Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Nagakura, H.; Richers, S.; Ott, C. D.; Iwakami, W.; Furusawa, S.; Sumiyoshi, K.; Yamada, S.; Matsufuru, H.; Imakura, A.

    2016-10-01

    We have developed a 7-dimensional Full Boltzmann-neutrino-radiation-hydrodynamical code and carried out ab-initio axisymmetric CCSNe simulations. I will talk about main results of our simulations and also discuss current ongoing projects.

  17. The Texas Supernova Search

    NASA Astrophysics Data System (ADS)

    Quimby, Robert

    2006-12-01

    Supernovae (SNe) are popular tools to explore the cosmological expansion of the Universe owing to their bright peak magnitudes and reasonably high rates; however, even the relatively homogeneous Type Ia supernovae are not perfect standard candles intrinsically. Their absolute peak brightness must be established by corrections that have been largely empirical. Hundreds of SNe are now found every year, shrinking the statistical errors in the cosmological terms, but most of these distant discoveries do little to further the physical understanding of SNe, which may illuminate unknown systematics. This talk will describe recent results from the The Texas Supernova Search, a campaign designed to discover not the most SNe nor the most distant SNe, but instead to amass a small collection of well-observed nearby SNe with detailed, multi-epoch spectral observations beginning at the earliest possible phases. For the past two years, we have pointed ROTSE-IIIb's 1.85 x 1.85 degree field of view at nearby galaxy clusters and searched thousands of galaxies, covering hundreds of square degrees on the sky, for supernovae. With ToO time on the neighboring 9.2m Hobby-Eberly Telescope, we have captured SNe spectra at some of the earliest phases ever. I will discuss the implications of these data on the physics of SNe explosions, including the propagation of the burning front and the progenitors of Type Ia supernovae.

  18. Nearby Newborns

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site] Figure 1

    This image shows six of the three-dozen 'ultraviolet luminous galaxies' spotted in our corner of the universe by NASA's Galaxy Evolution Explorer. These massive galaxies greatly resemble newborn galaxies that were common in the early universe. The discovery came as a surprise, because astronomers had thought that the universe's 'birth-rate' had declined, and that massive galaxies were no longer forming.

    The galaxies, located in the center of each panel, were discovered after the Galaxy Evolution Explorer scanned a large portion of the sky with its highly sensitive ultraviolet-light detectors. Because young stars pack most of their light into ultraviolet wavelengths, young galaxies appear to the Galaxy Evolution Explorer like diamonds in a field of stones. Astronomers mined for these rare 'gems' before, but missed them because they weren't able to examine a large enough slice of the sky. The Galaxy Evolution Explorer surveyed thousands of nearby galaxies before finding three-dozen newborns.

    While still relatively close in astronomical terms, these galaxies are far enough away to appear small to the Galaxy Evolution Explorer. Clockwise beginning from the upper left, they are called: GALEX_J232539.24+004507.1, GALEX_J231812.98-004126.1, GALEX_J015028.39+130858.5, GALEX_J021348.52+125951.3, GALEX_J143417.15+020742.5, GALEX_J020354.02-092452.5.

  19. SPECTRUM OF THE SUPERNOVA RELIC NEUTRINO BACKGROUND AND METALLICITY EVOLUTION OF GALAXIES

    SciTech Connect

    Nakazato, Ken’ichiro; Mochida, Eri; Suzuki, Hideyuki; Niino, Yuu

    2015-05-01

    The spectrum of the supernova relic neutrino (SRN) background from past stellar collapses including black hole formation (failed supernovae) is calculated. The redshift dependence of the black hole formation rate is considered on the basis of the metallicity evolution of galaxies. Assuming the mass and metallicity ranges of failed supernova progenitors, their contribution to SRNs is quantitatively estimated for the first time. Using this model, the dependences of SRNs on the cosmic star formation rate density (CSFRD), shock revival time, and equation of state (EOS) are investigated. The shock revival time is introduced as a parameter that should depend on the still unknown explosion mechanism of core collapse supernovae. The dependence on EOS is considered for failed supernovae, whose collapse dynamics and neutrino emission are certainly affected. It is found that the low-energy spectrum of SRNs is mainly determined by the CSFRD. These low-energy events will be observed in the Super-Kamiokande experiment with gadolinium-loaded water.

  20. Supernova remnants: the X-ray perspective

    NASA Astrophysics Data System (ADS)

    Vink, Jacco

    2012-12-01

    -ray observatories. In discussing the results of the last 15 years I have chosen to discuss a few topics that are of particular interest. These include the properties of Type Ia supernova remnants, which appear to be regularly shaped and have stratified ejecta, in contrast to core collapse supernova remnants, which have patchy ejecta distributions. For core collapse supernova remnants I discuss the spatial distribution of fresh nucleosynthesis products, but also their properties in connection to the neutron stars they contain. For the mature supernova remnants I focus on the prototypal supernova remnants Vela and the Cygnus Loop. And I discuss the interesting class of mixed-morphology remnants. Many of these mature supernova remnants contain still plasma with enhanced ejecta abundances. Over the last five years it has also become clear that many mixed-morphology remnants contain plasma that is overionized. This is in contrast to most other supernova remnants, which contain underionized plasmas. This text ends with a review of X-ray synchrotron radiation from shock regions, which has made it clear that some form of magnetic-field amplification is operating near shocks, and is an indication of efficient cosmic-ray acceleration.

  1. Electron-capture supernovae of super-asymptotic giant branch stars and the Crab supernova 1054

    NASA Astrophysics Data System (ADS)

    Nomoto, Ken'ichi; Tominaga, Nozomu; Blinnikov, Sergei I.

    2014-05-01

    An electron-capture supernova (ECSN) is a core-collapse supernova explosion of a super-asymptotic giant branch (SAGB) star with a main-sequence mass MMs ˜ 7 - 9.5M⊙. The explosion takes place in accordance with core bounce and subsequent neutrino heating and is a unique example successfully produced by first-principle simulations. This allows us to derive a first self-consistent multicolor light curves of a core-collapse supernova. Adopting the explosion properties derived by the first-principle simulation, i.e., the low explosion energy of 1.5 × 1050 erg and the small 56Ni mass of 2.5 × 10-3 M⊙, we perform a multigroup radiation hydrodynamics calculation of ECSNe and present multicolor light curves of ECSNe of SAGB stars with various envelope mass and hydrogen abundance. We demonstrate that a shock breakout has peak luminosity of L ˜ 2 × 1044 erg s-1 and can evaporate circumstellar dust up to R ˜ 1017 cm for a case of carbon dust, that plateau luminosity and plateau duration of ECSNe are L ˜ 1042 erg s-1 and t ˜ 60 - 100 days, respectively, and that a plateau is followed by a tail with a luminosity drop by ˜ 4 mag. The ECSN shows a bright and short plateau that is as bright as typical Type II plateau supernovae, and a faint tail that might be influenced by spin-down luminosity of a newborn pulsar. Furthermore, the theoretical models are compared with ECSN candidates: SN 1054 and SN 2008S. We find that SN 1054 shares the characteristics of the ECSNe. For SN 2008S, we find that its faint plateau requires a ECSN model with a significantly low explosion energy of E ˜ 1048 erg.

  2. Electron-capture supernovae of super-asymptotic giant branch stars and the Crab supernova 1054

    SciTech Connect

    Nomoto, Ken'ichi; Tominaga, Nozomu; Blinnikov, Sergei I.

    2014-05-02

    An electron-capture supernova (ECSN) is a core-collapse supernova explosion of a super-asymptotic giant branch (SAGB) star with a main-sequence mass M{sub Ms} ∼ 7 - 9.5M{sub ⊙}. The explosion takes place in accordance with core bounce and subsequent neutrino heating and is a unique example successfully produced by first-principle simulations. This allows us to derive a first self-consistent multicolor light curves of a core-collapse supernova. Adopting the explosion properties derived by the first-principle simulation, i.e., the low explosion energy of 1.5 × 10{sup 50} erg and the small {sup 56}Ni mass of 2.5 × 10{sup −3} M{sub ⊙}, we perform a multigroup radiation hydrodynamics calculation of ECSNe and present multicolor light curves of ECSNe of SAGB stars with various envelope mass and hydrogen abundance. We demonstrate that a shock breakout has peak luminosity of L ∼ 2 × 10{sup 44} erg s{sup −1} and can evaporate circumstellar dust up to R ∼ 10{sup 17} cm for a case of carbon dust, that plateau luminosity and plateau duration of ECSNe are L ∼ 10{sup 42} erg s{sup −1} and {sup t} ∼ 60 - 100 days, respectively, and that a plateau is followed by a tail with a luminosity drop by ∼ 4 mag. The ECSN shows a bright and short plateau that is as bright as typical Type II plateau supernovae, and a faint tail that might be influenced by spin-down luminosity of a newborn pulsar. Furthermore, the theoretical models are compared with ECSN candidates: SN 1054 and SN 2008S. We find that SN 1054 shares the characteristics of the ECSNe. For SN 2008S, we find that its faint plateau requires a ECSN model with a significantly low explosion energy of E ∼ 10{sup 48} erg.

  3. Effects of Ion Correlations in Supernovae and Neutron Star Crusts

    SciTech Connect

    Caballero, O. L.; Horowitz, C. J.

    2007-10-26

    Core-collapse supernovae are some of the most energetic explosions in the Universe. During the collapse 99 % of the energy is lost by neutrino emission. The dynamics of the explosion is highly sensitive to neutrino scattering from the stellar medium. We use molecular dynamics simulations to calculate ion structure factors, neutrino-nucleus scattering cross sections, and neutrino mean free paths. We find clear differences in the neutrino mean free path when the medium is composed of a mixture of ions compared with a medium composed of a single ion species.

  4. Supernova Remnants in High Definition

    NASA Astrophysics Data System (ADS)

    Slane, Patrick; Badenes, Carles; Freyer, Chris; Hughes, Jack; Lee, Herman Shiu-Hang; Lopez, Laura; Patnaude, Daniel; Reynolds, Steve; Temim, Tea; Williams, Brian; Wongwathanarat, Annop; Yamaguchi, Hiroya

    2015-10-01

    As the observable products of explosive stellar death, supernova remnants reveal some of the most direct information on the physics of the explosions, the properties of the progenitor systems, and the demographics of compact objects formed in the supernova events. High sensitivity X-ray observations have allowed us to probe the properties of the shocked plasma, providing constraints on abundances and ionization states that connect directly progenitor masses and metallicities, the nature of the explosions (core-collapse vs. thermonuclear), and the physics of shock heating and particle acceleration in fast shocks. Studies of SNRs in the Magellanic Clouds have provided information on source demographics in a low metallicity environment, and deep searches for point sources in Galactic SNRs imply that many remnants contain rapidly cooling neutron stars or black holes. Based on Chandra observations, we know that crucial measurements required to advance our knowledge in these areas are possible only with much more sensitive observations at high angular resolution. From identifying the effects of particle acceleration on the post-shock gas in young SNRs like Tycho to obtaining spatially resolved spectra - and identifying compact objects - for young SNRs in the Magellanic Clouds, the capabilities of a facility like the X-ray Surveyor are required. Here I present a summary of recent advances brought about by spectral investigations of SNRs, and discuss particular examples of new advances that will be enabled by X-ray Surveyor capabilities.

  5. Runaway Stars in Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Pannicke, Anna; Neuhaeuser, Ralph; Dinçel, Baha

    2016-07-01

    Half of all stars and in particular 70 % of the massive stars are a part of a multiple system. A possible development for the system after the core collapse supernova (SN) of the more massive component is as follows: The binary is disrupted by the SN. The formed neutron star is ejected by the SN kick whereas the companion star either remains within the system and is gravitationally bounded to the neutron star, or is ejected with a spatial velocity comparable to its former orbital velocity (up to 500 km/s). Such stars with a large peculiar space velocity are called runaway stars. We present our observational results of the supernova remnants (SNRs) G184.6-5.8, G74.0-8.5 and G119.5+10.2. The focus of this project lies on the detection of low mass runaway stars. We analyze the spectra of a number of candidates and discuss their possibility of being the former companions of the SN progenitor stars. The spectra were obtained with INT in Tenerife, Calar Alto Astronomical Observatory and the University Observatory Jena. Also we investigate the field stars in the neighborhood of the SNRs G74.0-8.5 and G119.5+10.2 and calculate more precise distances for these SNRs.

  6. Handbook of Supernovae

    NASA Astrophysics Data System (ADS)

    Athem Alsabti, Abdul

    2015-08-01

    Since the discovery of pulsars in 1967, few celestial phenomena have fascinated amateur and professional astronomers, and the public, more than supernovae - dying stars that explode spectacularly and, in so doing, may outshine a whole galaxy. Thousands of research papers, reviews, monographs and books have been published on this subject. These publications are often written either for a highly specific level of expertise or education, or with respect to a particular aspect of supernovae research. However, the study of supernovae is a very broad topic involving many integral yet connected aspects, including physics, mathematics, computation, history, theoretical studies and observation. More specifically, areas of study include historical supernovae, the different types and light curves, nucleosynthesis, explosion mechanisms, formation of black holes, neutron stars, cosmic rays, neutrinos and gravitational waves. Related questions include how supernovae remnants interact with interstellar matter nearby and how do these events affect the formation of new stars or planetary systems? Could they affect existing planetary systems? Closer to home, did any supernovae affect life on earth in the past or could they do so in the future? And on the larger scale, how did supernovae observations help measure the size and expansion of the universe? All these topics, and more, are to be covered in a new reference work, consisting of more than 100 articles and more than 1700 pages. It is intended to cover all the main facets of current supernovae research. It will be pitched at or above the level of a new postgraduate student, who will have successfully studied physics (or a similar scientific subject) to Bachelor degree level. It will be available in both print and electronic (updatable) formats, with the exception of the first section, which will consist of a review of all the topics of the handbook at a level that allows anyone with basic scientific knowledge to grasp the

  7. Rayleigh-Taylor mixing in supernova experiments

    NASA Astrophysics Data System (ADS)

    Swisher, N. C.; Kuranz, C. C.; Arnett, D.; Hurricane, O.; Remington, B. A.; Robey, H. F.; Abarzhi, S. I.

    2015-10-01

    We report a scrupulous analysis of data in supernova experiments that are conducted at high power laser facilities in order to study core-collapse supernova SN1987A. Parameters of the experimental system are properly scaled to investigate the interaction of a blast-wave with helium-hydrogen interface, and the induced Rayleigh-Taylor instability and Rayleigh-Taylor mixing of the denser and lighter fluids with time-dependent acceleration. We analyze all available experimental images of the Rayleigh-Taylor flow in supernova experiments and measure delicate features of the interfacial dynamics. A new scaling is identified for calibration of experimental data to enable their accurate analysis and comparisons. By properly accounting for the imprint of the experimental conditions, the data set size and statistics are substantially increased. New theoretical solutions are reported to describe asymptotic dynamics of Rayleigh-Taylor flow with time-dependent acceleration by applying theoretical analysis that considers symmetries and momentum transport. Good qualitative and quantitative agreement is achieved of the experimental data with the theory and simulations. Our study indicates that in supernova experiments Rayleigh-Taylor flow is in the mixing regime, the interface amplitude contributes substantially to the characteristic length scale for energy dissipation; Rayleigh-Taylor mixing keeps order.

  8. Rayleigh-Taylor mixing in supernova experiments

    NASA Astrophysics Data System (ADS)

    Swisher, Nora; Kuranz, Carolyn; Arnett, David; Hurricane, Omar; Remington, Bruce; Robey, Harry; Abarzhi, Snezhana

    2015-11-01

    We report a scrupulous analysis of data in supernova experiments that are conducted at high power laser facilities in order to study core-collapse supernova SN1987A. Parameters of the experimental system are properly scaled to investigate the interaction of a blast-wave with helium-hydrogen interface, and the induced Rayleigh-Taylor (RT) mixing of the denser and lighter fluids with time-dependent acceleration. We analyze all available experimental images of RT flow in supernova experiments, and measure delicate features of the interfacial dynamics. A new scaling is identified for calibration of experimental data to enable their accurate analysis and comparisons. By proper accounting for the imprint of the experimental conditions, the data set size and statistics are substantially increased. New theoretical solutions are identified to describe asymptotic dynamics of RT flow with time-dependent acceleration by applying theoretical analysis. Good qualitative and quantitative agreement is achieved of the experimental data with the theory and simulations. Our study indicates that in supernova experiments, the RT flow is in the mixing regime, the interface amplitude contributes substantially to the characteristic length scale for energy dissipation; the mixing flow may keep order. Support of the National Science Foundation is warmly appreciated.

  9. Rayleigh-Taylor mixing in supernova experiments

    SciTech Connect

    Swisher, N. C.; Abarzhi, S. I.; Kuranz, C. C.; Arnett, D.; Hurricane, O.; Remington, B. A.; Robey, H. F.

    2015-10-15

    We report a scrupulous analysis of data in supernova experiments that are conducted at high power laser facilities in order to study core-collapse supernova SN1987A. Parameters of the experimental system are properly scaled to investigate the interaction of a blast-wave with helium-hydrogen interface, and the induced Rayleigh-Taylor instability and Rayleigh-Taylor mixing of the denser and lighter fluids with time-dependent acceleration. We analyze all available experimental images of the Rayleigh-Taylor flow in supernova experiments and measure delicate features of the interfacial dynamics. A new scaling is identified for calibration of experimental data to enable their accurate analysis and comparisons. By properly accounting for the imprint of the experimental conditions, the data set size and statistics are substantially increased. New theoretical solutions are reported to describe asymptotic dynamics of Rayleigh-Taylor flow with time-dependent acceleration by applying theoretical analysis that considers symmetries and momentum transport. Good qualitative and quantitative agreement is achieved of the experimental data with the theory and simulations. Our study indicates that in supernova experiments Rayleigh-Taylor flow is in the mixing regime, the interface amplitude contributes substantially to the characteristic length scale for energy dissipation; Rayleigh-Taylor mixing keeps order.

  10. Supernova 1987A: 18 months later

    NASA Technical Reports Server (NTRS)

    Schramm, David N.

    1989-01-01

    An overview of the significance for physics of the closest visual supernova in almost 400 years is presented. The supernova occurred in the Large Magellanic Cloud (LMC), approx. 50 kpc away. The supernova star was a massive star of approx. 15 to 20 solar mass. Observations now show that it was once a red giant but lost its outer envelope. The lower than standard luminosity and higher observed velocities are a natural consequence of the pre-supernova star being a blue rather than a red (supergiant). Of particular importance to physicsts is the detection of neutrinos from the event by detectors in the United States and Japan. Not only did this establish extra-solar system neutrino astronomy, but it also constrained the properties of neutrino. It is shown that the well established Kamioka-IMB neutrino burst experimentally implies an event with about 2 to 4 x 10 to the 53rd power ergs emitted in neutrinos and a temperature, T sub nu e, of between 4 and 4.5 MeV. This event is in excellent agreement with what one would expect from the gravitational core collapse of a massive star. The anticipated frequency of collapse events in our Galaxy is discussed.

  11. THE ANGULAR MOMENTA OF NEUTRON STARS AND BLACK HOLES AS A WINDOW ON SUPERNOVAE

    SciTech Connect

    Miller, J. M.; Miller, M. C.; Reynolds, C. S.

    2011-04-10

    It is now clear that a subset of supernovae displays evidence for jets and is observed as gamma-ray bursts (GRBs). The angular momentum distribution of massive stellar endpoints provides a rare means of constraining the nature of the central engine in core-collapse explosions. Unlike supermassive black holes, the spin of stellar-mass black holes in X-ray binary systems is little affected by accretion and accurately reflects the spin set at birth. A modest number of stellar-mass black hole angular momenta have now been measured using two independent X-ray spectroscopic techniques. In contrast, rotation-powered pulsars spin down over time, via magnetic braking, but a modest number of natal spin periods have now been estimated. For both canonical and extreme neutron star parameters, statistical tests strongly suggest that the angular momentum distributions of black holes and neutron stars are markedly different. Within the context of prevalent models for core-collapse supernovae, the angular momentum distributions are consistent with black holes typically being produced in GRB-like supernovae with jets and with neutron stars typically being produced in supernovae with too little angular momentum to produce jets via magnetohydrodynamic processes. It is possible that neutron stars are with high spin initially and rapidly spun down shortly after the supernova event, but the available mechanisms may be inconsistent with some observed pulsar properties.

  12. A Comprehensive Investigation Into Modeling Supernovae Spectra

    NASA Astrophysics Data System (ADS)

    Hillier, Desmond

    Supernovae are a rich source of information. By studying their light curves and spectra we gain insights into stellar evolution, the nature of the progenitor star, surface abundances at the time of the explosion, whether previous mass-loss episodes have occurred, the physics of the explosion including the amount and type of elements synthesized, and whether the explosion has produced significant mixing between shells of different chemical composition. To maximize the information that can be gleaned from observations of supernovae it is essential that we have the necessary spectroscopic tools. To this end, we are developing a code, CMFGEN, capable of modeling supernova light curves and spectra. The code is currently being used, to study core-collapse supernovae as well as those arising from the nuclear detonation of a White Dwarf star. We wish to extend CMFGEN's capabilities by developing a procedure to handle non-monotonic velocity flows so that we can treat shock breakout and the interaction of supernova ejecta with circumstellar material. We will also investigate magnetar-powered SNe, and explore the connection between Type Ib and Type Ic supernovae and those supernovae associated with long-duration gamma-ray bursters. Through detailed studies of individual supernova, and through the construction of model grids, we are able to infer deficiencies in our modeling, in our atomic data, and in the progenitor models, and hence make refinements so that we can improve our understanding of all SNe classes. Previous (IUE), current (HST, Chandra, GALEX), and future NASA missions (James Webb Telescope) do/will provide a wealth of data on supernovae. The proposed research is related to strategic subgoal 3D: "Discover the origin, structure, evolution, and destiny of the universe, and search for Earth-like planets." Supernovae are inherently coupled to the evolution of the universe and life: They can trigger star formation and they provide the raw materials (e.g., oxygen

  13. Discovery of Two Supernovae in the Nuclear Regions of the Luminous Infrared Galaxy IC 883

    NASA Astrophysics Data System (ADS)

    Kankare, E.; Mattila, S.; Ryder, S.; Väisänen, P.; Alberdi, A.; Alonso-Herrero, A.; Colina, L.; Efstathiou, A.; Kotilainen, J.; Melinder, J.; Pérez-Torres, M.-A.; Romero-Cañizales, C.; Takalo, A.

    2012-01-01

    We report the discovery of two consecutive supernovae (SNe), 2010cu and 2011hi, located at 0farcs37 (180 pc) and 0farcs79 (380 pc) projected distance, respectively, from the center of the K-band nucleus of the luminous infrared galaxy (LIRG) IC 883. The SNe were discovered in an ongoing near-infrared K-band search for core-collapse SNe in such galaxies using the ALTAIR/NIRI adaptive optics system with laser guide star at the Gemini-North Telescope. These are thus the closest SNe yet discovered to an LIRG nucleus in optical or near-infrared wavelengths. The near-infrared light curves and colors of both SNe are consistent with core-collapse events. Both SNe seem to suffer from relatively low host galaxy extinction suggesting that regardless of their low projected galactocentric distances, they are not deeply buried in the nuclear regions of the host galaxy.

  14. Luminous blue variables and superluminous supernovae from binary mergers

    SciTech Connect

    Justham, Stephen; Podsiadlowski, Philipp; Vink, Jorick S. E-mail: podsi@astro.ox.ac.uk

    2014-12-01

    Evidence suggests that the direct progenitor stars of some core-collapse supernovae (CCSNe) are luminous blue variables (LBVs), perhaps including some Type II 'superluminous supernovae' (SLSNe). We examine models in which massive stars gain mass soon after the end of core hydrogen burning. These are mainly intended to represent mergers following a brief contact phase during early Case B mass transfer, but may also represent stars which gain mass in the Hertzsprung Gap or extremely late during the main-sequence phase for other reasons. The post-accretion stars spend their core helium-burning phase as blue supergiants (BSGs), and many examples are consistent with being LBVs at the time of core collapse. Other examples are yellow supergiants at explosion. We also investigate whether such post-accretion stars may explode successfully after core collapse. The final core properties of post-accretion models are broadly similar to those of single stars with the same initial mass as the pre-merger primary star. More surprisingly, when early Case B accretion does affect the final core properties, the effect appears likely to favor a successful SN explosion, i.e., to make the core properties more like those of a lower-mass single star. However, the detailed structures of these cores sometimes display qualitative differences to any single-star model we have calculated. The rate of appropriate binary mergers may match the rate of SNe with immediate LBV progenitors; for moderately optimistic assumptions we estimate that the progenitor birthrate is ∼1% of the CCSN rate.

  15. Role of nucleon strangeness in supernova explosions

    NASA Astrophysics Data System (ADS)

    Hobbs, T. J.; Alberg, Mary; Miller, Gerald A.

    2016-05-01

    Recent hydrodynamical simulations of core-collapse supernova (CCSN) evolution have highlighted the importance of thorough control over the microscopic physics responsible for such internal processes as neutrino heating. In particular, it has been suggested that modifications to the neutrino-nucleon elastic cross section can potentially play a crucial role in producing successful CCSN explosions. One possible source of such corrections can be found in a nonzero value for the nucleon's strange helicity content Δ s . In the present analysis, however, we show that theoretical and experimental progress over the past decade has suggested a comparatively small magnitude for Δ s , such that its sole effect is not sufficient to provide the physics leading to CCSN explosions.

  16. SUPERNOVA SIMULATIONS AND STRATEGIES FOR THE DARK ENERGY SURVEY

    SciTech Connect

    Bernstein, J. P.; Kuhlmann, S.; Biswas, R.; Kovacs, E.; Crane, I.; Hufford, T.; Kessler, R.; Frieman, J. A.; Aldering, G.; Kim, A. G.; Nugent, P.; D'Andrea, C. B.; Nichol, R. C.; Finley, D. A.; Marriner, J.; Reis, R. R. R.; Jarvis, M. J.; Mukherjee, P.; Parkinson, D.; Sako, M.; and others

    2012-07-10

    We present an analysis of supernova light curves simulated for the upcoming Dark Energy Survey (DES) supernova search. The simulations employ a code suite that generates and fits realistic light curves in order to obtain distance modulus/redshift pairs that are passed to a cosmology fitter. We investigated several different survey strategies including field selection, supernova selection biases, and photometric redshift measurements. Using the results of this study, we chose a 30 deg{sup 2} search area in the griz filter set. We forecast (1) that this survey will provide a homogeneous sample of up to 4000 Type Ia supernovae in the redshift range 0.05 supernova with an identified host galaxy will be obtained from spectroscopic observations of the host. A supernova spectrum will be obtained for a subset of the sample, which will be utilized for control studies. In addition, we have investigated the use of combined photometric redshifts taking into account data from both the host and supernova. We have investigated and estimated the likely contamination from core-collapse supernovae based on photometric identification, and have found that a Type Ia supernova sample purity of up to 98% is obtainable given specific assumptions. Furthermore, we present systematic uncertainties due to sample purity, photometric calibration, dust extinction priors, filter-centroid shifts, and inter-calibration. We conclude by estimating the uncertainty on the cosmological parameters that will be measured from the DES supernova data.

  17. Sloan Digital Sky Survey II (SDSS-II) Supernova Data

    DOE Data Explorer

    The Sloan Digital Sky Survey (SDSS) is a series of three interlocking imaging and spectroscopic surveys, carried out over an eight-year period with a dedicated 2.5m telescope located at Apache Point Observatory in Southern New Mexico. The SDSS Supernova Survey was one of those three components of SDSS and SDSS-II, a 3-year extension of the original SDSS that operated from July 2005 to July 2008. The Supernova Survey was a time-domain survey, involving repeat imaging of the same region of sky every other night, weather permitting. The primary scientific motivation was to detect and measure light curves for several hundred supernovae through repeat scans of the SDSS Southern equatorial stripe 82 (about 2.5? wide by ~120? long). Over the course of three 3-month campaigns SDSS-II SN discovered and measured multi-band lightcurves for ~500 spectroscopically confirmed Type Ia supernovae in the redshift range z=0.05-0.4. In addition, the project harvested a few hundred light curves for SNe Ia and discovered about 80 spectroscopically confirmed core-collapse supernovae (supernova types Ib/c and II).

  18. Frontier Field Supernova Search

    NASA Astrophysics Data System (ADS)

    Rodney, Steven

    2014-10-01

    The Frontier Fields program presents an extraordinary opportunity for the detection of high redshift supernovae (SNe). The combination of very deep imaging in each epoch with the added boost from gravitational lensing magnification will provide the means to detect both Type Ia SNe (SNIa) and core collapse SNe (CC SNe) out to z~3. We propose to capitalize on this unique new asset by processing and searching all of the Frontier Field data, and then triggering ToO follow-up observations for SNe of interest.We expect to discover ~20 new SNe over the entire 3-year program, including ~5 SNIa at z>1.5 and ~6 with strong lensing magnification. These samples are small but special: the high-z SNIa set has unique leverage for testing SNIa progenitor models through the delay time distribution; the lensed SNIa offer a chance to validate cluster mass models by directly measuring the lensing magnification. We will also be able to extend CCSN rate measurements for the first time beyond z~1, and our search will open up the small but exciting possibility of catching a truly rare event such as a multiply imaged SN or a superluminous SN at z>4.This follow-up program provides the color and light curve information necessary to unlock the science potential of these SNe. It is also designed for high efficiency: broad-band photometry and ground-based spectroscopy will be used to classify and characterize most of the SNe. For a small "New Frontier" sub-set comprising the SNIa candidates at never-before-seen redshifts, we will employ a novel medium band IR imaging strategy. All told, this program will classify and characterize all SNe of interest with just 60 orbits across 3 cycles.

  19. Frontier Field Supernova Search

    NASA Astrophysics Data System (ADS)

    Rodney, Steven

    2013-10-01

    The Frontier Fields program presents an extraordinary opportunity for the detection of high redshift supernovae (SNe). The combination of very deep imaging in each epoch with the added boost from gravitational lensing magnification will provide the means to detect both Type Ia SNe (SNIa) and core collapse SNe (CC SNe) out to z~3. We propose to capitalize on this unique new asset by processing and searching all of the Frontier Field data, and then triggering ToO follow-up observations for SNe of interest.We expect to discover ~20 new SNe over the entire 3-year program, including ~5 SNIa at z>1.5 and ~6 with strong lensing magnification. These samples are small but special: the high-z SNIa set has unique leverage for testing SNIa progenitor models through the delay time distribution; the lensed SNIa offer a chance to validate cluster mass models by directly measuring the lensing magnification. We will also be able to extend CCSN rate measurements for the first time beyond z~1, and our search will open up the small but exciting possibility of catching a truly rare event such as a multiply imaged SN or a superluminous SN at z>4.This follow-up program provides the color and light curve information necessary to unlock the science potential of these SNe. It is also designed for high efficiency: broad-band photometry and ground-based spectroscopy will be used to classify and characterize most of the SNe. For a small "New Frontier" sub-set comprising the SNIa candidates at never-before-seen redshifts, we will employ a novel medium band IR imaging strategy. All told, this program will classify and characterize all SNe of interest with just 60 orbits across 3 cycles.

  20. A very energetic supernova associated with the gamma-ray burst of 29 March 2003.

    PubMed

    Hjorth, Jens; Sollerman, Jesper; Møller, Palle; Fynbo, Johan P U; Woosley, Stan E; Kouveliotou, Chryssa; Tanvir, Nial R; Greiner, Jochen; Andersen, Michael I; Castro-Tirado, Alberto J; Castro Cerón, José María; Fruchter, Andrew S; Gorosabel, Javier; Jakobsson, Páll; Kaper, Lex; Klose, Sylvio; Masetti, Nicola; Pedersen, Holger; Pedersen, Kristian; Pian, Elena; Palazzi, Eliana; Rhoads, James E; Rol, Evert; van den Heuvel, Edward P J; Vreeswijk, Paul M; Watson, Darach; Wijers, Ralph A M J

    2003-06-19

    Over the past five years evidence has mounted that long-duration (>2 s) gamma-ray bursts (GRBs)-the most luminous of all astronomical explosions-signal the collapse of massive stars in our Universe. This evidence was originally based on the probable association of one unusual GRB with a supernova, but now includes the association of GRBs with regions of massive star formation in distant galaxies, the appearance of supernova-like 'bumps' in the optical afterglow light curves of several bursts and lines of freshly synthesized elements in the spectra of a few X-ray afterglows. These observations support, but do not yet conclusively demonstrate, the idea that long-duration GRBs are associated with the deaths of massive stars, presumably arising from core collapse. Here we report evidence that a very energetic supernova (a hypernova) was temporally and spatially coincident with a GRB at redshift z = 0.1685. The timing of the supernova indicates that it exploded within a few days of the GRB, strongly suggesting that core-collapse events can give rise to GRBs, thereby favouring the 'collapsar' model.

  1. A massive star origin for an unusual helium-rich supernova in an elliptical galaxy.

    PubMed

    Kawabata, K S; Maeda, K; Nomoto, K; Taubenberger, S; Tanaka, M; Deng, J; Pian, E; Hattori, T; Itagaki, K

    2010-05-20

    The unusual helium-rich (type Ib) supernova SN 2005E is distinguished from all supernovae hitherto observed by its faint and rapidly fading light curve, prominent calcium lines in late-phase spectra and lack of any mark of recent star formation near the supernova location. These properties are claimed to be explained by a helium detonation in a thin surface layer of an accreting white dwarf. Here we report that the observed properties of SN 2005cz, which appeared in an elliptical galaxy, resemble those of SN 2005E. We argue that these properties are best explained by a core-collapse supernova at the low-mass end (8-12 solar masses) of the range of massive stars that explode. Such a low-mass progenitor lost its hydrogen-rich envelope through binary interaction, had very thin oxygen-rich and silicon-rich layers above the collapsing core, and accordingly ejected a very small amount of radioactive (56)Ni and oxygen. Although the host galaxy NGC 4589 is an elliptical, some studies have revealed evidence of recent star-formation activity, consistent with the core-collapse model. PMID:20485430

  2. Sensitivity of neutrinos to the supernova turbulence power spectrum: Point source statistics

    SciTech Connect

    Kneller, James P.; Kabadi, Neel V.

    2015-07-16

    The neutrinos emitted from the proto-neutron star created in a core-collapse supernova must run through a significant amount of turbulence before exiting the star. Turbulence can modify the flavor evolution of the neutrinos imprinting itself upon the signal detected here at Earth. The turbulence effect upon individual neutrinos, and the correlation between pairs of neutrinos, might exhibit sensitivity to the power spectrum of the turbulence, and recent analysis of the turbulence in a two-dimensional hydrodynamical simulation of a core-collapse supernova indicates the power spectrum may not be the Kolmogorov 5 /3 inverse power law as has been previously assumed. In this paper we study the effect of non-Kolmogorov turbulence power spectra upon neutrinos from a point source as a function of neutrino energy and turbulence amplitude at a fixed postbounce epoch. We find the two effects of turbulence upon the neutrinos—the distorted phase effect and the stimulated transitions—both possess strong and weak limits in which dependence upon the power spectrum is absent or evident, respectively. Furthermore, since neutrinos of a given energy will exhibit these two effects at different epochs of the supernova each with evolving strength, we find there is sensitivity to the power spectrum present in the neutrino burst signal from a Galactic supernova.

  3. Sensitivity of neutrinos to the supernova turbulence power spectrum: Point source statistics

    DOE PAGES

    Kneller, James P.; Kabadi, Neel V.

    2015-07-16

    The neutrinos emitted from the proto-neutron star created in a core-collapse supernova must run through a significant amount of turbulence before exiting the star. Turbulence can modify the flavor evolution of the neutrinos imprinting itself upon the signal detected here at Earth. The turbulence effect upon individual neutrinos, and the correlation between pairs of neutrinos, might exhibit sensitivity to the power spectrum of the turbulence, and recent analysis of the turbulence in a two-dimensional hydrodynamical simulation of a core-collapse supernova indicates the power spectrum may not be the Kolmogorov 5 /3 inverse power law as has been previously assumed. Inmore » this paper we study the effect of non-Kolmogorov turbulence power spectra upon neutrinos from a point source as a function of neutrino energy and turbulence amplitude at a fixed postbounce epoch. We find the two effects of turbulence upon the neutrinos—the distorted phase effect and the stimulated transitions—both possess strong and weak limits in which dependence upon the power spectrum is absent or evident, respectively. Furthermore, since neutrinos of a given energy will exhibit these two effects at different epochs of the supernova each with evolving strength, we find there is sensitivity to the power spectrum present in the neutrino burst signal from a Galactic supernova.« less

  4. A massive star origin for an unusual helium-rich supernova in an elliptical galaxy.

    PubMed

    Kawabata, K S; Maeda, K; Nomoto, K; Taubenberger, S; Tanaka, M; Deng, J; Pian, E; Hattori, T; Itagaki, K

    2010-05-20

    The unusual helium-rich (type Ib) supernova SN 2005E is distinguished from all supernovae hitherto observed by its faint and rapidly fading light curve, prominent calcium lines in late-phase spectra and lack of any mark of recent star formation near the supernova locat