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Sample records for p-process supernova dynamics

  1. Impact of Supernova Dynamics on the νp-process

    NASA Astrophysics Data System (ADS)

    Arcones, A.; Fröhlich, C.; Martínez-Pinedo, G.

    2012-05-01

    We study the impact of the late-time dynamical evolution of ejecta from core-collapse supernovae on νp-process nucleosynthesis. Our results are based on hydrodynamical simulations of neutrino-driven wind ejecta. Motivated by recent two-dimensional wind simulations, we vary the dynamical evolution during the νp-process and show that final abundances strongly depend on the temperature evolution. When the expansion is very fast, there is not enough time for antineutrino absorption on protons to produce enough neutrons to overcome the β+-decay waiting points and no heavy elements beyond A = 64 are produced. The wind termination shock or reverse shock dramatically reduces the expansion speed of the ejecta. This extends the period during which matter remains at relatively high temperatures and is exposed to high neutrino fluxes, thus allowing for further (p, γ) and (n, p) reactions to occur and to synthesize elements beyond iron. We find that the νp-process starts to efficiently produce heavy elements only when the temperature drops below ~3 GK. At higher temperatures, due to the low alpha separation energy of 60Zn (S α = 2.7 MeV) the reaction 59Cu(p, α)56Ni is faster than the reaction 59Cu(p, γ)60Zn. This results in the closed NiCu cycle that we identify and discuss here for the first time. We also investigate the late phase of the νp-process when the temperatures become too low to maintain proton captures. Depending on the late neutron density, the evolution to stability is dominated by β+ decays or by (n, γ) reactions. In the latter case, the matter flow can even reach the neutron-rich side of stability and the isotopic composition of a given element is then dominated by neutron-rich isotopes.

  2. 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.

  3. Dynamics of Kepler's supernova remnant

    NASA Technical Reports Server (NTRS)

    Borkowski, Kazimierz J.; Blondin, John M.; Sarazin, Craig L.

    1992-01-01

    Observations of Kepler's SNR have revealed a strong interaction with the ambient medium, far in excess of that expected at a distance of about 600 pc away from the Galactic plane where Kepler's SNR is located. This has been interpreted as a result of the interaction of supernova ejecta with the dense circumstellar medium (CSM). Based on the bow-shock model of Bandiera (1985), we study the dynamics of this interaction. The CSM distribution consists of an undisturbed stellar wind of a moving supernova progenitor and a dense shell formed in its interaction with a tenuous interstellar medium. Supernova ejecta drive a blast wave through the stellar wind which splits into the transmitted and reflected shocks upon hitting this bow-shock shell. We identify the transmitted shock with the nonradiative, Balmer-dominated shocks found recently in Kepler's SNR. The transmitted shock most probably penetrated the shell in the vicinity of the stagnation point.

  4. Dynamics of Kepler's supernova remnant

    NASA Technical Reports Server (NTRS)

    Borkowski, Kazimierz J.; Blondin, John M.; Sarazin, Craig L.

    1992-01-01

    Observations of Kepler's SNR have revealed a strong interaction with the ambient medium, far in excess of that expected at a distance of about 600 pc away from the Galactic plane where Kepler's SNR is located. This has been interpreted as a result of the interaction of supernova ejecta with the dense circumstellar medium (CSM). Based on the bow-shock model of Bandiera (1985), we study the dynamics of this interaction. The CSM distribution consists of an undisturbed stellar wind of a moving supernova progenitor and a dense shell formed in its interaction with a tenuous interstellar medium. Supernova ejecta drive a blast wave through the stellar wind which splits into the transmitted and reflected shocks upon hitting this bow-shock shell. We identify the transmitted shock with the nonradiative, Balmer-dominated shocks found recently in Kepler's SNR. The transmitted shock most probably penetrated the shell in the vicinity of the stagnation point.

  5. Composition of the Innermost Core Collapse Supernova Ejecta and the νp-Process

    NASA Astrophysics Data System (ADS)

    Fröhlich, C.; Liebendörfer, M.; Martínez-Pinedo, G.; Thielemann, F.-K.; Bravo, E.; Zinner, N. T.; Hix, W. R.; Langanke, K.; Mezzacappa, A.; Nomoto, K.

    2006-07-01

    With presently known input physics and computer simulations in 1D, a self-consistent treatment of core collapse supernovae does not lead to explosions, while 2D models show some promise. Thus, there are strong indications that the delayed neutrino mechanism works combined with a multi-D convection treatment for unstable layers. On the other hand there is a need to provide correct nucleosynthesis abundances for the progressing field of galactic evolution and observations of low metallicity stars. The innermost ejecta is directly affected by the explosion mechanism, i.e. most strongly the yields of Fe-group nuclei for which an induced piston or thermal bomb treatment will not provide the correct yields because the effect of neutrino interactions is not included. We apply parameterized variations to the neutrino scattering cross sections and alternatively, parameterized variations to the neutrino absorption cross sections on nucleons in the ``gain region''. We find that both measures lead to similar results, causing explosions and a Ye larger than 0.5 in the innermost ejected layers, due to the combined effect of a short weak interaction time scale and a negligible electron degeneracy, unveiling the proton-neutron mass difference. The proton-rich environment results in enhanced abundances of 45Sc, 49Ti, and 64Zn as requested by chemical evolution studies and observations of low metallicity stars. Moreover, antineutrino capture on the free protons allows for an appreciable production of nuclei in the mass range up to A = 80 by the νp-process.

  6. The p-Process in the Carbon Deflagration Model for Type Ia Supernovae and Chronology of the Solar System Formation

    SciTech Connect

    Kusakabe, Motohiko; Iwamoto, Nobuyuki; Nomoto, Ken'ichi

    2006-07-12

    We study nucleosynthesis of p-nuclei in the carbon deflagration model for Type Ia supernovae (SNe Ia) by assuming that seed nuclei are produced by the s-process in accreting layers on a carbon-oxygen white dwarf during mass accretion from a binary companion. We find that about 50 % of the p-nuclides are synthesized in proportion to the solar abundance and that p-isotopes of Mo and Ru which are significantly underproduced in Type II supernovae (SNe II) are produced up to a level close to other p-nuclei. Comparing the yields of iron and p-nuclei in SNe Ia we find that SNe Ia can contribute to the galactic evolution of the p-nuclei. Next, we consider nucleochronology of the solar system formation by using four radioactive nuclides and apply the result of the p-process nucleosynthesis to simple galactic chemical evolution models. We find that when assumed three phases of interstellar medium are mixed by the interdiffusion with the timescale of about 40 Myr 53Mn/55Mn value in the early solar system is consistent with a meteoritic value. In addition, we put constraints to a scenario that SNe Ia induce the core collapse of the molecular cloud, which leads to the formation of the solar system.

  7. PRODUCTION OF THE p-PROCESS NUCLEI IN THE CARBON-DEFLAGRATION MODEL FOR TYPE Ia SUPERNOVAE

    SciTech Connect

    Kusakabe, Motohiko; Iwamoto, Nobuyuki; Nomoto, Ken'ichi E-mail: iwamoto.nobuyuki@jaea.go.jp

    2011-01-01

    We calculate the nucleosynthesis of proton-rich isotopes in the carbon-deflagration model for Type Ia supernovae (SNe Ia). The seed abundances are obtained by calculating the s-process nucleosynthesis that is expected to occur in the repeating helium shell flashes on the carbon-oxygen (CO) white dwarf (WD) during mass accretion from a binary companion. When the deflagration wave passes through the outer layer of the CO WD, p-nuclei are produced by photodisintegration reactions on s-nuclei in a region where the peak temperature ranges from 1.9 to 3.6 x 10{sup 9} K. We confirm the sensitivity of the p-process on the initial distribution of s-nuclei. We show that the initial C/O ratio in the WD does not affect much the yield of p-nuclei. On the other hand, the abundance of {sup 22}Ne left after s-processing has a large influence on the p-process via the {sup 22}Ne({alpha},n) reaction. We find that about 50% of p-nuclides are co-produced when normalized to their solar abundances in all adopted cases of seed distribution. Mo and Ru, which are largely underproduced in Type II supernovae (SNe II), are produced more than in SNe II although they are underproduced with respect to the yield levels of other p-nuclides. The ratios between p-nuclei and iron in the ejecta are larger than the solar ratios by a factor of 1.2. We also compare the yields of oxygen, iron, and p-nuclides in SNe Ia and SNe II and suggest that SNe Ia could make a larger contribution than SNe II to the solar system content of p-nuclei.

  8. TYPE Ia SUPERNOVAE AS SITES OF THE p-PROCESS: TWO-DIMENSIONAL MODELS COUPLED TO NUCLEOSYNTHESIS

    SciTech Connect

    Travaglio, C.; Gallino, R.; Roepke, F. K.; Hillebrandt, W. E-mail: claudia.travaglio@b2fh.org

    2011-10-01

    Beyond Fe, there is a class of 35 proton-rich nuclides, between {sup 74}Se and {sup 196}Hg, called p-nuclei. They are bypassed by the s and r neutron capture processes and are typically 10-1000 times less abundant than the s- and/or r-isotopes in the solar system. The bulk of p-isotopes is created in the 'gamma processes' by sequences of photodisintegrations and beta decays in explosive conditions in both core collapse supernovae (SNe II) and in Type Ia supernovae (SNe Ia). SNe II contribute to the production of p-nuclei through explosive neon and oxygen burning. However, the major problem in SN II ejecta is a general underproduction of the light p-nuclei for A < 120. We explore SNe Ia as p-process sites in the framework of a two-dimensional SN Ia delayed detonation model as well as pure deflagration models. The white dwarf precursor is assumed to have reached the Chandrasekhar mass in a binary system by mass accretion from a giant/main-sequence companion. We use enhanced s-seed distributions, with seeds directly obtained from a sequence of thermal pulse instabilities both in the asymptotic giant branch phase and in the accreted material. We apply the tracer-particle method to reconstruct the nucleosynthesis by the thermal histories of Lagrangian particles, passively advected in the hydrodynamic calculations. For each particle, we follow the explosive nucleosynthesis with a detailed nuclear reaction network for all isotopes up to {sup 209}Bi. We select tracers within the typical temperature range for p-process production, (1.5-3.7) x 10{sup 9} K, and analyze in detail their behavior, exploring the influence of different s-process distributions on the p-process nucleosynthesis. In addition, we discuss the sensitivity of p-process production to parameters of the explosion mechanism, taking into account the consequences on Fe and alpha elements. We find that SNe Ia can produce a large amount of p-nuclei, both the light p-nuclei below A = 120 and the heavy-p nuclei, at

  9. Possible effects of collective neutrino oscillations in three-flavor multiangle simulations of supernova ν p processes

    NASA Astrophysics Data System (ADS)

    Sasaki, H.; Kajino, T.; Takiwaki, T.; Hayakawa, T.; Balantekin, A. B.; Pehlivan, Y.

    2017-08-01

    We study the effects of collective neutrino oscillations on ν p process nucleosynthesis in proton-rich neutrino-driven winds by including both the multiangle 3 ×3 flavor mixing and the nucleosynthesis network calculation. The number flux of energetic electron antineutrinos is raised by collective neutrino oscillations in a 1D supernova model for the 40 M⊙ progenitor. When the gas temperature decreases down to ˜2 - 3 ×109 K , the increased flux of electron antineutrinos promotes the ν p process more actively, resulting in the enhancement of p -nuclei. In the early phase of neutrino-driven wind, blowing at 0.6 s after core bounce, oscillation effects are prominent in inverted mass hierarchy and p -nuclei are synthesized up to 106Cd and 108Cd. On the other hand, in the later wind trajectory at 1.1 s after core bounce, abundances of p -nuclei are increased remarkably by ˜10 - 104 times in normal mass hierarchy and even reaching heavier p -nuclei such as 124Xe, 126Xe and 130Ba. The averaged overproduction factor of p -nuclei is dominated by the later wind trajectories. Our results demonstrate that collective neutrino oscillations can strongly influence the ν p process, which indicates that they should be included in the network calculations in order to obtain precise abundances of p -nuclei. The conclusions of this paper depend on the difference of initial neutrino parameters between electron and nonelectron antineutrino flavors which is large in our case. Further systematic studies on input neutrino physics and wind trajectories are necessary to draw a robust conclusion. However, this finding would help understand the origin of solar-system isotopic abundances of p -nuclei such as Mo,9492 and Ru,9896 .

  10. Fluid dynamics nature of supernova remnant (Crab Nebula)

    NASA Astrophysics Data System (ADS)

    Estakhr, Ahmad Reza

    2015-04-01

    Supernova remnant (at early phase) is a high temperature fluid of gas and dust. after the explosion of a star in a supernova, the viscousity of supernova remnant changes with temperature. as supernova expand by time its temperature decreases and the viscousity increases, (or alternatively, the fluidity of supernova remnant tends to decreases) and leb to resistance phase of supernova remnant fluid to flow. Uμ = γ (c , u (r-> , t)) denotes four-velocity vector field of supernova. Jμ = ρUμ denotes four-current density of supernova fluid of gas and dust. Estakhr's Material-Geodesic equation is developed analogy of Navier Stokes equation and Einstein Geodesic equation to describe Fluid dynamics nature of supernova remnant (Crab Nebula): DJμ/Dτ =dJμ/Dτ + ΓαβμJαUβ =JνΩμν +∂νTμν + ΓαβμJαUβ Covariant formulation of Fluid dynamics nature of supernova remnant, describe the motion of fluid substances of supernova.

  11. Dynamical collective calculation of supernova neutrino signals.

    PubMed

    Gava, Jérôme; Kneller, James; Volpe, Cristina; McLaughlin, G C

    2009-08-14

    We present the first calculations with three flavors of collective and shock wave effects for neutrino propagation in core-collapse supernovae using hydrodynamical density profiles and the S matrix formalism. We explore the interplay between the neutrino-neutrino interaction and the effects of multiple resonances upon the time signal of positrons in supernova observatories. A specific signature is found for the inverted hierarchy and a large third neutrino mixing angle and we predict, in this case, a dearth of lower energy positrons in Cherenkov detectors midway through the neutrino signal and the simultaneous revelation of valuable information about the original fluxes. We show that this feature is also observable with current generation neutrino detectors at the level of several sigmas.

  12. Neutrino-nucleus reactions and their role in supernova dynamics and nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Langanke, K.; Martinez-Pinedo, Gabriel

    2017-06-01

    Neutrino reactions on nuclei play important roles for the dynamics of supernovae and their associated nucleosyn-thesis. This manuscript summarizes the current status in deriving the relevant cross sections for supernova neutrinos and brielly discusses a few recent advances in supernova simulations where these reactions play a role.

  13. The dynamical and radiative evolution of clumpy supernova ejecta

    NASA Technical Reports Server (NTRS)

    Anderson, M. C.; Jones, T. W.; Rudnick, L.; Tregillis, I. L.; Kang, Hyesung

    1994-01-01

    Numerical simulations describing the dynamical and radiative evolution of clumpy supernova ejecta are compared with observations of optical and radio emission knots in supernova remnant (SNR) Cassiopeia A. Three major phases are identified in the evolution of clumpy ejecta: a bow-shock phase, an instability phase, and a dispersal phase. The phenomenological and radiative signatures of each phase are discussed and compared with multi-epoch measurements of small-scale features in Cas A. Good correspondence is found between theory and observations. Both support the premise that compact radio emission features are controlled more by magnetic field amplification triggered in the instability phase than by in situ acceleration of new relativistic particles.

  14. 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.

  15. Supernova feedback in molecular clouds: global evolution and dynamics

    NASA Astrophysics Data System (ADS)

    Körtgen, Bastian; Seifried, Daniel; Banerjee, Robi; Vázquez-Semadeni, Enrique; Zamora-Avilés, Manuel

    2016-07-01

    We use magnetohydrodynamical simulations of converging warm neutral medium flows to analyse the formation and global evolution of magnetized and turbulent molecular clouds subject to supernova feedback from massive stars. We show that supernova feedback alone fails to disrupt entire, gravitationally bound, molecular clouds, but is able to disperse small-sized (˜10 pc) regions on time-scales of less than 1 Myr. Efficient radiative cooling of the supernova remnant as well as strong compression of the surrounding gas result in non-persistent energy and momentum input from the supernovae. However, if the time between subsequent supernovae is short and they are clustered, large hot bubbles form that disperse larger regions of the parental cloud. On longer time-scales, supernova feedback increases the amount of gas with moderate temperatures (T ≈ 300-3000 K). Despite its inability to disrupt molecular clouds, supernova feedback leaves a strong imprint on the star formation process. We find an overall reduction of the star formation efficiency by a factor of 2 and of the star formation rate by roughly factors of 2-4.

  16. The EASE Scenario: Dynamical Study of the Supernova Phase

    NASA Astrophysics Data System (ADS)

    Parmentier, Geneviève; Jehin, Emannuel; Magain, Pierre; Noels, Arlette; Thoul, Anne

    We revisit the most often encountered argument against self-enrichment in globular clusters, namely the ability of a few number of supernovae to disrupt the proto-globular cloud. We show that, within the context of the Fall and Rees theory, primordial proto-globular cluster clouds may sustain several hundreds of Type II supernovae. Furthermore, the corresponding self-enrichment level is in agreement with galactic halo globular cluster metallicities.

  17. Resonant neutrino spin-flavor precession and supernova nucleosynthesis and dynamics

    SciTech Connect

    Nunokawa, H.; Qian, Y.; Fuller, G.M.

    1997-03-01

    We discuss the effects of resonant spin-flavor precession (RSFP) of Majorana neutrinos on heavy element nucleosynthesis in neutrino-heated supernova ejecta and the dynamics of supernovae. In assessing the effects of RSFP, we explicitly include matter-enhanced (MSW) resonant neutrino flavor conversion effects where appropriate. We point out that for plausible ranges of neutrino magnetic moments and protoneutron star magnetic fields, spin-flavor conversion of {nu}{sub {tau}} (or {nu}{sub {mu}}) with a cosmologically significant mass (1{endash}100 eV) into a light {bar {nu}}{sub e} could lead to an enhanced neutron excess in neutrino-heated supernova ejecta. This could be beneficial for models of r-process nucleosynthesis associated with late-time neutrino-heated ejecta from supernovae. Similar spin-flavor conversion of neutrinos at earlier epochs could lead to an increased shock reheating rate and, concomitantly, a larger supernova explosion energy. We show, however, that such increased neutrino heating likely will be accompanied by an enhanced neutron excess which could exacerbate the problem of the overproduction of the neutron number N=50 nuclei in the supernova ejecta from this stage. In all of these scenarios, the average {bar {nu}}{sub e} energy will be increased over those predicted by supernova models with no neutrino mixings. This may allow the SN 1987A data to constrain RSFP-based schemes. {copyright} {ital 1997} {ital The American Physical Society}

  18. Late-time hohlraum pressure dynamics in supernova remnant experiments

    NASA Astrophysics Data System (ADS)

    Hurricane, O. A.; Glendinning, S. G.; Remington, B. A.; Drake, R. P.; Dannenberg, K. K.

    2001-06-01

    It is shown that laser driven hohlraums obtain significant internal pressures which affect the hydrodynamics of high-energy density shock-tube experiments. By incorporating this previously neglected hohlraum pressure effect (in addition to the usual x-ray drive) into computer simulations which model the NOVA laser driven supernova remnant experiment [R. P. Drake, S. G. Glendinning, K. Estabrook, B. A. Remington, R. McCray, R. J. Williams, L. J. Suter, T. B. Smith, J. J. Carroll III, R. A. London, and E. Liang, Phys. Rev. Lett. 81, 2068 (1998)], calculations are able to reproduce the observed structure of hydrodynamic features.

  19. X-Ray Measured Dynamics of Tycho's Supernova Remnant

    NASA Technical Reports Server (NTRS)

    Katsuda, Satoru; Petre, Robert; Hughes, John; Hwang, Una; Yamaguchi, Hiroya; Hayato, Asami; Mori, Koji; Tsunemi, Hiroshi

    2010-01-01

    We present X-ray proper-motion measurements of the forward shock and reverse-shocked ejecta in Tycho's supernova remnant, based on three sets of archival Chandra data taken in 2000, 2003, and 2007. We find that the proper motion of the edge of the remnant (i.e., the forward shock and protruding ejecta knots) varies from 0.''20 yr-1 (expansion index m = 0.33, where R = tm ) to 0.''40 yr-1 (m = 0.65) with azimuthal angle in 2000-2007 measurements, and 0.''14 yr-1 (m = 0.26) to 0.''40 yr-1 (m = 0.65) in 2003-2007 measurements. The azimuthal variation of the proper motion and the average expansion index of [approx]0.5 are consistent with those derived from radio observations. We also find proper motion and expansion index of the reverse-shocked ejecta to be 0.''21-0.''31 yr-1 and 0.43-0.64, respectively. From a comparison of the measured m-value with Type Ia supernova evolutionary models, we find a pre-shock ambient density around the remnant of [less, similar]0.2 cm-3.

  20. X-RAY MEASURED DYNAMICS OF TYCHO'S SUPERNOVA REMNANT

    SciTech Connect

    Katsuda, Satoru; Petre, Robert; Hwang, Una; Hughes, John P.; Yamaguchi, Hiroya; Hayato, Asami; Mori, Koji; Tsunemi, Hiroshi E-mail: Robert.Petre-1@nasa.go E-mail: jackph@physics.rutgers.ed E-mail: hayato@crab.riken.j E-mail: tsunemi@ess.sci.osaka-u.ac.j

    2010-02-01

    We present X-ray proper-motion measurements of the forward shock and reverse-shocked ejecta in Tycho's supernova remnant, based on three sets of archival Chandra data taken in 2000, 2003, and 2007. We find that the proper motion of the edge of the remnant (i.e., the forward shock and protruding ejecta knots) varies from 0.''20 yr{sup -1} (expansion index m = 0.33, where R = t{sup m} ) to 0.''40 yr{sup -1} (m = 0.65) with azimuthal angle in 2000-2007 measurements, and 0.''14 yr{sup -1} (m = 0.26) to 0.''40 yr{sup -1} (m = 0.65) in 2003-2007 measurements. The azimuthal variation of the proper motion and the average expansion index of approx0.5 are consistent with those derived from radio observations. We also find proper motion and expansion index of the reverse-shocked ejecta to be 0.''21-0.''31 yr{sup -1} and 0.43-0.64, respectively. From a comparison of the measured m-value with Type Ia supernova evolutionary models, we find a pre-shock ambient density around the remnant of approx<0.2 cm{sup -3}.

  1. Dynamics of Supernova Remnants with Ejecta and Circumstellar Bubbles

    NASA Astrophysics Data System (ADS)

    Blondin, M. J.; Featherstone, N.; Borkowski, J. K.; Reynolds, P. S.

    2001-09-01

    Progenitors of core-collapse supernovae (SNe) blow bubbles in the ambient medium and sweep it into shells with their powerful stellar winds. After the explosion, SN ejecta initially collide with the stellar wind, then with the wind-blown bubble, and finally with a dense wind-swept shell. This collision is particularly energetic for SNe whose progenitors lost most of their outer envelopes just prior to explosion: the brightest galactic supernova remnant (SNR), Cas A, is a prime example of such an interaction with the circumstellar medium (CSM). The SN ejecta are far from being smooth for such remnants, because of vigorous turbulence and mixing of heavy-element ejecta immediately after the explosion and subsequent growth of Ni-Fe bubbles powered by the radioactive decay. We study the interaction of ``bubbly'' SN ejecta with a CSM bubble and a swept CSM shell, using hydrodynamical simulations in 2 and 3 dimensions with the VH-1 hydrocode. We compare our simulations with analytic self-similar (Chevalier & Liang 1989) solutions and with our previous simulations of interaction of bubbly ejecta with a uniform ambient medium. When compared with these simulations, the impact of bubbly ejecta with the shell results in a more vigorous turbulence and mixing. Dense and cool ejecta at the boundaries of adjacent bubbles may penetrate the shell, leading to plume-like and ring-like features. We examine whether such an interaction is responsible for the observed morphology of Cas A as seen by the Chandra X-ray Observatory and the Hubble Space Telescope, and for the different expansion rates seen at X-ray and radio wavelengths.

  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. THE MORPHOLOGY AND DYNAMICS OF JET-DRIVEN SUPERNOVA REMNANTS: THE CASE OF W49B

    SciTech Connect

    González-Casanova, Diego F.; De Colle, Fabio; Ramirez-Ruiz, Enrico; Lopez, Laura A.

    2014-02-01

    The circumstellar medium (CSM) of a massive star is modified by its winds before a supernova (SN) explosion occurs, and thus the evolution of the resulting supernova remnant (SNR) is influenced by both the geometry of the explosion as well as the complex structure of the CSM. Motivated by recent work suggesting the SNR W49B was a jet-driven SN expanding in a complex CSM, we explore how the dynamics and the metal distributions in a jet-driven explosion are modified by the interaction with the surrounding environment. In particular, we perform hydrodynamical calculations to study the dynamics and explosive nucleosynthesis of a jet-driven SN triggered by the collapse of a 25 M {sub ☉} Wolf-Rayet star and its subsequent interaction with the CSM up to several hundred years following the explosion. We find that although the CSM has small-scale effects on the structure of the SNR, the overall morphology and abundance patterns are reflective of the initial asymmetry of the SN explosion. Thus, we predict that jet-driven SNRs, such as W49B, should be identifiable based on morphology and abundance patterns at ages up to several hundred years, even if they expand into a complex CSM environment.

  4. ALMA spectral survey of Supernova 1987A - molecular inventory, chemistry, dynamics and explosive nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Matsuura, M.; Indebetouw, R.; Woosley, S.; Bujarrabal, V.; Abellán, F. J.; McCray, R.; Kamenetzky, J.; Fransson, C.; Barlow, M. J.; Gomez, H. L.; Cigan, P.; De Looze, I.; Spyromilio, J.; Staveley-Smith, L.; Zanardo, G.; Roche, P.; Larsson, J.; Viti, S.; van Loon, J. Th.; Wheeler, J. C.; Baes, M.; Chevalier, R.; Lundqvist, P.; Marcaide, J. M.; Dwek, E.; Meixner, M.; Ng, C.-Y.; Sonneborn, G.; Yates, J.

    2017-08-01

    We report the first molecular line survey of Supernova 1987A in the millimetre wavelength range. In the Atacama Large Millimeter/submillimeter Array (ALMA) 210-300 and 340-360 GHz spectra, we detected cold (20-170 K) CO, 28SiO, HCO+ and SO, with weaker lines of 29SiO from ejecta. This is the first identification of HCO+ and SO in a young supernova remnant. We find a dip in the J = 6-5 and 5-4 SiO line profiles, suggesting that the ejecta morphology is likely elongated. The difference of the CO and SiO line profiles is consistent with hydrodynamic simulations, which show that Rayleigh-Taylor instabilities cause mixing of gas, with heavier elements much more disturbed, making more elongated structure. We obtained isotopologue ratios of 28SiO/29SiO > 13, 28SiO/30SiO > 14 and 12CO/13CO > 21, with the most likely limits of 28SiO/29SiO >128, 28SiO/30SiO >189. Low 29Si and 30Si abundances in SN 1987A are consistent with nucleosynthesis models that show inefficient formation of neutron-rich isotopes in a low-metallicity environment, such as the Large Magellanic Cloud. The deduced large mass of HCO+ (∼5 × 10-6 M⊙) and small SiS mass (<6 × 10-5 M⊙) might be explained by some mixing of elements immediately after the explosion. The mixing might have caused some hydrogen from the envelope to sink into carbon- and oxygen-rich zones after the explosion, enabling the formation of a substantial mass of HCO+. Oxygen atoms may have penetrated into silicon and sulphur zones, suppressing formation of SiS. Our ALMA observations open up a new window to investigate chemistry, dynamics and explosive nucleosynthesis in supernovae.

  5. 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

  6. Effects of inelastic neutrino-nucleus scattering on supernova dynamics and radiated neutrino spectra.

    PubMed

    Langanke, K; Martínez-Pinedo, G; Müller, B; Janka, H-Th; Marek, A; Hix, W R; Juodagalvis, A; Sampaio, J M

    2008-01-11

    Based on the shell model for Gamow-Teller and the random phase approximation for forbidden transitions, we calculate cross sections for inelastic neutrino-nucleus scattering (INNS) under supernova (SN) conditions, assuming a matter composition given by nuclear statistical equilibrium. The cross sections are incorporated into state-of-the-art stellar core-collapse simulations with detailed energy-dependent neutrino transport. While no significant effect on the SN dynamics is observed, INNS increases the neutrino opacities noticeably and strongly reduces the high-energy tail of the neutrino spectrum emitted in the neutrino burst at shock breakout. Relatedly the expected event rates for the observation of such neutrinos by earthbound detectors are reduced by up to about 60%.

  7. Effects of Inelastic Neutrino-Nucleus Scattering on Supernova Dynamics and Radiated Neutrino Spectra

    SciTech Connect

    Langanke, K.; Martinez-Pinedo, G.; Mueller, B.; Janka, H.-Th.; Marek, A.; Hix, W. R.; Juodagalvis, A.; Sampaio, J. M.

    2008-01-11

    Based on the shell model for Gamow-Teller and the random phase approximation for forbidden transitions, we calculate cross sections for inelastic neutrino-nucleus scattering (INNS) under supernova (SN) conditions, assuming a matter composition given by nuclear statistical equilibrium. The cross sections are incorporated into state-of-the-art stellar core-collapse simulations with detailed energy-dependent neutrino transport. While no significant effect on the SN dynamics is observed, INNS increases the neutrino opacities noticeably and strongly reduces the high-energy tail of the neutrino spectrum emitted in the neutrino burst at shock breakout. Relatedly the expected event rates for the observation of such neutrinos by earthbound detectors are reduced by up to about 60%.

  8. Are superluminous supernovae and long GRBs the products of dynamical processes in young dense star clusters?

    SciTech Connect

    Van den Heuvel, E. P. J.; Portegies Zwart, S. F.

    2013-12-20

    Superluminous supernovae (SLSNe) occur almost exclusively in small galaxies (Small/Large Magellanic Cloud (SMC/LMC)-like or smaller), and the few SLSNe observed in larger star-forming galaxies always occur close to the nuclei of their hosts. Another type of peculiar and highly energetic supernovae are the broad-line Type Ic SNe (SN Ic-BL) that are associated with long-duration gamma-ray bursts (LGRBs). Also these have a strong preference for occurring in small (SMC/LMC-like or smaller) star-forming galaxies, and in these galaxies LGRBs always occur in the brightest spots. Studies of nearby star-forming galaxies that are similar to the hosts of LGRBs show that these brightest spots are giant H II regions produced by massive dense young star clusters with many hundreds of O- and Wolf-Rayet-type stars. Such dense young clusters are also found in abundance within a few hundred parsecs from the nucleus of larger galaxies like our own. We argue that the SLSNe and the SNe Ic-BL/LGRBs are exclusive products of two types of dynamical interactions in dense young star clusters. In our model the high angular momentum of the collapsing stellar cores required for the engines of an SN Ic-BL results from the post-main-sequence mergers of dynamically produced cluster binaries with almost equal-mass components. The merger produces a critically rotating single helium star with sufficient angular momentum to produce an LGRB; the observed 'metal aversion' of LGRBs is a natural consequence of the model. We argue that, on the other hand, SLSNe could be the products of runaway multiple collisions in dense clusters, and we present (and quantize) plausible scenarios of how the different types of SLSNe can be produced.

  9. SN1987A-Neutrino emission from Supernova': in Dynamic universe model of cosmology

    NASA Astrophysics Data System (ADS)

    Naga Parameswara Gupta, Satyavarapu

    SN1987A-Neutrino emission from supernova before the star bursts' is an important discovery, when viewed from `Dynamic universe model of cosmology' point of view. In OMEG05, we have successfully presented the reasons for calculation error called `missing mass' in an inhomoge-neous, anisotropic and multi-body Dynamic universe Model, where this error is not occurring. But there are some new voices that say about generation of some flavors of neutrinos during Bigbang. We find from SN1987A Neutrino generation covers all flavors. Remaining flavors of Neutrinos are generated from sun and stars. This covers the whole spectrum. This paper covers all these aspects. And other earlier results by Dynamic Universe Model 1. Offers Singularity free solutions 2. Non-collapsing Galaxy structures 3. Solving Missing mass in Galaxies, and it finds reason for Galaxy circular velocity curves. . . . 4. Blue shifted and red shifted Galaxies co-existence. . . 5. Explains the force behind expansion of universe. 6. Explains the large voids and non-uniform matter densities. 7. Explains the Pioneer anomaly 8. Predicts the trajectory of New Horizons satellite. 9 Jeans swindle test 10. Existence of large number of blue shifted Galaxies `SITA Simulations' software was developed about 18 years back for Dynamic Universe Model of Cosmology. It is based on Newtonian physics. It is Classical singularity free N-body tensor solution to the old problem announced by King Oscar II and tried by Poincare in year AD1888 for 133 masses, tested extensively for so many years. This was developed on 486 based PC of those days; the same software was used repeatedly for so many years for solving different Physical problems on Different PCs and Laptops. It is based on Dynamic Universe Model's mathematical back ground.

  10. Reaction rate uncertainties and the {nu}p-process

    SciTech Connect

    Froehlich, C.; Rauscher, T.

    2012-11-12

    Current hydrodynamical simulations of core collapse supernovae find proton-rich early ejecta. At the same time, the models fail to eject neutron-rich matter, thus leaving the origin of the main r-process elements unsolved. However, the proton-rich neutrino-driven winds from supernovae have been identified as a possible production site for light n-capture elements beyond iron (such as Ge, Sr, Y, Zr) through the {nu}p-process. The detailed nucleosynthesis patterns of the {nu}p-process depend on the hydrodynamic conditions and the nuclear reaction rates of key reactions. We investigate the impact of reaction rate uncertainties on the {nu}p-process nucleosynthesis.

  11. Supernovae neutrino pasta interaction

    NASA Astrophysics Data System (ADS)

    Lin, Zidu; Horowitz, Charles; Caplan, Matthew; Berry, Donald; Roberts, Luke

    2017-01-01

    In core-collapse supernovae, the neutron rich matter is believed to have complex structures, such as spherical, slablike, and rodlike shapes. They are collectively called ``nuclear pasta''. Supernovae neutrinos may scatter coherently on the ``nuclear pasta'' since the wavelength of the supernovae neutrinos are comparable to the nuclear pasta scale. Consequently, the neutrino pasta scattering is important to understand the neutrino opacity in the supernovae. In this work we simulated the ``nuclear pasta'' at different temperatures and densities using our semi-classical molecular dynamics and calculated the corresponding static structure factor that describes ν-pasta scattering. We found the neutrino opacities are greatly modified when the ``pasta'' exist and may have influence on the supernovae neutrino flux and average energy. Our neutrino-pasta scattering effect can finally be involved in the current supernovae simulations and we present preliminary proto neutron star cooling simulations including our pasta opacities.

  12. Supernovae, neutrinos, and nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Fröhlich, Carla

    2014-04-01

    Core-collapse supernovae are the violent explosions at the end of the life of massive stars (≳ 8 - 10 M⊙). In these explosions a wide range of elements are synthesized and ejected: low-mass elements (O and Mg) from the hydrostatic evolution, intermediate-mass elements and Fe-group elements from explosive nucleosynthesis, and elements heavier than iron from the νp-process and potentially an r-process. However, supernova nucleosynthesis predictions are hampered by the not yet fully understood supernova explosion mechanism. In addition, recent progress in observational astronomy paints a fascinating picture for the origin of heavy elements, which is more complicated than the traditional s-, r-, and γ-processes. In this paper, we summarize the status of core-collapse supernova nucleosynthesis.

  13. Supernova kicks and dynamics of compact remnants in the Galactic Centre

    NASA Astrophysics Data System (ADS)

    Bortolas, Elisa; Mapelli, Michela; Spera, Mario

    2017-08-01

    The Galactic Centre (GC) is a unique place to study the extreme dynamical processes occurring near a supermassive black hole (SMBH). Here, we investigate the role of supernova (SN) explosions occurring in massive binary systems lying in a disc-like structure within the innermost parsec. We use a regularized algorithm to simulate 3 × 104 isolated three-body systems composed of a stellar binary orbiting the SMBH. We start the integration when the primary member undergoes an SN explosion and analyse the impact of SN kicks on the orbits of stars and compact remnants. We find that SN explosions scatter the lighter stars in the pair on completely different orbits, with higher eccentricity and inclination. In contrast, stellar-mass black holes (BHs) and massive stars retain memory of the orbit of their progenitor star. Our results suggest that SN kicks are not sufficient to eject BHs from the GC. We thus predict that all BHs that form in situ in the central parsec of our Galaxy remain in the GC, building up a cluster of dark remnants. In addition, the change of neutron star (NS) orbits induced by SNe may partially account for the observed dearth of NSs in the GC. About 40 per cent of remnants stay bound to the stellar companion after the kick; we expect up to 70 per cent of them might become X-ray binaries through Roche lobe filling. Finally, the eccentricity of some light stars becomes >0.7 as an effect of the SN kick, producing orbits similar to those of the G1 and G2 dusty objects.

  14. Supernova Flashback

    NASA Image and Video Library

    2008-10-01

    The Cassiopeia A supernova first flash of radiation makes six clumps of dust circled in annotated version unusually hot. The supernova remnant is the large white ball in the center. This infrared picture was taken by NASA Spitzer Space Telescope.

  15. Nuclear Reactions and the ν p-Process

    NASA Astrophysics Data System (ADS)

    Fröhlich, Carla; Hatcher, Daniel; Perdikakis, Georgios; Nikas, Stylianos

    In understanding the origin of the heavy elements, the "light heavy elements" pose a particular challenge: The two neutron-capture processes, r- and s-process, cannot explain the abundances patterns seen in very old galactic halo stars. A proposed solution to this problem is the ν p-process, which takes place in the strong neutrino-driven winds of core-collapse supernovae. In the ν p-process, a sequence of (n, p) and (p, γ ) reactions allows for the synthesis of elements with atomic numbers A > 64, which includes Sr, Y, Zr, and others possibly up to Sn. The relevant reaction rates are all based on statistical model predictions and carry some uncertainty. Here, the sensitivity of the final ν p-process abundance pattern on modifications of (n, p), (p, γ ), and (n, γ ) reactions are characterized. Only few reactions affect the final abundance pattern and hence warrant a more detailed study of the reaction rate.

  16. Dynamics of a Type Ia Supernova Remnant: X-ray and Radio Proper Motions in Tycho's SNR

    NASA Astrophysics Data System (ADS)

    Williams, Brian J.; Blondin, John M.; Borkowski, Kazimierz J.; Chomiuk, Laura; Ghavamian, Parviz; Hewitt, John W.; Petre, Robert; Reynolds, Stephen P.

    2016-01-01

    We present results from new Chandra X-ray and JVLA radio observations of Tycho's supernova remnant, the remains of the supernova of 1572 A.D. The high spatial resolution of these instruments allows for accurate measurements of the proper motion of the forward shock in Tycho, with baselines now at 15 years for the X-ray data and 30 years for the radio. Type Ia SNe are of fundamental importance in astrophysics, yet the nature of their environments and progenitor systems is poorly understood. In a recent work, we have shown that theISM surrounding Tycho varies systematically in density by a factor of 5, with larger excursions in some locations. A substantial density variation is consistent with limited previous proper motion studies that have been done in radio and X-rays. Our expanded baseline measurements allow us to further explore the variations in the dynamics of the shock wave, which can also be used to localize the explosion site. Previous proper motion measurements, made over much shorter time baselines, have shown some discrepancies in the shockvelocity as measured in radio and X-rays. With our new, much improved data, we can compare proper motions in these two energy bands with much greater accuracy.

  17. Supernova VLBI

    NASA Astrophysics Data System (ADS)

    Bartel, N.

    2009-08-01

    We review VLBI observations of supernovae over the last quarter century and discuss the prospect of imaging future supernovae with space VLBI in the context of VSOP-2. From thousands of discovered supernovae, most of them at cosmological distances, ˜50 have been detected at radio wavelengths, most of them in relatively nearby galaxies. All of the radio supernovae are Type II or Ib/c, which originate from the explosion of massive progenitor stars. Of these, 12 were observed with VLBI and four of them, SN 1979C, SN 1986J, SN 1993J, and SN 1987A, could be imaged in detail, the former three with VLBI. In addition, supernovae or young supernova remnants were discovered at radio wavelengths in highly dust-obscured galaxies, such as M82, Arp 299, and Arp 220, and some of them could also be imaged in detail. Four of the supernovae so far observed were sufficiently bright to be detectable with VSOP-2. With VSOP-2 the expansion of supernovae can be monitored and investigated with unsurpassed angular resolution, starting as early as the time of the supernova's transition from its opaque to transparent stage. Such studies can reveal, in a movie, the aftermath of a supernova explosion shortly after shock break out.

  18. Aspherical supernovae

    SciTech Connect

    Kasen, Daniel Nathan

    2004-01-01

    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

  19. Supernova Neutrinos

    SciTech Connect

    Beacom, John

    2009-11-14

    Supernovae in our Galaxy probably occur about 3 times per century, though 90% of them are invisible optically because of obscuration by dust. However, present solar neutrino detectors are sensitive to core-collapse supernovae anywhere in our Galaxy, and would detect of order 10,000 events from a supernova at a distance of 10 kpc (roughly the distance to the Galactic center). I will describe how this data can be used to understand the supernova itself, as well as to test the properties of neutrinos.

  20. The Cusp/Core problem: supernovae feedback versus the baryonic clumps and dynamical friction model

    NASA Astrophysics Data System (ADS)

    Del Popolo, A.; Pace, F.

    2016-05-01

    In the present paper, we compare the predictions of two well known mechanisms considered able to solve the cusp/core problem (a. supernova feedback; b. baryonic clumps-DM interaction) by comparing their theoretical predictions to recent observations of the inner slopes of galaxies with masses ranging from dSphs to normal spirals. We compare the α-V_{rot} and the α-M_{ast} relationships, predicted by the two models with high resolution data coming from Adams et al. (Astrophys. J. 789, 63, 2014), Simon et al. (Astrophys. J. 621, 757, 2005), LITTLE THINGS (Oh et al. in Astron. J. 149, 180, 2015), THINGS dwarves (Oh et al. in Astron. J. 141, 193, 2011a; Oh et al. in Astron. J. 142, 224, 2011b), THINGS spirals (Oh et al. in Astron. J. 149, 180, 2015), Sculptor, Fornax and the Milky Way. The comparison of the theoretical predictions with the complete set of data shows that the two models perform similarly, while when we restrict the analysis to a smaller subsample of higher quality, we show that the method presented in this paper (baryonic clumps-DM interaction) performs better than the one based on supernova feedback. We also show that, contrarily to the first model prediction, dSphs of small mass could have cored profiles. This means that observations of cored inner profiles in dSphs having a stellar mass <106 M_{⊙} not necessarily imply problems for the ΛCDM model.

  1. Stellar dynamics. The fastest unbound star in our Galaxy ejected by a thermonuclear supernova.

    PubMed

    Geier, S; Fürst, F; Ziegerer, E; Kupfer, T; Heber, U; Irrgang, A; Wang, B; Liu, Z; Han, Z; Sesar, B; Levitan, D; Kotak, R; Magnier, E; Smith, K; Burgett, W S; Chambers, K; Flewelling, H; Kaiser, N; Wainscoat, R; Waters, C

    2015-03-06

    Hypervelocity stars (HVSs) travel with velocities so high that they exceed the escape velocity of the Galaxy. Several acceleration mechanisms have been discussed. Only one HVS (US 708, HVS 2) is a compact helium star. Here we present a spectroscopic and kinematic analysis of US 708. Traveling with a velocity of ~1200 kilometers per second, it is the fastest unbound star in our Galaxy. In reconstructing its trajectory, the Galactic center becomes very unlikely as an origin, which is hardly consistent with the most favored ejection mechanism for the other HVSs. Furthermore, we detected that US 708 is a fast rotator. According to our binary evolution model, it was spun-up by tidal interaction in a close binary and is likely to be the ejected donor remnant of a thermonuclear supernova. Copyright © 2015, American Association for the Advancement of Science.

  2. supernovae: Photometric classification of supernovae

    NASA Astrophysics Data System (ADS)

    Charnock, Tom; Moss, Adam

    2017-05-01

    Supernovae classifies supernovae using their light curves directly as inputs to a deep recurrent neural network, which learns information from the sequence of observations. Observational time and filter fluxes are used as inputs; since the inputs are agnostic, additional data such as host galaxy information can also be included.

  3. Supernova models

    SciTech Connect

    Woosley, S.E.; Weaver, T.A.

    1980-01-01

    Recent progress in understanding the observed properties of Type I supernovae as a consequence of the thermonuclear detonation of white dwarf stars and the ensuing decay of the /sup 56/Ni produced therein is reviewed. Within the context of this model for Type I explosions and the 1978 model for Type II explosions, the expected nucleosynthesis and gamma-line spectra from both kinds of supernovae are presented. Finally, a qualitatively new approach to the problem of massive star death and Type II supernovae based upon a combination of rotation and thermonuclear burning is discussed.

  4. Supernova Neutrinos

    SciTech Connect

    Cardall, Christian Y

    2007-01-01

    A nascent neutron star resulting from stellar collapse is a prodigious source of neutrinos of all flavors. While the most basic features of this neutrino emission can be estimated from simple considerations, the detailed simulation of the neutrinos' decoupling from the hot neutron star is not yet computationally tractable in its full glory, being a time-dependent six-dimensional transport problem. Nevertheless, supernova neutrino fluxes are of great interest in connection with the core-collapse supernova explosion mechanism and supernova nucleosynthesis, and as a potential probe of the supernova environment and of some of the neutrino mixing parameters that remain unknown; hence, a variety of approximate transport schemes have been used to obtain results with reduced dimensionality. However, none of these approximate schemes have addressed a recent challenge to the conventional wisdom that neutrino flavor mixing cannot impact the explosion mechanism or r-process nucleosynthesis.

  5. Capture cross sections for the astrophysical p process

    NASA Astrophysics Data System (ADS)

    Quinn, Stephen J.

    This dissertation includes the design and development of the Summing NaI (SuN) 4pi gamma-ray detector at the National Superconducting Cyclotron Laboratory to measure proton and alpha radiative capture reactions relevant in the astrophysical p process. Discussions of p-process nucleosynthesis, the relevant nuclear reaction theory, experimental details, and analysis procedures are included. All reaction measurements were performed at the Nuclear Science Laboratory of the University of Notre Dame. The commissioning experiments in both regular and inverse kinematics were done using known resonances in the 27Al(p,gamma)28Si and 58Ni(p,gamma) 59Cu reactions, and the results agree well with previous literature values. The success of these proof-of-principle measurements marks the first time that the gamma-summing technique has been implemented in inverse kinematics. Furthermore, in an effort to investigate the synthesis of the light p-process nuclei, the 74Ge(p,gamma)75As, 74Ge(alpha,gamma) 78Se, and 90,92Zr(alpha,gamma)94,96Mo reactions were measured and compared to theoretical calculations using the nuclear statistical model. It was found that the new 74Ge(p,gamma) 75As measurements cause an enhancement in the overproduction of 74Se in p-process models, and that the updated 90Zr(alpha,gamma) 94Mo reaction rate seems to confirms the p-process branching point at 94Mo. Finally, the 58Ni(alpha,gamma) 62Zn reaction was measured for its role in nucleosynthesis in type Ia supernovae. The measurements here lower the reaction rate used in astrophysical models, which leads to a 5% reduction in the calculated abundances of several isotopes. All of the measurements in this dissertation greatly reduce the uncertainty in the reaction cross section.

  6. Dynamical Evolution and High-Energy Radiation of Mixed-Morphology Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Shimizu, Takafumi

    2014-03-01

    Evolution of a supernova remnant (SNR) without an active neutron star is basically described by probation of shock waves. The shock waves accelerate charged particles. The particles accelerated to GeV radiate synchrotron radio emission, which appears to be shelllike morphology. The shock waves heat matter up to keV, and heated-electrons ionize ions. Compared with a time-scale of shock-heating of electrons by the shock, a time-scale of ionization of ions by electron collisions in the shock down stream region is longer. Hence an ionization state of SNR plasma is thought to be under-ionized state in which the ionization temperature is lower than the electron temperature, or collisional ionization equilibrium state at late time. In fact, X-ray spectra of many SNRs are explained by such plasma state model. SNRs that exhibit shell-like morphology in thermal X-ray as well as radio are categorized into shell-like SNRs. In contrast to shell-like SNRs, some SNRs exhibit shell-like radio but center-filled thermal X-ray morphology. Such SNRs are categorized into mixed-morphology SNRs (MM SNRs). Many MM SNRs interact with molecular clouds, suggested by OH maser and near infrared observations, and hence are thought to be remnants of core-collapse supernova of massive stars. Interestingly, recombination radiation X-rays, which are evidence that X-ray emitting plasmas are over-ionized states in which the ionization temperature is higher than the electron temperature, are detected from six MM SNRs. The center-filled X-rays with recombination radiation can not be explained by a picture of shock-wave propagation that explains the X-rays of shell-like SNRs. As well as X-rays, MM SNRs are characteristic in γ-ray emission. Several MM SNRs and shell-like SNRs are detected in the GeV γ-ray band by Fermi. The 1 - 100 GeV γ-ray luminosities of MM SNRs are ˜ 1034-1036 erg s-1, which are systematically higher than those of shell-like SNRs of ˜ 1033-1035 erg s-1. Such high luminosities

  7. Luminous supernovae.

    PubMed

    Gal-Yam, Avishay

    2012-08-24

    Supernovae, the luminous explosions of stars, have been observed since antiquity. However, various examples of superluminous supernovae (SLSNe; luminosities >7 × 10(43) ergs per second) have only recently been documented. From the accumulated evidence, SLSNe can be classified as radioactively powered (SLSN-R), hydrogen-rich (SLSN-II), and hydrogen-poor (SLSN-I, the most luminous class). The SLSN-II and SLSN-I classes are more common, whereas the SLSN-R class is better understood. The physical origins of the extreme luminosity emitted by SLSNe are a focus of current research.

  8. Magnetares como fuentes para potenciar supernovas superluminosas

    NASA Astrophysics Data System (ADS)

    Bersten, M. C.; Benvenuto, O. G.

    2016-08-01

    Magnetars have been proposed as one of the possible sources to power the light curve of super-luminous supernovae. We have included the energy deposited by a hypothetical magnetar in our one-dimensional hydrodynamical code, and analyzed the dynamical effect on the supernova ejecta. In particular, we present a model for SN 2011kl, the first object associated with a ultra-long-duration gamma-ray burst. Finally, we show its effect on the light curves of hydrogen rich supernovae.

  9. Simulating Supernova Light Curves

    SciTech Connect

    Even, Wesley Paul; Dolence, Joshua C.

    2016-05-05

    This report discusses supernova light simulations. A brief review of supernovae, basics of supernova light curves, simulation tools used at LANL, and supernova results are included. Further, it happens that many of the same methods used to generate simulated supernova light curves can also be used to model the emission from fireballs generated by explosions in the earth’s atmosphere.

  10. Astronomical Resources: Supernovae.

    ERIC Educational Resources Information Center

    Fraknoi, Andrew

    1987-01-01

    Contains a partially annotated, nontechnical bibliography of recent materials about supernovae, including some about the discovery of a supernova in the Large Magellanic Cloud. Includes citations of general books and articles about supernovae, articles about Supernova 1987A, and a few science fiction stories using supernovae. (TW)

  11. Nonlinear growth of dynamical overstabilities in blast waves. [effects on supernova remnants

    NASA Technical Reports Server (NTRS)

    Mac Low, Mordecai-Mark; Norman, Michael L.

    1993-01-01

    The numerical gasdynamics code ZEUS-2D is used to directly model the dynamical overstabilities in blast waves. The linear analysis is confirmed by perturbing a blast wave with a low-amplitude eigenfunction of the overstability. The amplitude of the perturbations is increased in order to determine the nonlinear behavior of the overstabilities. The overstability is found to saturate due to weak transverse shocks in the shell. Transverse velocities in the dense shell reach the postshock sound speed, and high-density regions with sizes of the order of the shell thickness form. Transverse oscillations continue even after saturation. This confirms and explains the damping of the overstability experimentally discovered by Grun et al. (1991).

  12. Solar nebula heterogeneity in p-process samarium and neodymium isotopes.

    PubMed

    Andreasen, Rasmus; Sharma, Mukul

    2006-11-03

    Bulk carbonaceous chondrites display a deficit of approximately 100 parts per million (ppm) in 144Sm with respect to other meteorites and terrestrial standards, leading to a decrease in their 142Nd/144Nd ratios by approximately 11 ppm. The data require that samarium and neodymium isotopes produced by the p process associated with photodisintegration reactions in supernovae were heterogeneously distributed in the solar nebula. Other samarium and neodymium isotopes produced by rapid neutron capture (r process) in supernovae and by slow neutron capture (s process) in red giants were homogeneously distributed. The supernovae sources supplying the p- and r-process nuclides to the solar nebula were thus disconnected or only weakly connected.

  13. Superluminous Supernovae hydrodynamic models

    NASA Astrophysics Data System (ADS)

    Orellana, M.

    2017-07-01

    We use our radiation hydrodynamic code in order to simulate magnetar powered Superluminous Supernovae (SLSNe). It is assumed that a central rapidly rotating magnetar deposits all its rotational energy into the ejecta where is added to the usual power. The magnetar luminosity and spin-down timescale are adopted as the free parameters of the model. For the case of ASASSN-15lh, which has been claimed as the most luminous supernova ever discovered, we have found physically plausible magnetar parameters can reproduce the overall shape of the bolometric light curve (LC) provided the progenitor mass is ≍ 8M⊙. The ejecta dynamics of this event shows signs of the magnetar energy input which deviates the expansion from the usually assumed homologous behaviour. Our numerical experiments lead us to conclude that the hydrodynamical modeling is necessary in order to derive the properties of powerful magnetars driving SLSNe.

  14. EVALUATING SYSTEMATIC DEPENDENCIES OF TYPE Ia SUPERNOVAE: THE INFLUENCE OF PROGENITOR {sup 22}Ne CONTENT ON DYNAMICS

    SciTech Connect

    Townsley, Dean M.; Chamulak, David A.; Brown, Edward F.; Timmes, F. X.

    2009-08-20

    We present a theoretical framework for formal study of systematic effects in supernovae Type Ia (SNe Ia) that utilizes two-dimensional simulations to implement a form of the deflagration-detonation transition (DDT) explosion scenario. The framework is developed from a randomized initial condition that leads to a sample of simulated SNe Ia whose {sup 56}Ni masses have a similar average and range to those observed, and have many other modestly realistic features such as the velocity extent of intermediate-mass elements. The intended purpose is to enable statistically well defined studies of both physical and theoretical parameters of the SNe Ia explosion simulation. We present here a thorough description of the outcome of the SNe Ia explosions produced by our current simulations. A first application of this framework is utilized to study the dependence of the SNe Ia on the {sup 22}Ne content, which is known to be directly influenced by the progenitor stellar population's metallicity. Our study is very specifically tailored to measure how the {sup 22}Ne content influences the competition between the rise of plumes of burned material and the expansion of the star before these plumes reach DDT conditions. This influence arises from the dependence of the energy release, progenitor structure, and laminar flame speed on {sup 22}Ne content. For this study, we explore these three effects for a fixed carbon content and DDT density. By setting the density at which nucleosynthesis takes place during the detonation phase of the explosion, the competition between plume rise and stellar expansion controls the amount of material in nuclear statistical equilibrium (NSE) and therefore {sup 56}Ni produced. Of particular interest is how this influence of {sup 22}Ne content compares to the direct modification of the {sup 56}Ni mass via the inherent neutron excess as discussed by Timmes et al. Although the outcome following from any particular ignition condition can change dramatically

  15. Supernova Forensics

    NASA Astrophysics Data System (ADS)

    Soderberg, Alicia M.

    2014-01-01

    For decades, the study of stellar explosions -- supernovae -- have focused almost exclusively on the strong optical emission that dominates the bolometric luminosity in the days following the ultimate demise of the star. Yet many of the leading breakthroughs in our understanding of stellar death have been enabled by obtaining data at other wavelengths. For example, I have shown that 1% of all supernovae give rise to powerful relativistic jets, representing the biggest bangs in the Universe since the Big Bang. My recent serendipitous X-ray discovery of a supernova in the act of exploding (“in flagrante delicto”) revealed a novel technique to discover new events and provide clues on the shock physics at the heart of the explosion. With the advent of sensitive new radio telescopes, my research group combines clues from across the electromagnetic spectrum (radio to gamma-ray), leading us to a holistic study of stellar death, the physics of the explosions, and their role in fertilizing the Universe with new elements, by providing the community with cosmic autopsy reports.

  16. Abundances for p-process nucleosynthesis

    SciTech Connect

    De Laeter, John R.

    2008-04-15

    An important constraint in developing models of p-process nucleosynthesis is that the abundances of many of the p-process nuclides are not well known. A recent review of the p-process has identified six p-process nuclides that are of particular significance to p-process theorists [M. Arnould and S. Goriely, Phys. Rep. 384, 1 (2003)]. These nuclides are {sup 92,94}Mo, {sup 96,98}Ru, {sup 138}La, and {sup 180}Ta{sup m}. The absence of accurate abundances for these isotopes is due to the fact that the isotopic composition of the elements concerned have not been corrected for isotope fractionation induced by the thermal ionization mass spectrometric instruments used to measure them. To remedy this deficiency, a VG 354 mass spectrometer was calibrated using gravimetric mixtures of enriched isotopes to enable the absolute isotopic compositions of these elements to be obtained. Although the isotopic abundances of {sup 92,94}Mo, {sup 138}La, and {sup 180}Ta{sup m} have previously been reported, the absolute abundances of {sup 96,98}Ru are reported for the first time in this article, with a significant reduction in the magnitude of the values as compared to existing abundances.

  17. Supernova neutrinos

    SciTech Connect

    John Beacom

    2003-01-23

    We propose that neutrino-proton elastic scattering, {nu} + p {yields} {nu} + p, can be used for the detection of supernova neutrinos. Though the proton recoil kinetic energy spectrum is soft, with T{sub p} {approx_equal} 2E{sub {nu}}{sup 2}/M{sub p}, and the scintillation light output from slow, heavily ionizing protons is quenched, the yield above a realistic threshold is nearly as large as that from {bar {nu}}{sub e} + p {yields} e{sup +} + n. In addition, the measured proton spectrum is related to the incident neutrino spectrum, which solves a long-standing problem of how to separately measure the total energy release and temperature of {nu}{sub {mu}}, {nu}{sub {tau}}, {bar {nu}}{sub {mu}}, and {bar {nu}}{sub {tau}}. The ability to detect this signal would give detectors like KamLAND and Borexino a crucial and unique role in the quest to detect supernova neutrinos.

  18. First supernova companion star found

    NASA Astrophysics Data System (ADS)

    2004-01-01

    , 2100 seconds and 330W, 1200 seconds) shown in purple and blue, a deep blue filter (435W, 1000 seconds) shown in green and a green filter (555W, 1120 seconds) shown in red. The quarter-circle around the supernova companion is a so-called light echo originating from sheets of dust in the galaxy reflecting light from the original supernova explosion. The timing of the appearance of these echoes can be used to map out the dust structure around the supernova. The light echo was detected in late 2002 and early 2003 by two competing groups of scientists. Messier 81 spiral arm (WFPC2 image) hi-res Size hi-res: 1502 kb Credits: ESA and Justyn R. Maund (University of Cambridge) Messier 81 spiral arm (WFPC2 image) This NASA/ESA Hubble Space Telescope image shows a small portion of one of Messier 81’s spiral arms. It extends about 0.03 x 0.03 degrees. The supernova companion is the bluish star in the upper right hand corner. Dust lanes in the spiral arms of the galaxy are seen, as well as many other stars and a few star forming nebulae. The image is composed of four separate exposures from the ESO/ST-ECF Archive through a blue filter, a green filter, a red filter and a near-infrared filter. The image was taken with Hubble’s Wide Field and Planetary Camera 2. Acknowledgement: Bob Kirshner (Harvard University, USA) Grand Spiral Messier 81 (ground-based) hi-res Size hi-res: 1502 kb Credits: ESA/INT/DSS2 Grand Spiral Messier 81 (ground-based) This ground-based image shows the spiral galaxy Messier 81 in its entirety. The image is a combination of exposures from the Isaac Newton Telescope on La Palma (courtesy of Jonathan Irwin) and Digitized Sky Survey 2 images. The dynamic duo, Messier 81 and 82 (ground-based) hi-res Size hi-res: 1502 kb Credits: Robert Gendler (http://www.robgendlerastropics.com) The dynamic duo, Messier 81 and 82 (ground-based) This wide-angle image taken by astrophotographer Robert Gendler shows the amazing duo of Messier 81 (right) and Messier 82 (left

  19. Featured Image: Modeling Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-05-01

    This image shows a computer simulation of the hydrodynamics within a supernova remnant. The mixing between the outer layers (where color represents the log of density) is caused by turbulence from the Rayleigh-Taylor instability, an effect that arises when the expanding core gas of the supernova is accelerated into denser shell gas. The past standard for supernova-evolution simulations was to perform them in one dimension and then, in post-processing, manually smooth out regions that undergo Rayleigh-Taylor turbulence (an intrinsically multidimensional effect). But in a recent study, Paul Duffell (University of California, Berkeley) has explored how a 1D model could be used to reproduce the multidimensional dynamics that occur in turbulence from this instability. For more information, check out the paper below!CitationPaul C. Duffell 2016 ApJ 821 76. doi:10.3847/0004-637X/821/2/76

  20. Core-collapse supernova neutrinos and neutrino properties

    SciTech Connect

    Gava, J.; Volpe, C.

    2008-08-29

    Core-collapse supernovae are powerful neutrino sources. The observation of a future (extra-)galactic supernova explosion or of the relic supernova neutrinos might provide important information on the supernova dynamics, on the supernova formation rate and on neutrino properties. One might learn more about unknown neutrino properties either from indirect effects in the supernova (e.g. on the explosion or on in the r-process) or from modifications of the neutrino time or energy distributions in a detector on Earth. Here we will discuss in particular possible effects of CP violation in the lepton sector. We will also mention the interest of future neutrino-nucleus interaction measurements for the precise knowledge of supernova neutrino detector response to electron neutrinos.

  1. Magnetic Dipole and Gamow-Teller Modes in Neutrino-Nucleus Reactions: Impact on Supernova Dynamics and Nucleosynthesis

    SciTech Connect

    Neumann-Cosel, P. von; Byelikov, A.; Richter, A.; Shevchenko, A.; Adachi, T.; Fujita, Y.; Shimbara, Y.; Fujita, H.; Heger, A.; Kolbe, E.; Langanke, K.; Martinez-Pinedo, G.

    2006-03-13

    Some aspects of the importance of neutrino-induced reactions on nuclei within supernova physics are discussed. It is argued that important constraints on the experimentally unknown cross sections can be obtained from experimental studies of the nuclear response in selected cases. Examples are neutral-current induced reactions on fp-shell nuclei extracted from high-resolution inelastic electron scattering data providing the M1 strength distributions and the production of the exotic heavy, odd-odd nuclei 138La and 180Ta through charged-current reactions dominated by Gamow-Teller transitions. The Gamow-Teller strength can deduced from the (3He,t) charge-exchange reaction at zero degree.

  2. 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.

  3. Nuclear astrophysics of supernovae

    SciTech Connect

    Cooperstein, J.

    1988-01-01

    In this paper, I'll give a general introduction to Supernova Theory, beginning with the presupernova evolution and ending with the later stages of the explosion. This will be distilled from a colloquium type of talk. It is necessary to have the whole supernova picture in one's mind's eye when diving into some of its nooks and crannies, as it is quite a mess of contradictory ingredients. We will have some discussion of supernova 1987a, but will keep our discussion more general. Second, we'll look at the infall and bounce of the star, seeing why it goes unstable, what dynamics it follows as it collapses, and how and why it bounces back. From there, we will go on to look at the equation of state (EOS) in more detail. We'll consider the cases T = 0 and T > 0. We'll focus on /rho/ < /rho//sub 0/, and then /rho/ > /rho//sub 0/ and the EOS of neutron stars, and whether or not they contain cores of strange matter. There are many things we could discuss here and not enough time. If I had more lectures, the remaining time would focus on two more questions of special interest to nuclear physicists: the electron capture reactions and neutrino transport. If time permitted, we'd have some discussion of the nucleosynthetic reactions in the explosion's debris as well. However, we cannot cover such material adequately, and I have chosen these topics because they are analytically tractable, pedagogically useful, and rather important. 23 refs., 14 figs., 3 tabs.

  4. Supernova frequency estimates

    SciTech Connect

    Tsvetkov, D.Y.

    1983-01-01

    Estimates of the frequency of type I and II supernovae occurring in galaxies of different types are derived from observational material acquired by the supernova patrol of the Shternberg Astronomical Institute.

  5. 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.

  6. The Global Supernova Project

    NASA Astrophysics Data System (ADS)

    Howell, Dale Andrew; Global Supernova Project

    2017-06-01

    The Global Supernova Project is worldwide collaboration to study 600 supernovae of all types between May 2017 and July 2020. It is a Key Project at Las Cumbres Observatory, whose global robotic telescope network will provide lightcurves and spectra. Follow-up observations will be obtained on many other facilities, including Swift, VLA, K2, the NTT, IRTF, Keck, and Gemini. Observations are managed by the Supernova Exchange, a combination observatin database and telescope control system run by LCO. Here we report on results from the previous Supernova Key Project, and first results from the Global Supernova Project.

  7. Neutrino-induced nucleosynthesis of A>64 nuclei: the nu p process.

    PubMed

    Fröhlich, C; Martínez-Pinedo, G; Liebendörfer, M; Thielemann, F-K; Bravo, E; Hix, W R; Langanke, K; Zinner, N T

    2006-04-14

    We present a new nucleosynthesis process that we denote as the nu p process, which occurs in supernovae (and possibly gamma-ray bursts) when strong neutrino fluxes create proton-rich ejecta. In this process, antineutrino absorptions in the proton-rich environment produce neutrons that are immediately captured by neutron-deficient nuclei. This allows for the nucleosynthesis of nuclei with mass numbers A>64, , making this process a possible candidate to explain the origin of the solar abundances of (92,94)Mo and (96,98)Ru. This process also offers a natural explanation for the large abundance of Sr seen in a hyper-metal-poor star.

  8. Instabilities and the Supernova Mechanism

    NASA Astrophysics Data System (ADS)

    Burrows, Adam; Hayes, John

    1994-12-01

    Core collapse supernovae are thought to be powered not dynamically by the direct piston mechanism of core bounce, but by neutrino heating after the bounce shock has stalled into accretion. The theory we will describe provides a paradigm for understanding the neutrino heating mechanism. Both the critical condition for instability and the explosion energy are very steep functions of the driving neutrino luminosity. We will present recent 1D and 2D hydrodynamic calculations in which the basics of the supernova mechanism are elucidated. The shock wave that stalls within ten milliseconds of its creation during the collapse and bounce of the core of a massive star leaves behind it unstable lepton and entropy profiles that can drive a violent Rayleigh-Taylor overturn. Furthermore, the core neutrino luminosities can establish unstable entropy gradients near the shock 50 milliseconds after bounce. John Hayes, Bruce Fryxell and I have demonstrated the possible existence of a convective boost in the neutrino luminosities due to core lepton overturn that can ignite a supernova explosion and have verified the potential importance of nu -driven ``Bethe'' convection near the shock. Issues that surround the residual neutron star mass, the (56) Ni yields, the supernova energies, the progenitors, and the nucleosynthetic consequences will also be addressed.

  9. Nonstandard neutrino interactions in supernovae

    NASA Astrophysics Data System (ADS)

    Stapleford, Charles J.; Väänänen, Daavid J.; Kneller, James P.; McLaughlin, Gail C.; Shapiro, Brandon T.

    2016-11-01

    Nonstandard interactions (NSI) of neutrinos with matter can significantly alter neutrino flavor evolution in supernovae with the potential to impact explosion dynamics, nucleosynthesis, and the neutrinos signal. In this paper, we explore, both numerically and analytically, the landscape of neutrino flavor transformation effects in supernovae due to NSI and find a new, heretofore unseen transformation processes can occur. These new transformations can take place with NSI strengths well below current experimental limits. Within a broad swath of NSI parameter space, we observe symmetric and standard matter-neutrino resonances for supernovae neutrinos, a transformation effect previously only seen in compact object merger scenarios; in another region of the parameter space we find the NSI can induce neutrino collective effects in scenarios where none would appear with only the standard case of neutrino oscillation physics; and in a third region the NSI can lead to the disappearance of the high density Mikheyev-Smirnov-Wolfenstein resonance. Using a variety of analytical tools, we are able to describe quantitatively the numerical results allowing us to partition the NSI parameter according to the transformation processes observed. Our results indicate nonstandard interactions of supernova neutrinos provide a sensitive probe of beyond the Standard Model physics complementary to present and future terrestrial experiments.

  10. 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.

  11. Nonrelativistic Perpendicular Shocks Modeling Young Supernova Remnants: Nonstationary Dynamics and Particle Acceleration at Forward and Reverse Shocks

    NASA Astrophysics Data System (ADS)

    Wieland, Volkmar; Pohl, Martin; Niemiec, Jacek; Rafighi, Iman; Nishikawa, Ken-Ichi

    2016-03-01

    For parameters that are applicable to the conditions at young supernova remnants, we present results of two-dimensional, three-vector (2D3V) particle-in-cell simulations of a non-relativistic plasma shock with a large-scale perpendicular magnetic field inclined at a 45^\\circ angle to the simulation plane to approximate three-dimensional (3D) physics. We developed an improved clean setup that uses the collision of two plasma slabs with different densities and velocities, leading to the development of two distinctive shocks and a contact discontinuity. The shock formation is mediated by Weibel-type filamentation instabilities that generate magnetic turbulence. Cyclic reformation is observed in both shocks with similar period, for which we note global variations due to shock rippling and local variations arising from turbulent current filaments. The shock rippling occurs on spatial and temporal scales produced by the gyro-motions of shock-reflected ions. The drift motion of electrons and ions is not a gradient drift, but is commensurate with {\\boldsymbol{E}}× {\\boldsymbol{B}} drift. We observe a stable supra-thermal tail in the ion spectra, but no electron acceleration because the amplitude of the Buneman modes in the shock foot is insufficient for trapping relativistic electrons. We see no evidence of turbulent reconnection. A comparison with other two-dimensional (2D) simulation results suggests that the plasma beta and the ion-to-electron mass ratio are not decisive for efficient electron acceleration, but the pre-acceleration efficacy might be reduced with respect to the 2D results once 3D effects are fully accounted for. Other microphysical factors may also play a part in limiting the amplitude of the Buneman waves or preventing the return of electrons to the foot region.

  12. The dynamics of neutrino-driven supernova explosions after shock revival in 2D and 3D

    NASA Astrophysics Data System (ADS)

    Müller, B.

    2015-10-01

    We study the growth of the explosion energy after shock revival in neutrino-driven explosions in two and three dimensions (2D/3D) using multi-group neutrino hydrodynamics simulations of an 11.2 M⊙ star. The 3D model shows a faster and steadier growth of the explosion energy and already shows signs of subsiding accretion after one second. By contrast, the growth of the explosion energy in 2D is unsteady, and accretion lasts for several seconds as confirmed by additional long-time simulations of stars of similar masses. Appreciable explosion energies can still be reached, albeit at the expense of rather high neutron star masses. In 2D, the binding energy at the gain radius is larger because the strong excitation of downward-propagating g modes removes energy from the freshly accreted material in the downflows. Consequently, the mass outflow rate is considerably lower in 2D than in 3D. This is only partially compensated by additional heating by outward-propagating acoustic waves in 2D. Moreover, the mass outflow rate in 2D is reduced because much of the neutrino energy deposition occurs in downflows or bubbles confined by secondary shocks without driving outflows. Episodic constriction of outflows and vertical mixing of colder shocked material and hot, neutrino-heated ejecta due to Rayleigh-Taylor instability further hamper the growth of the explosion energy in 2D. Further simulations will be necessary to determine whether these effects are generic over a wider range of supernova progenitors.

  13. 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.

  14. The Supernova Key Project

    NASA Astrophysics Data System (ADS)

    Howell, Dale Andrew

    2017-01-01

    Las Cumbres Observatory is a global network of robotic telescopes specializing in time domain astronomy. It currently has nine 1m telescopes, two 2m telescopes, and seven 0.4m telescopes. The Supernova Key Project is a 3 year program to obtain light curves and spectra of 500 supernovae with Las Cumbres Observatory. Here we show recent results, detail plans for the next Supernova Key Project, and explain how the US community can get involved.

  15. SOUSA Supernova Surprises

    NASA Astrophysics Data System (ADS)

    Brown, Peter J.

    2017-01-01

    The Swift Optical/Ultraviolet Supernova Archive is an effort to make public the Swift UVOT images and final photometry of as many supernovae as possible. These include many of the nearest, brightest, and most exciting supernovae of the last decade. Hiding within the archive, however, are supernovae you have never heard of, which never the less show extremes in color or luminosity or interesting light curve behavior in the ultraviolet. I will highlight some of the extreme objects of different subtypes and puzzling objects which warrant further study.

  16. Surviving Companions of Supernovae

    NASA Astrophysics Data System (ADS)

    Kerzendorf, W.

    2016-06-01

    Most supernovae should occur in binaries. Massive stars, the progenitors of core collapse supernovae (SN II/Ib/c), have a very high binarity fraction of 80 percent (on average, they have 1.5 companions). Binary systems are also required to produce thermonuclear supernovae (SN Ia). Understanding the role that binarity plays in pre-supernova evolution is one of the great mysteries in supernova research. Finding and studying surviving companions of supernovae has the power to shed light on some of these mysteries. Searching Galactic and nearby supernova remnants for surviving companions is a particularly powerful technique. This might allow to study the surviving companion in great detail possibly enabling a relatively detailed reconstruction of the pre-supernova evolution. In this talk, I will summarize the multitude of theoretical studies that have simulated the impact of the shockwave on the companion star and the subsequent evolution of the survivor. I will then give an overview of the searches that used these theoretical findings to identify surviving companions in nearby supernova remnants as well as their results. Finally, I will give an outlook of new opportunities in the relatively young field.

  17. Atomic and molecular supernovae

    NASA Technical Reports Server (NTRS)

    Liu, Weihong

    1997-01-01

    Atomic and molecular physics of supernovae is discussed with an emphasis on the importance of detailed treatments of the critical atomic and molecular processes with the best available atomic and molecular data. The observations of molecules in SN 1987A are interpreted through a combination of spectral and chemical modelings, leading to strong constraints on the mixing and nucleosynthesis of the supernova. The non-equilibrium chemistry is used to argue that carbon dust can form in the oxygen-rich clumps where the efficient molecular cooling makes the nucleation of dust grains possible. For Type Ia supernovae, the analyses of their nebular spectra lead to strong constraints on the supernova explosion models.

  18. Pulsar Wind Bubble Blowout from a Supernova

    NASA Astrophysics Data System (ADS)

    Blondin, John M.; Chevalier, Roger A.

    2017-08-01

    For pulsars born in supernovae, the expansion of the shocked pulsar wind nebula is initially in the freely expanding ejecta of the supernova. While the nebula is in the inner flat part of the ejecta density profile, the swept-up, accelerating shell is subject to the Rayleigh-Taylor instability. We carried out two- and three-dimensional simulations showing that the instability gives rise to filamentary structure during this initial phase but does not greatly change the dynamics of the expanding shell. The flow is effectively self-similar. If the shell is powered into the outer steep part of the density profile, the shell is subject to a robust Rayleigh-Taylor instability in which the shell is fragmented and the shocked pulsar wind breaks out through the shell. The flow is not self-similar in this phase. For a wind nebula to reach this phase requires that the deposited pulsar energy be greater than the supernova energy, or that the initial pulsar period be in the ms range for a typical 1051 erg supernova. These conditions are satisfied by some magnetar models for Type I superluminous supernovae. We also consider the Crab Nebula, which may be associated with a low energy supernova for which this scenario applies.

  19. Matching Supernovae to Galaxies

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-12-01

    One of the major challenges for modern supernova surveys is identifying the galaxy that hosted each explosion. Is there an accurate and efficient way to do this that avoids investing significant human resources?Why Identify Hosts?One problem in host galaxy identification. Here, the supernova lies between two galaxies but though the centroid of the galaxy on the right is closer in angular separation, this may be a distant background galaxy that is not actually near the supernova. [Gupta et al. 2016]Supernovae are a critical tool for making cosmological predictions that help us to understand our universe. But supernova cosmology relies on accurately identifying the properties of the supernovae including their redshifts. Since spectroscopic followup of supernova detections often isnt possible, we rely on observations of the supernova host galaxies to obtain redshifts.But how do we identify which galaxy hosted a supernova? This seems like a simple problem, but there are many complicating factors a seemingly nearby galaxy could be a distant background galaxy, for instance, or a supernovas host could be too faint to spot.The authors algorithm takes into account confusion, a measure of how likely the supernova is to be mismatched. In these illustrations of low (left) and high (right) confusion, the supernova is represented by a blue star, and the green circles represent possible host galaxies. [Gupta et al. 2016]Turning to AutomationBefore the era of large supernovae surveys, searching for host galaxies was done primarily by visual inspection. But current projects like the Dark Energy Surveys Supernova Program is finding supernovae by the thousands, and the upcoming Large Synoptic Survey Telescope will likely discover hundreds of thousands. Visual inspection will not be possible in the face of this volume of data so an accurate and efficient automated method is clearly needed!To this end, a team of scientists led by Ravi Gupta (Argonne National Laboratory) has recently

  20. Synoptic sky surveys and the diffuse supernova neutrino background: Removing astrophysical uncertainties and revealing invisible supernovae

    SciTech Connect

    Lien, Amy; Fields, Brian D.; Beacom, John F.

    2010-04-15

    The cumulative (anti)neutrino production from all core-collapse supernovae within our cosmic horizon gives rise to the diffuse supernova neutrino background (DSNB), which is on the verge of detectability. The observed flux depends on supernova physics, but also on the cosmic history of supernova explosions; currently, the cosmic supernova rate introduces a substantial ({+-}40%) uncertainty, largely through its absolute normalization. However, a new class of wide-field, repeated-scan (synoptic) optical sky surveys is coming online, and will map the sky in the time domain with unprecedented depth, completeness, and dynamic range. We show that these surveys will obtain the cosmic supernova rate by direct counting, in an unbiased way and with high statistics, and thus will allow for precise predictions of the DSNB. Upcoming sky surveys will substantially reduce the uncertainties in the DSNB source history to an anticipated {+-}5% that is dominated by systematics, so that the observed high-energy flux thus will test supernova neutrino physics. The portion of the universe (z < or approx. 1) accessible to upcoming sky surveys includes the progenitors of a large fraction ({approx_equal}87%) of the expected 10-26 MeV DSNB event rate. We show that precision determination of the (optically detected) cosmic supernova history will also make the DSNB into a strong probe of an extra flux of neutrinos from optically invisible supernovae, which may be unseen either due to unexpected large dust obscuration in host galaxies, or because some core-collapse events proceed directly to black hole formation and fail to give an optical outburst.

  1. DYNAMICS OF X-RAY-EMITTING EJECTA IN THE OXYGEN-RICH SUPERNOVA REMNANT PUPPIS A REVEALED BY THE XMM-NEWTON REFLECTION GRATING SPECTROMETER

    SciTech Connect

    Katsuda, Satoru; Tamagawa, Toru; Ohira, Yutaka; Mori, Koji; Tsunemi, Hiroshi; Koyama, Katsuji; Uchida, Hiroyuki

    2013-05-10

    Using the unprecedented spectral resolution of the reflection grating spectrometer (RGS) on board XMM-Newton, we reveal dynamics of X-ray-emitting ejecta in the oxygen-rich supernova remnant Puppis A. The RGS spectrum shows prominent K-shell lines, including O VII He{alpha} forbidden and resonance, O VIII Ly{alpha}, O VIII Ly{beta}, and Ne IX He{alpha} resonance, from an ejecta knot positionally coincident with an optical oxygen-rich filament (the so-called {Omega} filament) in the northeast of the remnant. We find that the line centroids are blueshifted by 1480 {+-} 140 {+-} 60 km s{sup -1} (the first and second term errors are measurement and calibration uncertainties, respectively), which is fully consistent with that of the optical {Omega} filament. Line broadening at 654 eV (corresponding to O VIII Ly{alpha}) is obtained to be {sigma} {approx}< 0.9 eV, indicating an oxygen temperature of {approx}< 30 keV. Analysis of XMM-Newton MOS spectra shows an electron temperature of {approx}0.8 keV and an ionization timescale of {approx}2 Multiplication-Sign 10{sup 10} cm{sup -3} s. We show that the oxygen and electron temperatures as well as the ionization timescale can be reconciled if the ejecta knot was heated by a collisionless shock whose velocity is {approx}600-1200 km s{sup -1} and was subsequently equilibrated due to Coulomb interactions. The RGS spectrum also shows relatively weak K-shell lines of another ejecta feature located near the northeastern edge of the remnant, from which we measure redward Doppler velocities of 650 {+-} 70 {+-} 60 km s{sup -1}.

  2. Production of Light p-Process Isotopes in Neutrino-Irradiated Alpha-Rich Freezeouts

    NASA Astrophysics Data System (ADS)

    Swift, T. P.; Meyer, B. S.; The, L.-S.

    2000-12-01

    The origin of the light, neutron-capture bypassed (p-process) isotopes 92Mo, 94Mo, 96Ru, and 98Ru has long been a mystery. Sites that produce the majority of the p-process isotopes in correct solar proportions have long been known to underproduce the light species [1], thereby suggesting a different origin. The alpha-rich freezeout occurring near a nascent neutron star in Type II supernovae has been proposed [2,3,4]; however, only 92Mo is strongly produced, and it is never the most overproduced isotope, as is required for its site of origin. We explore models of alpha-rich freezeouts that include simultaneous irradiation of the nuclei by the copious neutrinos emitted during the explosion. We find that neutrino-nucleus interactions significantly enhance production of the light p-process species both by affecting the electron-nucleon ratio during the nucleosynthesis and by increasing the charge of nuclei once nuclear quasi-equilibrium clusters have broken. In many models studied, the light p-process isotopes are the most overproduced species, which supports the idea of this being a possible production site. The neutrino fluences required for light p-process isotope production are high--probably somewhat higher than current supernova models allow. Nevertheless, the results are encouraging and suggest further work is needed on this promising site. This work was supported by the NSF Research Experiences for Undergraduates (REU) Site Program through grant AST 96169939 to Florida Tech and the Southeastern Association for Research in Astronomy (SARA). It was also supported by NSF grant AST 9819877 and NASA grant NAG5-4703 at Clemson University. References: [1] Woosley, S. E., and Howard, W. M. 1978, ApJS, 36, 285 [2] Woosley, S. E., and Hoffman, R. D. 1992, ApJ, 395, 202 [3] Fuller, G. M., and Meyer, B. S. 1995, ApJ, 453, 792 [4] Hoffman, R. D., Woosley, S. E., Fuller, G. M., and Meyer, B. S. 1996, ApJ, 460, 478

  3. HUBBLE PINPOINTS DISTANT SUPERNOVAE

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These Hubble Space Telescope images pinpoint three distant supernovae, which exploded and died billions of years ago. Scientists are using these faraway light sources to estimate if the universe was expanding at a faster rate long ago and is now slowing down. Images of SN 1997cj are in the left hand column; SN 1997ce, in the middle; and SN 1997ck, on the right. All images were taken by the Hubble telescope's Wide Field and Planetary Camera 2. The top row of images are wider views of the supernovae. The supernovae were discovered in April 1997 in a ground-based survey at the Canada-France-Hawaii Telescope on Mauna Kea, Hawaii. Once the supernovae were discovered, the Hubble telescope was used to distinguish the supernovae from the light of their host galaxies. A series of Hubble telescope images were taken in May and June 1997 as the supernovae faded. Six Hubble telescope observations spanning five weeks were taken for each supernova. This time series enabled scientists to measure the brightness and create a light curve. Scientists then used the light curve to make an accurate estimate of the distances to the supernovae. Scientists combined the estimated distance with the measured velocity of the supernova's host galaxy to determine the expansion rate of the universe in the past (5 to 7 billion years ago) and compare it with the current rate. These supernovae belong to a class called Type Ia, which are considered reliable distance indicators. Looking at great distances also means looking back in time because of the finite velocity of light. SN 1997ck exploded when the universe was half its present age. It is the most distant supernova ever discovered (at a redshift of 0.97), erupting 7.7 billion years ago. The two other supernovae exploded about 5 billion years ago. SN 1997ce has a redshift of 0.44; SN 1997cj, 0.50. SN 1997ck is in the constellation Hercules, SN 1997ce is in Lynx, just north of Gemini; and SN 1997cj is in Ursa Major, near the Hubble Deep Field

  4. HUBBLE PINPOINTS DISTANT SUPERNOVAE

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These Hubble Space Telescope images pinpoint three distant supernovae, which exploded and died billions of years ago. Scientists are using these faraway light sources to estimate if the universe was expanding at a faster rate long ago and is now slowing down. Images of SN 1997cj are in the left hand column; SN 1997ce, in the middle; and SN 1997ck, on the right. All images were taken by the Hubble telescope's Wide Field and Planetary Camera 2. The top row of images are wider views of the supernovae. The supernovae were discovered in April 1997 in a ground-based survey at the Canada-France-Hawaii Telescope on Mauna Kea, Hawaii. Once the supernovae were discovered, the Hubble telescope was used to distinguish the supernovae from the light of their host galaxies. A series of Hubble telescope images were taken in May and June 1997 as the supernovae faded. Six Hubble telescope observations spanning five weeks were taken for each supernova. This time series enabled scientists to measure the brightness and create a light curve. Scientists then used the light curve to make an accurate estimate of the distances to the supernovae. Scientists combined the estimated distance with the measured velocity of the supernova's host galaxy to determine the expansion rate of the universe in the past (5 to 7 billion years ago) and compare it with the current rate. These supernovae belong to a class called Type Ia, which are considered reliable distance indicators. Looking at great distances also means looking back in time because of the finite velocity of light. SN 1997ck exploded when the universe was half its present age. It is the most distant supernova ever discovered (at a redshift of 0.97), erupting 7.7 billion years ago. The two other supernovae exploded about 5 billion years ago. SN 1997ce has a redshift of 0.44; SN 1997cj, 0.50. SN 1997ck is in the constellation Hercules, SN 1997ce is in Lynx, just north of Gemini; and SN 1997cj is in Ursa Major, near the Hubble Deep Field

  5. Experimental challenge to nuclear physics problems in the {nu}p-process

    SciTech Connect

    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.; and others

    2012-11-12

    Astrophysical stellar reactions at extremely high temperatures involve a variety of problems both in nuclear reactions and nuclear structures. Specifically, the problems in the {nu}pprocess were discussed in this talk based on our recent experimental results with low-energy RI beams and a simulation study. The {nu}p-process is one of the key processes for investigating the mechanism of type II supernovae, and the process could be possibly responsible for 'the excess production' of p-nuclei around mass 90-100. Alpha cluster resonances have been discovered experimentally to play a crucial role for the stellar ({alpha}, p) reactions just above the alpha threshold. Neutron induced reactions in the proton-rich nuclear regions in the {nu}p-process are also suggested to play an important role, which involve nuclear structures of high level density at high excitation energies, probably giant resonances. The discussion also covered the p-nuclei production through the {nu}p-process at around mass 100.

  6. The physics of core collapse supernovae

    NASA Astrophysics Data System (ADS)

    Swesty, Frank Douglas

    1993-01-01

    I have developed an equation of state (EOS) for hot, dense matter that is intended specifically for use in radiation hydrodynamic simulations of supernovae, proto-neutron star cooling, and neutron stars. This EOS makes use of an adjustable nucleon-nucleon interaction that allows for the input of various nuclear force parameters that are not well determined by laboratory measurements. Properties of the EOS as a function of these input parameters were studied and comparisons were made to another EOS that is currently used in stellar collapse simulations. Using this EOS I have conducted simulations of core collapse supernovae with several ideas in mind. First, I have attempted to delineate role of the incompressibility of dense matter in supernovae. I have conducted a parameter study in which the compression modulous of bulk nuclear matter was varied and have found some new and surprising results. When the EOS is constrained by the observed mass of 1.44M(solar mass) for one of the components of the binary pulsar system PSR1913+16, the 'stiffness' of the EOS no longer plays a role in the shock dynamics of the supernova. Secondly, I varied the symmetry energy coefficients in the EOS to determine the role of these coefficients in supernovae. I have found that the symmetry energy behavior of the EOS has potentially observable effects and may play an important role in determining the efficacy of the late-time heating mechanism for the explosion and the stability of the post-bounce core against convection. Finally, I have developed an implicit, general relativistic, radiation hydrodynamics algorithm for the numerical simulation of supernovae. By allowing simulation timesteps to exceed the Courant timescale, this algorithm makes practical high resolution simulations of supernovae to late times. I discuss this algorithm and the associated computer code along with code verification tests and an example of a late-time calculation.

  7. Galaxy Zoo Supernovae

    NASA Astrophysics Data System (ADS)

    Smith, A. M.; Lynn, S.; Sullivan, M.; Lintott, C. J.; Nugent, P. E.; Botyanszki, J.; Kasliwal, M.; Quimby, R.; Bamford, S. P.; Fortson, L. F.; Schawinski, K.; Hook, I.; Blake, S.; Podsiadlowski, P.; Jönsson, J.; Gal-Yam, A.; Arcavi, I.; Howell, D. A.; Bloom, J. S.; Jacobsen, J.; Kulkarni, S. R.; Law, N. M.; Ofek, E. O.; Walters, R.

    2011-04-01

    This paper presents the first results from a new citizen science project: Galaxy Zoo Supernovae. This proof-of-concept project uses members of the public to identify supernova candidates from the latest generation of wide-field imaging transient surveys. We describe the Galaxy Zoo Supernovae operations and scoring model, and demonstrate the effectiveness of this novel method using imaging data and transients from the Palomar Transient Factory (PTF). We examine the results collected over the period 2010 April-July, during which nearly 14 000 supernova candidates from the PTF were classified by more than 2500 individuals within a few hours of data collection. We compare the transients selected by the citizen scientists to those identified by experienced PTF scanners and find the agreement to be remarkable - Galaxy Zoo Supernovae performs comparably to the PTF scanners and identified as transients 93 per cent of the ˜130 spectroscopically confirmed supernovae (SNe) that the PTF located during the trial period (with no false positive identifications). Further analysis shows that only a small fraction of the lowest signal-to-noise ratio detections (r > 19.5) are given low scores: Galaxy Zoo Supernovae correctly identifies all SNe with ≥8σ detections in the PTF imaging data. The Galaxy Zoo Supernovae project has direct applicability to future transient searches, such as the Large Synoptic Survey Telescope, by both rapidly identifying candidate transient events and via the training and improvement of existing machine classifier algorithms. This publication has been made possible by the participation of more than 10 000 volunteers in the Galaxy Zoo Supernovae project ().

  8. Formation of nuclear "pasta" in supernovae.

    PubMed

    Watanabe, Gentaro; Sonoda, Hidetaka; Maruyama, Toshiki; Sato, Katsuhiko; Yasuoka, Kenji; Ebisuzaki, Toshikazu

    2009-09-18

    In supernova cores, nuclear "pasta" phases such as a triangular lattice of rodlike nuclei and layered structure of slablike nuclei are considered to exist. However, it is still unclear whether or not they are actually formed in collapsing supernova cores. Using ab initio simulations called quantum molecular dynamics, here we solve this problem by demonstrating that a lattice of rodlike nuclei is formed from a bcc lattice by compression. We also find that, in the transition process, the system undergoes a zigzag configuration of elongated nuclei, which are formed by a fusion of two original spherical nuclei.

  9. Deflagrations and detonations in thermonuclear supernovae.

    PubMed

    Gamezo, Vadim N; Khokhlov, Alexei M; Oran, Elaine S

    2004-05-28

    We study a type Ia supernova explosion using three-dimensional numerical simulations based on reactive fluid dynamics. We consider a delayed-detonation model that assumes a deflagration-to-detonation transition. In contrast with the pure deflagration model, the delayed-detonation model releases enough energy to account for a healthy explosion, and does not leave carbon, oxygen, and intermediate-mass elements in central parts of a white dwarf. This removes the key disagreement between simulations and observations, and makes a delayed detonation the mostly likely mechanism for type Ia supernovae.

  10. TOPICAL REVIEW: Neutrino flavour transformation in supernovae

    NASA Astrophysics Data System (ADS)

    Duan, H.; Kneller, J. P.

    2009-11-01

    Rapid progress has been made during recent years in the understanding of the flavour oscillations that occur as neutrinos traverse through supernova. The previous paradigm has given way and it is now clear that the neutrino signals we shall receive from future galactic supernovae will allow us both to peer inside these extraordinary cosmic events and to probe some of the fundamental properties of these elusive particles. In this review, we aim to distill the progress that has been made focusing upon the effects of the dynamic density profile and the emergence of collective flavour oscillations due to neutrino self-interactions.

  11. Neutrino Nucleosynthesis in Supernovae

    SciTech Connect

    Yoshida, Takashi; Suzuki, Toshio; Chiba, Satoshi; Kajino, Toshitaka; Yokomakura, Hidekazu; Kimura, Keiichi; Takamura, Akira; Hartmann, Dieter H.

    2009-05-04

    Neutrino nucleosynthesis is an important synthesis process for light elements in supernovae. One important physics input of neutrino nucleosynthesis is cross sections of neutrino-nucleus reactions. The cross sections of neutrino-{sup 12}C and {sup 4}He reactions are derived using new shell model Hamiltonians. With the new cross sections, light element synthesis of a supernova is investigated. The appropriate range of the neutrino temperature for supernovae is constrained to be between 4.3 MeV and 6.5 MeV from the {sup 11}B abundance in Galactic chemical evolution. Effects by neutrino oscillations are also discussed.

  12. Neutrinos and Supernovae

    SciTech Connect

    Meyer, Bradley S.

    2008-05-12

    Core-collapse supernovae are one of the few astrophysical environments in which neutrinos play a dominant role. Neutrinos emission is the means by which a newly-born neutron star formed in a core-collapse event cools. Neutrinos may play a significant role in causing the supernova explosion. Finally neutrinos may significantly affect the nucleosynthesis occurring in the layers of the exploding star that are eventually ejected into interstellar space. This paper reviews some interesting neutrino-nucleus processes that may occur in the cores of exploding massive stars and then discusses some effects neutrinos may have on explosive nucleosynthesis in supernovae.

  13. Supernova Remnants And GLAST

    SciTech Connect

    Slane, Patrick; /Harvard-Smithsonian Ctr. Astrophys.

    2011-11-29

    It has long been speculated that supernova remnants represent a major source of cosmic rays in the Galaxy. Observations over the past decade have ceremoniously unveiled direct evidence of particle acceleration in SNRs to energies approaching the knee of the cosmic ray spectrum. Nonthermal X-ray emission from shell-type SNRs reveals multi-TeV electrons, and the dynamical properties of several SNRs point to efficient acceleration of ions. Observations of TeV gamma-ray emission have confirmed the presence of energetic particles in several remnants as well, but there remains considerable debate as to whether this emission originates with high energy electrons or ions. Equally uncertain are the exact conditions that lead to efficient particle acceleration. Based on the catalog of EGRET sources, we know that there is a large population of Galactic gamma-ray sources whose distribution is similar to that of SNRs.With the increased resolution and sensitivity of GLAST, the gamma-ray SNRs from this population will be identified. Their detailed emission structure, along with their spectra, will provide the link between their environments and their spectra in other wavebands to constrain emission models and to potentially identify direct evidence of ion acceleration in SNRs. Here I summarize recent observational and theoretical work in the area of cosmic ray acceleration by SNRs, and discuss the contributions GLAST will bring to our understanding of this problem.

  14. Nuclear reactions in shock wave front during supernova events

    NASA Technical Reports Server (NTRS)

    Lavrukhina, A. K.

    1985-01-01

    The new unique isotopic anomalous coponent of Xe(XeX) was found in the carbonaceous chondrites. It is enriched in light shielded isotopes (124Xe and 126Xe) and in heavy nonshielded isotopes (134Xe and 136Xe. All characteristics of Xe-X can be explained by a model of nucleosynthesis of the Xe isotopes in shock wave front passed through the He envelope during supernova events. The light isotopes are created by p process and the heavy isotopes are created by n process (slow r process). They were captured with high temperature carbon grains condensing by supernova shock waves.

  15. 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.

  16. Evolution of a Supernova

    NASA Image and Video Library

    2014-02-19

    A massive star left, which has created elements as heavy as iron in its interior, blows up in a tremendous explosion middle, scattering its outer layers in a structure called a supernova remnant right.

  17. Nucleosynthesis in Thermonuclear Supernovae

    SciTech Connect

    Claudia, Travaglio; Hix, William Raphael

    2013-01-01

    We review our understanding of the nucleosynthesis that occurs in thermonuclear supernovae and their contribution to Galactic Chemical evolution. We discuss the prospects to improve the modeling of the nucleosynthesis within simulations of these events.

  18. Infrared supernovae in starbursts

    SciTech Connect

    Van Buren, D.; Norman, C.A.

    1989-01-01

    The problem of uniquely confirming that the luminosity source of starburst galaxies is a young population of massive stars is considered. Unambiguous detection of the supernova explosion associated with a massive stellar population would provide proof of the starburst hypothesis. High spatial resolution narrow-band infrared imaging of starburst galaxies directly detects the cobalt synthesized in Type II supernova explosions. Coupled with observations of other infrared lines and continuum, progenitor masses can be at least roughly estimated. A statistically large sample of starburst supernovae will lead to an average starburst initial mass function. Standard candles can also be constructed, based on both individual and populations of supernovae. With current and planned instruments, K-band can be found out to cosmological distances. 27 references.

  19. Berkeley automated supernova search

    SciTech Connect

    Kare, J.T.; Pennypacker, C.R.; Muller, R.A.; Mast, T.S.; Crawford, F.S.; Burns, M.S.

    1981-01-01

    The Berkeley automated supernova search employs a computer controlled 36-inch telescope and charge coupled device (CCD) detector to image 2500 galaxies per night. A dedicated minicomputer compares each galaxy image with stored reference data to identify supernovae in real time. The threshold for detection is m/sub v/ = 18.8. We plan to monitor roughly 500 galaxies in Virgo and closer every night, and an additional 6000 galaxies out to 70 Mpc on a three night cycle. This should yield very early detection of several supernovae per year for detailed study, and reliable premaximum detection of roughly 100 supernovae per year for statistical studies. The search should be operational in mid-1982.

  20. The SILCC (SImulating the LifeCycle of molecular Clouds) project - II. Dynamical evolution of the supernova-driven ISM and the launching of outflows

    NASA Astrophysics Data System (ADS)

    Girichidis, Philipp; Walch, Stefanie; Naab, Thorsten; Gatto, Andrea; Wünsch, Richard; Glover, Simon C. O.; Klessen, Ralf S.; Clark, Paul C.; Peters, Thomas; Derigs, Dominik; Baczynski, Christian

    2016-03-01

    The SILCC project (SImulating the Life-Cycle of molecular Clouds) aims at a more self-consistent understanding of the interstellar medium (ISM) on small scales and its link to galaxy evolution. We present three-dimensional (magneto)hydrodynamic simulations of the ISM in a vertically stratified box including self-gravity, an external potential due to the stellar component of the galactic disc, and stellar feedback in the form of an interstellar radiation field and supernovae (SNe). The cooling of the gas is based on a chemical network that follows the abundances of H+, H, H2, C+, and CO and takes shielding into account consistently. We vary the SN feedback by comparing different SN rates, clustering and different positioning, in particular SNe in density peaks and at random positions, which has a major impact on the dynamics. Only for random SN positions the energy is injected in sufficiently low-density environments to reduce energy losses and enhance the effective kinetic coupling of the SNe with the gas. This leads to more realistic velocity dispersions (σ _H I≈ 0.8σ _{300{-}8000 K}˜ 10-20 km s^{-1}, σ _H α ≈ 0.6σ _{8000-3× 10^5 K}˜ 20-30 km s^{-1}), and strong outflows with mass loading factors (ratio of outflow to star formation rate) of up to 10 even for solar neighbourhood conditions. Clustered SNe abet the onset of outflows compared to individual SNe but do not influence the net outflow rate. The outflows do not contain any molecular gas and are mainly composed of atomic hydrogen. The bulk of the outflowing mass is dense (ρ ˜ 10-25-10-24 g cm-3) and slow (v ˜ 20-40 km s-1) but there is a high-velocity tail of up to v ˜ 500 km s-1 with ρ ˜ 10-28-10-27 g cm-3.

  1. Supernova 1987A

    NASA Astrophysics Data System (ADS)

    McCray, R.; Murdin, P.

    2002-10-01

    Supernova 1987A (SN1987A) in the LARGE MAGELLANIC CLOUD (LMC) is the brightest supernova to be observed since SN1604 (Kepler), the first to be observed in every band of the ELECTROMAGNETIC SPECTRUM and the first to be detected through its initial burst of NEUTRINOS. Although the bolometric luminosity of SN1987A today is ≈10-6 of its value at maximum light (Lmax≈2.5×108L⊙), it ...

  2. 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

  3. Physics of supernovae

    SciTech Connect

    Woosley, S.E.; Weaver, T.A.

    1985-12-13

    Presupernova models of massive stars are presented and their explosion by ''delayed neutrino transport'' examined. A new form of long duration Type II supernova model is also explored based upon repeated encounter with the electron-positron pair instability in stars heavier than about 60 Msub solar. Carbon deflagration in white dwarfs is discussed as the probable explanation of Type I supernovae and special attention is paid to the physical processes whereby a nuclear flame propagates through degenerate carbon. 89 refs., 12 figs.

  4. Dust in supernova remnants

    NASA Astrophysics Data System (ADS)

    Gomez, H.

    In this Review, I will discuss our changing view on supernovae as interstellar dust sources. In particular I will focus on infrared and submillimetre studies of the historical supernova remnants Cassiopeia A, the Crab Nebula, SN 1987A, Tycho and Kepler. In the last decade (and particularly in recent years), SCUBA, Herschel and ALMA have now demonstrated that core-collapse supernovae are prolific dust factories, with evidence of 0.1 - 0.7 M⊙ of dust formed in the ejecta, though there is little evidence (as yet) for significant dust production in Type Ia supernova ejecta. There is no longer any question that dust (and molecule) formation is efficient after some supernova events, though it is not clear how much of this will survive over longer timescales. Current and future instruments will allow us to investigate the spatial distribution of dust within corecollapse ejecta, and whether this component contributes a significant amount to the dust content of the Universe or if supernovae ultimately provide a net loss once dust destruction by shocks is taken into account.

  5. Neutrinos from supernovae.

    NASA Astrophysics Data System (ADS)

    Burrows, A. S.

    First, the author presents a short history of supernova neutrino theory. Then, the theory of core collapse supernovae is reviewed. Because of the profound opacity to light of the dense core that experiences collapse, we "see" this core directly only through its neutrino signature. Every bump and wiggle echoes the internal convulsions of the event and can provide clues about both the supernova mechanism and the neutron star that remains. The author discusses the only neutrino observations of a supernova so far, SN 1987A. While the agreement with calculations has been gratifying, there remain, of course, plenty of outstanding issues in supernova theory to be tested. These are high-lighted throughout the text. Since neutrinos give us the only real access to the physics inside the collapse, it is important that observation of these particles continue. In an appendix the author describes some of the available or contemplated neutrino detectors capable of good time resolution and therefore of shedding light on supernova mechanisms.

  6. PROGENITORS OF RECOMBINING SUPERNOVA REMNANTS

    SciTech Connect

    Moriya, Takashi J.

    2012-05-01

    Usual supernova remnants have either ionizing plasma or plasma in collisional ionization equilibrium, i.e., the ionization temperature is lower than or equal to the electron temperature. However, the existence of recombining supernova remnants, i.e., supernova remnants with ionization temperature higher than the electron temperature, has been recently confirmed. One suggested way to have recombining plasma in a supernova remnant is to have a dense circumstellar medium at the time of the supernova explosion. If the circumstellar medium is dense enough, collisional ionization equilibrium can be established in the early stage of the evolution of the supernova remnant and subsequent adiabatic cooling, which occurs after the shock wave gets out of the dense circumstellar medium, makes the electron temperature lower than the ionization temperature. We study the circumstellar medium around several supernova progenitors and show which supernova progenitors can have a circumstellar medium dense enough to establish collisional ionization equilibrium soon after the explosion. We find that the circumstellar medium around red supergiants (especially massive ones) and the circumstellar medium dense enough to make Type IIn supernovae can establish collisional ionization equilibrium soon after the explosion and can evolve to become recombining supernova remnants. Wolf-Rayet stars and white dwarfs have the possibility to be recombining supernova remnants but the fraction is expected to be very small. As the occurrence rate of the explosions of red supergiants is much higher than that of Type IIn supernovae, the major progenitors of recombining supernova remnants are likely to be red supergiants.

  7. 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.

  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

    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.

  10. A high-resolution radio image of a young supernova

    NASA Technical Reports Server (NTRS)

    Bartel, N.; Rupen, M. P.; Shapiro, I. I.; Preston, R. A.; Rius, A.

    1991-01-01

    A VLBI radio images of the bright supernova 1986J, which occurred in the galaxy NGC891 at a distance of about 12 Mpc, is presented. No detailed image of any supernova or remnant has been obtained before so soon after the explosion. The image shows a shell of emission with jetlike protrusions. Analysis of the images should advance understanding of the dynamics of the expanding debris, the dissipation of energy into the surrounding circumstellar medium, and the evolution of the supernova into the remnant.

  11. An effective Lagrangian description of supernova-core bounce

    NASA Astrophysics Data System (ADS)

    Rodrigues, H.; Deavila, V.; Duarte, S. J. B.; Kodama, T.

    1990-08-01

    The global dynamical aspects of a supernova event are studied in terms of an effective Lagrangian formulation. The equation of motion derived from this Lagrangian is solved numerically for different supernova core masses. An equation of state for cold matter is introduced by means of an adiabatic index parametrization which is a smooth function of the matter density. The energy transfer from the inner to the outer core is estimated in the context of the hydrodynamic bounce mechanism. It is found that only a very restricted mass distribution to pre-supernova core configuration generate a strong enough shock wave leading to a prompt bounce ejection.

  12. Dark matter triggers of supernovae

    NASA Astrophysics Data System (ADS)

    Graham, Peter W.; Rajendran, Surjeet; Varela, Jaime

    2015-09-01

    The transit of primordial black holes through a white dwarf causes localized heating around the trajectory of the black hole through dynamical friction. For sufficiently massive black holes, this heat can initiate runaway thermonuclear fusion causing the white dwarf to explode as a supernova. The shape of the observed distribution of white dwarfs with masses up to 1.25 M⊙ rules out primordial black holes with masses ˜1019- 1020 gm as a dominant constituent of the local dark matter density. Black holes with masses as large as 1024 gm will be excluded if recent observations by the NuStar Collaboration of a population of white dwarfs near the galactic center are confirmed. Black holes in the mass range 1020- 1022 gm are also constrained by the observed supernova rate, though these bounds are subject to astrophysical uncertainties. These bounds can be further strengthened through measurements of white dwarf binaries in gravitational wave observatories. The mechanism proposed in this paper can constrain a variety of other dark matter scenarios such as Q balls, annihilation/collision of large composite states of dark matter and models of dark matter where the accretion of dark matter leads to the formation of compact cores within the star. White dwarfs, with their astronomical lifetimes and sizes, can thus act as large spacetime volume detectors enabling a unique probe of the properties of dark matter, especially of dark matter candidates that have low number density. This mechanism also raises the intriguing possibility that a class of supernova may be triggered through rare events induced by dark matter rather than the conventional mechanism of accreting white dwarfs that explode upon reaching the Chandrasekhar mass.

  13. Modeling Core Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Mezzacappa, Anthony

    2017-01-01

    Core collapse supernovae, or the death throes of massive stars, are general relativistic, neutrino-magneto-hydrodynamic events. The core collapse supernova mechanism is still not in hand, though key components have been illuminated, and the potential for multiple mechanisms for different progenitors exists. Core collapse supernovae are the single most important source of elements in the Universe, and serve other critical roles in galactic chemical and thermal evolution, the birth of neutron stars, pulsars, and stellar mass black holes, the production of a subclass of gamma-ray bursts, and as potential cosmic laboratories for fundamental nuclear and particle physics. Given this, the so called ``supernova problem'' is one of the most important unsolved problems in astrophysics. It has been fifty years since the first numerical simulations of core collapse supernovae were performed. Progress in the past decade, and especially within the past five years, has been exponential, yet much work remains. Spherically symmetric simulations over nearly four decades laid the foundation for this progress. Two-dimensional modeling that assumes axial symmetry is maturing. And three-dimensional modeling, while in its infancy, has begun in earnest. I will present some of the recent work from the ``Oak Ridge'' group, and will discuss this work in the context of the broader work by other researchers in the field. I will then point to future requirements and challenges. Connections with other experimental, observational, and theoretical efforts will be discussed, as well.

  14. Supernovae by the Hundreds: the LCOGT Supernova Key Project

    NASA Astrophysics Data System (ADS)

    Howell, Dale Andrew; Arcavi, Iair; Hosseinzadeh, Griffin; McCully, Curtis; Valenti, Stefano; LCOGT Key Project

    2016-01-01

    The LCOGT Supernova Key Project is a three year project to obtain lightcurves and spectra of 600 supernovae. To do this, it has been awarded 2900 hours per year on the 9 one meter and 2 two meter robotic telescopes of the Las Cumbres Observatory Global Telescope network (LCOGT). At the midway point of the Key Project, it is on track to achieving its goals. I will discuss recent insights into supernova progenitors, exotic individual supernovae, and some of the large samples of supernovae studied by the project.

  15. Supernova and cosmic rays

    NASA Technical Reports Server (NTRS)

    Wefel, J. P.

    1981-01-01

    A general overview of supernova astronomy is presented, followed by a discussion of the relationship between SN and galactic cosmic rays. Pre-supernova evolution is traced to core collapse, explosion, and mass ejection. The two types of SN light curves are discussed in terms of their causes, and the different nucleosynthetic processes inside SNs are reviewed. Physical events in SN remnants are discussed. The three main connections between cosmic rays and SNs, the energy requirement, the acceleration mechanism, and the detailed composition of CR, are detailed.

  16. 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''.

  17. Demonstrating Supernova Remnant Evolution

    NASA Astrophysics Data System (ADS)

    Leahy, Denis A.; Williams, Jacqueline

    2017-01-01

    We have created a software tool to calculate at display supernova remnant evolution which includes all stages from early ejecta dominated phase to late-time merging with the interstellar medium. The software was created using Python, and can be distributed as Python code, or as an executable file. The purpose of the software is to demonstrate the different phases and transitions that a supernova remnant undergoes, and will be used in upper level undergraduate astrophysics courses as a teaching tool. The usage of the software and its graphical user interface will be demonstrated.

  18. The WFIRST Supernova Survey

    NASA Astrophysics Data System (ADS)

    Foley, Ryan J.; Hounsell, Rebekah; Scolnic, Daniel; WFIRST Supernova Science Investigation Team

    2017-01-01

    WFRIST is expected to launch in the mid 2020s. As part of its main mission, it will conduct a survey to measure the Universe's cosmic expansion history with supernovae. I will present the first simulations of this survey. The simulations take into account our current knowledge of the hardware, realistic properties of the supernovae, and our understanding of the relevant systematic uncertainties. I will compare the ultimate dark enegery figures of merit derived from the simulations and discuss future plans. These data will be extremely useful for other science; other transient science and studies of the resulting deep static images will particularly benefit.

  19. Supernova remnant morphology

    NASA Astrophysics Data System (ADS)

    Manchester, R. N.

    1994-04-01

    The morphology of supernova remnants is principally determined by two components, a shell formed by interaction of the supernova ejecta with the surrounding medium, and a nebula which is powered directly by the associated pulsar. This nebula, often called a 'plerion', is usually located within the shell. These two components appear to evolve independently; in many cases there is no detectable plerion and in a few cases, the Crab Nebula being the most notable example, there is no detectable shell. A 'theoretician's supernova remnant' has spherical symmetry, but observers know that this is rarely the case. There are four main possible sources of non-sphericity, namely, the surrounding interstellar medium, the circumstellar medium, the surpernova explosion, and the associated pulsar. Supernovae often occured in active star formation regions and these regions often have complex networks of cavities blown by strong stellar winds. A supernova remnant expanding in this environment can consist of a several shell-like structure. IC443 is a good example (Braun and Strom, 1986, Astron. Astrophys., 1264, 193). The enhancement of Supernova remnant (SNR) shell brightness toward the Galactic plane (Caswell, 1977, Proc. Astron. Soc. Aust., 3, 130) is further evidence of the influence of the large-scale structure of the interstellar medium. One of the most common forms of non-sphericity is a bilateral symmetry attributed to a barrel-shaped enhancement of the shell (Kesteven and Caswell, 1987, Astron. Astrophys., 183, 118). There is good evidence that this and the associated bi-annular structure often obseved (Manchester, 1987, Astron. Astrophys., 171, 205) ar due to structure in the circumstellar material resulting from mass loss from the pre-supernova star (Storey et al., 1992, Astron. Astrophys., 265, 752). supernova remants (e.g., Tuohy, Clark and Burton, 1982, Astrophys. &J., 260, L65) are evidence that

  20. Supernova 1987A

    NASA Technical Reports Server (NTRS)

    Mccray, Richard; Li, Hong Wei

    1988-01-01

    Supernova 1987A (February 23, 1987) in the Large Magellanic Cloud is the brightest supernova to be observed since SN 1604 AD (Kepler). Detection of a burst of neutrinos indicates that a neutron star was formed. Radioactive decay of about 0.07 solar mass of Co-56 is responsible for the observed optical light as well as hard X-rays and gamma-ray lines. Ultraviolet, optical, and infrared 'light echoes' and soft X-rays provide information on the distribution of circumstellar matter and the evolution of the progenitor star.

  1. Supernova science with LCOGT

    NASA Astrophysics Data System (ADS)

    Howell, Dale A.; Valenti, S.; Sand, D. J.; Parrent, J. T.; Arcavi, I.; Graham, M. L.

    2014-01-01

    Las Cumbres Observatory Global Telescope Network (LCOGT.net) is a collection of nine robotic one meter telescopes with imagers spaced around the world in longitude, operated as a single network. There are also two robotic FLOYDS spectrographs on the two meter Faulkes telescopes in Siding Spring, Australia, and Haleakala, Hawaii. Here we describe recent supernova lightcurves and spectra with taken with LCOGT after being triggered from Pan-STARRS1, the La Silla-QUEST survey, the intermediate Palomar Transient Factory, and the IAU circulars. Since at least one telescope is always in the dark, and the facilities are robotic, LCOGT is uniquely suited to early-time supernova science.

  2. Supernova 1987A

    NASA Technical Reports Server (NTRS)

    Mccray, Richard; Li, Hong Wei

    1988-01-01

    Supernova 1987A (February 23, 1987) in the Large Magellanic Cloud is the brightest supernova to be observed since SN 1604 AD (Kepler). Detection of a burst of neutrinos indicates that a neutron star was formed. Radioactive decay of about 0.07 solar mass of Co-56 is responsible for the observed optical light as well as hard X-rays and gamma-ray lines. Ultraviolet, optical, and infrared 'light echoes' and soft X-rays provide information on the distribution of circumstellar matter and the evolution of the progenitor star.

  3. A more direct measure of supernova rates in starburst galaxies

    NASA Technical Reports Server (NTRS)

    Van Buren, Dave; Greenhouse, Matthew A.

    1994-01-01

    We determine ages for young supernova remnants in the starburst galaxies M82 and NGC 253 by applying Chevalier's model for radio emission from supernova blast waves expanding into the ejecta of their precursor stars. Absolute ages are determined by calibrating the model with radio observations of Cas A. We derive supernova rates of 0.10 and 0.08/yr for M82 and NGC 253, respectively. Assuming L (sub FIR) to be proportional to the supernova rate, we find r(sub SN) approximately equal 2 x 10(exp -12) x L(sub FIR), solar yr(exp -1) for these archetypal starburst galaxies. This approach is unique in that the supernova rate is derived from direct observation of supernova remnants rather than from star formation rates and an assumed initial mass function (IMF). We suggest that the approach presented here can be used to derive star-formation rates that are more directly related to observable quantities than those derived by other methods. We find that the supernova rate, far infrared (FIR) luminosity, and dynamical mass of the M82 starburst place few constraints on the initial mass function (IMF) slope and mass limits.

  4. Electron antineutrino detection from simulated supernovae

    NASA Astrophysics Data System (ADS)

    Luoma, Steffon Jon

    Supernova 1987A demonstrated that neutrinos from a nearby supernova could be detected terrestrially. The partition of events between the neutrino flavours generated by stellar collapse can provide details about supernova dynamics and by using Monte Carlo simulations we can prepare for the analysis of data from the next such supernova. Through its sensitivity to the charged current, neutral current and elastic scattering interactions in both the heavy and light waters, the Sudbury Neutrino Observatory (SNO) is able to measure this partition. The unique signal of the charged current [Special characters omitted.] interactions with deuterium nuclei ([Special characters omitted.] + d [arrow right] n + n + e + ) allows a direct count of the number of [Special characters omitted.] 's to be made. With the addition of NaCl to the heavy water the efficiency of detecting neutrons was increased, which in turn increased the sensitivity for the detection of [Special characters omitted.] 's. This work explores methods of identifying [Special characters omitted.] 's in the high flux environment of a modeled supernova source in SNO during the salt phase. The differences in energy spectrum and in PMT hit pattern of positrons and neutrons allow for distinction between the two, and thus permits classification. Association of these particles to the [Special characters omitted.] interaction is made possible by measuring the time and space between detection of the positron and each neutron generated from the same [Special characters omitted.] . A [Special characters omitted.] is considered to be identified when the correct final state particles generated from the interaction with a deuterium nucleus are associated with each other. Because the expected data rate may be very high and may have a large dynamic range, causing some improper particle association, a pivotal component of this analysis is understanding the rate dependencies. To accomplish this, datasets were generated at several

  5. First stars, hypernovae, and superluminous supernovae

    NASA Astrophysics Data System (ADS)

    Nomoto, Ken'Ichi

    2016-07-01

    After the big bang, production of heavy elements in the early universe takes place starting from the formation of the first (Pop III) stars, their evolution, and explosion. The Pop III supernova (SN) explosions have strong dynamical, thermal, and chemical feedback on the formation of subsequent stars and evolution of galaxies. However, the nature of Pop III stars/supernovae (SNe) have not been well-understood. The signature of nucleosynthesis yields of the first SN can be seen in the elemental abundance patterns observed in extremely metal-poor (EMP) stars. We show that the abundance patterns of EMP stars, e.g. the excess of C, Co, Zn relative to Fe, are in better agreement with the yields of hyper-energetic explosions (Hypernovae, (HNe)) rather than normal supernovae. We note the large variation of the abundance patterns of EMP stars propose that such a variation is related to the diversity of the GRB-SNe and posssibly superluminous supernovae (SLSNe). For example, the carbon-enhanced metal-poor (CEMP) stars may be related to the faint SNe (or dark HNe), which could be the explosions induced by relativistic jets. Finally, we examine the various mechanisms of SLSNe.

  6. Cooling and evolution of a supernova remnant.

    NASA Technical Reports Server (NTRS)

    Cox, D. P.

    1972-01-01

    Discussion of the structure, evolution, and cooling of an old supernova remnant, aimed at providing a theoretical framework for relating remnants with similar energies and environments but of different ages. Discussed evolution details include the Sedov-Taylor blast wave, the electron-ion equipartition and thermal conduction, the temperature sag and the dynamics in the process of transition to a dense shell, and the history of remnant luminosity.

  7. 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.

  8. 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.

  9. QCD and Supernovas

    NASA Astrophysics Data System (ADS)

    Barnes, T.

    2005-12-01

    In this contribution we briefly summarize aspects of the physics of QCD which are relevant to the supernova problem. The topic of greatest importance is the equation of state (EOS) of nuclear and strongly-interacting matter, which is required to describe the physics of the proto-neutron star (PNS) and the neutron star remnant (NSR) formed during a supernova event. Evaluation of the EOS in the regime of relevance for these systems, especially the NSR, requires detailed knowledge of the spectrum and strong interactions of hadrons of the accessible hadronic species, as well as other possible phases of strongly interacting matter, such as the quark-gluon plasma (QGP). The forces between pairs of baryons (both nonstrange and strange) are especially important in determining the EOS at NSR densities. Predictions for these forces are unfortunately rather model dependent where not constrained by data, and there are several suggestions for the QCD mechanism underlying these short-range hadronic interactions. The models most often employed for determining these strong interactions are broadly of two types, 1) meson exchange models (usually assumed in the existing neutron star and supernova literature), and 2) quark-gluon models (mainly encountered in the hadron, nuclear and heavy-ion literature). Here we will discuss the assumptions made in these models, and discuss how they are applied to the determination of hadronic forces that are relevant to the supernova problem.

  10. Supernova Photometric Lightcurve Classification

    NASA Astrophysics Data System (ADS)

    Zaidi, Tayeb; Narayan, Gautham

    2016-01-01

    This is a preliminary report on photometric supernova classification. We first explore the properties of supernova light curves, and attempt to restructure the unevenly sampled and sparse data from assorted datasets to allow for processing and classification. The data was primarily drawn from the Dark Energy Survey (DES) simulated data, created for the Supernova Photometric Classification Challenge. This poster shows a method for producing a non-parametric representation of the light curve data, and applying a Random Forest classifier algorithm to distinguish between supernovae types. We examine the impact of Principal Component Analysis to reduce the dimensionality of the dataset, for future classification work. The classification code will be used in a stage of the ANTARES pipeline, created for use on the Large Synoptic Survey Telescope alert data and other wide-field surveys. The final figure-of-merit for the DES data in the r band was 60% for binary classification (Type I vs II).Zaidi was supported by the NOAO/KPNO Research Experiences for Undergraduates (REU) Program which is funded by the National Science Foundation Research Experiences for Undergraduates Program (AST-1262829).

  11. Supernova Confetti in Meteorites

    NASA Astrophysics Data System (ADS)

    Taylor, G. J.

    2010-11-01

    Chromium has four isotopes, with atomic weights of 50, 52, 53, and 54. In terrestrial rocks the isotopes behave in predictable ways, with their variations in relative abundance governed by geochemical processes. In contrast, some meteorites have deviant abundances of the heaviest (hence the one with the most neutrons) Cr isotope, chromium-54. These anomalies in isotopic composition are almost certainly caused by nuclear reactions in stars that existed before our Sun was formed. However, the mineralogical carrier of the special chromium-54 was not known until Nicolas Dauphas (University of Chicago) and eight colleagues there and at the California Institute of Technology, the Museum National d'Histoire Naturelle in Paris, the Jet Propulsion Laboratory, and the Universite de Lille (France) made detailed analyses of chemical and physical separates from the Orgueil and Murchison carbonaceous chondrites. They found that the carrier of the isotopically-anomalous Cr is spinel, Cr-bearing oxide grains generally smaller than 100 nanometers. Only supernovae can produce the chromium-54 anomalies, although which specific type of supernova is not clear. An intriguing possibility is that the chromium-54-rich nano-oxide particles were produced in the same supernova that made two other short-lived isotopes, iron-60 and aluminum-26, which also existed in the Solar System when it formed. This suggests that formation of the Solar System was triggered by a supernova explosion.

  12. A Supernova Shockwaves

    NASA Image and Video Library

    2007-06-13

    Supernovae are the explosive deaths of the universe most massive stars. This false-color composite from NASA Spitzer Space Telescope and NASA Chandra X-ray Observatory shows the remnant of N132D, the wispy pink shell of gas at center.

  13. Direct Measurement of the Supernova Rate in Starburst Galaxies

    NASA Technical Reports Server (NTRS)

    Bregman, Jesse D.; Temi, Pasquale; Rank, David; DeVincenzi, Donald L. (Technical Monitor)

    1999-01-01

    Supernovae play a key role in the dynamics, structure, and chemical evolution of galaxies. The massive stars that end their lives as supernovae live for short times. Many are still associated with dusty star formation regions when they explode, making them difficult to observe at visible wavelengths. In active star forming regions (galactic nuclei and starburst regions), dust extintion is especially severe. Thus, determining the supernova rate in the active star forming regions of galaxies, where the supernova rate can be one or two orders of magnitude higher than the average, has proven to be difficult. From observations of SN1987A, we know that the [NiII] 6.63 micron emission line was the strongest line in the infrared spectrum for a period of a year and a half after the explosion. Since dust extintion is much less at 6.63 pm than at visible wavelengths (A(sub 6.63)/A(sub V) = 0.025), the NiII line can be used as a sensitive probe for the detection of recent supernovae. We have observed a sample of starburst galaxies at 6.63 micron using ISOCAM to search for the NiII emission line characteristic of recent supernovae. We did not detect any NiII line emission brighter than a 5sigma limit of 5 mJy. We can set upper limits to the supernova rate in our sample, scaled to the rate in M82, of less than 0.3 per year at the 90% confidence level using Bayesian methods. Assuming that a supernova would have a NiII with the same luminosity as observed in SN1987A, we find less than 0.09 and 0.15 per year at the 50% and 67% confidence levels. These rates are somewhat less if a more normal type II supernovae has a NiII line luminosity greater than the line in SN1987A.

  14. Direct Measurement of the Supernova Rate in Starburst Galaxies

    NASA Technical Reports Server (NTRS)

    Bregman, J. D.; Temi, P.; Rank, D.

    2000-01-01

    Supernovae play a key role in the dynamics, structure, and chemical evolution of galaxies. The massive stars that end their lives as supernovae live for short enough times that many are still associated with dusty star formation regions when they explode, making them difficult to observe at visible wavelengths. In active star forming regions (galactic nuclei and starburst regions), dust extinction is especially severe. Thus, determining the supernova rate in active star forming regions of galaxies, where the supernova rate can be one or two orders of magnitude higher than the average, has proven to be difficult. From observations of SN1987A, we know that the [NiII] 6.63 micrometer emission line was the strongest line in the infrared spectrum for a period of a year and half after th explosion. Since dust extinction is much less at 6.63 micrometers than at visible wavelengths (A(sub 6.63)/A(sub V) = 0.025), the [NiII] line can be used as a sensitive probe for the detection of recent supernovae. We have observed a sample of starburst galaxies at 6.63 micrometers using ISOCAM to search for the [NiII] emission line characteristic of recent supernovae. We did not detect any [NiII] line emission brighter than a 5-sigma limit of 5 mJy. We can set upper limits to the supernova rate in our sample, scaled ot the rate in M82, of less than 0.3 per year at the 90% confidence level using Bayesian methods. Assuming that a supernova would have a [NiII] line with the same luminosity as observed in SN1987A, we find less than 0.09 and 0.15 per year at the 50% and 67% confidence levels. These rates are somewhat less if a more normal type II supernovae has a [NiII] line luminosity greater than the line in SN1987A.

  15. Radio emision from supernova remnants

    NASA Astrophysics Data System (ADS)

    Dubner, G.

    2016-06-01

    The vast majority of supernova remnants (SNRs) in our Galaxy and nearby galaxies have been discovered through radio observations, and only a very small number of the SNRs catalogued in the Milky Way have not been detected in the radio band, or are poorly defined by current radio observations. The study of the radio emission from SNRs is an excellent tool to investigate morphological characteristics, marking the location of shock fronts and contact discontinuities; the presence, orientation and intensity of the magnetic field; the energy spectrum of the emitting particles; and the dynamical consequences of the interaction with the circumstellar and interstellar medium. I will review the present knowledge of different important aspects of radio remnants and their impact on the interstellar gas. Also, new radio studies of the Crab Nebula carried out with the Karl Jansky Very Large Array (JVLA) at 3 GHz and with ALMA at 100 GHz, will be presented.

  16. Probing the core-collapse supernova mechanism with gravitational waves

    NASA Astrophysics Data System (ADS)

    Ott, Christian D.

    2009-10-01

    The mechanism of core-collapse supernova explosions must draw on the energy provided by gravitational collapse and transfer the necessary fraction to the kinetic and internal energy of the ejecta. Despite many decades of concerted theoretical effort, the detailed mechanism of core-collapse supernova explosions is still unknown, but indications are strong that multi-D processes lie at its heart. This opens up the possibility of probing the supernova mechanism with gravitational waves, carrying direct dynamical information from the supernova engine deep inside a dying massive star. I present a concise overview of the physics and primary multi-D dynamics in neutrino-driven, magnetorotational, and acoustically driven core-collapse supernova explosion scenarios. Discussing and contrasting estimates for the gravitational-wave emission characteristics of these mechanisms, I argue that their gravitational-wave signatures are clearly distinct and that the observation (or non-observation) of gravitational waves from a nearby core-collapse event could put strong constraints on the supernova mechanism.

  17. A DYNAMICAL STUDY OF SUSPECTED RUNAWAY STARS AS TRACES OF PAST SUPERNOVA EXPLOSIONS IN THE REGION OF THE SCORPIUS-CENTAURUS OB ASSOCIATION

    SciTech Connect

    Jilinski, E.; Ortega, V. G.; Drake, N. A.; De la Reza, R.

    2010-09-20

    We address the question of identifying possible past supernovae events taking place in the region of the Scorpius-Centaurus (Sco-Cen) OB association based on stars proposed by Hoogerwerf et al. With this purpose, we obtained a time series of high-resolution spectra of six stars (HIP 42038, HIP 46950, HIP 48943, HIP 69491, HIP 76013, and HIP 82868) which, according to Hoogerwerf et al., may have been runaway stars with origins in the region of the Sco-Cen association. This also includes the nearby young open clusters IC 2391 and IC 2602. If confirmed, such supernovae events could, in principle, have played a role in triggering the formation of some small stellar groups thought to be associated with the Sco-Cen association. Our analysis shows that, except for HIP 48943, the remaining stars are spectroscopic binary systems. For HIP 46950 and HIP 69491, this was already noted by other authors. Our high-resolution spectra allowed us to obtain the radial velocities for all the stars which, combined with their proper motions and parallaxes from Hipparcos, provide a means to investigate, by retracing their orbits, if the Sco-Cen region was, in fact, the origin of these stars. We find that none of these systems originated in the Sco-Cen region. Exploring the possibility that the birthplace of the studied stars occurred in the clusters IC 2391 and IC 2602, we noticed that at the epoch of 2-3 Myr ago these clusters were at a distance comparable with their tidal radii.

  18. 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.

  19. Binary progenitors of supernovae

    NASA Astrophysics Data System (ADS)

    Trimble, V.

    1984-12-01

    Among the massive stars that are expected to produce Type II, hydrogen-rich supernovae, the presence of a close companion can increase the main sequence mass needed to yield a collapsing core. In addition, due to mass transfer from the primary to the secondary, the companion enhances the stripping of the stellar hydrogen envelope produced by single star winds and thereby makes it harder for the star to give rise to a typical SN II light curve. Among the less massive stars that may be the basis for Type I, hydrogen-free supernovae, a close companion could be an innocent bystander to carbon detonation/deflagration in the primary. It may alternatively be a vital participant which transfers material to a white dwarf primary and drives it to explosive conditions.

  20. 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.

  1. Supernova Science Center

    SciTech Connect

    S. E. Woosley

    2008-05-05

    The Supernova Science Center (SNSC) was founded in 2001 to carry out theoretical and computational research leading to a better understanding of supernovae and related transients. The SNSC, a four-institutional collaboration, included scientists from LANL, LLNL, the University of Arizona (UA), and the University of California at Santa Cruz (UCSC). Intitially, the SNSC was funded for three years of operation, but in 2004 an opportunity was provided to submit a renewal proposal for two years. That proposal was funded and subsequently, at UCSC, a one year no-cost extension was granted. The total operational time of the SNSC was thus July 15, 2001 - July 15, 2007. This document summarizes the research and findings of the SNSC and provides a cummulative publication list.

  2. Supernova research with VLBI

    NASA Astrophysics Data System (ADS)

    Bartel, Norbert; Bietenholz, Michael F.

    2016-06-01

    Core-collapse supernovae have been monitored with VLBI from shortly after the explosion to many years thereafter. Radio emission is produced as the ejecta hit the stellar wind left over from the dyingstar. Images show the details of the interaction as the shock front expands into the circumstellar medium. Measurements of the velocity and deceleration of the expansion provide information on both the ejecta and the circumstellar medium. VLBI observations can also search for the stellar remnant of the explosion, a neutron star or a black hole. Combining the transverse expansion rate with the radial expansion rate from optical spectra allows a geometric determination of the distance to the host galaxy. We will present results from recent VLBI observations, focus on their interpretations, and show updated movies of supernovae from soon after their explosion to the present.

  3. Supernova 1987A!

    PubMed

    Woosley, S E; Phillips, M M

    1988-05-06

    Light from the brightest supernova in almost 400 years arrived at Earth on 23 February 1987. Although located 160,000 light years away in a satellite galaxy of our own known as the Large Magellanic Cloud, this supernova's relative proximity compared to all others that have been observed in modern times has allowed observations, which were never possible before, to be made from space, from detectors on the ground and carried by balloons and airplanes, and from neutrino detectors deep underground. What emerges is a greater understanding of one of the most violent events in the universe, the death of a massive star. For the most part, theoretical expectations have been borne out, but some major surprises have made the event all the more fascinating.

  4. Core bounce supernovae

    SciTech Connect

    Cooperstein, J.

    1987-01-01

    The gravitational collapse mechanism for Type II supernovae is considered, concentrating on the direct implosion - core bounce - hydrodynamic explosion picture. We examine the influence of the stiffness of the dense matter equation of state and discuss how the shock wave is formed. Its chances of success are determined by the equation of state, general relativistic effects, neutrino transport, and the size of presupernova iron core. 12 refs., 1 tab.

  5. Are There Hidden Supernovae?

    NASA Astrophysics Data System (ADS)

    Bregman, Jesse; Harker, David; Dunham, E.; Rank, David; Temi, Pasquale

    1997-02-01

    Ames Research Center and UCSC have been working on the development of a Mid IR Camera for the KAO in order to search for extra galactic supernovae. The development of the camera and its associated data reduction software have been successfully completed. Spectral Imaging of the Orion Bar at 6.2 and 7.8 microns demonstrates the derotation and data reduction software which was developed.

  6. Are There Hidden Supernovae?

    NASA Technical Reports Server (NTRS)

    Bregman, Jesse; Harker, David; Dunham, E.; Rank, David; Temi, Pasquale

    1997-01-01

    Ames Research Center and UCSC have been working on the development of a Mid IR Camera for the KAO in order to search for extra galactic supernovae. The development of the camera and its associated data reduction software have been successfully completed. Spectral Imaging of the Orion Bar at 6.2 and 7.8 microns demonstrates the derotation and data reduction software which was developed.

  7. The diffuse supernova neutrino flux

    NASA Astrophysics Data System (ADS)

    Lunardini, Cecilia

    2011-12-01

    I review the status and perspectives of the research on the diffuse flux of (core collapse) supernova neutrinos (DSNνF). Several upper bounds exist on this flux in different detection channels. The strongest is the limit from SuperKamiokande (SK) of 1.2 electron antineutrinos cm-2s-1 at 90% confidence level above 19.3 MeV of neutrino energy. The predictions of the DSNνF depend on the supernova rate and on the neutrino emission in a individual supernova. Above the SK threshold, they range between 0.05 electron antineutrinos cm-2s-1 up to touching the SK limit. The SK bound constrains part of the parameter space of the supernova rate - and indirectly of the star formation rate - only in models with relatively hard neutrino spectra. Experimentally, a feasible and very important goal for the future is the improvement of background discrimination and the resulting lowering of the detection threshold. Theory instead will benefit from reducing the uncertainties on the supernova neutrino emission (either with more precise numerical modeling or with data from a galactic supernova) and on the supernova rate. The latter will be provided precisely by next generation supernova surveys up to a normalization factor. Therefore, the detection of the DSNνF is likely to be precious chiefly to constrain such normalization and to study the physics of neutrino emission in supernovae.

  8. Radio emission from supernova remnants

    NASA Astrophysics Data System (ADS)

    Dubner, Gloria; Giacani, Elsa

    2015-09-01

    The explosion of a supernova releases almost instantaneously about 10^{51} ergs of mechanic energy, changing irreversibly the physical and chemical properties of large regions in the galaxies. The stellar ejecta, the nebula resulting from the powerful shock waves, and sometimes a compact stellar remnant, constitute a supernova remnant (SNR). They can radiate their energy across the whole electromagnetic spectrum, but the great majority are radio sources. Almost 70 years after the first detection of radio emission coming from an SNR, great progress has been achieved in the comprehension of their physical characteristics and evolution. We review the present knowledge of different aspects of radio remnants, focusing on sources of the Milky Way and the Magellanic Clouds, where the SNRs can be spatially resolved. We present a brief overview of theoretical background, analyze morphology and polarization properties, and review and critically discuss different methods applied to determine the radio spectrum and distances. The consequences of the interaction between the SNR shocks and the surrounding medium are examined, including the question of whether SNRs can trigger the formation of new stars. Cases of multispectral comparison are presented. A section is devoted to reviewing recent results of radio SNRs in the Magellanic Clouds, with particular emphasis on the radio properties of SN 1987A, an ideal laboratory to investigate dynamical evolution of an SNR in near real time. The review concludes with a summary of issues on radio SNRs that deserve further study, and analysis of the prospects for future research with the latest-generation radio telescopes.

  9. Supernova Dust Factories

    NASA Astrophysics Data System (ADS)

    Gomez, Haley; Consortium, MESS; LCOGT

    2013-01-01

    The origin of interstellar dust in galaxies is poorly understood, particularly the relative contribution from supernovae. We present infrared and submillimeter photometry and spectroscopy from the Herschel Space Observatory of the Galactic remnants Tycho, Kepler and the Crab Nebula, taken as part of the Mass Loss from Evolved StarS program (MESS). Although we detect small amounts of dust surrounding Tycho and Kepler (the remnants of Type Ia supernovae), we show this is due to swept-up interstellar and circumstellar material respectively. The lack of dust grains in the ejecta suggests that Type Ia remnants do not produce substantial quantities of iron-rich dust grains and has important consequences for the ‘missing’ iron mass observed in ejecta. After carefully subtracting the synchrotron and line emission from the Crab, the remaining far-infrared continuum originates from 0.1-0.2 solar masses of dust. These observations suggest that the Crab Nebula has condensed most of the relevant refractory elements into dust and that these grains appear well set to survive their journey into the interstellar medium. In summary, our Herschel observations show that significantly less dust forms in the ejecta of Type Ia supernovae than in the remnants of core-collapse explosions, placing stringent constraints on the environments in which dust and molecules can form.

  10. Type IA Supernovae

    NASA Technical Reports Server (NTRS)

    Wheeler, J. Craig

    1992-01-01

    Spectral calculations show that a model based on the thermonuclear explosion of a degenerate carbon/oxygen white dwarf provides excellent agreement with observations of Type Ia supernovae. Identification of suitable evolutionary progenitors remains a severe problem. General problems with estimation of supernova rates are outlined and the origin of Type Ia supernovae from double degenerate systems are discussed in the context of new rates of explosion per H band luminosity, the lack of observed candidates, and the likely presence of H in the vicinity of some SN Ia events. Re-examination of the problems of triggering Type Ia by accretion of hydrogen from a companion shows that there may be an avenue involving cataclysmic variables, especially if extreme hibernation occurs. Novae may channel accreting white dwarfs to a unique locus in accretion rate/mass space. Systems that undergo secular evolution to higher mass transfer rates could lead to just the conditions necessary for a Type Ia explosion. Tests involving fluorescence or absorption in a surrounding circumstellar medium and the detection of hydrogen stripped from a companion, which should appear at low velocity inside the white dwarf ejecta, are suggested. Possible observational confirmation of the former is described.

  11. Supernovae and neutrinos

    SciTech Connect

    John F. Beacom

    2002-09-19

    A long-standing problem in supernova physics is how to measure the total energy and temperature of {nu}{sub {mu}}, {nu}{sub {tau}}, {bar {nu}}{sub {mu}}, and {bar {nu}}{sub {tau}}. While of the highest importance, this is very difficult because these flavors only have neutral-current detector interactions. We propose that neutrino-proton elastic scattering, {nu} + p {yields} {nu} + p, can be used for the detection of supernova neutrinos in scintillator detectors. It should be emphasized immediately that the dominant signal is on free protons. Though the proton recoil kinetic energy spectrum is soft, with T{sub p} {approx_equal} 2E{sub {nu}}{sup 2}/M{sub p}, and the scintillation light output from slow, heavily ionizing protons is quenched, the yield above a realistic threshold is nearly as large as that from {bar {nu}}{sub e} + p {yields} e{sup +} + n. In addition, the measured proton spectrum is related to the incident neutrino spectrum. The ability to detect this signal would give detectors like KamLAND and Borexino a crucial and unique role in the quest to detect supernova neutrinos.

  12. The Origin of Kepler's Supernova Remnant

    NASA Astrophysics Data System (ADS)

    Patnaude, Daniel J.; Badenes, Carles; Park, Sangwook; Laming, J. Martin

    2012-09-01

    It is now well established that Kepler's supernova remnant (SNR) is the result of a Type Ia explosion. With an age of 407 yr and an angular diameter of ~4', Kepler is estimated to be between 3.0 and 7.0 kpc distant. Unlike other Galactic Type Ia SNRs such as Tycho and SN 1006, and SNR 0509-67.5 in the Large Magellanic Cloud, Kepler shows evidence for a strong circumstellar interaction. A bowshock structure in the north is thought to originate from the motion of a mass-losing system through the interstellar medium prior to the supernova. We present results of hydrodynamical and spectral modeling aimed at constraining the circumstellar environment of the system and the amount of 56Ni produced in the explosion. Using models that contain either 0.3 M ⊙ (subenergetic) or 1.0 M ⊙ (energetic) of 56Ni, we simulate the interaction between supernova Ia ejecta and various circumstellar density models. Based on dynamical considerations alone, we find that the subenergetic models favor a distance to the SNR of <6.4 kpc, while the model that produces 1 M ⊙ of 56Ni requires a distance to the SNR of >7 kpc. The X-ray spectrum is consistent with an explosion that produced ~1 M ⊙ of 56Ni, ruling out the subenergetic models, and suggesting that Kepler's SNR was an SN 1991T-like event. Additionally, the X-ray spectrum rules out a pure r -2 wind profile expected from isotropic mass loss up to the time of the supernova. Introducing a small cavity around the progenitor system results in modeled X-ray spectra that are consistent with the observed spectrum. If a wind-shaped circumstellar environment is necessary to explain the dynamics and X-ray emission from the shocked ejecta in Kepler's SNR, then we require that the distance to the remnant be greater than 7 kpc.

  13. Interacting supernovae and supernova impostors: Evidence of incoming supernova explosions?

    SciTech Connect

    Tartaglia, L.

    2015-02-24

    Violent eruptions, and consequently major mass loss, are a common feature of the so–called Luminous Blue Variable (LBV) stars. During major eruptive episodes LBVs mimic the behavior of real type IIn supernovae (SNe), showing comparable radiated energy and similar spectroscopic properties. For this reason these events are frequently labelled as SN impostors. Type IIn SN spectra are characterized by the presence of prominent narrow Balmer lines in emission. In most cases, SNe IIn arise from massive stars (M>8{sub ⊙}) exploding in a dense H–rich circumstellar medium (CSM), produced by progenitor’s mass loss prior to the SN explosion. Although the mechanisms triggering these eruptions are still unknown, recently we had direct proofs of the connection between very massive stars, their eruptions and ejecta-CSM interacting SNe. SNe 2006jc, 2010mc, 2011ht and the controversial SN 2009ip are famous cases in which we observed the explosion of the star months to years after major outbursts. In this context, the case of a recent transient event, LSQ13zm, is extremely interesting since we observed an outburst just ∼3 weeks before the terminal SN explosion. All of this may suggest that SN impostors occasionally herald true SN explosions. Nonetheless, there are several cases where major eruptions are followed by a quiescent phase in the LBV life. The impostor SN 2007sv is one of these cases, since it showed a single outburst event. Its photometric (a relatively faint absolute magnitude at the maximum) and spectroscopic properties (low velocity and temperature of the ejecta, and the absence of the typical elements produced in the explosive nucleosynthesis) strongly suggest that SN 2007sv was the giant eruption of an LBV, which has then returned in a quiescent stage.

  14. Interacting supernovae and supernova impostors: Evidence of incoming supernova explosions?

    NASA Astrophysics Data System (ADS)

    Tartaglia, L.

    2015-02-01

    Violent eruptions, and consequently major mass loss, are a common feature of the so-called Luminous Blue Variable (LBV) stars. During major eruptive episodes LBVs mimic the behavior of real type IIn supernovae (SNe), showing comparable radiated energy and similar spectroscopic properties. For this reason these events are frequently labelled as SN impostors. Type IIn SN spectra are characterized by the presence of prominent narrow Balmer lines in emission. In most cases, SNe IIn arise from massive stars (M>8⊙) exploding in a dense H-rich circumstellar medium (CSM), produced by progenitor's mass loss prior to the SN explosion. Although the mechanisms triggering these eruptions are still unknown, recently we had direct proofs of the connection between very massive stars, their eruptions and ejecta-CSM interacting SNe. SNe 2006jc, 2010mc, 2011ht and the controversial SN 2009ip are famous cases in which we observed the explosion of the star months to years after major outbursts. In this context, the case of a recent transient event, LSQ13zm, is extremely interesting since we observed an outburst just ˜3 weeks before the terminal SN explosion. All of this may suggest that SN impostors occasionally herald true SN explosions. Nonetheless, there are several cases where major eruptions are followed by a quiescent phase in the LBV life. The impostor SN 2007sv is one of these cases, since it showed a single outburst event. Its photometric (a relatively faint absolute magnitude at the maximum) and spectroscopic properties (low velocity and temperature of the ejecta, and the absence of the typical elements produced in the explosive nucleosynthesis) strongly suggest that SN 2007sv was the giant eruption of an LBV, which has then returned in a quiescent stage.

  15. 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.

  16. Distribution of p-process 174Hf in early solar system materials and the origin of nucleosynthetic Hf and W isotope anomalies in Ca-Al rich inclusions

    NASA Astrophysics Data System (ADS)

    Peters, Stefan T. M.; Münker, Carsten; Pfeifer, Markus; Elfers, Bo-Magnus; Sprung, Peter

    2017-02-01

    Some nuclides that were produced in supernovae are heterogeneously distributed between different meteoritic materials. In some cases these heterogeneities have been interpreted as the result of interaction between ejecta from a nearby supernova and the nascent solar system. Particularly in the case of the oldest objects that formed in the solar system - Ca-Al rich inclusions (CAIs) - this view is confirm the hypothesis that a nearby supernova event facilitated or even triggered solar system formation. We present Hf isotope data for bulk meteorites, terrestrial materials and CAIs, for the first time including the low-abundance isotope 174Hf (∼0.16%). This rare isotope was likely produced during explosive O/Ne shell burning in massive stars (i.e., the classical "p-process"), and therefore its abundance potentially provides a sensitive tracer for putative heterogeneities within the solar system that were introduced by supernova ejecta. For CAIs and one LL chondrite, also complementary W isotope data are reported for the same sample cuts. Once corrected for small neutron capture effects, different chondrite groups, eucrites, a silicate inclusion of a IAB iron meteorite, and terrestrial materials display homogeneous Hf isotope compositions including 174Hf. Hafnium-174 was thus uniformly distributed in the inner solar system when planetesimals formed at the <50 ppm level. This finding is in good agreement with the evidently homogeneous distributions of p-process isotopes 180W, 184Os and possibly 190Pt between different iron meteorite groups. In contrast to bulk meteorite samples, CAIs show variable depletions in p-process 174Hf with respect to the inner solar system composition, and also variable r-process (or s-process) Hf and W contributions. Based on combined Hf and W isotope compositions, we show that CAIs sampled at least one component in which the proportion of r- and s-process derived Hf and W deviates from that of supernova ejecta. The Hf and W isotope

  17. Supernova ejecta with a relativistic wind from a central compact object: a unified picture for extraordinary supernovae

    NASA Astrophysics Data System (ADS)

    Suzuki, Akihiro; Maeda, Keiichi

    2017-04-01

    The hydrodynamical interaction between freely expanding supernova ejecta and a relativistic wind injected from the central region is studied in analytic and numerical ways. As a result of the collision between the ejecta and the wind, a geometrically thin shell surrounding a hot bubble forms and expands in the ejecta. We use a self-similar solution to describe the early dynamical evolution of the shell and carry out a two-dimensional special relativistic hydrodynamic simulation to follow further evolution. The Rayleigh-Taylor instability inevitably develops at the contact surface separating the shocked wind and ejecta, leading to the complete destruction of the shell and the leakage of hot gas from the hot bubble. The leaking hot materials immediately catch up with the outermost layer of the supernova ejecta and thus different layers of the ejecta are mixed. We present the spatial profiles of hydrodynamical variables and the kinetic energy distributions of the ejecta. We stop the energy injection when a total energy of 1052 erg, which is 10 times larger than the initial kinetic energy of the supernova ejecta, is deposited into the ejecta and follow the subsequent evolution. From the results of our simulations, we consider expected emission from supernova ejecta powered by the energy injection at the centre and discuss the possibility that superluminous supernovae and broad-lined Ic supernovae could be produced by similar mechanisms.

  18. Gravitational Lensing of Supernova Neutrinos

    SciTech Connect

    Mena, Olga; Mocioiu, Irina; Quigg, Chris; /Fermilab

    2006-10-01

    The black hole at the center of the galaxy is a powerful lens for supernova neutrinos. In the very special circumstance of a supernova near the extended line of sight from Earth to the galactic center, lensing could dramatically enhance the neutrino flux at Earth and stretch the neutrino pulse.

  19. 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.

  20. The r-, s-, and p-Processes in Nucleosynthesis

    NASA Technical Reports Server (NTRS)

    Meyer, Bradley S.

    1994-01-01

    A goal of this paper is to review the recent progress astrophysicists, astronomers, and physicists have made in the r-, s-, and p-processes in nucleosynthesis and to point out the problems that remain in our understanding of the formation of the heavy nuclei. Another, perhaps deeper, goal is to to seek some understanding of why there are three major processes available to nature for synthesis of heavy elements.

  1. Young supernova remnants: Issues and prospects

    NASA Astrophysics Data System (ADS)

    McKee, Christopher F.

    2001-05-01

    The dynamical evolution of young supernova remnants (YSNRs) is governed by the density distribution in the ejecta and in the ambient medium. Analytic solutions are available for spherically symmetric expansion, including the transition from the ejecta-dominated stage to the Sedov-Taylor stage. YSNRs serve as valuable physics laboratories, in which we can study nucleosynthesis, the early evolution of compact objects, pulsar physics, particle acceleration, the formation and destruction of dust, hydrodynamics at high Reynolds numbers, shock physics at high Mach numbers, and the effects of thermal conduction in interstellar plasmas. There are several challenges in YSNR research: (1) Where are the very young remnants in the Galaxy? We expect 5-10 to have occurred since Cas A, but with the possible exception of a remnant reported at this conference, none have been seen. (2) Can very young SNRs produce gamma-ray bursts? The acceleration of a shock in the outer layers of a supernova, first suggested by Colgate, can account for gamma-ray bursts such as that believed to be associated with SN 1998bw, and more powerful explosions can account for the energies seen in many cosmological bursts. (3) The Connections Challenge: Can one infer the nature of the supernova and its progenitor star from observations of the YSNR? .

  2. 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.

  3. 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.

  4. GALAXY OUTFLOWS WITHOUT SUPERNOVAE

    SciTech Connect

    Sur, Sharanya; Scannapieco, Evan; Ostriker, Eve C. E-mail: sharanya.sur@asu.edu

    2016-02-10

    High surface density, rapidly star-forming galaxies are observed to have ≈50–100 km s{sup −1} line of sight velocity dispersions, which are much higher than expected from supernova driving alone, but may arise from large-scale gravitational instabilities. Using three-dimensional simulations of local regions of the interstellar medium, we explore the impact of high velocity dispersions that arise from these disk instabilities. Parametrizing disks by their surface densities and epicyclic frequencies, we conduct a series of simulations that probe a broad range of conditions. Turbulence is driven purely horizontally and on large scales, neglecting any energy input from supernovae. We find that such motions lead to strong global outflows in the highly compact disks that were common at high redshifts, but weak or negligible mass loss in the more diffuse disks that are prevalent today. Substantial outflows are generated if the one-dimensional horizontal velocity dispersion exceeds ≈35 km s{sup −1}, as occurs in the dense disks that have star-formation rate (SFR) densities above ≈0.1 M{sub ⊙} yr{sup −1} kpc{sup −2}. These outflows are triggered by a thermal runaway, arising from the inefficient cooling of hot material coupled with successive heating from turbulent driving. Thus, even in the absence of stellar feedback, a critical value of the SFR density for outflow generation can arise due to a turbulent heating instability. This suggests that in strongly self-gravitating disks, outflows may be enhanced by, but need not caused by, energy input from supernovae.

  5. Radio Emission from Supernovae

    SciTech Connect

    Weiler, Kurt W.; Panagia, Nino; Sramek, Richard A.; Van Dyk, Schuyler D.; Stockdale, Christopher J.; Kelley, Matthew T.

    2009-05-03

    Study of radio supernovae over the past 27 years includes more than three dozen detected objects and more than 150 upper limits. From this work it is possible to identify classes of radio properties, demonstrate conformance to and deviations from existing models, estimate the density and structure of the circumstellar material and, by inference, the evolution of the presupernova stellar wind, and reveal the last stages of stellar evolution before explosion. It is also possible to detect ionized hydrogen along the line of sight, to demonstrate binary properties of the presupernova stellar system, and to detect dumpiness of the circumstellar material.

  6. CRTS Supernova Candidate

    NASA Astrophysics Data System (ADS)

    Drake, A. J.; Djorgovski, S. G.; Graham, M. J.; Williams, R.; Mahabal, A.; Beshore, E. C.; Larson, S. M.; Hill, R.; Catelan, M.; Christensen, E.

    2008-09-01

    We have detected a likely supernova in CSS images from 24 Sep 2008 UT. The object has the following parameters:

    CSS080924:044524+182425 2008-09-24 UT 11:17:06 RA 04:45:24.00 Dec 18:24:25.1 Mag 17.5 Type SN
    The object is near the edge of galaxy LCSB L0250N (z=0.0155).

  7. Supernova 2002hi

    NASA Astrophysics Data System (ADS)

    Pooley, D.; Lewin, W. H. G.

    2003-01-01

    D. Pooley and W. H. G. Lewin, Massachusetts Institute of Technology, on behalf of a larger collaboration, report the detection of X-ray emission at the position of the type-IIn supernova (SN) 2002hi (IAUC 8006) with the Chandra X-ray observatory: An ACIS-S3 observation of 10 ks was made on Dec. 10.73. In the 0.5-10 keV range, we searched a 2x2 pixel region (approx. 1" by 1") around the reported position of the SN and detected 2 counts.

  8. Supernova Acceleration Probe: Studying Dark Energy with Type Ia Supernovae

    SciTech Connect

    Albert, J.; Aldering, G.; Allam, S.; Althouse, W.; Amanullah, R.; Annis, J.; Astier, P.; Aumeunier, M.; Bailey, S.; Baltay, C.; Barrelet, E.; Basa, S.; Bebek, C.; Bergstom, L.; Bernstein, G.; Bester, M.; Besuner, B.; Bigelow, B.; Blandford, R.; Bohlin, R.; Bonissent, A.; /Caltech /LBL, Berkeley /Fermilab /SLAC /Stockholm U. /Paris, IN2P3 /Marseille, CPPM /Marseille, Lab. Astrophys. /Yale U. /Pennsylvania U. /UC, Berkeley /Michigan U. /Baltimore, Space Telescope Sci. /Indiana U. /Caltech, JPL /Australian Natl. U., Canberra /American Astron. Society /Chicago U. /Cambridge U. /Saclay /Lyon, IPN

    2005-08-08

    The Supernova Acceleration Probe (SNAP) will use Type Ia supernovae (SNe Ia) as distance indicators to measure the effect of dark energy on the expansion history of the Universe. (SNAP's weak-lensing program is described in a separate White Paper.) The experiment exploits supernova distance measurements up to their fundamental systematic limit; strict requirements on the monitoring of each supernova's properties leads to the need for a space-based mission. Results from pre-SNAP experiments, which characterize fundamental SN Ia properties, will be used to optimize the SNAP observing strategy to yield data, which minimize both systematic and statistical uncertainties. With early R&D funding, we have achieved technological readiness and the collaboration is poised to begin construction. Pre-JDEM AO R&D support will further reduce technical and cost risk. Specific details on the SNAP mission can be found in Aldering et al. (2004, 2005). The primary goal of the SNAP supernova program is to provide a dataset which gives tight constraints on parameters which characterize the dark-energy, e.g. w{sub 0} and w{sub a} where w(a) = w{sub 0} + w{sub a}(1-a). SNAP data can also be used to directly test and discriminate among specific dark energy models. We will do so by building the Hubble diagram of high-redshift supernovae, the same methodology used in the original discovery of the acceleration of the expansion of the Universe that established the existence of dark energy (Perlmutter et al. 1998; Garnavich et al. 1998; Riess et al. 1998; Perlmutter et al. 1999). The SNAP SN Ia program focuses on minimizing the systematic floor of the supernova method through the use of characterized supernovae that can be sorted into subsets based on subtle signatures of heterogeneity. Subsets may be defined based on host-galaxy morphology, spectral-feature strength and velocity, early-time behavior, inter alia. Independent cosmological analysis of each subset of ''like'' supernovae can be

  9. Uncertainties in Supernova Yields

    NASA Astrophysics Data System (ADS)

    Young, Patrick A.; Fryer, C. L.

    2006-12-01

    Theoretical nucleosynthetic yields from supernovae are sensitive to both the details of the progenitor star and the explosion calculation. We attempt to comprehensively identify the sources of uncertainties in these yields. In this poster we concentrate on the variations in yields from a single progenitor arising from common 1-dimensional methods of approximating a supernova explosion. 3-dimensional effects in the explosion and the progenitor and improved physics in the progenitor evolution are also given preliminary consideration. For the 1-dimensional explosions we find that both elemental and isotopic yields for Si and heavier elements are a sensitive function of explosion energy. Also, piston-driven and thermal bomb type explosions have different yields for the same explosion energy. Yields derived from 1-dimensional explosions are non-unique. Bulk yields of common elements can vary by factors of several depending upon the assumptions of the calculation. This work was carried out in part under the auspices of the National Nuclear Security Administration of the U.S. Department of Energy at Los Alamos National Laboratory and supported by Contract No. DE-AC52-06NA25396, by a DOE SciDAC grant DE-FC02-01ER41176, an NNSA ASC grant, and a subcontract to the ASCI FLASH Center at the University of Chicago.

  10. Cassiopeia A supernova

    NASA Image and Video Library

    2017-09-27

    NASA's Fermi Closes on Source of Cosmic Rays New images from NASA's Fermi Gamma-ray Space Telescope show where supernova remnants emit radiation a billion times more energetic than visible light. The images bring astronomers a step closer to understanding the source of some of the universe's most energetic particles -- cosmic rays. This composite shows the Cassiopeia A supernova remnant across the spectrum: Gamma rays (magenta) from NASA's Fermi Gamma-ray Space Telescope; X-rays (blue, green) from NASA's Chandra X-ray Observatory; visible light (yellow) from the Hubble Space Telescope; infrared (red) from NASA's Spitzer Space Telescope; and radio (orange) from the Very Large Array near Socorro, N.M. Credit: NASA/DOE/Fermi LAT Collaboration, CXC/SAO/JPL-Caltech/Steward/O. Krause et al., and NRAO/AUI For more information: www.nasa.gov/mission_pages/GLAST/news/cosmic-rays-source.... NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

  11. Automated Supernova Discovery (Abstract)

    NASA Astrophysics Data System (ADS)

    Post, R. S.

    2015-12-01

    (Abstract only) We are developing a system of robotic telescopes for automatic recognition of Supernovas as well as other transient events in collaboration with the Puckett Supernova Search Team. At the SAS2014 meeting, the discovery program, SNARE, was first described. Since then, it has been continuously improved to handle searches under a wide variety of atmospheric conditions. Currently, two telescopes are used to build a reference library while searching for PSN with a partial library. Since data is taken every night without clouds, we must deal with varying atmospheric and high background illumination from the moon. Software is configured to identify a PSN, reshoot for verification with options to change the run plan to acquire photometric or spectrographic data. The telescopes are 24-inch CDK24, with Alta U230 cameras, one in CA and one in NM. Images and run plans are sent between sites so the CA telescope can search while photometry is done in NM. Our goal is to find bright PSNs with magnitude 17.5 or less which is the limit of our planned spectroscopy. We present results from our first automated PSN discoveries and plans for PSN data acquisition.

  12. 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.

  13. The r-, s-, and p-Processes in Nucleosynthesis

    NASA Technical Reports Server (NTRS)

    Meyer, Bradley S.

    1994-01-01

    Burbidge et al (1957) and Cameron (1957) laid out the framework for our understanding of the formation of the heavy nuclei (those nuclei with mass number A approx. greater than 70). From systematics in the solar system abundance distribution, Burbidge et al determined that the heavy nuclei were formed in three distinct nucleosynthetic processes, which they termed the r-, s-, and p-processes. That we still use these terms today is a credit to the soundness of this work done 37 years ago. We may understand how Burbidge et al and Cameron arrived at their conclusions from Figure 1. One population of nuclei, the s-nuclei, shows an abundance distribution with peaks near mass numbers 87, 138, and 208. These nuclei are made in a slow neutron-capture process, the s-process. A rapid neutron-capture process, the r-process, is responsible for the r-nuclei, whose abundance distribution shows peaks at mass numbers 80, 130, and 195. The p-process is responsible for production of the rarer, more proton-rich heavy isotopes (the p-nuclei) that cannot be made by neutron capture. The first quantitative evaluations of the ideas of Burbidge et al and Cameron came to light in the early 1960s with work on the s-process (Clayton et al 1961, Seeger et al 1965) and the r-process (Seeger et al 1965). These calculations further elucidated the mechanisms for heavy-element formation and showed the plausibility of the framework developed in the 1950s. Subsequent work has focused on determining the astrophysical sites where the r-, s-, and p-processes occurred with the help of improved nuclear details, stellar models, and abundances. A goal of this paper is to review the recent progress astrophysicists, astronomers, and physicists have made in these directions and to point out the problems that remain in our understanding of the formation of the heavy nuclei. Another, perhaps deeper, goal is to to seek some understanding of why there are three major processes available to nature for synthesis of

  14. The r-, s-, and p-Processes in Nucleosynthesis

    NASA Technical Reports Server (NTRS)

    Meyer, Bradley S.

    1994-01-01

    Burbidge et al (1957) and Cameron (1957) laid out the framework for our understanding of the formation of the heavy nuclei (those nuclei with mass number A approx. greater than 70). From systematics in the solar system abundance distribution, Burbidge et al determined that the heavy nuclei were formed in three distinct nucleosynthetic processes, which they termed the r-, s-, and p-processes. That we still use these terms today is a credit to the soundness of this work done 37 years ago. We may understand how Burbidge et al and Cameron arrived at their conclusions from Figure 1. One population of nuclei, the s-nuclei, shows an abundance distribution with peaks near mass numbers 87, 138, and 208. These nuclei are made in a slow neutron-capture process, the s-process. A rapid neutron-capture process, the r-process, is responsible for the r-nuclei, whose abundance distribution shows peaks at mass numbers 80, 130, and 195. The p-process is responsible for production of the rarer, more proton-rich heavy isotopes (the p-nuclei) that cannot be made by neutron capture. The first quantitative evaluations of the ideas of Burbidge et al and Cameron came to light in the early 1960s with work on the s-process (Clayton et al 1961, Seeger et al 1965) and the r-process (Seeger et al 1965). These calculations further elucidated the mechanisms for heavy-element formation and showed the plausibility of the framework developed in the 1950s. Subsequent work has focused on determining the astrophysical sites where the r-, s-, and p-processes occurred with the help of improved nuclear details, stellar models, and abundances. A goal of this paper is to review the recent progress astrophysicists, astronomers, and physicists have made in these directions and to point out the problems that remain in our understanding of the formation of the heavy nuclei. Another, perhaps deeper, goal is to to seek some understanding of why there are three major processes available to nature for synthesis of

  15. On the nature of the Monoceros supernova remnant.

    NASA Technical Reports Server (NTRS)

    Gebel, W. L.; Shore, S. N.

    1972-01-01

    A dynamical expansion time of 300,000 years and an envelope of 100 km/sec are derived for the filamentary Monoceros Loop supernova remnant. Through arguments connecting three O stars with the supernova remnant, a lower limit of 25-30 solar masses is derived for the progenitor star. A thermal soft X-ray point source is predicted based on the hypothesis of a cooling neutron star. By analogy, we interpret the Cygnus Loop X-ray source as a neutron star.

  16. Measuring the Symmetry of Supernova Remnants in the Radio

    NASA Astrophysics Data System (ADS)

    Stafford, Jennifer; Lopez, Laura A.

    2017-01-01

    Nearly 300 supernova remnants (SNRs) are known in the MIlky Way galaxy, and they offer an important means to study the explosions and interactions of supernovae at sub-pc scales. In this poster, we present analysis of the morphology of Galactic SNRs at radio wavelengths. Specifically, we measure the symmetry of several tens of SNRs in 6- and 20-cm Very Large Array images using a multipole expansion technique, the power-ratio method. We explore how the SNRs' morphology changes as a function of their size and estimated dynamical ages, with the aim of probing how SNR shapes evolve with time.

  17. 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.

  18. Supernova 1987A: The Supernova of a Lifetime

    NASA Astrophysics Data System (ADS)

    Kirshner, Robert

    2017-01-01

    Supernova 1987A, the brightest supernova since Kepler's in 1604, was detected 30 years ago at a distance of 160 000 light years in the Large Magellanic Cloud, a satellite galaxy of the Milky Way. Visible with the naked eye and detected with the full range of technology constructed since Kepler's time, SN 1987A has continued to be a rich source of empirical information to help understand supernova explosions and their evolution into supernova remnants. While the light output has faded by a factor of 10 000 000 over those 30 years, instrumentation, like the Hubble Space Telescope, the Chandra X-ray Observatory, and the Atacama Large Millimeter Array has continued to improve so that this supernova continues to be visible in X-rays, ultraviolet light, visible light, infrared light and in radio emission. In this review, I will sketch what has been learned from these observations about the pre-supernova star and its final stages of evolution, the explosion physics, the energy sources for emission, and the shock physics as the expanding debris encounters the circumstellar ring that was created about 20 000 years before the explosion. Today, SN 1987A is making the transition to a supernova remnant- the energetics are no longer dominated by the radioactive elements produced in the explosion, but by the interaction of the expanding debris with the surrounding gas. While we are confident that the supernova explosion had its origin in gravitational collapse, careful searches for a compact object at the center of the remnant place upper limits of a few solar luminosities on that relic. Support for HST GO programs 13401 and 13405 was provided by NASA through grants from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  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. Thermonuclear supernova models, and observations of Type Ia supernovae

    SciTech Connect

    Bravo, E.; Garcia-Senz, D.; Badenes, C.

    2005-10-21

    In this paper, we review the present state of theoretical models of thermonuclear supernovae, and compare their predictions with the constraints derived from observations of Type Ia supernovae. The diversity of explosion mechanisms usually found in one-dimensional simulations is a direct consequence of the impossibility to resolve the flame structure under the assumption of spherical symmetry. Spherically symmetric models have been successful in explaining many of the observational features of Type Ia supernovae, but they rely on two kinds of empirical models: one that describes the behaviour of the flame on the scales unresolved by the code, and another that takes account of the evolution of the flame shape. In contrast, three-dimensional simulations are able to compute the flame shape in a self-consistent way, but they still need a model for the propagation of the flame in the scales unresolved by the code. Furthermore, in three dimensions the number of degrees of freedom of the initial configuration of the white dwarf at runaway is much larger than in one dimension. Recent simulations have shown that the sensitivity of the explosion output to the initial conditions can be extremely large. New paradigms of thermonuclear supernovae have emerged from this situation, as the Pulsating Reverse Detonation. The resolution of all these issues must rely on the predictions of observational properties of the models, and their comparison with current Type Ia supernova data, including X-ray spectra of Type Ia supernova remnants.

  1. Supernova Candidate from CSS

    NASA Astrophysics Data System (ADS)

    Drake, A. J.; Mahabal, A.; Djorgovski, S. G.; Williams, R.; Graham, M. J.; Christensen, E.; Beshore, E. C.; Larson, S. M.

    2008-06-01

    We have detected a likely Supernova in Catalina Sky Survey images from 11 Jun 2008 UT. The object has the following parameters:

    CSS080611:121642+410211 2008-06-11 UT 04:52:41 RA 12:16:41.53 Dec 41:02:11.2 Mag 17.7 Type SN
    The object is near the edge of galaxy SDSSJ121642.18+410223.7 (z = 0.039, mags: g~ 17.9, r~17.6, i~17.3, z~17.5).

  2. The Vela Supernova Remnant

    NASA Astrophysics Data System (ADS)

    Raymond, John C.

    We wish to obtain both emission and absorption line observations of the Vela Supernova remnant. The filament we wish to study in emission is the brightest filament in the SNR, so it will provide a spectrum twice the quality of any in existence. It is also located at the edge of an unusual bulge in the SNR, and it can be used to test the level of departure from pressure equilibrium in the remnant, which is useful as a test of evaporative models of SNR evolution. The absorption line studies will look for evidence of the drastically unstable behavior of shocks above 150 km/s predicted by Innes and Giddings. Four of the stars studied by Jenkins, Silk and Wallerstein showed marginal evidence for two positive or two negative high velocity components. If these multiple velocity components are confirmed, they support the secondary shock predictions of Innes and Giddings.

  3. Pulsars and supernova remnants

    SciTech Connect

    Narayan, R.; Schaudt, K.J.

    1988-02-01

    With the recent discovery of the pulsar PSR 1951 + 22 in CTB 80, four pulsars are now known in supernova remnants (SNRs) of the plerion and composite classes. It is argued that this success rate of pulsar detections implies that young fast pulsars have long fan-beams that enable them to be seen from most directions. Based on calculations that use a pulsar luminosity model and allow for selection effects, it is suggested that the best SNRs for future pulsar searches are 3C 58, MSH 11-62, G24.7 + 0.6, and MSH 15-56. It is also concluded that the failure to detect pulsars in shell SNRs implies either that there are no pulsars in these SNRs or that the pulsars are unusually weak, possibly due to slow rotation or weak magnetic fields. 25 references.

  4. Variety in Supernovae

    NASA Astrophysics Data System (ADS)

    Turatto, Massimo; Benetti, Stefano; Cappellaro, Enrico

    Detailed observations of a growing number of supernovae have determined a bloom of new peculiar events. In this paper we take a short tour through the SN diversity and discuss some important, physical issues related to it. Because of the role of SN Ia in determining the cosmological parameters, it is crucial to understand the physical origin of even subtle, observed differences. An important issue is also the reddening correction. We believe that the measure of interstellar lines on medium resolution spectra of SNe can be used to derive lower limits on the interstellar extinction. A few physical parameters of the progenitor, namely radius, mass, density structure and angular momentum, may explain most of the diversity of core-collapse events. In addition, if the ejecta expand into a dense circumstellar medium the ejecta-CSM interaction may dominate the observed outcome and provide a mean to probe the mass loss history of the SN progenitor in the last stages of its evolution.

  5. Dimming supernovae without cosmic acceleration.

    PubMed

    Csáki, Csaba; Kaloper, Nemanja; Terning, John

    2002-04-22

    We present a simple model where photons propagating in extragalactic magnetic fields can oscillate into very light axions. The oscillations may convert some of the photons, departing a distant supernova, into axions, making the supernova appear dimmer and hence more distant than it really is. Averaging over different configurations of the magnetic field we find that the dimming saturates at about one-third of the light from the supernovae at very large redshifts. This results in a luminosity distance versus redshift curve almost indistinguishable from that produced by the accelerating Universe, if the axion mass and coupling scale are m approximately 10(-16) eV, M approximately 4 x 10(11) GeV. This phenomenon may be an alternative to the accelerating Universe for explaining supernova observations.

  6. Supernova olivine from cometary dust

    NASA Technical Reports Server (NTRS)

    Messenger, Scott; Keller, Lindsay P.; Lauretta, Dante S.

    2005-01-01

    An interplanetary dust particle contains a submicrometer crystalline silicate aggregate of probable supernova origin. The grain has a pronounced enrichment in 18O/16O (13 times the solar value) and depletions in 17O/16O (one-third solar) and 29Si/28Si (<0.8 times solar), indicative of formation from a type II supernova. The aggregate contains olivine (forsterite 83) grains <100 nanometers in size, with microstructures that are consistent with minimal thermal alteration. This unusually iron-rich olivine grain could have formed by equilibrium condensation from cooling supernova ejecta if several different nucleosynthetic zones mixed in the proper proportions. The supernova grain is also partially encased in nitrogen-15-rich organic matter that likely formed in a presolar cold molecular cloud.

  7. Hardy Star Survives Supernova Blast

    NASA Image and Video Library

    2014-03-20

    This composite image contains data from Chandra (purple) that provides evidence for the survival of a companion star from the blast of a supernova explosion. Chandra's X-rays reveal a point-like source in the supernova remnant at the location of a massive star. The data suggest that mass is being pulled away from the massive star towards a neutron star or a black hole companion. If confirmed, this would be only the third binary system containing both a massive star and a neutron star or black hole ever found in the aftermath of a supernova. This supernova remnant is found embedded in clouds of ionized hydrogen, which are shown in optical light (yellow and cyan) from the MCELS survey, along with additional optical data from the DSS (white).

  8. Supernova Remnant in 3-D

    NASA Image and Video Library

    2009-01-06

    For the first time, a multiwavelength three-dimensional reconstruction of a supernova remnant has been created. This visualization of Cassiopeia A, or Cas A, the result of an explosion approximately 330 years ago, uses data from several NASA telescopes.

  9. Supernova olivine from cometary dust.

    PubMed

    Messenger, Scott; Keller, Lindsay P; Lauretta, Dante S

    2005-07-29

    An interplanetary dust particle contains a submicrometer crystalline silicate aggregate of probable supernova origin. The grain has a pronounced enrichment in 18O/16O (13 times the solar value) and depletions in 17O/16O (one-third solar) and 29Si/28Si (<0.8 times solar), indicative of formation from a type II supernova. The aggregate contains olivine (forsterite 83) grains <100 nanometers in size, with microstructures that are consistent with minimal thermal alteration. This unusually iron-rich olivine grain could have formed by equilibrium condensation from cooling supernova ejecta if several different nucleosynthetic zones mixed in the proper proportions. The supernova grain is also partially encased in nitrogen-15-rich organic matter that likely formed in a presolar cold molecular cloud.

  10. Spectroscopic classification of supernova candidates

    NASA Astrophysics Data System (ADS)

    Hodgkin, S. T.; Hall, A.; Fraser, M.; Campbell, H.; Wyrzykowski, L.; Kostrzewa-Rutkowska, Z.; Pietro, N.

    2014-09-01

    We report the spectroscopic classification of four supernovae at the 2.5m Isaac Newton Telescope on La Palma, using the Intermediate Dispersion Spectrograph and the R300V grating (3500-8000 Ang; ~6 Ang resolution).

  11. Fritz Zwicky: Novae Become Supernovae

    NASA Astrophysics Data System (ADS)

    Koenig, T.

    2005-12-01

    The Swiss physicist Fritz Zwicky (1898-1974) dabbled in a plethora of disciplines, including astronomy and astrophysics. His dabblings were with vested interest and he has left quite an impact. His first great success was his nova research. In the early 1930s, while supermarkets and Superman were flying, he labelled the distinctly brighter nova Supernova. It had been believed that novae were the collision of two stars, but Zwicky came to recognize supernovae as a phenomenon quite distinct from novae. He and Walter Baade explained supernova by melding astronomy and physics and in this aim they created neutron stars, explained the origin of cosmic rays, initiated the first sky survey, and confirmed that a number of historical novae were indeed supernovae. This was truly an important work in the history of astrophysics.

  12. Simulation of Kepler Supernova Explosion

    NASA Image and Video Library

    This video shows a simulation of the Kepler supernova as it interacts with material expelled by the giant star companion to the white dwarf before the latter exploded. It was assumed that the bulk ...

  13. Supernova Modeling: Progress and Challenges

    SciTech Connect

    Cardall, Christian Y

    2012-01-01

    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.

  14. Exploring the {alpha}p-process with Grand Raiden

    SciTech Connect

    O'Brien, S.; Berg, G. P. A.; Couder, M.; Goerres, J.; Patel, D.; Sault, K.; Wiescher, M.; Adachi, T.; Hatanaka, K.; Ishikawa, D.; Matsubara, H.; Okamura, H.; Ong, H. J.; Suzuki, T.; Tamii, A.; Zenihiro, J.; Dozono, M.; Wakasa, T.; Fujita, H.; Fujita, Y.

    2009-01-28

    {sup 22}Mg, {sup 30}S, {sup 34}Ar and {sup 38}Ca have been investigated using (p,t) reactions at RCNP with the intent of identifying energy levels in nuclei that determine the reaction rates along the pathway of the {alpha}p-process. These experiments exploit the high resolution and 0 deg. capabilities of the Grand Raiden spectrometer and the WS beamline, which can deliver a fully dispersion matched beam to target. The level information is vital to understanding the nucleosynthesis occurring during explosive hydrogen burning, which, for example, is thought to occur during type I X-ray bursts. In the case of {sup 22}Mg, new reaction rate calculations have been performed for the {sup 18}Ne({alpha},p){sup 21}Na reaction. The experimental technique will be discussed, and the experimental results will be presented.

  15. 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.

  16. New Hubble Observations of Supernova 1987A Trace Shock Wave

    NASA Image and Video Library

    2017-09-28

    Image release September 2, 2010 ABOUT THIS IMAGE: This image shows the entire region around supernova 1987A. The most prominent feature in the image is a ring with dozens of bright spots. A shock wave of material unleashed by the stellar blast is slamming into regions along the ring's inner regions, heating them up, and causing them to glow. The ring, about a light-year across, was probably shed by the star about 20,000 years before it exploded. An international team of astronomers using the Hubble Space Telescope reports a significant brightening of the emissions from Supernova 1987A. The results, which appear in this week's Science magazine, are consistent with theoretical predictions about how supernovae interact with their immediate galactic environment. The team observed the supernova remnant in optical, ultraviolet, and near-infrared light. They studied the interaction between the ejecta from the stellar explosion and a glowing 6-trillion-mile-diameter ring of gas encircling the supernova remnant. The gas ring was probably shed some 20,000 years before the supernova exploded. Shock waves resulting from the impact of the ejecta onto the ring have brightened 30 to 40 pearl-like "hot spots" in the ring. These blobs likely will grow and merge together in the coming years to form a continuous, glowing circle. "We are seeing the effect a supernova can have in the surrounding galaxy, including how the energy deposited by these stellar explosions changes the dynamics and chemistry of the environment," said University of Colorado at Boulder Research Associate Kevin France of the Center for Astrophysics and Space Astronomy. "We can use these new data to understand how supernova processes regulate the evolution of galaxies." Discovered in 1987, Supernova 1987A is the closest exploding star to Earth to be detected since 1604 and it resides in the nearby Large Magellanic Cloud, a dwarf galaxy adjacent to our own Milky Way Galaxy. Credit: NASA, ESA, K. France (University

  17. The Search for Lensed Supernovae

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2017-01-01

    Type Ia supernovae that have multiple images due to gravitational lensing can provide us with a wealth of information both about the supernovae themselves and about our surrounding universe. But how can we find these rare explosions?Clues from Multiple ImagesWhen light from a distant object passes by a massive foreground galaxy, the galaxys strong gravitational pull can bend the light, distorting our view of the backgroundobject. In severe cases, this process can cause multiple images of the distant object to appear in the foreground lensing galaxy.An illustration of gravitational lensing. Light from the distant supernova is bent as it passes through a giant elliptical galaxy in the foreground, causing multiple images of the supernova to appear to be hosted by the elliptical galaxy. [Adapted from image by NASA/ESA/A. Feild (STScI)]Observations of multiply-imaged Type Ia supernovae (explosions that occur when white dwarfs in binary systems exceed their maximum allowed mass) could answer a number of astronomical questions. Because Type Ia supernovae are standard candles, distant, lensed Type Ia supernovae can be used to extend the Hubble diagram to high redshifts. Furthermore, the lensing time delays from the multiply-imaged explosion can provide high-precision constraints on cosmological parameters.The catch? So far, weve only found one multiply-imaged Type Ia supernova: iPTF16geu, discovered late last year. Were going to need a lot more of them to develop a useful sample! So how do we identify themutiply-imaged Type Ias among the many billions of fleeting events discovered in current and future surveys of transients?Searching for AnomaliesAbsolute magnitudes for Type Ia supernovae in elliptical galaxies. None are expected to be above -20 in the B band, so if we calculate a magnitude for a Type Ia supernova thats larger than this, its probably not hosted by the galaxy we think it is! [Goldstein Nugent 2017]Two scientists from University of California, Berkeley and

  18. 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

  19. The ESSENCE Supernova Survey: Survey Optimization, Observations, and Supernova Photometry

    SciTech Connect

    Miknaitis, Gajus; Pignata, G.; Rest, A.; Wood-Vasey, W.M.; Blondin, S.; Challis, P.; Smith, R.C.; Stubbs, C.W.; Suntzeff, N.B.; Foley, R.J.; Matheson, T.; Tonry, J.L.; Aguilera, C.; Blackman, J.W.; Becker, A.C.; Clocchiatti, A.; Covarrubias, R.; Davis, T.M.; Filippenko, A.V.; Garg, A.; Garnavich, P.M.; /Fermilab /Chile U., Catolica /Cerro-Tololo InterAmerican Obs. /Harvard-Smithsonian Ctr. Astrophys. /Harvard U. /UC, Berkeley, Astron. Dept. /NOAO, Tucson /Inst. Astron., Honolulu /Res. Sch. Astron. Astrophys., Weston Creek /Washington U., Seattle, Astron. Dept. /Bohr Inst. /Notre Dame U. /KIPAC, Menlo Park /Texas A-M /European Southern Observ. /Ohio State U., Dept. Astron. /Baltimore, Space Telescope Sci. /Johns Hopkins U. /Stockholm U.

    2007-01-08

    We describe the implementation and optimization of the ESSENCE supernova survey, which we have undertaken to measure the equation of state parameter of the dark energy. We present a method for optimizing the survey exposure times and cadence to maximize our sensitivity to the dark energy equation of state parameter w = P/{rho}c{sup 2} for a given fixed amount of telescope time. For our survey on the CTIO 4m telescope, measuring the luminosity distances and redshifts for supernovae at modest redshifts (z {approx} 0.5 {+-} 0.2) is optimal for determining w. We describe the data analysis pipeline based on using reliable and robust image subtraction to find supernovae automatically and in near real-time. Since making cosmological inferences with supernovae relies crucially on accurate measurement of their brightnesses, we describe our efforts to establish a thorough calibration of the CTIO 4m natural photometric system. In its first four years, ESSENCE has discovered and spectroscopically confirmed 102 type Ia SNe, at redshifts from 0.10 to 0.78, identified through an impartial, effective methodology for spectroscopic classification and redshift determination. We present the resulting light curves for the all type Ia supernovae found by ESSENCE and used in our measurement of w, presented in Wood-Vasey et al. (2007).

  20. Superluminous Extragalactic Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Chen, C. H. R.; Chu, Y.-H.

    1998-12-01

    Extragalactic supernova remnants (SNRs) are conventionally surveyed by optical emission-line images, using the [S II]/Hα line ratio to diagnose SNRs. The majority of the optically identified extragalactic SNRs are too faint to be confirmed at X-ray or radio wavelengths. Conversely, extragalactic SNRs that are initially identified by X-ray or radio observations are all superluminous, e.g., the X-ray SNR in NGC 6946 (Blair & Fesen 1994, ApJ, 424, L103) and the radio SNR in NGC 5471 (Skillman 1985, ApJ, 290, 449). NGC 5471 is a giant H II region in M101. Optical echelle observations of the SNR in NGC 5471 have detected high-velocity gas with a FWZI of at least 350 km/s. Decomposing the narrow H II component and the broad SNR component in the Hα velocity profile, Chu & Kennicutt (1986) derived a total mass of 6500+/-3000 M_sun and a kinetic energy of a few *E(50) ergs. Using archival ROSAT X-ray observations, Williams & Chu (1995) measured an X-ray luminosity of ~ 1 x 10(38) ergs/s for NGC 5471. Apparently, the SNR in NGC 5471 is superluminous at all wavelengths. To determine the physical conditions and nature of the superluminous SNR in NGC 5471, we have obtained HST WFPC2 images of NGC 5471 in the Hα and [S II] lines and two continuum bands. These high-resolution images reveal a [S II]-enhanced shell with a diameter of ~ 60 pc. A recent 180-ks ROSAT High Resolution Imager image of M101 shows that the X-ray emission from NGC 5471 peaks at this SNR shell. We are thus confident in the identification of the superluminous SNR in NGC 5471. Are superluminous SNRs produced by particularly powerful supernova explosions? Are they associated with gamma-ray bursters? Are their luminosities caused by dense interstellar environment? We will report the detailed physical properties of the SNR in NGC 5471, compare it to the other superluminous SNRs, and address these questions.

  1. Measuring the Universe with Supernovae

    NASA Astrophysics Data System (ADS)

    Kirshner, Robert

    1996-05-01

    Supernova explosions lead to luminous optical objects which can be used to measure distances in the Universe. Supernova 1987A in the nearby Large Magellanic Cloud provides a direct geometric distance to this galaxy, and a check on the Cepheid variable star distance scale. Using observations of SN 1987A with the Hubble Space Telescope, we find a distance of 51 ± 3 kiloparsec which is consistent with the Cepheid scale. Type II supernovae, which result from the core collapse of a massive star, emit a spectrum which can be accurately modeled. Based on understanding of the radiation transport through the expanding atmospheres, observations of SN II provide distances to 18 galaxies at redshifts up to 14500 km s-1. These distances agree within the errors with distances found from Cepheids, and correspond to a value of the Hubble Contant of 72 ± 7 km s-1Mpc-1. Finally, the Type Ia supernovae, thought to arise from the thermonuclear incineration of a carbon-oxygen white dwarf, provide the best and the brightest tools for measuring extragalactic distances. Careful study shows that these supernovae are not identical, but that there is a well-determined relation between the supernova luminosity and the time history of its light emission: the supernova light curve. Recent work on the ``Multicolor Light Curve Shape Method'' accounts for this effect in an optimal way, and allows an independent determination of the absorption by dust along the line of sight for each object. Using a sample of 20 SN Ia, and calibrating this with distances determined by Hubble Space Telescope observations of Cepheids yields a Hubble Constant of 65 ± 6 km s-1Mpc-1. This corresponds to an age of the Universe (for Ω = 0 ) of about 15 billion years, which is consistent with the age of the elements and the age of globular cluster stars.

  2. New experimental developments for s- and p-process research

    NASA Astrophysics Data System (ADS)

    Reifarth, R.; Ershova, O.; Glorius, J.; Göbel, K.; Langer, C.; Meusel, O.; Plag, R.; Schmidt, S.; Sonnabend, K.; Heil, M.

    2012-12-01

    Almost all of the heavy elements are produced via neutron-induced processes in a multitude of stellar production sites. The remaining minor part is produced via photon- and proton-induced reactions. The predictive power of the underlying stellar models is currently limited because they contain poorly constrained physics components such as convection, rotation or magnetic fields. An important tool to determine such components is the comparison of observed with modeled abundance distributions based on improved nuclear physics input. The FRANZ facility at the Goethe University Frankfurt, which is currently under construction will provide unprecedented neutron fluxes and proton currents available for nuclear astrophysics. It will be possible to investigate important branchpoint nuclei of the s-process nucleosynthesis path and proton-induced reactions important for p-process modeling. At the GSI close to Darmstadt radioactive isotopes can be investigated in inverse kinematics. This allows experiments such as proton-induced cross section measurements using a heavy-ion storage ring or measurements of gamma-induced reactions using the Coulomb dissociation method. The future FAIR facility will allow similar experiments on very exotic nuclei, since orders of magnitude higher radioactive ions beams will be possible.

  3. Supernova Explosions Stay In Shape

    NASA Astrophysics Data System (ADS)

    2009-12-01

    At a very early age, children learn how to classify objects according to their shape. Now, new research suggests studying the shape of the aftermath of supernovas may allow astronomers to do the same. A new study of images from NASA's Chandra X-ray Observatory on supernova remnants - the debris from exploded stars - shows that the symmetry of the remnants, or lack thereof, reveals how the star exploded. This is an important discovery because it shows that the remnants retain information about how the star exploded even though hundreds or thousands of years have passed. "It's almost like the supernova remnants have a 'memory' of the original explosion," said Laura Lopez of the University of California at Santa Cruz, who led the study. "This is the first time anyone has systematically compared the shape of these remnants in X-rays in this way." Astronomers sort supernovas into several categories, or "types", based on properties observed days after the explosion and which reflect very different physical mechanisms that cause stars to explode. But, since observed remnants of supernovas are leftover from explosions that occurred long ago, other methods are needed to accurately classify the original supernovas. Lopez and colleagues focused on the relatively young supernova remnants that exhibited strong X-ray emission from silicon ejected by the explosion so as to rule out the effects of interstellar matter surrounding the explosion. Their analysis showed that the X-ray images of the ejecta can be used to identify the way the star exploded. The team studied 17 supernova remnants both in the Milky Way galaxy and a neighboring galaxy, the Large Magellanic Cloud. For each of these remnants there is independent information about the type of supernova involved, based not on the shape of the remnant but, for example, on the elements observed in it. The researchers found that one type of supernova explosion - the so-called Type Ia - left behind relatively symmetric, circular

  4. Constraining inverse-curvature gravity with supernovae.

    PubMed

    Mena, Olga; Santiago, José; Weller, Jochen

    2006-02-03

    We show that models of generalized modified gravity, with inverse powers of the curvature, can explain the current accelerated expansion of the Universe without resorting to dark energy and without conflicting with solar system experiments. We have solved the Friedmann equations for the full dynamical range of the evolution of the Universe and performed a detailed analysis of supernovae data in the context of such models that results in an excellent fit. If we further include constraints on the current expansion of the Universe and on its age, we obtain that the matter content of the Universe is 0.07dynamics of the Universe just with a baryonic matter component.

  5. Light-echo spectroscopy of historic Supernovae

    NASA Astrophysics Data System (ADS)

    Krause, Oliver

    Young Galactic supernova remnants are unique laboratories for supernova physics. Due to their proximity they provide us with the most detailed view of the outcome of a supernova. However, the exact spectroscopic types of their original explosions have been undetermined so far -hindering to link the wealth of multi-wavelength knowledge about their remnants with the diverse population of supernovae. Light echoes, reflektions of the brilliant supernova burst of light by interstellar dust, provide a unique opportunity to reobserve today -with powerful scientific instruments of the 21st century -historic supernova exlosions even after hundreds of years and to conclude on their nature. We report on optical light-echo spectroscopy of two famous Galactic supernovae: Tycho Brahe's SN 1572 and the supernova that created the Cassiopeia A remnant around the year 1680. These observations finally recovered the missing spectroscopic classifications and provide new constraints on explosion models for future studies.

  6. Open Supernova Catalog objects subsample characteristics

    NASA Astrophysics Data System (ADS)

    Khyzhniak, E. V.; Arkhangelskaja, I. V.; Lyapin, A. R.

    2017-01-01

    The homogeneous subsample characteristics understanding is necessary for the investigation of any astrophysical objects redshift distribution, for example, gamma-ray bursts. The type Ia supernovae considered as a homogeneous subsample because of suggestion that these luminous events might be used as standard candles for cosmological measurements occurs since the earliest studies of supernovae in 1938. The parameters of our Metagalaxy Ω and Λ were determine due sample of Ia supernovae from the Supernova Cosmology Project analysis in 1998. Since then more than 4000 supernovae were added. The results of the redshift distribution analysis for supernova from the two catalogues (Asiago Supernova Catalogue and Open Supernova Catalog) are presented in this work. The ability to use an analyzed dataset as homogeneous subsample also is discussed

  7. Discovery of Three ASAS-SN Supernovae

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Brown, J. S.; Vallely, P.; Stanek, K. Z.; Kochanek, C. S.; Shields, J.; Thompson, T. A.; Holoien, T. W.-S.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Conseil, E.; Marples, P.; Stone, G.

    2017-09-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered three new transient sources, most likely supernovae.

  8. Supernovae - Still a challenge

    NASA Astrophysics Data System (ADS)

    Reddy, F.

    1983-12-01

    Historical data on supernovae (SN) occurrences are surveyed, together with present models for the physical processes occurring during the events. Type I SN feature low intensity hydrogen lines, while the hydrogen lines are prominant in Type II phenomena. Only Type I events seem to occur in elliptical galaxies, implying that the Type I events involve relatively old, low-mass objects. Both types occur in spatial galaxies, although the Type II objects are usually located in gas-rich stellar nurseries of the spiral arms, suggesting the Type II SN progenitor stars are only a few million years old. The light curves of Type I SN maintain a peak brightness significantly longer than do Type II SN, whose brightness declines irregularly. The incineration of a white dwarf that could account for observations of nickel abundances in a Type I burst, which may be confined to binary systems, is outlined. Processes that occur in a core bounce in a Type II SN, when a massive star collapses and gravitational energy abruptly changes into expansive energy, are discussed.

  9. A Supernova's Shockwaves

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Supernovae are the explosive deaths of the universe's most massive stars. In death, these volatile creatures blast tons of energetic waves into the cosmos, destroying much of the dust surrounding them.

    This false-color composite from NASA's Spitzer Space Telescope and NASA's Chandra X-ray Observatory shows the remnant of one such explosion. The remnant, called N132D, is the wispy pink shell of gas at the center of this image. The pinkish color reveals a clash between the explosion's high-energy shockwaves and surrounding dust grains.

    In the background, small organic molecules called polycyclic aromatic hydrocarbons are shown as tints of green. The blue spots represent stars in our galaxy along this line of sight.

    N132D is located 163,000 light-years away in a neighboring galaxy called, the Large Magellanic Cloud.

    In this image, infrared light at 4.5 microns is mapped to blue, 8.0 microns to green and 24 microns to red. Broadband X-ray light is mapped purple. The infrared data were taken by Spitzer's infrared array camera and multiband imaging photometer, while the X-ray data were captured by Chandra.

  10. A Supernova's Shockwaves

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Supernovae are the explosive deaths of the universe's most massive stars. In death, these volatile creatures blast tons of energetic waves into the cosmos, destroying much of the dust surrounding them.

    This false-color composite from NASA's Spitzer Space Telescope and NASA's Chandra X-ray Observatory shows the remnant of one such explosion. The remnant, called N132D, is the wispy pink shell of gas at the center of this image. The pinkish color reveals a clash between the explosion's high-energy shockwaves and surrounding dust grains.

    In the background, small organic molecules called polycyclic aromatic hydrocarbons are shown as tints of green. The blue spots represent stars in our galaxy along this line of sight.

    N132D is located 163,000 light-years away in a neighboring galaxy called, the Large Magellanic Cloud.

    In this image, infrared light at 4.5 microns is mapped to blue, 8.0 microns to green and 24 microns to red. Broadband X-ray light is mapped purple. The infrared data were taken by Spitzer's infrared array camera and multiband imaging photometer, while the X-ray data were captured by Chandra.

  11. Supernovae. Old supernova dust factory revealed at the Galactic center.

    PubMed

    Lau, R M; Herter, T L; Morris, M R; Li, Z; Adams, J D

    2015-04-24

    Dust formation in supernova ejecta is currently the leading candidate to explain the large quantities of dust observed in the distant, early universe. However, it is unclear whether the ejecta-formed dust can survive the hot interior of the supernova remnant (SNR). We present infrared observations of ~0.02 solar masses of warm (~100 kelvin) dust seen near the center of the ~10,000-year-old Sagittarius A East SNR at the Galactic center. Our findings indicate the detection of dust within an older SNR that is expanding into a relatively dense surrounding medium (electron density ~10(3) centimeters(-3)) and has survived the passage of the reverse shock. The results suggest that supernovae may be the dominant dust-production mechanism in the dense environment of galaxies of the early universe.

  12. The Shape of Superluminous Supernovae

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-11-01

    What causes the tremendous explosions of superluminous supernovae? New observations reveal the geometry of one such explosion, SN 2015bn, providing clues as to its source.A New Class of ExplosionsImage of a type Ia supernova in the galaxy NGC 4526. [NASA/ESA]Supernovae are powerful explosions that can briefly outshine the galaxies that host them. There are several different classifications of supernovae, each with a different physical source such as thermonuclear instability in a white dwarf, caused by accretion of too much mass, or the exhaustion of fuel in the core of a massive star, leading to the cores collapse and expulsion of its outer layers.In recent years, however, weve detected another type of supernovae, referred to as superluminous supernovae. These particularly energetic explosions last longer months instead of weeks and are brighter at their peaks than normal supernovae by factors of tens to hundreds.The physical cause of these unusual explosions is still a topic of debate. Recently, however, a team of scientists led by Cosimo Inserra (Queens University Belfast) has obtained new observations of a superluminous supernova that might help address this question.The flux and the polarization level (black lines) along the dominant axis of SN 2015bn, 24 days before peak flux (left) and 28 days after peak flux (right). Blue lines show the authors best-fitting model. [Inserra et al. 2016]Probing GeometryInserra and collaborators obtained two sets of observations of SN 2015bn one roughly a month before and one a month after the superluminous supernovas peak brightness using a spectrograph on the Very Large Telescope in Chile. These observations mark the first spectropolarimetric data for a superluminous supernova.Spectropolarimetry is the practice of obtaining information about the polarization of radiation from an objects spectrum. Polarization carries information about broken spatial symmetries in the object: only if the object is perfectly symmetric can it

  13. empiriciSN: Supernova parameter generator

    NASA Astrophysics Data System (ADS)

    Holoien, Thomas W.-S.; Marshall, Philip J.; Wechsler, Risa H.

    2017-08-01

    empiriciSN generates realistic supernova parameters given photometric observations of a potential host galaxy, based entirely on empirical correlations measured from supernova datasets. It is intended to be used to improve supernova simulation for DES and LSST. It is extendable such that additional datasets may be added in the future to improve the fitting algorithm or so that additional light curve parameters or supernova types may be fit.

  14. Supernova explosions in the Universe.

    PubMed

    Burrows, A

    2000-02-17

    During the lifetime of our Milky Way galaxy, there have been something like 100 million supernova explosions, which have enriched the Galaxy with the oxygen we breathe, the iron in our cars, the calcium in our bones and the silicon in the rocks beneath our feet. These exploding stars also influence the birth of new stars and are the source of the energetic cosmic rays that irradiate us on the Earth. The prodigious amount of energy (approximately 10(51), or approximately 2.5 x 10(28) megatonnes of TNT equivalent) and momentum associated with each supernova may even have helped to shape galaxies as they formed in the early Universe. Supernovae are now being used to measure the geometry of the Universe, and have recently been implicated in the decades-old mystery of the origin of the gamma-ray bursts. Together with major conceptual advances in our theoretical understanding of supernovae, these developments have made supernovae the centre of attention in astrophysics.

  15. Theory and phenomenology of supernova neutrinos

    SciTech Connect

    Lunardini, Cecilia

    2015-07-15

    The theory and phenomenology of supernova neutrinos is reviewed, with focus on the most recent advancements on the neutrino flux predicted by supernova numerical models, on neutrino oscillations inside the star and in the Earth, and on the physics of the diffuse supernova neutrino background. Future directions of research are briefly summarized.

  16. Red supergiants as supernova progenitors

    NASA Astrophysics Data System (ADS)

    Davies, Ben

    2017-09-01

    It is now well-established from pre-explosion imaging that red supergiants (RSGs) are the direct progenitors of Type-IIP supernovae. These images have been used to infer the physical properties of the exploding stars, yielding some surprising results. In particular, the differences between the observed and predicted mass spectrum has provided a challenge to our view of stellar evolutionary theory. However, turning what is typically a small number of pre-explosion photometric points into the physical quantities of stellar luminosity and mass requires a number of assumptions about the spectral appearance of RSGs, as well as their evolution in the last few years of life. Here I will review what we know about RSGs, with a few recent updates on how they look and how their appearance changes as they approach supernova. This article is part of the themed issue 'Bridging the gap: from massive stars to supernovae'.

  17. Explosive supernova core overturn and mass ejection

    SciTech Connect

    Colgate, S.A.; Petschek, A.G.

    1980-03-15

    We show that Raleigh-Taylor convective overturn of the dynamically formed lepton-trapped core of a supernova is a likely outcome of three sequential events: (1) the bounce or weak reversal shock; (2) the diffusive and convective lepton release from the neutrinosphere during a fraction of the reversal time (approx.100 ms); and (3) the rapid (< or approx. = ms) Rayleigh-Taylor growth of the l=2 mode of an initial rotational perturbation. The overturn is explosive in the sense that the increase of gravitational binding energy appears as radial outgoing kinetic energy of a fraction of the mass of the core. The increased binding energy is due to the adiabatic interchange of lepton-poor ''heavier'' matter from the outside of the core with lepton-trapped matter from the center of the core. The difference in binding energy is 30--50 MeV per nucleon. The resulting kinetic energy of approx.7 x 10/sup 52/ ergs in more than adequate to cause the observed supernova emission. Also, it is larger than the approx.7 x 10/sup 51/ ergs of approx.10 MeV neutrinos suddenly released from the neutrinosphere as previously noted by Colgate and by Bruenn, Buchler, and Livio.

  18. Distant Supernovae Indicate Ever-Expanding Universe

    NASA Astrophysics Data System (ADS)

    1998-12-01

    parameters, the age of the Universe and the geometry of space can be derived. They have been the focus of a large number of astronomical programmes over the past decades. Many aspects of the currently preferred cosmological model, the Hot Big Bang , have been impressively confirmed by observations of the expansion of the Universe, the cosmic background radiation, and also the explanation of the synthesis of light elements. Still, our knowledge about the dynamical state of the Universe, as well as the early formation of structures, i.e., of galaxies and stars, is far from complete - this remains a field of active research. Possibly, the simplest way to test our present assumptions in this direction is to measure accurate distances and compare them with the expected cosmic scale. This is where the recent results contribute to our understanding of the Universe. The key role of supernovae The two research teams, both with participation from ESO [1], have concentrated on the study of rare stellar explosions, during which certain old stars undergo internal incineration. In this process, explosive nuclear fusion burns matter into the most stable atomic nucleus, iron, and releases a gigantic amount of energy. ESO PR Photo 50a/98 ESO PR Photo 50a/98 [Preview - JPEG: 800 x 648 pix - 768k] [High-Res - JPEG: 3000 x 2431 pix - 8.5Mb] ESO PR Photo 50b/98 ESO PR Photo 50b/98 [Preview - JPEG: 800 x 649 pix - 784k] [High-Res - JPEG: 3000 x 2432 pix - 8.4Mb] These photos illustrate the follow-up observations on which the new results described in this Press Release are based. Sky fields with clusters of galaxies are monitored with the 4-m telescope at Cerro Tololo Interamerican Observatory (CTIO) in Chile and spectra are obtained of suddenly appearing star-like objects that may be supernovae. Confirmed Type Ia supernovae are then monitored by ESO telescopes at La Silla and at other observatories. In PR Photo 50a/98 , a supernova at redshift z = 0.51 [2] (corresponding to a distance of about 10

  19. Software Based Supernova Recognition

    NASA Astrophysics Data System (ADS)

    Walters, Stephen M.

    2014-05-01

    This paper describes software for detecting Supernova (SN) in images. The software can operate in real-time to discover SN while data is being collected so the instrumentation can immediately be re-tasked to perform spectroscopy or photometry of a discovery. Because the instrumentation captures two images per minute, the realtime budget is constrained to 30 seconds per target, a challenging goal. Using a set of two to four images, the program creates a "Reference" (REF) image and a "New" (NEW) image where all images are used in both NEW and REF but any SN survives the combination process only in the NEW image. This process produces good quality images having similar noise characteristics but without artifacts that might be interpreted as SN. The images are then adjusted for seeing and brightness differences using a variant of Tomaney and Crotts method of Point Spread Function (PSF) matching after which REF is subtracted from NEW to produce a Difference (DIF) image. A Classifier is then trained on a grid of artificial SN to estimate the statistical properties of four attributes and used in a process to mask false positives that can be clearly identified as such. Further training to avoid any remaining false positives sets the range, in standard deviations for each attribute, that the Classifier will accept as a valid SN. This training enables the Classifier to discriminate between SN and most subtraction residue. Lastly, the DIF image is scanned and measured by the Classifier to find locations where all four properties fall within their acceptance ranges. If multiple locations are found, the one best conforming to the training estimates is chosen. This location is then declared as a Candidate SN, the instrumentation re-tasked and the operator notified.

  20. Evolution of clustered supernovae

    NASA Astrophysics Data System (ADS)

    Vasiliev, Evgenii O.; Shchekinov, Yuri A.; Nath, Biman B.

    2017-07-01

    We study the merging and evolution of isolated supernova (SN) remnants in a stellar cluster into a collective superbubble, with the help of 3D hydrodynamic simulations. We particularly focus on the transition stage when the isolated SN remnants gradually combine to form a superbubble. We find that when the SN rate is high (νsn ˜ 10-9 pc-3 yr-1), the merging phase lasts for ˜104 yr, for n = 1-10 cm-3, and the merging phase lasts for a longer time (˜0.1 Myr or more) for lower SN rates (νsn ≤ 10-10 pc-3 yr-1). During this transition phase, the growing superbubble is filled with dense and cool fragments of shells, and most of the energy is radiated away during this merging process. After passing through the intermediate phase, the superbubble eventually settles on to a new power-law wind asymptote that is smaller than estimated in a continuous wind model. This results in a significant (more than several times) underestimation of the mechanical luminosity needed to feed the bubble. We determine the X-ray and H α surface brightnesses as functions of time for such merging SNe in a stellar cluster and find that clusters with high SN rate shine predominantly in soft X-rays and H α. In particular, a low value of the volume-averaged H α-to-H β ratio and its large spread can be a good indicator of the transition phase of merging SNe.

  1. Nature of type 1 Supernovae

    NASA Technical Reports Server (NTRS)

    Shklovskiy, I. S.

    1980-01-01

    The nature of type 1 supernovae (SN 1) is discussed through a comparison of observational evidence and theoretical perspectives relating to both type 1 and 2 supernovae. In particular two hypotheses relating to SN 1 phenomenon are examined: the first proposing that SN 1 are components of binary systems in which, at a comparatively late stage of evolution, overflow of the mass occurs; the second considers pre-SN 1 to be recently evolved stars with a mass greater than 1.4 solar mass (white dwarfs). In addition, an explanation of the reduced frequency of flares of SN 1 in spiral galaxies as related to that in elliptical galaxies is presented.

  2. Dust around Type Ia supernovae

    SciTech Connect

    Wang, Lifan

    2005-10-20

    An explanation is given of the low value of R lambda triple bond A lambda/E(B - V), the ratio of absolute to selective extinction deduced from Type Ia supernova observations. The idea involves scattering by dust clouds located in the circumstellar environment, or at the highest velocity shells of the supernova ejecta. The scattered light tends to reduce the effective R lambda in the optical, but has an opposite effect in the ultraviolet. The presence of circumstellar dust can be tested by ultraviolet to near infrared observations and by multi-epoch spectropolarimetry of SNe Ia.

  3. Educational Resources on Supernovae for Children

    NASA Astrophysics Data System (ADS)

    Struck, James T.

    The National Science Education Standards (1996, National Academy Press) suggest mention of objects like the ``sun, moon, stars" in grades K-4 and element formation in grades 9-12. Children's librarians and some astronomy librarians should know about some of the resources for children on supernovae not only because supernovae are critical to higher element formation, but also to educate others about the universe's expansion and stars. In addition, basic bibliometrics on these resources yields lessons on the importance of using many indexes, the pattern of literature for children on supernovae, the types of resources on supernovae, and the scattering of resources/information for children on supernovae.

  4. Magnetar-Powered Supernovae in Two Dimensions. I. Superluminous Supernovae

    NASA Astrophysics Data System (ADS)

    Chen, Ke-Jung; Woosley, S. E.; Sukhbold, Tuguldur

    2016-11-01

    Previous studies have shown that the radiation emitted by a rapidly rotating magnetar embedded in a young supernova can greatly amplify its luminosity. These one-dimensional studies have also revealed the existence of an instability arising from the piling up of radiatively accelerated matter in a thin dense shell deep inside the supernova. Here, we examine the problem in two dimensions and find that, while instabilities cause mixing and fracture this shell into filamentary structures that reduce the density contrast, the concentration of matter in a hollow shell persists. The extent of the mixing depends upon the relative energy input by the magnetar and the kinetic energy of the inner ejecta. The light curve and spectrum of the resulting supernova will be appreciably altered, as will the appearance of the supernova remnant, which will be shellular and filamentary. A similar pile up and mixing might characterize other events where energy is input over an extended period by a centrally concentrated source, e.g., a pulsar, radioactive decay, a neutrino-powered wind, or colliding shells. The relevance of our models to the recent luminous transient ASASSN-15lh is briefly discussed.

  5. Pair Instability Supernovae of Very Massive Population III Stars

    NASA Astrophysics Data System (ADS)

    Chen, Ke-Jung; Heger, Alexander; Woosley, Stan; Almgren, Ann; Whalen, Daniel J.

    2014-09-01

    Numerical studies of primordial star formation suggest that the first stars in the universe may have been very massive. Stellar models indicate that non-rotating Population III stars with initial masses of 140-260 M ⊙ die as highly energetic pair-instability supernovae. We present new two-dimensional simulations of primordial pair-instability supernovae done with the CASTRO code. Our simulations begin at earlier times than previous multidimensional models, at the onset of core contraction, to capture any dynamical instabilities that may be seeded by core contraction and explosive burning. Such instabilities could enhance explosive yields by mixing hot ash with fuel, thereby accelerating nuclear burning, and affect the spectra of the supernova by dredging up heavy elements from greater depths in the star at early times. Our grid of models includes both blue supergiants and red supergiants over the range in progenitor mass expected for these events. We find that fluid instabilities driven by oxygen and helium burning arise at the upper and lower boundaries of the oxygen shell ~20-100 s after core bounce. Instabilities driven by burning freeze out after the SN shock exits the helium core. As the shock later propagates through the hydrogen envelope, a strong reverse shock forms that drives the growth of Rayleigh-Taylor instabilities. In red supergiant progenitors, the amplitudes of these instabilities are sufficient to mix the supernova ejecta.

  6. Pair instability supernovae of very massive population III stars

    SciTech Connect

    Chen, Ke-Jung; Woosley, Stan; Heger, Alexander; Almgren, Ann; Whalen, Daniel J.

    2014-09-01

    Numerical studies of primordial star formation suggest that the first stars in the universe may have been very massive. Stellar models indicate that non-rotating Population III stars with initial masses of 140-260 M {sub ☉} die as highly energetic pair-instability supernovae. We present new two-dimensional simulations of primordial pair-instability supernovae done with the CASTRO code. Our simulations begin at earlier times than previous multidimensional models, at the onset of core contraction, to capture any dynamical instabilities that may be seeded by core contraction and explosive burning. Such instabilities could enhance explosive yields by mixing hot ash with fuel, thereby accelerating nuclear burning, and affect the spectra of the supernova by dredging up heavy elements from greater depths in the star at early times. Our grid of models includes both blue supergiants and red supergiants over the range in progenitor mass expected for these events. We find that fluid instabilities driven by oxygen and helium burning arise at the upper and lower boundaries of the oxygen shell ∼20-100 s after core bounce. Instabilities driven by burning freeze out after the SN shock exits the helium core. As the shock later propagates through the hydrogen envelope, a strong reverse shock forms that drives the growth of Rayleigh-Taylor instabilities. In red supergiant progenitors, the amplitudes of these instabilities are sufficient to mix the supernova ejecta.

  7. Nucleosynthesis in Early Supernova Winds II: The Role of Neutrinos

    SciTech Connect

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

    2005-11-04

    One of the outstanding unsolved riddles of nuclear astrophysics is the origin of the so called ''p-process'' nuclei from A = 92 to 126. Both the lighter and heavier p-process nuclei are adequately produced in the neon and oxygen shells of ordinary Type II supernovae, but the origin of these intermediate isotopes, especially {sup 92,94}Mo and {sup 96,98}Ru, has long been mysterious. Here we explore the production of these nuclei in the neutrino-driven wind from a young neutron star. We consider such early times that the wind still contains a proton excess because the rates for {nu}{sub e} and positron captures on neutrons are faster than those for the inverse captures on protons. Following a suggestion by Froehlich et al. (2005), they also include the possibility that, in addition to the protons, {alpha}-particles, and heavy seed, a small flux of neutrons is maintained by the reaction p({bar {nu}}{sub e}, e{sup +})n. This flux of neutrons is critical in bridging the long waiting points along the path of the rp-process by (n,p) and (n,{gamma}) reactions. Using the unmodified ejecta histories from a recent two-dimensional supernova model by Janka, Buras, and Rampp (2003), they find synthesis of p-rich nuclei up to {sup 102}Pd. However, if the entropy of these ejecta is increased by a factor of two, the synthesis extends to {sup 120}Te. Still larger increases in entropy, that might reflect the role of magnetic fields or vibrational energy input neglected in the hydrodynamical model, result in the production of numerous r-, s-, and p-process nuclei up to A {approx} 170, even in winds that are proton-rich.

  8. Are supernovae recorded in indigenous astronomical traditions?

    NASA Astrophysics Data System (ADS)

    Hamacher, Duane W.

    2014-07-01

    Novae and supernovae are rare astronomical events that would have had an influence on the skywatching peoples who witnessed them. Although several bright novae/supernovae have been visible during recorded human history, there are many proposed but no confirmed accounts of supernovae in indigenous oral traditions or material culture. Criteria are established for confirming novae/supernovae in oral traditions and material culture, and claims from around the world are discussed to determine if they meet these criteria. Aboriginal Australian traditions are explored for possible descriptions of novae/supernovae. Although representations of supernovae may exist in Aboriginal traditions, there are currently no confirmed accounts of supernovae in Indigenous Australian oral or material traditions.

  9. Consequences of nuclear electron capture in core collapse supernovae.

    PubMed

    Hix, W R; Messer, O E B; Mezzacappa, A; Liebendörfer, M; Sampaio, J; Langanke, K; Dean, D J; Martínez-Pinedo, G

    2003-11-14

    The most important weak nuclear interaction to the dynamics of stellar core collapse is electron capture, primarily on nuclei with masses larger than 60. In prior simulations of core collapse, electron capture on these nuclei has been treated in a highly parametrized fashion, if not ignored. With realistic treatment of electron capture on heavy nuclei come significant changes in the hydrodynamics of core collapse and bounce. We discuss these as well as the ramifications for the postbounce evolution in core collapse supernovae.

  10. Supernova remnants and their effects on the interstellar medium

    NASA Astrophysics Data System (ADS)

    Giacani, E.

    2017-07-01

    Supernova remnants (SNRs) are one of the main sources of energy injection in galaxies and great modifiers of the dynamics and chemistry of the interstellar medium, constituting a very valuable astrophysical laboratory to study numerous physical processes involved in their evolution and the interaction with the surrounding material. In this contribution I summarize the current state of knowledge of two of the main phenomena associated with these objects: if they are sources of galactic cosmic rays and triggers of formation of new stars.

  11. Radio studies of extragalactic supernovae.

    PubMed

    Weiler, K W; Sramek, R A; Panagia, N

    1986-03-14

    Some exploding stars (supernovae) are powerful emitters of centimeter radio radiation. Detailed observations have shown that these supernovae quickly become detectable in the radio range, first at shorter wavelengths (higher frequencies) and later at progressively longer and longer wavelengths (lower frequencies). This part of the phenomenon appears to be well explained by a monotonic decrease in the amount of ionized material surrounding the radio-emitting regions as the shock from the explosion travels outward. The radio emission itself is of a nonthermal, synchrotron origin, as is the case in most bright cosmic radio sources. Once the absorption effects become negligible, the radio intensity declines with time until reaching the detection limit of the telescope. Models suggest that the absorbing material originates in a dense wind of matter lost by the supernova progenitor star, or by its companion if it is in a binary system, in the last stages of evolution before the explosion. The synchrotron radio emission can be generated either externally by the shock wave from the explosion propagating through this same high density stellar wind or internally by a rapidly rotating neutron star, which is the collapsed core of the exploded star. Present results appear to favor the former model for at least the first several years after the supernova explosion, although the latter model remains viable.

  12. Cosmology from High Redshift Supernovae

    NASA Astrophysics Data System (ADS)

    Garnavich, Peter

    The discovery of a correlation between the light curve shape and intrinsic b rightness has made Type Ia supernovae exceptionally accurate distance indicators out to cosmologically interesting redshifts. Ground-based searches and follow-up as well as Hubble S pace Telescope observations of Type Ia supernovae have produced a significant number of object s with redshifts between 0.3 and 1.0. The distant SNe, when combined with a local samp le analyzed in the same way, provide reliable constraints on the deceleration and age of th e Universe. Early this year, an analysis of a handful of Type Ia events indicated that the deceleration was too small for gravitating matter alone to make a flat Universe. A larger sa mple of supernovae gives the surprising result that the Universe is accelerating, implying the exi stence of a cosmological constant or some other exotic form of energy. The success of this research has depended on the development of algorithms and software to register, scale and subtract CCD images taken weeks apart and to search for var iable objects. A good fraction of the point-sources identified are asteroids, variable stars, or AGN, so spectra are needed to confirm the identification as a Type Ia supernova and obt ain a redshift. The best candidates are followed photometrically to construct light curves. The steps to transform the observed light curves into cosmologically interestin g results will also be described.

  13. The supernova: A stellar spectacle

    NASA Technical Reports Server (NTRS)

    Straka, W. C.

    1976-01-01

    The life of a star, the supernova, related objects and their importance in astronomy and science in general are discussed. Written primarily for science teachers of secondary school chemistry, physics, and earth sciences, the booklet contains a glossary, reference sources, suggested topics for discussion, and projects for individual or group assignment.

  14. 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.

  15. The Supernova - A Stellar Spectacle.

    ERIC Educational Resources Information Center

    Straka, W. C.

    This booklet is part of an American Astronomical Society curriculum project designed to provide teaching materials to teachers of secondary school chemistry, physics, and earth science. The following topics concerning supernovae are included: the outburst as observed and according to theory, the stellar remnant, the nebular remnant, and a summary…

  16. Pulsational Pair-instability Supernovae

    NASA Astrophysics Data System (ADS)

    Woosley, S. E.

    2017-02-01

    The final evolution of stars in the mass range 70-140 {\\text{}}{M}⊙ is explored. Depending upon their mass loss history and rotation rates, these stars will end their lives as pulsational pair-instability supernovae (PPISN) producing a great variety of observational transients with total durations ranging from weeks to millennia and luminosities from 1041 to over 1044 erg s-1. No nonrotating model radiates more than 5× {10}50 erg of light or has a kinetic energy exceeding 5× {10}51 erg, but greater energies are possible, in principle, in magnetar-powered explosions, which are explored. Many events resemble SNe Ibn, SNe Icn, and SNe IIn, and some potential observational counterparts are mentioned. Some PPISN can exist in a dormant state for extended periods, producing explosions millennia after their first violent pulse. These dormant supernovae contain bright Wolf-Rayet stars, possibly embedded in bright X-ray and radio sources. The relevance of PPISN to supernova impostors like Eta Carinae, to superluminous supernovae, and to sources of gravitational radiation is discussed. No black holes between 52 and 133 {\\text{}}{M}⊙ are expected from stellar evolution in close binaries.

  17. The impact of supernova remnants on interstellar turbulence and star formation

    NASA Astrophysics Data System (ADS)

    Pan, Liubin; Padoan, Paolo; Haugboelle, Troels; Nordlund, Ake

    2016-06-01

    The explosion energy of supernovae is believed to be a major energy source to drive and maintain turbulent motions in the interstellar gas. The interaction of supernova remnants with the interstellar medium plays a crucial role in shaping the statistics of interstellar turbulence, and has important effects on physical properties of molecular clouds. To investigate supernova-driven turbulence in molecular clouds and the implications for star formation, we conducted a large-scale MHD simulation, keeping track of the evolution of supernova remnants and their interactions with the interstellar gas in a region of 250 pc. The simulation accounts for the effects of gas heating and cooling, the magnetic fields and self-gravity, and the explosion energy of supernovae is injected as thermal energy at randomly selected locations in the simulation box. We analyzed the dense molecular clouds formed in our simulation, and showed that their properties, including the mass-size, velocity-size relations, mass and size probability distributions, and magnetic field-density relation, are all consistent with observational results, suggesting that the dynamics and structure of molecular clouds are the natural result of supernova-driven turbulence. We also found that, at the scale of molecular clouds, turbulent motions contain more power in solenoidal modes than in compressive modes. This suggests that the effective driving force for interstellar turbulence is largely solenoidal, in contrast to the recenthypothesis that supernova driving is purely compressive. The physical reason is that, as a supernova remnant impacts the ambient interstellar gas, the baroclinic effect arises immediately, which preferentially converts compressive motions to solenoidal modes throughout the evolution of the remnant in the interstellar medium. The implications of our results concerning the statistics of supernova-driven turbulence in molecular clouds on theoretical modeling of star formation will be

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

    DOE PAGES

    Foglizzo, Thierry; Kazeroni, Rémi; Guilet, Jérôme; ...

    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

  19. The changing morphology and increasing deceleration of supernova 1993J in M81

    PubMed

    Bartel; Bietenholz; Rupen; Beasley; Graham; Altunin; Venturi; Umana; Cannon; Conway

    2000-01-07

    Twenty consecutive Very Long Baseline Interferometry images of supernova 1993J from the time of explosion to the present show the dynamic evolution of the expanding radio shell of an exploded star. High-precision astrometry reveals that the supernova expands isotropically from its explosion center. Systematic changes in the images may reflect a pattern of anisotropies and inhomogeneities in the material left over from the progenitor star. As the shock front sweeps up the material in the surrounding medium, it is increasingly decelerated and influenced by the material. After 5 years, the supernova has slowed to half of its original expansion velocity and may have entered the early stages of the adiabatic phase common in much older supernova remnants in the Milky Way Galaxy.

  20. Core-collapse supernova simulations

    NASA Astrophysics Data System (ADS)

    Mueller, Bernhard

    2017-01-01

    Core-collapse supernovae, the deaths of massive stars, are among the most spectacular phenomena in astrophysics: Not only can supernovae outshine their host galaxy for weeks; they are also laboratories for the behavior of matter at supranuclear densities, and one of the few environments where collective neutrino effects can become important. Moreover, supernovae play a central role in the cosmic matter cycle, e.g., as the dominant producers of oxygen in the Universe. Yet the mechanism by which massive stars explode has eluded us for decades, partly because classical astronomical observations across the electromagnetic spectrum cannot directly probe the supernovae ``engine''. Numerical simulations are thus our primary tool for understanding the explosion mechanism(s) of massive stars. Rigorous modeling needs to take a host of important physical ingredients into account, such as the emission and partial reabsorption of neutrinos from the young proto-neutron star, multi-dimensional fluid motions, general relativistic gravity, the equation of state of nuclear matter, and magnetic fields. This is a challenging multi-physics problem that has not been fully solved yet. Nonetheless, as I shall argue in this talk, recent first-principle 3D simulations have gone a long way towards demonstrating the viability of the most popular explosion scenario, the ``neutrino-driven mechanism''. Focusing on successful explosion models of the MPA-QUB-Monash collaboration, I will discuss possible requirements for robust explosions across a wide range of progenitors, such as accurate neutrino opacities, stellar rotation, and seed asymmetries from convective shell burning. With the advent of successful explosion models, supernova theory can also be confronted with astronomical observations. I will show that recent 3D models come closer to matching observed explosion parameters (explosion energies, neutron star kicks) than older 2D models, although there are still discrepancies. This work has

  1. Interaction of Supernova Remnants with a Circumstellar Shell

    NASA Astrophysics Data System (ADS)

    Dwarkadas, V. V.

    1995-12-01

    We are studying the interaction of supernova remnants (SNRs) with circumstellar shells, with an emphasis on Type II supernovae (SNe). These supernovae arise from massive progenitor stars (> 8 Msun), which lose mass during their lifetime, primarily in the form of a stellar wind. Often the stellar wind creates a circumstellar bubble surrounded by a dense shell. When the star explodes as a supernova, the resulting shock wave eventually collides with this dense shell. In a recent paper on SN 1987A (Chevalier & Dwarkadas, ApJL, 452, L45) we have shown that from the radio and X-ray emission, one can infer the presence of a high density region interior to the dense circumstellar shell. This can be explained as an HII region photoionized by the flux from the pre-supernova star. Using the Zeus code and assuming spherical symmetry, we have studied the dynamics of the shock wave interacting first with the HII region and then the circumstellar shell in SN 1987A. Collision with the HII region results in a significant deceleration of the shock wave, forming a high-density shocked region that grows with time, and is primarily responsible for the X-ray emission. X-ray emission from the reflected shock may begin to dominate when the forward shock hits the dense circumstellar shell and is considerably slowed down. Simulations are in progress with parameters suited to other remnants such as Cas A and W44. Radio and X-ray images of Cas A show a shell structure, which may result from interaction with a stellar bubble. W44 also shows a double-shell structure that may have been produced by a SN explosion inside a pre-existing wind bubble. The interaction is subject to instabilities that may give rise to filamentary structure.

  2. HALO the helium and lead observatory for supernova neutrinos

    NASA Astrophysics Data System (ADS)

    Duba, C. A.; Duncan, F.; Farine, J.; Habig, A.; Hime, A.; Robertson, R. G. H.; Scholberg, K.; Shantz, T.; Virtue, C. J.; Wilkerson, J. F.; Yen, S.

    2008-11-01

    The Helium and Lead Observatory (HALO) is a supernova neutrino detector under development for construction at SNOLAB. It is intended to fulfill a niche as a long term, low cost, high livetime, and low maintenance, dedicated supernova detector. It will be constructed from 80 tonnes of lead, from the decommissioning of the Deep River Cosmic Ray Station, and instrumented with approximately 384 meters of 3He neutron detectors from the final phase of the SNO experiment. Charged- and Neutral-Current neutrino interactions in lead expel neutrons from the lead nuclei making a burst of detected neutrons the signature for the detection of a supernova. Existing neutrino detectors are mostly of the water Cerenkov and liquid scintillator types, which are primarily sensitive to electron anti-neutrinos via charged-current interactions on the hydrogen nuclei in these materials. By contrast, the large neutron excess of a heavy nucleus like Pb acts to Pauli-block pranglen transitions induced by electron anti-neutrinos, making HALO primarily sensitive to electron neutrinos. While any supernova neutrino data would provide an invaluable window into supernova dynamics, the electron neutrino CC channel has interesting sensitivity to particle physics through flavour-swapping and spectral splitting due to MSW-like collective neutrino-neutrino interactions in the core of the supernova, the only place in the universe where there is a sufficient density of neutrinos for this to occur. Such data could provide a test for θ13 ≠ 0 and an inverted neutrino mass hierarchy. In addition, the ratio of 1-neutron to 2-neutron events would be a measure of the temperature of the cooling neutron star. For the 80 tonne detector, a supernova at 10 kpc is estimated to produce 43 detected neutrons in the absence of collective ν-ν interactions, and many more in their presence. The high neutrino cross-section and low neutron absorption cross-section of lead, along with the modest cost of lead, makes this

  3. Unmasking the Supernova Impostors

    NASA Astrophysics Data System (ADS)

    Kochanek, C. S.; Szczygieł, D. M.; Stanek, K. Z.

    2012-10-01

    The canonical picture of a supernova impostor is a short (~months) -11 <~ MV <~ -14 optical transient from a massive (M * >~ 40 M ⊙) star during which the star ejects a dense shell of material. Dust formed in the ejecta then obscures the star. In this picture, the geometric expansion of the shell leads to clear predictions for the evolution of the optical depths and hence the evolution of the optical through mid-IR emissions. Here, we review the theory of this standard model and then examine the impostors SN 1954J, SN 1997bs, SN 1999bw, SN 2000ch, SN 2001ac, SN 2002bu, SN 2002kg, and SN 2003gm, as well as the potential archetype η Carinae. SN 1999bw, SN 2000ch, SN 2001ac, SN 2002bu, and SN 2003gm all show mid-IR emission indicative of dust, and the luminosities of SN 1999bw, SN 2001ac, SN 2002bu, and SN 2003gm are dominated by dust emission. We find only upper limits on dust emission from SN 1954J, SN 1997bs, and SN 2002kg. The properties of these sources are, however, broadly inconsistent with the predictions of the canonical model. Based on their mid-IR properties, there are at least three classes of objects being labeled as "impostors." The first class, containing the luminous blue variable (LBV) SN 2002kg and the non-LBV SN 2000ch, consists of variable stars with little or no dust formation as a consequence of the transient. The second class contains the "classical" impostors SN 1954J, SN 1997bs, and (maybe) SN 2003gm that may be weaker analogs of η Carinae. However, if these sources are stellar eruptions, the visual transient is simply a signal that the star is entering a phase with high mass-loss rates and dust formation that must last far longer than the observed optical transient. The third class consists of the SN 2008S-like transients, SN 1999bw, SN 2001ac, SN 2002bu, and (maybe) SN 2003gm, which are obscured by dust re-forming in a pre-existing wind after it was destroyed by an explosive transient. For all three classes of source, there are no cases

  4. Finding Distances to Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-03-01

    Type Ia supernovae are known as standard candles due to their consistency, allowing us to measure distances based on their brightness. But what if these explosions arent quite as consistent as we thought? Due scientific diligence requires careful checks, so a recent study investigates whether the metallicity of a supernovas environment affects the peak luminosity of the explosion.Metallicity Dependence?Type Ia supernovae are incredibly powerful tools for determining distances in our universe. Because these supernovae are formed by white dwarfs that explode when they reach a uniform accreted mass, the supernova peak luminosity is thought to be very consistent. This consistency allows these supernovae to be used as standard candles to measure distances to their host galaxies.But what if that peak luminosity is affected by a factor that we havent taken into account? Theorists have proposed that the luminosities of Type Ia supernovae might depend on the metallicity of their environments with high-metallicity environments suppressing supernova luminosities. If this is true, then we could be systematically mis-measuring cosmological distances using these supernovae.Testing AbundancesSupernova brightnesses vs. the metallicity of their environments. Low-metallicity supernovae (blue shading) and high-metallicity supernovae (red shading) have an average magnitude difference of ~0.14. [Adapted from Moreno-Raya et al. 2016]A team led by Manuel Moreno-Raya, of the Center for Energy, Environment and Technology (CIEMAT) in Spain, has observed 28 Type Ia supernovae in an effort to test for such a metallicity dependence. These supernovae each have independent distance measurements (e.g., from Cepheids or the Tully-Fisher relation).Moreno-Raya and collaborators used spectra from the 4.2-m William Herschel Telescope to estimate oxygen abundances in the region where each of these supernovae exploded. They then used these measurements to determine if metallicity of the local region

  5. Gravitational lensing statistics of amplified supernovae

    NASA Technical Reports Server (NTRS)

    Linder, Eric V.; Wagoner, Robert V.; Schneider, P.

    1988-01-01

    Amplification statistics of gravitationally lensed supernovae can provide a valuable probe of the lensing matter in the universe. A general probability distribution for amplification by compact objects is derived which allows calculation of the lensed fraction of supernovae at or greater than an amplification A and at or less than an apparent magnitude. Comparison of the computed fractions with future results from ongoing supernova searches can lead to determination of the mass density of compact dark matter components with masses greater than about 0.001 solar mass, while the time-dependent amplification (and polarization) of the expanding supernovae constrain the individual masses. Type II supernovae are found to give the largest fraction for deep surveys, and the optimum flux-limited search is found to be at approximately 23d magnitude, if evolution of the supernova rate is neglected.

  6. Improvements to type Ia supernova models

    NASA Astrophysics Data System (ADS)

    Saunders, Clare M.

    Type Ia Supernovae provided the first strong evidence of dark energy and are still an important tool for measuring the accelerated expansion of the universe. However, future improvements will be limited by systematic uncertainties in our use of Type Ia supernovae as standard candles. Using Type Ia supernovae for cosmology relies on our ability to standardize their absolute magnitudes, but this relies on imperfect models of supernova spectra time series. This thesis is focused on using data from the Nearby Supernova Factory both to understand current sources of uncertainty in standardizing Type Ia supernovae and to develop techniques that can be used to limit uncertainty in future analyses. (Abstract shortened by ProQuest.).

  7. Preview of a Forthcoming Supernova

    NASA Image and Video Library

    2017-09-28

    Supernova Supernovae can occur one of two ways. The first occurs when a white dwarf—the vestigial ember of a dead star—passes so close to a living star that its matter leaks into the white dwarf. This causes a catastrophic explosion. However most people understand supernovae as the death of a massive star. When the star runs out of fuel toward the end of its life, the gravity at its heart sucks the surrounding mass into its center. At temperatures rocketing above 100 billion degrees Fahrenheit, all the layers of the star abruptly explode outward. The explosions produced by supernovae are so brilliant that astronomers use their luminosity to measure the distance between galaxies, the scale of the universe and the effects of dark energy. For a short period of time, one dying star can appear to shine as brightly as an entire galaxy. Supernovae are relatively common events, one occurring in our own galaxy once every 100 years. In 2014, a person could see the supernova M82 with a pair of binoculars. The cosmologist Tycho Brahe’s observation of a supernova in 1572 allowed him to disprove Aristotle’s theory that the heavens never changed. After a supernova, material expelled in the explosion can form a nebula—an interstellar pile of gas and dust. Over millions of years, gravity pulls the nebula’s materials into a dense orb called a protostar, which will become a new star. Within a few million years, this new star could go supernova as well. ------------------------------ Original Caption: NASA image release Feb. 24, 2012 At the turn of the 19th century, the binary star system Eta Carinae was faint and undistinguished. In the first decades of the century, it became brighter and brighter, until, by April 1843, it was the second brightest star in the sky, outshone only by Sirius (which is almost a thousand times closer to Earth). In the years that followed, it gradually dimmed again and by the 20th century was totally invisible to the naked eye. The star has

  8. Asymmetric Type Ia Supernovae from Detonating Failed Deflagrations

    NASA Astrophysics Data System (ADS)

    Plewa, T.; Kasen, D.; Brown, E. F.

    2005-05-01

    Despite four decades of vigorous research and substantial progress made in studying thermonuclear supernovae, the origins and nature of these objects remain a mystery. From a modeler's point of view, Type Ia supernovae are one of the most demanding and complex supercomputer applications. The final stages of their lives involve the slow evolution under conditions close to a hydrostatic equilibrium followed by a strongly dynamical phase with the possible transition from a subsonic to supersonic mode of thermonuclear combustion. The explosion dynamics involve instabilities on scales from centimeters to hundreds of kilometers, and are accompanied by thermonuclear reactions releasing sufficient energy to unbind the white dwarf. Numerical models of thermonuclear supernovae must also include realistic initial conditions, an element that may prove crucial in our quest to explain the nature of those fascinating objects. We are presently studying the incineration of a massive white dwarf following the mild ignition of a thermonuclear flame close to the stellar center. In this scenario, the initial off-center deflagration only consumes a small amount of the stellar fuel and fails to unbind the star. This deflagration does, however, expand the stellar material and accelerates the outer layers of the white dwarf. These flows interact and then trigger a detonation. The overall evolution resembles that of the previously discussed gravitationally confined detonation model and shares many of its properties. The present numerical model features a revised energy delivery scheme resulting in a weaker deflagration, longer evolutionary timescales, and stronger preexpansion of the stellar material.

  9. White dwarf models for type 1 supernovae and quiet supernovae, and presupernova evolution

    NASA Technical Reports Server (NTRS)

    Nomoto, K.

    1980-01-01

    Supernova mechanisms in accreting white dwarfs are considered with emphasis on deflagration as a plausible mechanism for producing Type I supernovae and electron captures to form quiet supernovae leaving neutron stars. These outcomes depend on accretion rate of helium, initial mass and composition of the white dwarf. The various types of hydrogen shell burning in the presupernova stage are also discussed.

  10. La supernova galattica è in ritardo?

    NASA Astrophysics Data System (ADS)

    Sigismondi, Costantino

    2005-06-01

    After 400 years we are still waiting to see a galactic supernova. A simple galactic model based upon interstellar absorption is shown in order to explain the rate of observed galactic supernovae. The history of variable stars observations in modern epoch is sketched and the hypothesis for Bethlehem Star made by Kepler in occasion of the last galactic supernova, exploded in Ophiuchus on 9 October 1604, is also presented.

  11. Connecting supernovae with their environments

    NASA Astrophysics Data System (ADS)

    Galbany, L.

    2017-03-01

    We present MUSE observations of galaxy NGC 7469 from its Science Verification to show how powerful is the combination of high-resolution wide-field integral field spectroscopy with both photometric and spectroscopic observations of supernova (SN) explosions. Using STARLIGHT and H II explorer, we selected all H II regions of the galaxy and produced 2-dimensional maps of the Hα equivalent width, average luminosity-weighted stellar age, and oxygen abundance. We measured deprojected galactocentric distances for all H II regions, and radial gradients for all above-mentioned parameters. We positioned the type Ia SN2008ec in the Branch et al. diagram, and finally discussed the characteristics of the SN parent H II region compared to all other H II regions in the galaxy. In a near future, the AMUSING survey will be able to reproduce this analysis and construct statistical samples to enable the characterization of the progenitors of different supernova types.

  12. SUPERNOVA FALLBACK ONTO MAGNETARS AND PROPELLER-POWERED SUPERNOVAE

    SciTech Connect

    Piro, Anthony L.; Ott, Christian D. E-mail: cott@tapir.caltech.edu

    2011-08-01

    We explore fallback accretion onto newly born magnetars during the supernova of massive stars. Strong magnetic fields ({approx}10{sup 15} G) and short spin periods ({approx}1-10 ms) have an important influence on how the magnetar interacts with the infalling material. At long spin periods, weak magnetic fields, and high accretion rates, sufficient material is accreted to form a black hole, as is commonly found for massive progenitor stars. When B {approx}< 5 x 10{sup 14} G, accretion causes the magnetar to spin sufficiently rapidly to deform triaxially and produces gravitational waves, but only for {approx}50-200 s until it collapses to a black hole. Conversely, at short spin periods, strong magnetic fields, and low accretion rates, the magnetar is in the 'propeller regime' and avoids becoming a black hole by expelling incoming material. This process spins down the magnetar, so that gravitational waves are only expected if the initial protoneutron star is spinning rapidly. Even when the magnetar survives, it accretes at least {approx}0.3 M{sub sun}, so we expect magnetars born within these types of environments to be more massive than the 1.4 M{sub sun} typically associated with neutron stars. The propeller mechanism converts the {approx}10{sup 52} erg of spin energy in the magnetar into the kinetic energy of an outflow, which shock heats the outgoing supernova ejecta during the first {approx}10-30 s. For a small {approx}5 M{sub sun} hydrogen-poor envelope, this energy creates a brighter, faster evolving supernova with high ejecta velocities {approx}(1-3) x 10{sup 4} km s{sup -1} and may appear as a broad-lined Type Ib/c supernova. For a large {approx}> 10 M{sub sun} hydrogen-rich envelope, the result is a bright Type IIP supernova with a plateau luminosity of {approx}> 10{sup 43} erg s{sup -1} lasting for a timescale of {approx}60-80 days.

  13. Supernovae and neutron stars: playgrounds of dense matter and neutrinos

    NASA Astrophysics Data System (ADS)

    Sumiyoshi, Kohsuke

    2017-06-01

    Core-collapse supernovae are vital as the birthplace of compact objects, where one expects various phases of the dense matter. The current status of supernova studies with the nuclear data for dense matter and neutrino reactions is overviewed with a focus on recent progress of the neutrino-radiation hydrodynamics in two- an three-dimensions and remaining mysteries. In addition to its importance for the explosion mechanism, the equation of state is also essential to predict the neutrino bursts, which can be used to probe deep inside the compact objects. It is valuable to discuss variations of the extreme conditions for hyperons and quarks in central objects during explosive phenomena by looking into the pattern of neutrino signals in relation with dynamics and dense matter.

  14. Convection in Type 2 supernovae

    SciTech Connect

    Miller, Douglas Scott

    1993-10-15

    Results are presented here from several two dimensional numerical calculations of events in Type II supernovae. A new 2-D hydrodynamics and neutrino transport code has been used to compute the effect on the supernova explosion mechanism of convection between the neutrinosphere and the shock. This convection is referred to as exterior convection to distinguish it from convection beneath the neutrinosphere. The model equations and initial and boundary conditions are presented along with the simulation results. The 2-D code was used to compute an exterior convective velocity to compare with the convective model of the Mayle and Wilson 1-D code. Results are presented from several runs with varying sizes of initial perturbation, as well as a case with no initial perturbation but including the effects of rotation. The M&W code does not produce an explosion using the 2-D convective velocity. Exterior convection enhances the outward propagation of the shock, but not enough to ensure a successful explosion. Analytic estimates of the growth rate of the neutron finger instability axe presented. It is shown that this instability can occur beneath the neutrinosphere of the proto-neutron star in a supernova explosion with a growth time of ~ 3 microseconds. The behavior of the high entropy bubble that forms between the shock and the neutrinosphere in one dimensional calculations of supernova is investigated. It has been speculated that this bubble is a site for γ-process generation of heavy elements. Two dimensional calculations are presented of the time evolution of the hot bubble and the surrounding stellar material. Unlike one dimensional calculations, the 2D code fails to achieve high entropies in the bubble. When run in a spherically symmetric mode the 2-D code reaches entropies of ~ 200. When convection is allowed, the bubble reaches ~60 then the bubble begins to move upward into the cooler, denser material above it.

  15. The Union3 Supernova Ia Compilation

    NASA Astrophysics Data System (ADS)

    Rubin, David; Aldering, Greg Scott; Amanullah, Rahman; Barbary, Kyle H.; Bruce, Adam; Chappell, Greta; Currie, Miles; Dawson, Kyle S.; Deustua, Susana E.; Doi, Mamoru; Fakhouri, Hannah; Fruchter, Andrew S.; Gibbons, Rachel A.; Goobar, Ariel; Hsiao, Eric; Huang, Xiaosheng; Ihara, Yutaka; Kim, Alex G.; Knop, Robert A.; Kowalski, Marek; Krechmer, Evan; Lidman, Chris; Linder, Eric; Meyers, Joshua; Morokuma, Tomoki; Nordin, Jakob; Perlmutter, Saul; Ripoche, Pascal; Rykoff, Eli S.; Saunders, Clare; Spadafora, Anthony L.; Suzuki, Nao; Takanashi, Naohiro; Yasuda, Naoki; Supernova Cosmology Project

    2015-01-01

    High-redshift supernovae observed with the Hubble Space Telescope (HST) are crucial for constraining any time variation in dark energy. In a forthcoming paper (Rubin+, in prep), we will present a cosmological analysis incorporating existing supernovae with improved calibrations, and new HST-observed supernovae. We combine these data with most of the world's current literature data, and fit using SALT2-4 to create the Union3 Supernova compilation. We present a new analysis framework that allows non-linear light-curve width and color corrections, direct modeling of color dispersion, and a redshift-dependent host-mass correction.

  16. 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.

  17. 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.

  18. MHD simulations of supernova driven ISM turbulence

    NASA Astrophysics Data System (ADS)

    Gressel, Oliver; Ziegler, Udo

    The dynamic evolution of the (stratified) turbulent interstellar medium (ISM) is simulated utilizing a three-dimensional MHD model including various physical effects. The computational domain covers a box of 0.5x0.5x2.0 kpc at a resolution of typically 128x128x1024 grid cells. The model includes (constant kinematic) viscosity and magnetic diffusivity. The adiabatic equation of state is supplemented by a parameterized heating- and cooling-function allowing for thermal instability (TI). The update due to heating and cooling is implemented implicitly using a Patankar-type discretization. Turbulence is driven by supernova explosions which are modelled as local injections of thermal energy, smeared over three standard-deviations of a Gaussian support with FWHM of 20pc. Supernova rates are adopted for typical cited values. Within our model we make a distinction between Type I and Type II SNe. Latter are statistically clustered by the (artificial) constraint that the density at the explosion site be above average (with respect to a horizontal slab) - former are spatially uncorrelated. The dual-energy feature of the conservative NIRVANA-code is used to tackle the extreme ratio of kinetic to internal energy that arises from the violent energy input. We stress the importance of using a conservative scheme to properly transfer the injected energy to kinetic motion. The model also includes a differentially rotating background (with shearing boundary conditions in radial direction) as well as vertical stratification. The initial density and pressure profiles are in hydrostatic equilibrium with respect to the equation of state given by the radiative equilibrium. Including z-dependent heating rates this leads to a considerable deviation from usual isothermal initial models. The primary focus of this work is on the galactic dynamo and the generation of large-scale magnetic fields. As a secondary target we are also interested in general properties of the ISM that are of importance

  19. Baryon Loaded Relativistic Blast Waves in Supernovae

    NASA Astrophysics Data System (ADS)

    Chakraborti, Sayan; Ray, Alak

    2011-03-01

    We provide a new analytic blast wave solution which generalizes the Blandford-McKee solution to arbitrary ejecta masses and Lorentz factors. Until recently relativistic supernovae have been discovered only through their association with long-duration gamma-ray bursts (GRBs). The blast waves of such explosions are well described by the Blandford-McKee (in the ultra-relativistic regime) and Sedov-Taylor (in the non-relativistic regime) solutions during their afterglows, as the ejecta mass is negligible in comparison to the swept-up mass. The recent discovery of the relativistic supernova SN 2009bb, without a detected GRB, opens up the possibility of highly baryon loaded, mildly relativistic outflows which remains in nearly free-expansion phase during the radio afterglow. In this work, we consider a massive, relativistic shell, launched by a Central Engine Driven EXplosion (CEDEX), decelerating adiabatically due to its collision with the pre-explosion circumstellar wind profile of the progenitor. We compute the synchrotron emission from relativistic electrons in the shock amplified magnetic field. This models the radio emission from the circumstellar interaction of a CEDEX. We show that this model explains the observed radio evolution of the prototypical SN 2009bb and demonstrate that SN 2009bb had a highly baryon loaded, mildly relativistic outflow. We discuss the effect of baryon loading on the dynamics and observational manifestations of a CEDEX. In particular, our predicted angular size of SN 2009bb is consistent with very long baseline interferometric (VLBI) upper limits on day 85, but is presently resolvable on VLBI angular scales, since the relativistic ejecta is still in the nearly free-expansion phase.

  20. 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.

  1. Supernova 2009ig Has Brightened

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2009-09-01

    The Type-Ia Supernova 2009ig in NGC 1015 has brightened from its discovery magnitude of 17.5 on Aug. 20.48 UT (I. Kleiser, S. B. Cenko, W. Li, and A. V. Filippenko, University of California; LOSS discovery on unfiltered KAIT images) to unfiltered CCD magnitude 14.0 on Sep. 20.646 UT (Yoshiteru Matsuura, Nada-ku, Kobe, Japan). H. Navasardyan, E. Cappellaro, and S. Benetti, Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova, report that a spectrogram obtained on Aug. 21.08 UT with the Asiago 1.82-m telescope indicates that the object is a type-Ia supernova caught soon after explosion. They note some similarity to early spectra of SN 2002bo (Benetti et al. 2004, MNRAS 348, 261), although Si II 597.2-nm and S II 564.0-nm are not yet present. Instructions for CCD observing are given in accordance with AAVSO policy on the observation of Type-Ia supernovae brighter than magnitude 15.0. Data should be submitted to the AAVSO International Database; FITS images should be uploaded to ftp.aavso.org.

  2. Chandra Maps Vital Elements From Supernova

    NASA Astrophysics Data System (ADS)

    1999-12-01

    composition of the various knots and filaments of stellar material visible in Cas A. Not only could the astronomers determine the composition of many knots in the remnant from the Chandra data, they were also able to infer where in the exploding star the knots had originated. For example, the most compact and brightest knots were composed mostly of silicon and sulfur, with little or no iron. This pointed to an origin deep in the star's interior where the temperatures had reached three billion degrees during the collapse and resulting supernova. Elsewhere, they found fainter features that contained significant amounts of iron as well as some silicon and sulfur. This material was produced even deeper in the star, where the temperatures during the explosion had reached higher values of four to five billion degrees. When Hughes and his collaborators compared where the compact silicon-rich knots and fainter iron-rich features were located in Cas A, they discovered that the iron-rich features from deepest in the star were near the outer edge of the remnant. This meant that they had been flung the furthest by the explosion that created Cas A. Even now this material appears to be streaming away from the site of the explosion with greater speed than the rest of the remnant. By studying the Cas A Chandra data further, astronomers hope to identify which of the several processes proposed by theoretical studies is likely to be the correct mechanism for explaining supernova explosions, both in terms of the dynamics and elements they produce. "In addition to understanding how iron and the other elements are produced in stars, we also want to learn how it gets out of stars and into the interstellar medium. This is why the study of supernovas and supernova remnants is so important," said Hughes. "Once released from stars, newly-created elements can then participate in the formation of new stars and planets in a great cycle that has gone on numerous times already. It is remarkable to realize

  3. Cygnus Loop Supernova Blast Wave

    NASA Technical Reports Server (NTRS)

    1993-01-01

    This is an image of a small portion of the Cygnus Loop supernova remnant, which marks the edge of a bubble-like, expanding blast wave from a colossal stellar explosion, occurring about 15,000 years ago. The HST image shows the structure behind the shock waves, allowing astronomers for the first time to directly compare the actual structure of the shock with theoretical model calculations. Besides supernova remnants, these shock models are important in understanding a wide range of astrophysical phenomena, from winds in newly-formed stars to cataclysmic stellar outbursts. The supernova blast is slamming into tenuous clouds of insterstellar gas. This collision heats and compresses the gas, causing it to glow. The shock thus acts as a searchlight revealing the structure of the interstellar medium. The detailed HST image shows the blast wave overrunning dense clumps of gas, which despite HST's high resolution, cannot be resolved. This means that the clumps of gas must be small enough to fit inside our solar system, making them relatively small structures by interstellar standards. A bluish ribbon of light stretching left to right across the picture might be a knot of gas ejected by the supernova; this interstellar 'bullet' traveling over three million miles per hour (5 million kilometres) is just catching up with the shock front, which has slowed down by ploughing into interstellar material. The Cygnus Loop appears as a faint ring of glowing gases about three degrees across (six times the diameter of the full Moon), located in the northern constellation, Cygnus the Swan. The supernova remnant is within the plane of our Milky Way galaxy and is 2,600 light-years away. The photo is a combination of separate images taken in three colors, oxygen atoms (blue) emit light at temperatures of 30,000 to 60,000 degrees Celsius (50,000 to 100,000 degrees Farenheit). Hydrogen atoms (green) arise throughout the region of shocked gas. Sulfur atoms (red) form when the gas cools to

  4. See Change: the Supernova Sample from the Supernova Cosmology Project High Redshift Cluster Supernova Survey

    NASA Astrophysics Data System (ADS)

    Hayden, Brian; Perlmutter, Saul; Boone, Kyle; Nordin, Jakob; Rubin, David; Lidman, Chris; Deustua, Susana E.; Fruchter, Andrew S.; Aldering, Greg Scott; Brodwin, Mark; Cunha, Carlos E.; Eisenhardt, Peter R.; Gonzalez, Anthony H.; Jee, James; Hildebrandt, Hendrik; Hoekstra, Henk; Santos, Joana; Stanford, S. Adam; Stern, Daniel; Fassbender, Rene; Richard, Johan; Rosati, Piero; Wechsler, Risa H.; Muzzin, Adam; Willis, Jon; Boehringer, Hans; Gladders, Michael; Goobar, Ariel; Amanullah, Rahman; Hook, Isobel; Huterer, Dragan; Huang, Xiaosheng; Kim, Alex G.; Kowalski, Marek; Linder, Eric; Pain, Reynald; Saunders, Clare; Suzuki, Nao; Barbary, Kyle H.; Rykoff, Eli S.; Meyers, Joshua; Spadafora, Anthony L.; Sofiatti, Caroline; Wilson, Gillian; Rozo, Eduardo; Hilton, Matt; Ruiz-Lapuente, Pilar; Luther, Kyle; Yen, Mike; Fagrelius, Parker; Dixon, Samantha; Williams, Steven

    2017-01-01

    The Supernova Cosmology Project has finished executing a large (174 orbits, cycles 22-23) Hubble Space Telescope program, which has measured ~30 type Ia Supernovae above z~1 in the highest-redshift, most massive galaxy clusters known to date. Our SN Ia sample closely matches our pre-survey predictions; this sample will improve the constraint by a factor of 3 on the Dark Energy equation of state above z~1, allowing an unprecedented probe of Dark Energy time variation. When combined with the improved cluster mass calibration from gravitational lensing provided by the deep WFC3-IR observations of the clusters, See Change will triple the Dark Energy Task Force Figure of Merit. With the primary observing campaign completed, we present the preliminary supernova sample and our path forward to the supernova cosmology results. We also compare the number of SNe Ia discovered in each cluster with our pre-survey expectations based on cluster mass and SFR estimates. Our extensive HST and ground-based campaign has already produced unique results; we have confirmed several of the highest redshift cluster members known to date, confirmed the redshift of one of the most massive galaxy clusters at z~1.2 expected across the entire sky, and characterized one of the most extreme starburst environments yet known in a z~1.7 cluster. We have also discovered a lensed SN Ia at z=2.22 magnified by a factor of ~2.7, which is the highest spectroscopic redshift SN Ia currently known.

  5. Origin of the p-process radionuclides 92Nb and 146Sm in the early solar system and inferences on the birth of the Sun

    PubMed Central

    Lugaro, Maria; Pignatari, Marco; Ott, Ulrich; Zuber, Kai; Travaglio, Claudia; Gyürky, György; Fülöp, Zsolt

    2016-01-01

    The abundances of 92Nb and 146Sm in the early solar system are determined from meteoritic analysis, and their stellar production is attributed to the p process. We investigate if their origin from thermonuclear supernovae deriving from the explosion of white dwarfs with mass above the Chandrasekhar limit is in agreement with the abundance of 53Mn, another radionuclide present in the early solar system and produced in the same events. A consistent solution for 92Nb and 53Mn cannot be found within the current uncertainties and requires the 92Nb/92Mo ratio in the early solar system to be at least 50% lower than the current nominal value, which is outside its present error bars. A different solution is to invoke another production site for 92Nb, which we find in the α-rich freezeout during core-collapse supernovae from massive stars. Whichever scenario we consider, we find that a relatively long time interval of at least ∼10 My must have elapsed from when the star-forming region where the Sun was born was isolated from the interstellar medium and the birth of the Sun. This is in agreement with results obtained from radionuclides heavier than iron produced by neutron captures and lends further support to the idea that the Sun was born in a massive star-forming region together with many thousands of stellar siblings. PMID:26755600

  6. Origin of the p-process radionuclides 92Nb and 146Sm in the early solar system and inferences on the birth of the Sun.

    PubMed

    Lugaro, Maria; Pignatari, Marco; Ott, Ulrich; Zuber, Kai; Travaglio, Claudia; Gyürky, György; Fülöp, Zsolt

    2016-01-26

    The abundances of (92)Nb and (146)Sm in the early solar system are determined from meteoritic analysis, and their stellar production is attributed to the p process. We investigate if their origin from thermonuclear supernovae deriving from the explosion of white dwarfs with mass above the Chandrasekhar limit is in agreement with the abundance of (53)Mn, another radionuclide present in the early solar system and produced in the same events. A consistent solution for (92)Nb and (53)Mn cannot be found within the current uncertainties and requires the (92)Nb/(92)Mo ratio in the early solar system to be at least 50% lower than the current nominal value, which is outside its present error bars. A different solution is to invoke another production site for (92)Nb, which we find in the α-rich freezeout during core-collapse supernovae from massive stars. Whichever scenario we consider, we find that a relatively long time interval of at least ∼ 10 My must have elapsed from when the star-forming region where the Sun was born was isolated from the interstellar medium and the birth of the Sun. This is in agreement with results obtained from radionuclides heavier than iron produced by neutron captures and lends further support to the idea that the Sun was born in a massive star-forming region together with many thousands of stellar siblings.

  7. Origin of the p-process radionuclides 92Nb and 146Sm in the early solar system and inferences on the birth of the Sun

    NASA Astrophysics Data System (ADS)

    Lugaro, Maria; Pignatari, Marco; Ott, Ulrich; Zuber, Kai; Travaglio, Claudia; Gyürky, György; Fülöp, Zsolt

    2016-01-01

    The abundances of 92Nb and 146Sm in the early solar system are determined from meteoritic analysis, and their stellar production is attributed to the p process. We investigate if their origin from thermonuclear supernovae deriving from the explosion of white dwarfs with mass above the Chandrasekhar limit is in agreement with the abundance of 53Mn, another radionuclide present in the early solar system and produced in the same events. A consistent solution for 92Nb and 53Mn cannot be found within the current uncertainties and requires the 92Nb/92Mo ratio in the early solar system to be at least 50% lower than the current nominal value, which is outside its present error bars. A different solution is to invoke another production site for 92Nb, which we find in the α-rich freezeout during core-collapse supernovae from massive stars. Whichever scenario we consider, we find that a relatively long time interval of at least ˜10 My must have elapsed from when the star-forming region where the Sun was born was isolated from the interstellar medium and the birth of the Sun. This is in agreement with results obtained from radionuclides heavier than iron produced by neutron captures and lends further support to the idea that the Sun was born in a massive star-forming region together with many thousands of stellar siblings.

  8. 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

  9. The Carnegie Supernova Project: Intrinsic colors of type Ia supernovae

    SciTech Connect

    Burns, Christopher R.; Persson, S. E.; Freedman, Wendy L.; Madore, Barry F.; Stritzinger, Maximilian; Contreras, Carlos; Phillips, M. M.; Hsiao, E. Y.; Boldt, Luis; Campillay, Abdo; Castellón, Sergio; Morrell, Nidia; Salgado, Francisco; Folatelli, Gaston; Suntzeff, Nicholas B.

    2014-07-01

    We present an updated analysis of the intrinsic colors of Type Ia supernova (SNe Ia) using the latest data release of the Carnegie Supernova Project. We introduce a new light-curve parameter very similar to stretch that is better suited for fast-declining events, and find that these peculiar types can be seen as extensions to the population of 'normal' SNe Ia. With a larger number of objects, an updated fit to the Lira relation is presented along with evidence for a dependence on the late-time slope of the B – V light-curves with stretch and color. Using the full wavelength range from u to H band, we place constraints on the reddening law for the sample as a whole and also for individual events/hosts based solely on the observed colors. The photometric data continue to favor low values of R{sub V} , though with large variations from event to event, indicating an intrinsic distribution. We confirm the findings of other groups that there appears to be a correlation between the derived reddening law, R{sub V} , and the color excess, E(B – V), such that larger E(B – V) tends to favor lower R{sub V} . The intrinsic u-band colors show a relatively large scatter that cannot be explained by variations in R{sub V} or by the Goobar power-law for circumstellar dust, but rather is correlated with spectroscopic features of the supernova and is therefore likely due to metallicity effects.

  10. Topics in the Physics of Supernovae and Neutron Stars

    NASA Astrophysics Data System (ADS)

    Abbar, Sajad

    A star with a mass larger than 8-10 solar masses can end its life in a supernova explosion and possibly form a neutron star. In this dissertation, I study two important aspects of the physics of supernovae and neutron stars. In the first part, I consider neutrino flavor oscillations in supernovae. Neutrino flavor oscillations in the presence of ambient neutrinos is nonlinear in nature which leads to interesting phenomenology that has not been well understood. This phenomenon in the supernova context has been studied in the so-called neutrino Bulb model which is a restricted, stationary supernova model and which possesses the (spatial) spherical symmetry about the center of the supernova and the (directional) axial symmetry around the radial direction. By studying the problem of the neutrino oscillations in a two dimensional toy model, the so-called neutrino Line model, I show that the spatial symmetries can be broken spontaneously in a dense neutrino gas. Using a time-dependent version of the neutrino Bulb model, I also show that the stationarity of a neutrino gas can be broken spontaneously as well. In the second part, I compute the thermal conductivity of the neutron star crust. I use the quantum Monte Carlo (QMC) technique to calculate the static structure function S(q) of a one-component ion lattice and use it to compute the thermal conductivity kappa of high-density solid matter expected in the neutron star crust. By making detailed comparisons with the results obtained using one-phonon approximation (OPA), and the multi-phonon harmonic approximation, we assess the temperature regime where S( q) from QMC can be used directly to calculate kappa. We also compare the QMC results to those obtained using the classical Monte Carlo technique to quantitatively assess the magnitude of the quantum corrections. We show that the quantum effects become relevant at temperature T ≲ 0.3 Op, where Op is the ion plasma frequency. At T ≃ 0.1 Op the quantum effects suppress

  11. Search for gamma ray lines from supernovae and supernova remnants

    NASA Technical Reports Server (NTRS)

    Chupp, E. L.; Forrest, D. J.; Suri, A. N.; Adams, R.; Tsai, C.

    1974-01-01

    A gamma ray monitor with a NaI crystal shielded with a cup-shaped CsI cover was contained in the rotating wheel compartment of the OSO-7 spacecraft for measuring the gamma ray spectra from 0.3 to 10 MeV in search for gamma ray lines from a possible remnant in the Gum Nebula and the apparent Type I supernovae in NGC5253. A brief analysis of data yielded no positive indications for X-rays, gamma ray lines, or continuum from these sources.

  12. Two possible active supernovae in IC 2150

    NASA Astrophysics Data System (ADS)

    Parker, Stu; Bock, Greg; Marples, Peter; Drescher, Colin; Pearl, Patrick; BOSS Team; Contreras, Carlos; Phillips, Mark; Morrell, Nidia; Hsiao, Eric; Carnegie Supernova Project

    2016-03-01

    Stu Parker and the BOSS team report the discovery of a rare event involving two possible active supernovae in IC 2150 (z=0.010404; NED) which were recorded in images obtained by Stu Parker during the ongoing program by the Backyard Observatory Supernova Search (BOSS) team.

  13. Single Degenerate Progenitors of Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Bours, Madelon; Toonen, Silvia; Nelemans, Gijs

    2013-01-01

    There is a general agreement that Type Ia supernovae correspond to the thermonuclear runaway of a white dwarf (WD) in a compact binary. The details of these progenitor systems are still unclear. Using the population synthesis code SeBa and several assumption for the WD retention efficiency, we estimate the delay times and supernova rates for the single degenerate scenario.

  14. 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.

  15. Discovery of Several ASAS-SN Supernovae

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Post, R. S.; Stone, G.; Wiethoff, W.; Brown, J. S.; Stanek, K. Z.; Dong, Subo; Holoien, T. W.-S.; Kochanek, C. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Bose, S.; Chen, Ping; Cacella, P.

    2017-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii and the 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered several new transient sources most likely associated with recent supernovae.

  16. Rates and progenitors of type Ia supernovae

    SciTech Connect

    Wood-Vasey, William Michael

    2004-01-01

    The remarkable uniformity of Type Ia supernovae has allowed astronomers to use them as distance indicators to measure the properties and expansion history of the Universe. However, Type Ia supernovae exhibit intrinsic variation in both their spectra and observed brightness. The brightness variations have been approximately corrected by various methods, but there remain intrinsic variations that limit the statistical power of current and future observations of distant supernovae for cosmological purposes. There may be systematic effects in this residual variation that evolve with redshift and thus limit the cosmological power of SN Ia luminosity-distance experiments. To reduce these systematic uncertainties, we need a deeper understanding of the observed variations in Type Ia supernovae. Toward this end, the Nearby Supernova Factory has been designed to discover hundreds of Type Ia supernovae in a systematic and automated fashion and study them in detail. This project will observe these supernovae spectrophotometrically to provide the homogeneous high-quality data set necessary to improve the understanding and calibration of these vital cosmological yardsticks. From 1998 to 2003, in collaboration with the Near-Earth Asteroid Tracking group at the Jet Propulsion Laboratory, a systematic and automated searching program was conceived and executed using the computing facilities at Lawrence Berkeley National Laboratory and the National Energy Research Supercomputing Center. An automated search had never been attempted on this scale. A number of planned future large supernovae projects are predicated on the ability to find supernovae quickly, reliably, and efficiently in large datasets. A prototype run of the SNfactory search pipeline conducted from 2002 to 2003 discovered 83 SNe at a final rate of 12 SNe/month. A large, homogeneous search of this scale offers an excellent opportunity to measure the rate of Type Ia supernovae. This thesis presents a new method for

  17. Four Papers by the Supernova Cosmology Project

    SciTech Connect

    Perlmutter, S.; et al.

    1995-06-01

    Our search for high-redshift Type Ia supernovae discovered, in its first years, a sample of seven supernovae. Using a 'batch' search strategy, almost all were discovered before maximum light and were observed over the peak of their light curves. The spectra and light curves indicate that almost all were Type Ia supernovae at redshifts z = 0.35 - 0.5. These high-redshift supernovae can provide a distance indicator and 'standard clock' to study the cosmological parameters q{sub 0}, {Lambda}, {Omega}{sub 0}, and H{sub 0}. This presentation and the following presentations of Kim et al. (1996), Goldhaber et al. (1996), and Pain et al. (1996) will discuss observation strategies and rates, analysis and calibration issues, the sources of measurement uncertainty, and the cosmological implications, including bounds on q{sub 0}, of these first high-redshift supernovae from our ongoing search.

  18. 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.

  19. Supernovae and cosmology with future European facilities.

    PubMed

    Hook, I M

    2013-06-13

    Prospects for future supernova surveys are discussed, focusing on the European Space Agency's Euclid mission and the European Extremely Large Telescope (E-ELT), both expected to be in operation around the turn of the decade. Euclid is a 1.2 m space survey telescope that will operate at visible and near-infrared wavelengths, and has the potential to find and obtain multi-band lightcurves for thousands of distant supernovae. The E-ELT is a planned, general-purpose ground-based, 40-m-class optical-infrared telescope with adaptive optics built in, which will be capable of obtaining spectra of type Ia supernovae to redshifts of at least four. The contribution to supernova cosmology with these facilities will be discussed in the context of other future supernova programmes such as those proposed for DES, JWST, LSST and WFIRST.

  20. 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.

  1. 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.

  2. Rapidly Rising Transients in the Supernova - Superluminous Supernova Gap

    NASA Technical Reports Server (NTRS)

    Arcavi, Iair; Wolf, William M.; Howell, D. Andrew; Bildsten, Lars; Leloudas, Giorgos; Hardin, Delphine; Prajs, Szymon; Perley, Daniel A.; Svirski, Gilad; Cenko, S. Bradley

    2016-01-01

    We present observations of four rapidly rising (t(sub rise) approximately equals 10 days) transients with peak luminosities between those of supernovae (SNe) and superluminous SNe (M(sub peak) approximately equals -20) - one discovered and followed by the PalomarTransient Factory (PTF) and three by the Supernova Legacy Survey. The light curves resemble those of SN 2011kl, recently shown to be associated with an ultra-long-duration gamma-ray burst (GRB), though no GRB was seen to accompany our SNe. The rapid rise to a luminous peak places these events in a unique part of SN phase space, challenging standard SN emission mechanisms. Spectra of the PTF event formally classify it as an SN II due to broad H alpha emission, but an unusual absorption feature, which can be interpreted as either high velocity H alpha (though deeper than in previously known cases) or Si II (as seen in SNe Ia), is also observed. We find that existing models of white dwarf detonations, CSM interaction, shock breakout in a wind (or steeper CSM), and magnetar spin down cannot readily explain the observations. We consider the possibility that a Type 1.5 SN scenario could be the origin of our events. More detailed models for these kinds of transients and more constraining observations of future such events should help to better determine their nature.

  3. The Effects of Collective Neutrino Oscillations on Supernova Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Seadrow, Shaquann; Frohlich, C.; Duan, H.; Friedland, A.; McLaughlin, G.; Keohane, J. W.

    2014-01-01

    A core-collapse supernova originates from the implosion of the electron degenerate core inside a massive star. Runaway electron capture produces on the order of 1057 neutrinos containing about 1053 erg of energy in total. While the vast majority of neutrinos are eventually released, during the first few seconds these neutrinos drive both the dynamics, and likewise the nucleosynthesis, inside the supernova. Recently, our understanding of oscillations among the different flavors of neutrinos (electron, muon, and tau) has significantly improved, allowing us to ask if neutrino flavor change has a significant effect on nucleosynthesis in a core-collapse supernova. To investigate the effects of collective neutrino flavor oscillations, we use the hydrodynamic conditions from a spherically-symmetrical model of the implosion, bounce, and explosion of the 1.4 solar mass core that is inside an 8.8 solar mass star (Huedepohl et al. 2009). We select 20 mass tracers in the ejecta, varying in initial radii, and follow these trajectories for the first 9 seconds following bounce. We include these trajectories into a nuclear reaction network in order to calculate the detailed nucleosynthesis. We use three sets of neutrino reaction rates, all of which are calculated consistently with the conditions in the supernova model: (i) no collective flavor oscillations, (ii) collective oscillations for normal neutrino mass hierarchy, and (iii) collective oscillations for inverted neutrino mass hierarchy. We calculate the detailed nucleosynthesis for each trajectory for all three sets of neutrino rates. We find that the inclusion of collective oscillations (ii or iii) significantly increases the free neutron abundance; however, we obtain similar results regardless of which hierarchy is used. The increase in free neutrons also increases the subsequent rate of neutron capture, but has only a small effect on the predicted final abundances. This work was performed as part of North Carolina State

  4. Models for Type I supernovae

    SciTech Connect

    Woosley, S.E.; Weaver, T.A.; Taam, R.E.

    1980-06-17

    Two rather disjoint scenarios for Type I supernovae are presented. One is based upon mass accretion by a white dwarf in a binary system. The second involves a star having some 8 to 10 times the mass of the sun which may or may not be a solitary star. Despite the apparent dissimilarities in the models it may be that each occurs to some extent in nature for they both share the possibility of producing substantial quantities of /sup 56/Ni and explosions in stars devoid of hydrogen envelopes. These are believed to be two properties that must be shared by any viable Type I model.

  5. 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.

  6. 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

    2016-06-01

    We highlight results from the Las Cumbres Observatory Global Telescope (LCOGT) Supernova Key Project -- a 3 year program to obtain lightcurves and spectra of approximately 500 low-redshift SNe. LCOGT is a robotic network of elevent one and two meter telescopes spaced around the globe. We are involved in a variety of surveys, including the intermediate Palomar Transient Factory, LaSilla Quest, PESSTO, and KMTNet. Recent results include analysis of large samples of core-collaspe SNe, the largest sample of SNe Ibn, evidence of the progenitors of SNe Ia from companion shocking, and new findings about superluminious SNe.

  7. SNRPy: Supernova remnant evolution modeling

    NASA Astrophysics Data System (ADS)

    Leahy, Denis A.; Williams, Jacqueline

    2017-03-01

    SNRPy (Super Nova Remnant Python) models supernova remnant (SNR) evolution and is useful for understanding SNR evolution and to model observations of SNR for obtaining good estimates of SNR properties. It includes all phases for the standard path of evolution for spherically symmetric SNRs and includes alternate evolutionary models, including evolution in a cloudy ISM, the fractional energy loss model, and evolution in a hot low-density ISM. The graphical interface takes in various parameters and produces outputs such as shock radius and velocity vs. time, SNR surface brightness profile and spectrum.

  8. Photometric monitoring of bright supernovae

    NASA Astrophysics Data System (ADS)

    Tsvetkov, D. Yu.; Pavlyuk, N. N.; Volkov, I. M.; Shugarov, S. Yu.

    2014-03-01

    The program of CCD photometric monitoring of bright supernovae (SNe) is carried out at 0.4 — 1.0 meter telescopes of the Sternberg Astronomical Institute, Crimean Astrophysical Observatory and Stará Lesná Observatory since 1998. We have observed more than 250 SNe of different types. We present the results of observations of SNe Ia 2003du, 2009nr and 2011fe, type IIb SNe 2008ax, 2011dh, type II SNe 2004ek and 2005kd and discuss physical parameters of the explosions. %

  9. A doubly robotic telescope - The Berkeley Automated Supernova Search

    NASA Technical Reports Server (NTRS)

    Perlmutter, Saul; Muller, Richard A.; Newberg, Heidi J. M.; Pennypacker, Carlton R.; Sasseen, Timothy P.; Smith, Craig K.

    1992-01-01

    We have designed, built, and are successfully using a completely robotic supernova search, with an automated observatory and automated real-time analysis and scheduling. This system has detected 20 supernovae so far, resulting in early supernova observations, surprising supernova rates, and new evidence against a true 'inclination effect' in galaxies.

  10. How supernovae launch galactic winds?

    NASA Astrophysics Data System (ADS)

    Fielding, Drummond; Quataert, Eliot; Martizzi, Davide; Faucher-Giguère, Claude-André

    2017-09-01

    We use idealized three-dimensional hydrodynamic simulations of global galactic discs to study the launching of galactic winds by supernovae (SNe). The simulations resolve the cooling radii of the majority of supernova remnants (SNRs) and thus self-consistently capture how SNe drive galactic winds. We find that SNe launch highly supersonic winds with properties that agree reasonably well with expectations from analytic models. The energy loading (η _E= \\dot{E}_wind/ \\dot{E}_SN) of the winds in our simulations are well converged with spatial resolution while the wind mass loading (η _M= \\dot{M}_wind/\\dot{M}_\\star) decreases with resolution at the resolutions we achieve. We present a simple analytic model based on the concept that SNRs with cooling radii greater than the local scaleheight break out of the disc and power the wind. This model successfully explains the dependence (or lack thereof) of ηE (and by extension ηM) on the gas surface density, star formation efficiency, disc radius and the clustering of SNe. The winds our simulations are weaker than expected in reality, likely due to the fact that we seed SNe preferentially at density peaks. Clustering SNe in time and space substantially increases the wind power.

  11. 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.

  12. Runaway Stars in Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Pannicke, A.; Dincel, B.; Neuhauser, R.

    2016-06-01

    Half of all stars and in particular 70 percent of the massive stars are 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.

  13. 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.

  14. The Supernova Remnant CTA 1

    NASA Technical Reports Server (NTRS)

    Seward, Frederick D.

    1996-01-01

    The supernova remnants G327.1-1.1 and G327.4+0.4 (Kes 27) are located 1.5 deg apart in the constellation Norma. In 1980, Einstein IPC observations discovered that both were irregular filled-center X-ray sources with possible point sources superposed. This paper describes new ROSAT position sensitive proportional counter (PSPC) observations which both map the diffuse structure and clearly show several unresolved sources in each field. Both remnants have bright emitting regions inside the limb which might indicate the presence of high energy electrons accelerated by a pulsar. The interior region is more prominent in G327.1-1.1 than in Kes 27. The spectra are relatively strongly absorbed, as expected from distant remnants close to the galactic plane. Comparison of the X-ray and radio maps of each remnant allows us to attribute some emission to a shell and some to the interior. With this information, a blast-wave model is used to derive approximate ages and energy release. Indications are that the Kes 27 supernova deposited approximately 10(exp 51) ergs in the surrounding medium. The G327.1-1.1 event probably deposited a factor of 3-10 less.

  15. Gamma ray constraints on the Galactic supernova rate

    NASA Technical Reports Server (NTRS)

    Hartmann, D.; The, L.-S.; Clayton, Donald D.; Leising, M.; Mathews, G.; Woosley, S. E.

    1991-01-01

    We perform Monte Carlo simulations of the expected gamma ray signatures of Galactic supernovae of all types to estimate the significance of the lack of a gamma ray signal due to supernovae occurring during the last millenium. Using recent estimates of the nuclear yields, we determine mean Galactic supernova rates consistent with the historic supernova record and the gamma ray limits. Another objective of these calculations of Galactic supernova histories is their application to surveys of diffuse Galactic gamma ray line emission.

  16. Supernovae: lights in the darkness

    NASA Astrophysics Data System (ADS)

    Every year, at the end of the summer, the Section of Physics and Technique of the "Institut Menorquí d'Estudis" and the "Societat Catalana de Física" organize the "Trobades Científiques de la Mediterrània" with the support of several academic institutions. The 2007 edition has been devoted to stellar explosions, the true evolutionary engines of galaxies. Whenever a star explodes, it injects into the interstellar medium a kinetic energy of 1051 erg and between one and several solar masses of newly synthesized elements as a result of the thermonuclear reactions that have taken place within the stellar interior. Two mechanisms are able to provide these enormous amounts of energy: one of them thermonuclear and the other, gravitational. Thermonuclear supernovae are the result of the incineration of a carbon-oxygen white dwarf that is the compact star of a binary stellar system. If the two stars are sufficiently close to each other, the white dwarf accretes matter from its companion, approaches the mass of Chandrasekhar, and ends up exploding. The processes previous to the explosion, the explosion itself, as well as the exact nature of the double stellar system that explodes, are still a matter of discussion. This point is particularly important because these explosions, known as Type Ia Supernovae, are very homogenous and can be used to measure cosmological distances. The most spectacular result obtained, is the discovery of the accelerated expansion of the Universe, but it still feels uncomfortable that such a fundamental result is based on a "measuring system" whose origin and behaviour in time is unknown. At the end of their lives, massive stars generate an iron nucleus that gets unstable when approaching the Chandrasekhar mass. Its collapse gives rise to the formation of a neutron star or a black hole, and the external manifestation of the energy that is released, about a 1053 erg, consists of a Type II or Ib/c supernova, of a Gamma Ray Burst (GRB) or even of

  17. 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).

  18. The effect of core-collapse supernova accretion phase turbulence on neutrino flavor evolution

    NASA Astrophysics Data System (ADS)

    Kneller, James P.; de los Reyes, Mithi

    2017-08-01

    During the accretion phase of a core-collapse supernovae, large amplitude turbulence is generated by the combination of the standing accretion shock instability and convection driven by neutrino heating. The turbulence directly affects the dynamics of the explosion, but there is also the possibility of an additional, indirect, feedback mechanism due to the effect turbulence can have upon neutrino flavor evolution and thus the neutrino heating. In this paper we consider the effect of turbulence during the accretion phase upon neutrino evolution, both numerically and analytically. Adopting representative supernova profiles taken from the accretion phase of a supernova simulation, we find the numerical calculations exhibit no effect from turbulence. We explain this absence using two analytic descriptions: the stimulated transition model and the distorted phase effect model. In the stimulated transition model turbulence effects depend upon six different lengthscales, and three criteria must be satisfied between them if one is to observe a change in the flavor evolution due to stimulated transition. We further demonstrate that the distorted phase effect depends upon the presence of multiple semi-adiabatic MSW resonances or discontinuities that also can be expressed as a relationship between three of the same lengthscales. When we examine the supernova profiles used in the numerical calculations we find the three stimulated transition criteria cannot be satisfied, independent of the form of the turbulence power spectrum, and that the same supernova profiles lack the multiple semi-adiabatic MSW resonances or discontinuities necessary to produce a distorted phase effect. Thus, we conclude that even though large amplitude turbulence is present in supernova during the accretion phase, it has no effect upon neutrino flavor evolution. This article belongs to the Focus on Microphysics in Core-Collapse Supernovae: 30 years Since SN1987A special issue.

  19. Type Ia Supernova Modeling with Spectrophotometric Data from the Nearby Supernova Factory

    NASA Astrophysics Data System (ADS)

    Saunders, Clare; Nearby Supernova Factory

    2017-01-01

    Type Ia supernova cosmology is currently limited by dispersion in standardized magnitudes, driven by a combination of calibration uncertainty and so-called ‘intrinsic dispersion.' This intrinsic dispersion is caused by supernova behavior that the current lightcurve fitters do not account for, and it can involve systematic trends. Using data from the Nearby Supernova Factory, we have developed an empirical model that captures a wider range of Type Ia supernova behavior and can be used to improve standardized magnitude dispersion. To do this, Gaussian Processes and Expectation Maximization Factor Analysis are used to generate spectral time series templates that can be combined linearly. Variations of this model are optimized, alternatively for supernova standardization or for maximum accuracy in the description of supernova spectral features. We present these models along with interpretation of the model components. Methods are discussed for the most efficient application of the models in cosmological surveys.

  20. Thermonuclear supernovae: simulations of the deflagration stage and their implications.

    PubMed

    Gamezo, Vadim N; Khokhlov, Alexei M; Oran, Elaine S; Chtchelkanova, Almadena Y; Rosenberg, Robert O

    2003-01-03

    Large-scale, three-dimensional numerical simulations of the deflagration stage of a thermonuclear supernova explosion show the formation and evolution of a highly convoluted turbulent flame in the gravitational field of an expanding carbon-oxygen white dwarf. The flame dynamics are dominated by the gravity-induced Rayleigh-Taylor instability that controls the burning rate. The thermonuclear deflagration releases enough energy to produce a healthy explosion. The turbulent flame, however, leaves large amounts of unburned and partially burned material near the star center, whereas observations that imply these materials are present only in outer layers. This disagreement could be resolved if the deflagration triggers a detonation.

  1. The Low-Redshift Carnegie Supernova Program

    NASA Astrophysics Data System (ADS)

    Phillips, M. M.; Hamuy, M.; Freedman, W. L.; Persson, S. E.; Suntzeff, N. B.; Folatelli, G.; Gonzalez, S.; Krzeminski, W.; Morrell, N.; Murphy, D.; Roth, M.; Li, W.; Filippenko, A.; Carlberg, R.; Maza, J.; Pinto, P.

    2004-12-01

    The Carnegie Supernova Program (CSP) is a 5-year program designed to 1) provide a precise calibration of Type Ia supernova luminosity distances based on observations of nearby Type Ia and II supernovae, and 2) use this calibration to set constraints on the nature of the dark energy from restframe I-band photometry of high-redshift Type Ia supernovae. In this paper, we describe the low-redshift portion of the CSP, the major goal of which is to generate a fundamental dataset of precise u'BVg'r'i'YJHK light curves and optical spectrophotometry for 100 Type Ia supernovae (z < 0.07) and 100 Type II supernovae (z < 0.05). These data will be used to refine techniques for obtaining distances and reddenings to both types of supernovae, and to study possible evolutionary effects in Type Ia events. An important component of the low-z CSP is the near-IR photometry, which offers the promise of improving the precision of distance determinations due to the reduced effects of dust extinction and (for Type Ia supernovae) the smaller intrinsic variation in the peak luminosities at these wavelengths. The combination of optical and near-IR photometry should also yield much more reliable dust extinction corrections than can be obtained from optical data alone. The low-z CSP began taking data in Sept. 2004, and is projected to run through May 2009. Preliminary light curves and spectra for the first few supernovae observed are presented, as is a brief description of the various data reduction pipelines. This project is supported by NSF grant AST-0306969.

  2. An Open Catalog for Supernova Data

    NASA Astrophysics Data System (ADS)

    Guillochon, James; Parrent, Jerod; Kelley, Luke Zoltan; Margutti, Raffaella

    2017-01-01

    We present the Open Supernova Catalog, an online collection of observations and metadata for presently 36,000+ supernovae and related candidates. The catalog is freely available on the web (https://sne.space), with its main interface having been designed to be a user-friendly, rapidly searchable table accessible on desktop and mobile devices. In addition to the primary catalog table containing supernova metadata, an individual page is generated for each supernova, which displays its available metadata, light curves, and spectra spanning X-ray to radio frequencies. The data presented in the catalog is automatically rebuilt on a daily basis and is constructed by parsing several dozen sources, including the data presented in the supernova literature and from secondary sources such as other web-based catalogs. Individual supernova data is stored in the hierarchical, human- and machine-readable JSON format, with the entirety of each supernova’s data being contained within a single JSON file bearing its name. The setup we present here, which is based on open-source software maintained via git repositories hosted on github, enables anyone to download the entirety of the supernova data set to their home computer in minutes, and to make contributions of their own data back to the catalog via git. As the supernova data set continues to grow, especially in the upcoming era of all-sky synoptic telescopes, which will increase the total number of events by orders of magnitude, we hope that the catalog we have designed will be a valuable tool for the community to analyze both historical and contemporary supernovae.

  3. ASCERTAINING THE CORE COLLAPSE SUPERNOVA MECHANISM: The State of the Art and the Road Ahead

    NASA Astrophysics Data System (ADS)

    Mezzacappa, Anthony

    2005-12-01

    More than four decades have elapsed since modeling of the core collapse supernova mechanism began in earnest. To date, the mechanism remains elusive, at least in detail, although significant progress has been made in understanding these multiscale, multiphysics events. One-, two-, and three-dimensional simulations of or relevant to core collapse supernovae have shown that (a) neutrino transport, (b) fluid instabilities, (c) rotation, and (d) magnetic fields, together with proper treatments of (e) the sub- and super- nuclear density stellar core equation of state, (f) the neutrino interactions, and (g) gravity are all important. The importance of these ingredients applies to both the explosion mechanism and to phenomena directly associated with the mechanism, such as neutron star kicks, supernova neutrino and gravitational wave emission, and supernova spectropolarimetry.Not surprisingly, current two- and three-dimensional models have yet to include (a) (d) with sufficient realism. One-dimensional spherically symmetric models have achieved a significant level of sophistication but, by definition, cannot incorporate (b) (d), except phenomenologically. Fully general relativistic spherically symmetric simulations with Boltzmann neutrino transport do not yield explosions, demonstrating that some combination of (b), (c), and (d) is required to achieve this. Systematic layering of the dimensionality and the physics will be needed to achieve a complete understanding of the supernova mechanism and phenomenology. The past modeling efforts alluded to above have illuminated that core collapse supernovae may be neutrino driven, magnetohydrodynamically (MHD) driven, or both, but uncertainties in the current models prevent us from being able to answer even this most basic question. And it may be that more than one possibility is realized in nature. Nonetheless, if a supernova is neutrino driven, magnetic fields will likely have an impact on the dynamics of the explosion. Similarly

  4. Postexplosion hydrodynamics of supernovae in red supergiants

    NASA Technical Reports Server (NTRS)

    Herant, Marc; Woosley, S. E.

    1994-01-01

    Shock propagation, mixing, and clumping are studied in the explosion of red supergiants as Type II supernovae using a two-dimensional smooth particle hydrodynamic (SPH) code. We show that extensive Rayleigh-Talor instabilities develop in the ejecta in the wake of the reverse shock wave. In all cases, the shell structure of the progenitor is obliterated to leave a clumpy, well-mixed supernova remnant. However, the occurrence of mass loss during the lifetime of the progenitor can significantly reduce the amount of mixing. These results are independent of the Type II supernova explosion mechanism.

  5. Diffuse neutrino flux from failed supernovae.

    PubMed

    Lunardini, Cecilia

    2009-06-12

    I study the diffuse flux of electron antineutrinos from stellar collapses with direct black hole formation (failed supernovae). This flux is more energetic than that from successful supernovae, and therefore it might contribute substantially to the total diffuse flux above realistic detection thresholds. The total flux might be considerably higher than previously thought, and approach the sensitivity of Super-Kamiokande. For more conservative values of the parameters, the flux from failed supernovae dominates for antineutrino energies above 30-45 MeV, with potential to give an observable spectral distortion at megaton detectors.

  6. Supernovae and Gamma-Ray Bursts

    NASA Astrophysics Data System (ADS)

    Livio, Mario; Panagia, Nino; Sahu, Kailash

    2001-07-01

    Participants; Preface; Gamma-ray burst-supernova relation B. Paczynski; Observations of gamma-ray bursts G. Fishman; Fireballs T. Piran; Gamma-ray mechanisms M. Rees; Prompt optical emission from gamma-ray bursts R. Kehoe, C. Akerlof, R. Balsano, S. Barthelmy, J. Bloch, P. Butterworth, D. Casperson, T. Cline, S. Fletcher, F. Frontera, G. Gisler, J. Heise, J. Hills, K. Hurley, B. Lee, S. Marshall, T. McKay, A. Pawl, L. Piro, B. Priedhorsky, J. Szymanski and J. Wren; X-ray afterglows of gamma-ray bursts L. Piro; The first year of optical-IR observations of SN1998bw I. Danziger, T. Augusteijn, J. Brewer, E. Cappellaro, V. Doublier, T. Galama, J. Gonzalez, O. Hainaut, B. Leibundgut, C. Lidman, P. Mazzali, K. Nomoto, F. Patat, J. Spyromilio, M. Turatto, J. Van Paradijs, P. Vreeswijk and J. Walsh; X-ray emission of Supernova 1998bw in the error box of GRB980425 E. Pian; Direct analysis of spectra of type Ic supernovae D. Branch; The interaction of supernovae and gamma-ray bursts with their surroundings R. Chevalier; Magnetars, soft gamma-ray repeaters and gamma-ray bursts A. Harding; Super-luminous supernova remnants Y. -H. Chu, C. -H. Chen and S. -P. Lai; The properties of hypernovae: SNe Ic 1998bw, 1997ef, and SN IIn 1997cy K. Nomoto, P. Mazzali, T. Nakamura, K. Iwanmoto, K. Maeda, T. Suzuki, M. Turatto, I. Danziger and F. Patat; Collapsars, Gamma-Ray Bursts, and Supernovae S. Woosley, A. MacFadyen and A. Heger; Pre-supernova evolution of massive stars N. Panagia and G. Bono; Radio supernovae and GRB 980425 K. Weiler, N. Panagia, R. Sramek, S. Van Dyk, M. Montes and C. Lacey; Models for Ia supernovae and evolutionary effects P. Hoflich and I. Dominguez; Deflagration to detonation A. Khokhlov; Universality in SN Iae and the Phillips relation D. Arnett; Abundances from supernovae F. -K. Thielemann, F. Brachwitz, C. Freiburghaus, S. Rosswog, K. Iwamoto, T. Nakamura, K. Nomoto, H. Umeda, K. Langanke, G. Martinez-Pinedo, D. Dean, W. Hix and M. Strayer; Sne, GRBs, and the

  7. Supernovae effects on the terrestrial atmosphere

    NASA Technical Reports Server (NTRS)

    Aikin, A. C.; Chandra, S.; Stecher, T. P.

    1980-01-01

    The first effects of a nearby (10 parsec) supernova on the earth's atmosphere will be caused by ultraviolet radiation dissociating molecular oxygen. The event will be of about one month's duration. Several months later nuclear gamma radiation may arrive, causing a decrease in atmospheric ozone. Cosmic radiation from the supernova remnant will not intercept the earth for at least 1000 years at which time ozone will be seriously depleted. Supernova ultraviolet radiation increases column ozone and atomic oxygen. Atmospheric thermal structure is modified with a large temperature increase in the mesosphere and lower thermosphere and a decrease at higher altitudes caused by enhanced heat loss due to atomic oxygen radiation and conduction.

  8. 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.

  9. Chiral transport of neutrinos in supernovae

    NASA Astrophysics Data System (ADS)

    Yamamoto, Naoki

    2017-03-01

    The conventional neutrino transport theory for core-collapse supernovae misses one key property of neutrinos: the left-handedness. The chirality of neutrinos modifies the hydrodynamic behavior at the macroscopic scale and leads to topological transport phenomena. We argue that such transport phenomena should play important roles in the evolution of core-collapse supernovae, and, in particular, lead to a tendency toward the inverse energy cascade from small to larger scales, which may be relevant to the origin of the supernova explosion.

  10. 3 New Supernova Discoveries/Classifications

    NASA Astrophysics Data System (ADS)

    Nugent, Peter; Sullivan, Mark; Howell, D. Andrew

    2009-08-01

    The Type Ia supernova science working group of the Palomar Transient Factory (ATEL#1964) reports the discovery of three nearby supernova. Confirmation spectra were taken on the Double Beam Spectrograph on the Palomar Hale telescope on August 19 UT by R. Ellis and J. Cooke. Classification of the spectra were carried out using Superfit (Howell et al. 2005). As all three are quite young, STIS/UV spectroscopic observations on the Hubble Space Telescope were triggered by the ToO program "Verifying the Utility of Type Ia Supernovae as Cosmological Probes: Evolution and Dispersion in the Ultraviolet Spectra " (PI: R.

  11. Supernovae data and perturbative deviation from homogeneity

    SciTech Connect

    Enqvist, Kari; Mattsson, Maria; Rigopoulos, Gerasimos E-mail: maria.ronkainen@helsinki.fi

    2009-09-01

    We show that a spherically symmetric perturbation of a dust dominated Ω = 1 FRW universe in the Newtonian gauge can lead to an apparent acceleration of standard candles and provide a fit to the magnitude-redshift relation inferred from the supernovae data, while the perturbation in the gravitational potential remains small at all scales. We also demonstrate that the supernovae data does not necessarily imply the presence of some additional non-perturbative contribution by showing that any Lemaitre-Tolman-Bondi model fitting the supernovae data (with appropriate initial conditions) will be equivalent to a perturbed FRW spacetime along the past light cone.

  12. SPECTROSCOPY OF TYPE Ia SUPERNOVAE BY THE CARNEGIE SUPERNOVA PROJECT

    SciTech Connect

    Folatelli, Gaston; Morrell, Nidia; Phillips, Mark M.; Hsiao, Eric; Campillay, Abdo; Contreras, Carlos; Castellon, Sergio; Roth, Miguel; Hamuy, Mario; Anderson, Joseph P.; Krzeminski, Wojtek; Stritzinger, Maximilian; Burns, Christopher R.; Freedman, Wendy L.; Madore, Barry F.; Murphy, David; Persson, S. E.; Prieto, Jose L.; Suntzeff, Nicholas B.; Krisciunas, Kevin; and others

    2013-08-10

    This is the first release of optical spectroscopic data of low-redshift Type Ia supernovae (SNe Ia) by the Carnegie Supernova Project including 604 previously unpublished spectra of 93 SNe Ia. The observations cover a range of phases from 12 days before to over 150 days after the time of B-band maximum light. With the addition of 228 near-maximum spectra from the literature, we study the diversity among SNe Ia in a quantitative manner. For that purpose, spectroscopic parameters are employed such as expansion velocities from spectral line blueshifts and pseudo-equivalent widths (pW). The values of those parameters at maximum light are obtained for 78 objects, thus providing a characterization of SNe Ia that may help to improve our understanding of the properties of the exploding systems and the thermonuclear flame propagation. Two objects, namely, SNe 2005M and 2006is, stand out from the sample by showing peculiar Si II and S II velocities but otherwise standard velocities for the rest of the ions. We further study the correlations between spectroscopic and photometric parameters such as light-curve decline rate and color. In agreement with previous studies, we find that the pW of Si II absorption features are very good indicators of light-curve decline rate. Furthermore, we demonstrate that parameters such as pW2 (Si II 4130) and pW6 (Si II 5972) provide precise calibrations of the peak B-band luminosity with dispersions of Almost-Equal-To 0.15 mag. In the search for a secondary parameter in the calibration of peak luminosity for SNe Ia, we find a Almost-Equal-To 2{sigma}-3{sigma} correlation between B-band Hubble residuals and the velocity at maximum light of S II and Si II lines.

  13. Supernova Relic Neutrinos and the Supernova Rate Problem: Analysis of Uncertainties and Detectability of ONeMg and Failed Supernovae

    NASA Astrophysics Data System (ADS)

    Mathews, Grant J.; Hidaka, Jun; Kajino, Toshitaka; Suzuki, Jyutaro

    2014-08-01

    Direct measurements of the core collapse supernova rate (R 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 106 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 SN has large uncertainties {\\sim }1.8^{+1.6}_{-0.6} 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 {\\sim }1.1^{+1.0}_{-0.4} 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 neutrino temperature and

  14. 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

  15. Supernova 1993J as a spectroscopic link between type II and type Ib supernovae

    NASA Technical Reports Server (NTRS)

    Swartz, D. A.; Clocchiatti, A.; Benjamin, R.; Lester, D. F.; Wheeler, J. C.

    1993-01-01

    Supernova 1993J in the nearby galaxy M81 is one of the closest - and hence brightest - supernovae to be witnessed this century. The early spectrum of SN1993J showed the characteristic hydrogen signature of type II supernovae, but its subsequent evolution is atypical for this class of supernova. Here we present optical and infrared spectra of SN1993J up to 43 days after outburst, which reveal the onset of the helium absorption and emission features more commonly associated with hydrogen-free type Ib supernovae. Corresponding model spectra show that the progenitor star must have possessed an unusually thin (for type II supernovae) hydrogen-rich envelope overlying a helium-rich mantle. Moreover, the supernova ejecta must have remained compositionally stratified, with little transport of the hydrogen-rich material down into the underlying helium layer or mixing of heavier elements outwards. SN1993J therefore represents a transition object between hydrogen-dominated type II supernovae, and hydrogen-free, helium-dominated type Ib supernovae.

  16. X-ray studies of supernova remnants: a different view of supernova explosions.

    PubMed

    Badenes, Carles

    2010-04-20

    The unprecedented spatial and spectral resolutions of Chandra have revolutionized our view of the X-ray emission from supernova remnants. The excellent datasets accumulated on young, ejecta-dominated objects like Cas A or Tycho present a unique opportunity to study at the same time the chemical and physical structure of the explosion debris and the characteristics of the circumstellar medium sculpted by the progenitor before the explosion. Supernova remnants can thus put strong constraints on fundamental aspects of both supernova explosion physics and stellar evolution scenarios for supernova progenitors. This view of the supernova phenomenon is completely independent of, and complementary to, the study of distant extragalactic supernovae at optical wavelengths. The calibration of these two techniques has recently become possible thanks to the detection and spectroscopic follow-up of supernova light echoes. In this paper, I review the most relevant results on supernova remnants obtained during the first decade of Chandra and the impact that these results have had on open issues in supernova research.

  17. Radio Supernovae: Circum-Stellar Investigation (C.S.I.) of Supernova Progenitor Stars

    DTIC Science & Technology

    2009-02-24

    ar X iv :0 90 2. 40 59 v1 [ as tr o- ph .H E ] 2 4 Fe b 20 09 Radio Supernovae : Circum-Stellar Investigation (C.S.I.) of Supernova Progenitor...FEB 2009 2. REPORT TYPE 3. DATES COVERED 00-00-2009 to 00-00-2009 4. TITLE AND SUBTITLE Radio Supernovae : Circum-Stellar Investigation (C.S.I...of Supernova Progenitor Stars 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f

  18. X-ray studies of supernova remnants: A different view of supernova explosions

    PubMed Central

    Badenes, Carles

    2010-01-01

    The unprecedented spatial and spectral resolutions of Chandra have revolutionized our view of the X-ray emission from supernova remnants. The excellent datasets accumulated on young, ejecta-dominated objects like Cas A or Tycho present a unique opportunity to study at the same time the chemical and physical structure of the explosion debris and the characteristics of the circumstellar medium sculpted by the progenitor before the explosion. Supernova remnants can thus put strong constraints on fundamental aspects of both supernova explosion physics and stellar evolution scenarios for supernova progenitors. This view of the supernova phenomenon is completely independent of, and complementary to, the study of distant extragalactic supernovae at optical wavelengths. The calibration of these two techniques has recently become possible thanks to the detection and spectroscopic follow-up of supernova light echoes. In this paper, I review the most relevant results on supernova remnants obtained during the first decade of Chandra and the impact that these results have had on open issues in supernova research. PMID:20404206

  19. Supernova Ejecta in the Youngest Galactic Supernova Remnant G1.9+0.3

    NASA Technical Reports Server (NTRS)

    Borkowski, Kazimierz J.; Reynolds, Stephen P.; Hwang, Una; Green, David A.; Petre, Robert; Krishnamurthy, Kalyani; Willett, Rebecca

    2013-01-01

    G1.9+0.3 is the youngest known Galactic supernova remnant (SNR), with an estimated supernova (SN) explosion date of approximately 1900, and most likely located near the Galactic Center. Only the outermost ejecta layers with free-expansion velocities (is) approximately greater than 18,000 km s-1 have been shocked so far in this dynamically young, likely Type Ia SNR. A long (980 ks) Chandra observation in 2011 allowed spatially-resolved spectroscopy of heavy-element ejecta. We denoised Chandra data with the spatio-spectral method of Krishnamurthy et al., and used a wavelet based technique to spatially localize thermal emission produced by intermediate-mass elements (IMEs: Si and S) and iron. The spatial distribution of both IMEs and Fe is extremely asymmetric, with the strongest ejecta emission in the northern rim. Fe K alpha emission is particularly prominent there, and fits with thermal models indicate strongly oversolar Fe abundances. In a localized, outlying region in the northern rim, IMEs are less abundant than Fe, indicating that undiluted Fe-group elements (including 56Ni) with velocities greater than 18,000 km s-1 were ejected by this SN. But in the inner west rim, we find Si- and S-rich ejecta without any traces of Fe, so high-velocity products of O-burning were also ejected. G1.9+0.3 appears similar to energetic Type Ia SNe such as SN 2010jn where iron-group elements at such high free-expansion velocities have been recently detected. The pronounced asymmetry in the ejecta distribution and abundance inhomogeneities are best explained by a strongly asymmetric SN explosion, similar to those produced in some recent 3D delayed-detonation Type Ia models.

  20. Observing the next galactic supernova

    SciTech Connect

    Adams, Scott M.; Kochanek, C. S.; Beacom, John F.; Stanek, K. Z.; Vagins, Mark R.

    2013-12-01

    No supernova (SN) in the Milky Way has been observed since the invention of the optical telescope, instruments for other wavelengths, neutrino detectors, or gravitational wave observatories. It would be a tragedy to miss the opportunity to fully characterize the next one. To aid preparations for its observations, we model the distance, extinction, and magnitude probability distributions of a successful Galactic core-collapse supernova (ccSN), its shock breakout radiation, and its massive star progenitor. We find, at very high probability (≅ 100%), that the next Galactic SN will easily be detectable in the near-IR and that near-IR photometry of the progenitor star very likely (≅ 92%) already exists in the Two Micron All Sky Survey. Most ccSNe (98%) will be easily observed in the optical, but a significant fraction (43%) will lack observations of the progenitor due to a combination of survey sensitivity and confusion. If neutrino detection experiments can quickly disseminate a likely position (∼3°), we show that a modestly priced IR camera system can probably detect the shock breakout radiation pulse even in daytime (64% for the cheapest design). Neutrino experiments should seriously consider adding such systems, both for their scientific return and as an added and internal layer of protection against false triggers. We find that shock breakouts from failed ccSNe of red supergiants may be more observable than those of successful SNe due to their lower radiation temperatures. We review the process by which neutrinos from a Galactic ccSN would be detected and announced. We provide new information on the EGADS system and its potential for providing instant neutrino alerts. We also discuss the distance, extinction, and magnitude probability distributions for the next Galactic Type Ia supernova (SN Ia). Based on our modeled observability, we find a Galactic ccSN rate of 3.2{sub −2.6}{sup +7.3} per century and a Galactic SN Ia rate of 1.4{sub −0.8}{sup +1.4} per

  1. 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.

  2. Expansion of Kes 73, a shell supernova remnant containing a magnetar

    NASA Astrophysics Data System (ADS)

    Borkowski, Kazimierz

    2014-09-01

    Formation and evolution of highly magnetized neutron stars (magnetars) remain poorly understood. We can learn about magnetars by studying their remnants. Kes 73 is a young supernova remnant containing a magnetar. But basic properties of Kes 73, including its age, remain poorly known. We propose a third-epoch observation of Kes 73 with Chandra. When combined with the 2000 and 2006 observations, this will allow for determination of the remnant's age through expansion rate measurements. We will also search for spatial variations in expansion rate that will help in understanding of the remnant's dynamics. New observations will also be used to determine abundances of heavy-element supernova ejecta, placing further constraints on the supernova that produced Kes 73.

  3. The SHOES Program: Supernovae and HO for the Dark Energy Equation of State

    NASA Astrophysics Data System (ADS)

    Riess, Adam G.; Macri, L.

    2007-12-01

    The present uncertainty in the value of the Hubble constant (resulting in an uncertainty in OmegaM) and the paucity of Type Ia supernovae at redshifts exceeding 1 are leading obstacles to determining the nature of dark energy. We conducted a single, integrated set of observations in Cycle 15 to provide a 40% improvement in constraints on dark energy. This program observed known Cepheids in six reliable hosts of Type Ia supernovae with NICMOS, to reduce the uncertainty in H0 by a factor of two because of the smaller dispersion along the instability strip, the diminished extinction, and the weaker metallicity dependence in the infrared. In parallel with ACS, at the same time the NICMOS observations were underway, we discovered and followed a sample of Type Ia supernovae at z > 1. Together, these measurements, along with prior constraints from WMAP, should provide a significant improvement in our ability to distinguish between a static, cosmological constant and dynamical dark energy.

  4. SN 1993J: A Type IIb supernova

    NASA Technical Reports Server (NTRS)

    Woosley, S. E.; Eastman, Ronald G. (Editor); Weaver, Thomas A; Pinto, Philip A.

    1994-01-01

    The evolution of the bright Type II supernova discovered last year in M81, SN 1993J, is consistent with that expected for the explosion of a star which on the main sequence had a mass of 13-16 Solar Mass but which, owing to mass exchange with a binary companion (a intially approximately 3-5 AU, depending upon the actual presupernova radius and the masses of the two stars) lost almost all of its hydrogen-rich envelope during late helium burning. At the time of explosion, the helium core mass was 4.0 +/- 0.5 Solar Mass and the hydrogen envelope, 0.20 +/- 0.05 Solar Mass. The envelope was helium and nitrogen-rich (carbon-deficient) and the radius of the star, 4 +/- 1 x 10(exp 13) cm. The luminosity of the presupernova star was 3 + 1 x 10(exp 38) ergs/s, with the companion star contributing an additional approximately 10(exp 38) ergs/s. The star may have been a pulsating variable at the time of the explosion. For an explosion energy near 10(exp 51) ergs (KE at infinity) and an assumed distance of 3.3 Mpc, a mass of Ni-56 in the range 0.07 +/- 0.01 Solar Mass was produced and ejected. This presciption gives a light curve which compares favorably with the bolomatric observations. Color photometry is more restrictive and requires a model in which the hydrogen-envelope mass is low and the mixing of hydrogen inward has been small, but in which appreciable Ni-56 has been mixed outward into the helium and heavy-element core. It is possible to obtain good agreement with B and V light curves during the first 50 days, but later photometry, especially in bands other than B and V, will require a non-local thermo-dynamic equilibrium (LTE) spectral calculation for comparison. Based upon our model, we predict a flux of approximately 10(exp -5)(3.3 Mpc/D)(exp 2) photons/sq cm/s in the 847 keV line of CO-56 at peak during 1993 August. It may be easier to detect the Computonized continuum which peaks at a few times 10(exp -4) photons /s/sq cm/MeV at 40 keV a few months after the

  5. Happy birthday, supernova. [1987A

    SciTech Connect

    Schorn, R.A.

    1988-02-01

    The advances in understanding that have been made concerning SN 1987A in the year since it appeared are reviewed. The rapidity of the initial rise in brightness and the relatively faint absolute magnitude during the first few weeks have been found to be due to the progenitor star's being a blue giant, relatively small compared to a red giant. The nitrogen lines in the spectrum are evidence that the star was once a red giant whose stellar wind was so strong that the resulting loss of material converted the star into a blue giant. The variations in the light curve of the supernova are explained in terms of the radioactive decay of Ni-56 and Co-56 and the interaction of the resulting gamma rays with the debris cloud. Some of the remaining unanswered questions are summarized.

  6. Progenitors of Supernovae Type Ia

    NASA Astrophysics Data System (ADS)

    Toonen, S.; Nelemans, G.; Bours, M.; Portegies Zwart, S.; Claeys, J.; Mennekens, N.; Ruiter, A.

    2013-01-01

    Despite the significance of Type Ia supernovae (SNeIa) in many fields in astrophysics, SNeIa lack a theoretical explanation. The standard scenarios involve thermonuclear explosions of carbon/oxygen white dwarfs approaching the Chandrasekhar mass; either by accretion from a companion or by a merger of two white dwarfs. We investigate the contribution from both channels to the SNIa rate with the binary population synthesis (BPS) code SeBa in order to constrain binary processes such as the mass retention efficiency of WD accretion and common envelope evolution. We determine the theoretical rates and delay time distribution of SNIa progenitors and in particular study how assumptions affect the predicted rates.

  7. ANTIPROTONS PRODUCED IN SUPERNOVA REMNANTS

    SciTech Connect

    Berezhko, E. G.; Ksenofontov, L. T.

    2014-08-20

    We present the energy spectrum of an antiproton cosmic ray (CR) component calculated on the basis of the nonlinear kinetic model of CR production in supernova remnants (SNRs). The model includes the reacceleration of antiprotons already existing in the interstellar medium as well as the creation of antiprotons in nuclear collisions of accelerated protons with gas nuclei and their subsequent acceleration by SNR shocks. It is shown that the production of antiprotons in SNRs produces a considerable effect in their resultant energy spectrum, making it essentially flatter above 10 GeV so that the spectrum at TeV energies increases by a factor of 5. The calculated antiproton spectrum is consistent with the PAMELA data, which correspond to energies below 100 GeV. As a consistency check, we have also calculated within the same model the energy spectra of secondary nuclei and show that the measured boron-to-carbon ratio is consistent with the significant SNR contribution.

  8. Cosmic Chandlery with thermonuclear supernovae

    DOE PAGES

    Calder, Alan C.; Krueger, Brendan K.; Jackson, A. P.; ...

    2017-05-30

    Thermonuclear (Type Ia) supernovae are bright stellar explosions, the light curves of which can be calibrated to allow for use as "standard candles" for measuring cosmological distances. Contemporary research investigates how the brightness of an event may be influenced by properties of the progenitor system that follow from properties of the host galaxy such as composition and age. The goals are to better understand systematic effects and to assess the intrinsic scatter in the brightness, thereby reducing uncertainties in cosmological studies. We present the results from ensembles of simulations in the single-degenerate paradigm addressing the influence of age and metallicitymore » on the brightness of an event and compare our results to observed variations of brightness that correlate with properties of the host galaxy. As a result, we also present results from "hybrid" progenitor models that incorporate recent advances in stellar evolution.« less

  9. Cosmic Chandlery with Thermonuclear Supernovae

    NASA Astrophysics Data System (ADS)

    Calder, A. C.; Krueger, B. K.; Jackson, A. P.; Willcox, D. E.; Miles, B. J.; Townsley, D. M.

    2017-05-01

    Thermonuclear (Type Ia) supernovae are bright stellar explosions, the light curves of which can be calibrated to allow for use as “standard candles” for measuring cosmological distances. Contemporary research investigates how the brightness of an event may be influenced by properties of the progenitor system that follow from properties of the host galaxy such as composition and age. The goals are to better understand systematic effects and to assess the intrinsic scatter in the brightness, thereby reducing uncertainties in cosmological studies. We present the results from ensembles of simulations in the single-degenerate paradigm addressing the influence of age and metallicity on the brightness of an event and compare our results to observed variations of brightness that correlate with properties of the host galaxy. We also present results from “hybrid” progenitor models that incorporate recent advances in stellar evolution.

  10. 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.

  11. Supernovae and the Accelerating Universe

    NASA Technical Reports Server (NTRS)

    Wood, H. John

    2003-01-01

    Orbiting high above the turbulence of the earth's atmosphere, the Hubble Space Telescope (HST) has provided breathtaking views of astronomical objects never before seen in such detail. The steady diffraction-limited images allow this medium-size telescope to reach faint galaxies of 30th stellar magnitude. Some of these galaxies are seen as early as 2 billion years after the Big Bang in a 15 billion year old universe. Up until recently, astronomers assumed that all of the laws of physics and astronomy applied back then as they do today. Now, using the discovery that certain supernovae are standard candles, astronomers have found that the universe is expanding faster today than it was back then: the universe is accelerating in its expansion.

  12. Supernova 1987A at 30

    NASA Astrophysics Data System (ADS)

    Spyromilio, J.; Leibundgut, B.; Fransson, C.; Larsson, J.; Migotto, K.; Girard, J.

    2017-03-01

    Thirty years on, SN 1987A continues to develop and, over the last decade in particular, has: revealed the presence of a large centrally concentrated reservoir of dust; shown the presence of molecular species within the ejecta; expanded such that the ejecta structure is angularly resolved; begun the destruction of the circumstellar ring and transitioned to being dominated by energy sources external to the ejecta. We are participating in a live experiment in the creation of a supernova remnant and here the recent progress is briefly overviewed. Exciting developments can be expected as the ejecta and the reverse shock continue their interaction, the X-rays penetrate into the cold molecular core and we observe the return of the material into the interstellar medium. We anticipate that the nature of the remnant of the leptonisation event in the centre will also be revealed.

  13. Supernovae and the Accelerating Universe

    NASA Technical Reports Server (NTRS)

    Wood, H. John

    2003-01-01

    Orbiting high above the turbulence of the earth's atmosphere, the Hubble Space Telescope (HST) has provided breathtaking views of astronomical objects never before seen in such detail. The steady diffraction-limited images allow this medium-size telescope to reach faint galaxies of 30th stellar magnitude. Some of these galaxies are seen as early as 2 billion years after the Big Bang in a 15 billion year old universe. Up until recently, astronomers assumed that all of the laws of physics and astronomy applied back then as they do today. Now, using the discovery that certain supernovae are standard candles, astronomers have found that the universe is expanding faster today than it was back then: the universe is accelerating in its expansion.

  14. Mass extinctions and supernova explosions.

    PubMed Central

    Crutzen, P J; Brühl, C

    1996-01-01

    In a recent contribution to this journal Ellis and Schramm [Ellis, J. & Schramm, D. N. (1995) Proc. Natl. Acad. Sci. USA 92, 235-238] claim that supernova explosions can cause massive biological extinctions as a result of strongly enhanced stratospheric NOx (NO + NO2) production by accompanying galactic cosmic rays. They suggested that these NOx productions which would last over several centuries and occur once every few hundred million years would result in ozone depletions of about 95%, leading to vastly increased levels of biologically damaging solar ultraviolet radiation. Our detailed model calculations show, however, substantially smaller ozone depletions ranging from at most 60% at high latitudes to below 20% at the equator. PMID:11607631

  15. The Union3 Supernova Ia Compilation

    NASA Astrophysics Data System (ADS)

    Rubin, David; Aldering, Greg Scott; Amanullah, Rahman; Barbary, Kyle H.; Bruce, Adam; Chappell, Greta; Currie, Miles; Dawson, Kyle S.; Deustua, Susana E.; Doi, Mamoru; Fakhouri, Hannah; Fruchter, Andrew S.; Gibbons, Rachel A.; Goobar, Ariel; Hsiao, Eric; Huang, Xiaosheng; Ihara, Yutaka; Kim, Alex G.; Knop, Robert A.; Kowalski, Marek; Krechmer, Evan; Lidman, Chris; Linder, Eric; Meyers, Joshua; Morokuma, Tomoki; Nordin, Jakob; Perlmutter, Saul; Ripoche, Pascal; Ruiz-Lapuente, Pilar; Rykoff, Eli S.; Saunders, Clare; Spadafora, Anthony L.; Suzuki, Nao; Takanashi, Naohiro; Yasuda, Naoki; Supernova Cosmology Project

    2016-01-01

    High-redshift supernovae observed with the Hubble Space Telescope (HST) are crucial for constraining any time variation in dark energy. In a forthcoming paper (Rubin+, in prep), we will present a cosmological analysis incorporating existing supernovae with improved calibrations, and new HST-observed supernovae (six above z=1). We combine these data with current literature data, and fit them using SALT2-4 to create the Union3 Supernova compilation. We build on the Unified Inference for Type Ia cosmologY (UNITY) framework (Rubin+ 2015b), incorporating non-linear light-curve width and color relations, a model for unexplained dispersion, an outlier model, and a redshift-dependent host-mass correction.

  16. CSP spectroscopic classification of two supernovae

    NASA Astrophysics Data System (ADS)

    Stritzinger, M.; Hsiao, E.; Taddia, F.; Morrell, N.

    2015-01-01

    On behalf of the Carnegie Supernova Project, we report spectroscopic classification of PSN J08293820-1717473 and ASASSN-14my (ATel#6860), based on visual-wavelength spectra obtained with the Nordic Optical Telescope (+Alfosc).

  17. The Supernova Impostor SN 2010da

    NASA Astrophysics Data System (ADS)

    Binder, Breanna A.; Williams, Benjamin F.; Kong, Albert K. H.; Plucinsky, Paul P.; Gaetz, Terrance J.; Skillman, Evan D.; Dolphin, Andrew E.

    2016-01-01

    Supernova impostors are optical transients that, despite being assigned a supernova designation, do not signal the death of a massive star or accreting white dwarf. Instead, many impostors are thought to be major eruptions from luminous blue variables. Although the physical cause of these eruptions is still debated, tidal interactions from a binary companion has recently gained traction as a possible explanation for observations of some supernova impostors. In this talk, I will discuss the particularly interesting impostor SN 2010da, which exhibits high-luminosity, variable X-ray emission. The X-ray emission is consistent with accretion onto a neutron star, making SN 2010da a likely high mass X-ray binary in addition to a supernova impostor. SN 2010da is a unique laboratory for understanding both binary interactions as drivers of massive star eruptions and the evolutionary processes that create high mass X-ray binaries.

  18. Understanding the Ultraviolet Flux from Supernovae

    NASA Astrophysics Data System (ADS)

    Brown, Peter J.

    2016-01-01

    The conversion of observed magnitudes into flux densities for the creation of spectral energy distributions or integrating bolometric fluxes depends on the spectral shape of the source and the characteristics of the filters. Such details are often neglected, though the effects can be significant. We demonstrate the complexities of conversion as they relate to ultraviolet observations of supernovae, though the principles have broader application. These complexities include spectral model testing, the meaning of effective wavelengths, the endpoints of integration, and extinction corrections. Using data from the Swift Optical Ultraviolet Supernova Archive (SOUSA) we will present integrated luminosity curves from example supernovae of all types. We will also show the unprecedented ultraviolet luminosity of ASASSN-15lh/SN2015L. The creation of ultraviolet/optical spectral energy distributions is helpful in predicting the observed brightness and detectability of these supernovae at higher redshifts with optical telescopes such as the Dark Energy Survey and the Large Synoptic Survey Telescope.

  19. Classification of 17 DES supernovae by SALT

    NASA Astrophysics Data System (ADS)

    Kasai, E.; Bassett, B.; Crawford, S.; Childress, M.; D'Andrea, C.; Smith, M.; Sullivan, M.; Maartens, R.; Gupta, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.; Aldering, G.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Nugent, P.; Perlmutter, S.; Foley, R. J.; Pan, Y.-C.; Casas, R.; Castander, F. J.; Desai, S.; Paech, K.; Smith, R. C.; Schubnell, M.; Kessler, R.; Lasker, J.; Scolnic, D.; Brout, D. J.; Gladney, L.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.; Nichol, R.; Papadopoulos, A.

    2016-02-01

    We report optical spectroscopy of 17 supernovae discovered by the Dark Energy Survey (ATel #4668). The spectra (380-820nm) were obtained using the Robert Stobie Spectrograph (RSS) on the South African Large Telescope (SALT).

  20. Supernova cooling in a dark matter smog

    SciTech Connect

    Zhang, Yue

    2014-11-27

    A light hidden gauge boson with kinetic mixing with the usual photon is a popular setup in theories of dark matter. The supernova cooling via radiating the hidden boson is known to put an important constraint on the mixing. I consider the possible role dark matter, which under reasonable assumptions naturally exists inside supernova, can play in the cooling picture. Because the interaction between the hidden gauge boson and DM is likely unsuppressed, even a small number of dark matter compared to protons inside the supernova could dramatically shorten the free streaming length of the hidden boson. A picture of a dark matter “smog” inside the supernova, which substantially relaxes the cooling constraint, is discussed in detail.

  1. How to See a Recently Discovered Supernova

    SciTech Connect

    Nugent, Peter

    2011-01-01

    Berkeley Lab scientist Peter Nugent discusses a recently discovered supernova that is closer to Earth — approximately 21 million light-years away — than any other of its kind in a generation. Astronomers believe they caught the supernova within hours of its explosion, a rare feat made possible with a specialized survey telescope and state-of-the-art computational tools. The finding of such a supernova so early and so close has energized the astronomical community as they are scrambling to observe it with as many telescopes as possible, including the Hubble Space Telescope. More info on how to see it: http://newscenter.lbl.gov/feature-stories/2011/08/31/glimpse-cosmic-explosion/ News release: http://newscenter.lbl.gov/feature-stories/2011/08/25/supernova/

  2. An LSST Deep Supernova Cosmology Program

    NASA Astrophysics Data System (ADS)

    Pinto, P. A.; Smith, C. R.; Garnavich, P. M.

    2004-12-01

    Because of its rapid observing cadence and large aperture, the LSST presents an ideal tool for studying type Ia supernovae and exploiting them as cosmological tools to redshifts near unity. We present a series of simulations of an observing program which would use the LSST in a different mode from it usual cadence. It would use a small fraction of each night to do a deep supernova search in a ``staring mode," with 10-20 minutes total exposure per day on each of several ten-square-degree fields. Assuming no evolution in the type Ia supernova rate, a year-long campaign will yield close to 2000 supernovae in each field with a mean redshift near 0.75, with 60-100 photometric points per lightcurve in five photometric bands. We discuss the use of this dataset for constraining the dark energy equation of state and especially any variation it might have with direction on the sky.

  3. Astrophysics: Echo from an ancient supernova

    NASA Astrophysics Data System (ADS)

    Pastorello, Andrea; Patat, Ferdinando

    2008-12-01

    Light reflected off a dust cloud in the vicinity of the relic of Tycho Brahe's supernova, whose light first swept past Earth more than four centuries ago, literally sheds light on the nature of this cosmic explosion.

  4. How to See a Recently Discovered Supernova

    ScienceCinema

    Nugent, Peter

    2016-07-12

    Berkeley Lab scientist Peter Nugent discusses a recently discovered supernova that is closer to Earth — approximately 21 million light-years away — than any other of its kind in a generation. Astronomers believe they caught the supernova within hours of its explosion, a rare feat made possible with a specialized survey telescope and state-of-the-art computational tools. The finding of such a supernova so early and so close has energized the astronomical community as they are scrambling to observe it with as many telescopes as possible, including the Hubble Space Telescope. More info on how to see it: http://newscenter.lbl.gov/feature-stories/2011/08/31/glimpse-cosmic-explosion/ News release: http://newscenter.lbl.gov/feature-stories/2011/08/25/supernova/

  5. Type Ia Supernova Rate from SDSS Spectra

    NASA Astrophysics Data System (ADS)

    Krughoff, K. Simon; Connolly, A. J.; Scranton, R.; Frieman, J.; SubbaRao, M.

    2009-12-01

    Understanding the evolution of the Type Ia supernova rate is essential to our understanding of the star formation history of the Universe. Lately, high redshift measurements of the Type Ia rate have been receiving a lot of publicity, but understanding supernovae in the local universe is also important.In particular, comparison of detection methods and the associated rate measurements at low redshift can improve methods at higher redshift. We present a novel approach for detecting Type Ia supernovae in single epoch spectroscopic observations. Application of this method to the SDSS spectroscopic sample finds 100 supernovae resulting in a luminosity weighted rate of 0.24±0.01 SNu at z=0.1. Our measurement is in good agreement with others at low redshift. We discuss the application of this method to high redshift spectroscopic samples. This work was funded by the NSF through grant 0851007.

  6. Supernova Classification Using Swift UVOT Photometry

    NASA Astrophysics Data System (ADS)

    Smith, Madison; Brown, Peter J.

    2017-01-01

    With the great influx of supernova discoveries over the past few years, the observation time needed to acquire the spectroscopic data needed to classify supernova by type has become unobtainable. Instead, using the photometry of supernovae could greatly reduce the amount of time between discovery and classification. For this project we looked at the relationship between colors and supernova types through machine learning packages in Python. Using data from the Swift Ultraviolet/Optical Telescope (UVOT), each photometric point was assigned values corresponding to colors, absolute magnitudes, and the relative times from the peak brightness in several filters. These values were fed into three classifying methods, the nearest neighbors, decision tree, and random forest methods. We will discuss the success of these classification systems, the optimal filters for photometric classification, and ways to improve the classification.

  7. An ''archaeological'' quest for galactic supernova neutrinos

    SciTech Connect

    Lazauskas, Rimantas; Volpe, Cristina E-mail: Cecilia.Lunardini@asu.edu

    2009-04-15

    We explore the possibility to observe the effects of electron neutrinos from past galactic supernovae, through a geochemical measurement of the amount of Technetium 97 produced by neutrino-induced reactions in a Molybdenum ore. The calculations we present take into account the recent advances in our knowledge of neutrino interactions, of neutrino oscillations inside a supernova, of the solar neutrino flux at Earth and of possible failed supernovae. The predicted Technetium 97 abundance is of the order of 10{sup 7} atoms per 10 kilotons of ore, which is close to the current geochemical experimental sensitivity. Of this, {approx} 10-20% is from supernovae. Considering the comparable size of uncertainties, more precision in the modeling of neutrino fluxes as well as of neutrino cross sections is required for a meaningful measurement.

  8. Supernovae at the Highest Angular Resolution

    NASA Technical Reports Server (NTRS)

    Dyk, S. Van; Weiler, K.; Sramek, R.; Panagia, N.; Lacey, C.; Montes, M.; Mercaide, J.; Lewin, W.; Fox, D.; Filippenko, A.; Peng, C.

    2000-01-01

    The study of supernovae (SNe) and their environments in host galaxies at the highest possible angular resolution in a number of wavelength regimes is providing vital clues to the nature of their progenitor stars.

  9. Optical spectrosopy of HiTS supernovae

    NASA Astrophysics Data System (ADS)

    Anderson, J.; Forster, F.; Smith, C.; Vivas, K.; Pignata, G.; Olivares, F.; Hamuy, M.; Martin, J. San; Maureira, J. C.; Cabrera, G.; Gonzalez-Gaitan, S.; Galbany, L.; Bufano, F.; de Jaeger, T.; Hsiao, E.; Munoz, R.; Vera, E.

    2015-04-01

    We report optical wavelength spectroscopy obtained using the Goodman instrument mounted on the SOAR at CTIO on UT 2015-03-30, for two supernovae discovered by HiTS, the High Cadence Transient Survey (see ATELs #7289, #7290).

  10. SN 1054: A pulsar-powered supernova?

    NASA Astrophysics Data System (ADS)

    Li, Shao-Ze; Yu, Yun-Wei; Huang, Yan

    2015-11-01

    The famous ancient supernova SN 1054 could have been too bright to be explained in the “standard” radioactive-powered supernova scenario. As an alternative attempt, we demonstrate that the spin-down of the newly born Crab pulsar could provide a sufficient energy supply to make SN 1054 visible at daytime for 23 days and at night for 653 days, where a one-zone semi-analytical model is employed. Our results indicate that SN 1054 could be a “normal” cousin of magnetar-powered superluminous supernovae. Therefore, SN 1054-like supernovae could be a probe to uncover the properties of newly born neutron stars, which provide initial conditions for studies on neutron star evolutions.

  11. Detecting supernovae neutrino with Earth matter effect

    NASA Astrophysics Data System (ADS)

    Liao, Wei

    2016-12-01

    We study Earth matter effect in oscillations of supernovae neutrinos. We show that detecting Earth matter effect gives an independent measurement of spectra of supernovae neutrinos, i.e., the flavor difference of the spectra of supernovae neutrinos. We study the effect of energy resolution and angular resolution of a final electron or positron on detecting the signal of Earth matter effect. We show that varying the widths of energy bins in analysis can change the signal strength of Earth matter effect and the statistical fluctuation. A reasonable choice of energy bins can both suppress the statistical fluctuation and make a good signal strength relative to the statistical fluctuation. Neutrino detectors with good energy resolution and good angular resolution are therefore preferred so that there is more freedom to vary energy bins and to optimize the signal of Earth matter effect in analyzing events of supernovae neutrinos.

  12. Stellar astrophysics: Supernovae in the neighbourhood

    NASA Astrophysics Data System (ADS)

    Melott, Adrian L.

    2016-04-01

    Detailed measurements of radioisotopes in deep-sea deposits, plus modelling of how they reached Earth, indicate that many supernovae have occurred near enough to have potentially influenced evolution. See Letters p.69 & p.73

  13. Shock Heated Dust in Young Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Braun, R.; Strom, R. G.; van der Laan, H.; Greidanus, H.

    Infrared emission in young supernova remnants is interpreted as coming from shock-heated dust. Using models and data from other wavelength regimes, many physical parameters of the remnants can accurately be derived.

  14. Fermi Proves Supernova Remnants Make Cosmic Rays

    NASA Image and Video Library

    The husks of exploded stars produce some of the fastest particles in the cosmos. New findings by NASA's Fermi show that two supernova remnants accelerate protons to near the speed of light. The pro...

  15. A Quick Look at Supernova 1987A

    NASA Image and Video Library

    2017-02-24

    On February 24, 1987, astronomers in the southern hemisphere saw a supernova in the Large Magellanic Cloud. This new object was dubbed “Supernova 1987A” and was the brightest stellar explosion seen in over four centuries. Chandra has observed Supernova 1987A many times and the X-ray data reveal important information about this object. X-rays from Chandra have shown the expanding blast wave from the original explosion slamming into a ring of material expelled by the star before it exploded. The latest Chandra data reveal the blast wave has moved beyond the ring into a region that astronomers do not know much about. These observations can help astronomers learn how supernovas impact their environments and affect future generations of stars and planets.

  16. After the Explosion: Investigating Supernova Sites

    NASA Image and Video Library

    2015-03-26

    A new study analyzes several sites where dead stars once exploded. The explosions, called Type Ia supernovae, occurred within galaxies, six of which are shown in these images from the Sloan Digital Sky Survey.

  17. Supernova Dust Factory in M74

    NASA Image and Video Library

    2006-06-09

    Astronomers using NASA Spitzer Space Telescope have spotted a dust factory 30 million light-years away in the spiral galaxy M74. The factory is located at the scene of a massive star explosive death, or supernova.

  18. Physical processes in collapse driven supernova

    SciTech Connect

    Mayle, R.W.

    1985-11-01

    A model of the supernova explosion is discussed. The method of neutrino transport is discussed, since the explosive mechanism depends on neutrino heating of the material behind the accretion shock. The core region of these exploding stars becomes unstable to convective motions during the supernova evolution. Convective mixing allows more neutrinos to escape from under the neutrinosphere, and thus increases the amount of heating by neutrinos. An approximate method of incorporating convection is described, and some results of including convection in a computer model is presented. Another phenomena is seen in computer simulations of supernova, oscillations in the neutrino luminosity and mass accretion rate onto the protoneutron star. The last topic discussed in this thesis describes the attempt to understand this oscillation by perturbation of the steady state solution to equations approximating the complex physical processes occurring in the late time supernova. 42 refs., 31 figs.

  19. MDM OSMOS Spectroscopic classification of Supernovae

    NASA Astrophysics Data System (ADS)

    Bose, Subhash; Dong, Subo; Chen, Ping; Klusmeyer, J.; Prieto, Jose Luis; Shappee, B.; Shields, J.; Brown, J.; Stanek, K. Z.; Kochanek, C.

    2016-11-01

    We report optical spectroscopic classification of supernova candidates 2016hgd (ATel #9651), 2016hli (ATel #9685), CSS161013:015319+171853 and CSS161013:020130+141534 (http://nesssi.cacr.caltech.edu/catalina/AllSN.html).

  20. Supernova brightening from chameleon-photon mixing

    SciTech Connect

    Burrage, C.

    2008-02-15

    Measurements of standard candles and measurements of standard rulers give an inconsistent picture of the history of the universe. This discrepancy can be explained if photon number is not conserved as computations of the luminosity distance must be modified. I show that photon number is not conserved when photons mix with chameleons in the presence of a magnetic field. The strong magnetic fields in a supernova mean that the probability of a photon converting into a chameleon in the interior of the supernova is high, this results in a large flux of chameleons at the surface of the supernova. Chameleons and photons also mix as a result of the intergalactic magnetic field. These two effects combined cause the image of the supernova to be brightened resulting in a model which fits both observations of standard candles and observations of standard rulers.

  1. 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.

  2. Supernova cooling in a dark matter smog

    SciTech Connect

    Zhang, Yue

    2014-11-01

    A light hidden gauge boson with kinetic mixing with the usual photon is a popular setup in theories of dark matter. The supernova cooling via radiating the hidden boson is known to put an important constraint on the mixing. I consider the possible role dark matter, which under reasonable assumptions naturally exists inside supernova, can play in the cooling picture. Because the interaction between the hidden gauge boson and DM is likely unsuppressed, even a small number of dark matter compared to protons inside the supernova could dramatically shorten the free streaming length of the hidden boson. A picture of a dark matter ''smog'' inside the supernova, which substantially relaxes the cooling constraint, is discussed in detail.

  3. Type Ia Supernova Carbon Footprints

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    We present convincing evidence of unburned carbon at photospheric velocities in new observations of five Type Ia supernovae (SNe Ia) obtained by the Nearby Supernova Factory. These SNe are identified by examining 346 spectra from 124 SNe obtained before +2.5 days relative to maximum. Detections are based on the presence of relatively strong C II λ6580 absorption "notches" in multiple spectra of each SN, aided by automated fitting with the SYNAPPS code. Four of the five SNe in question are otherwise spectroscopically unremarkable, with ions and ejection velocities typical of SNe Ia, but spectra of the fifth exhibit high-velocity (v > 20, 000 km s-1) Si II and Ca II features. On the other hand, the light curve properties are preferentially grouped, strongly suggesting a connection between carbon-positivity and broadband light curve/color behavior: three of the five have relatively narrow light curves but also blue colors and a fourth may be a dust-reddened member of this family. Accounting for signal to noise and phase, we estimate that 22+10 - 6% of SNe Ia exhibit spectroscopic C II signatures as late as -5 days with respect to maximum. We place these new objects in the context of previously recognized carbon-positive SNe Ia and consider reasonable scenarios seeking to explain a physical connection between light curve properties and the presence of photospheric carbon. We also examine the detailed evolution of the detected carbon signatures and the surrounding wavelength regions to shed light on the distribution of carbon in the ejecta. Our ability to reconstruct the C II λ6580 feature in detail under the assumption of purely spherical symmetry casts doubt on a "carbon blobs" hypothesis, but does not rule out all asymmetric models. A low volume filling factor for carbon, combined with line-of-sight effects, seems unlikely to explain the scarcity of detected carbon in SNe Ia by itself.

  4. 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.

  5. 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).

  6. 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.

  7. 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.

  8. Suzaku Finds "Fossil" Fireballs from Supernovae

    NASA Image and Video Library

    2017-09-27

    Suzaku Finds "Fossil" Fireballs from Supernovae In a supernova remnant known as the Jellyfish Nebula, Suzaku detected X-rays from fully ionized silicon and sulfur -- an imprint of higher-temperature conditions immediately following the star's explosion. The nebula is about 65 light-years across. (12/30/2009) Credit: JAXA/NASA/Suzaku To learn more go to: www.nasa.gov/mission_pages/astro-e2/news/fossil-fireballs...

  9. Simulated Studies of Supernova Cosmology for LSST

    NASA Astrophysics Data System (ADS)

    Biswas, Rahul

    2017-01-01

    We discuss methods for simulating Type Ia SN observations from LSST based on the Operation Simulation (OpSim) ouptuts supplied by the LSST project and emperical, data driven models of supernovae. Such simulations can be used to assess the Survey strategies implemented in OpSim in terms of the success of different programs in supernova cosmology based on the results of analysis of the simulations.

  10. The Distant Type Ia Supernova Rate

    DOE R&D Accomplishments Database

    Pain, R.; Fabbro, S.; Sullivan, M.; Ellis, R. S.; Aldering, G.; Astier, P.; Deustua, S. E.; Fruchter, A. S.; Goldhaber, G.; Goobar, A.; Groom, D. E.; Hardin, D.; Hook, I. M.; Howell, D. A.; Irwin, M. J.; Kim, A. G.; Kim, M. Y.; Knop, R. A.; Lee, J. C.; Perlmutter, S.; Ruiz-Lapuente, P.; Schahmaneche, K.; Schaefer, B.; Walton, N. A.

    2002-05-28

    We present a measurement of the rate of distant Type Ia supernovae derived using 4 large subsets of data from the Supernova Cosmology Project. Within this fiducial sample, which surveyed about 12 square degrees, thirty-eight supernovae were detected at redshifts 0.25--0.85. In a spatially flat cosmological model consistent with the results obtained by the Supernova Cosmology Project, we derive a rest-frame Type Ia supernova rate at a mean red shift z {approx_equal} 0.55 of 1.53 {sub -0.25}{sub -0.31}{sup 0.28}{sup 0.32} x 10{sup -4} h{sup 3} Mpc{sup -3} yr{sup -1} or 0.58{sub -0.09}{sub -0.09}{sup +0.10}{sup +0.10} h{sup 2} SNu(1 SNu = 1 supernova per century per 10{sup 10} L{sub B}sun), where the first uncertainty is statistical and the second includes systematic effects. The dependence of the rate on the assumed cosmological parameters is studied and the redshift dependence of the rate per unit comoving volume is contrasted with local estimates in the context of possible cosmic star formation histories and progenitor models.

  11. The distant type Ia supernova rate

    SciTech Connect

    Pain, R.; Fabbro, S.; Sullivan, M.; Ellis, R.S.; Aldering, G.; Astier, P.; Deustua, S.E.; Fruchter, A.S.; Goldhaber, G.; Goobar, A.; Groom, D.E.; Hardin, D.; Hook, I.M.; Howell, D.A.; Irwin, M.J.; Kim, A.G.; Kim, M.Y.; Knop, R.A.; Lee, J.C.; Perlmutter, S.; Ruiz-Lapuente, P.; Schahmaneche, K.; Schaefer, B.; Walton, N.A.

    2002-05-20

    We present a measurement of the rate of distant Type Ia supernovae derived using 4 large subsets of data from the Supernova Cosmology Project. Within this fiducial sample,which surveyed about 12 square degrees, thirty-eight supernovae were detected at redshifts 0.25--0.85. In a spatially flat cosmological model consistent with the results obtained by the Supernova Cosmology Project, we derive a rest-frame Type Ia supernova rate at a mean red shift z {approx_equal} 0.55 of 1.53 {sub -0.25}{sub -0.31}{sup 0.28}{sup 0.32} x 10{sup -4} h{sup 3} Mpc{sup -3} yr{sup -1} or 0.58{sub -0.09}{sub -0.09}{sup +0.10}{sup +0.10} h{sup 2} SNu(1 SNu = 1 supernova per century per 10{sup 10} L{sub B}sun), where the first uncertainty is statistical and the second includes systematic effects. The dependence of the rate on the assumed cosmological parameters is studied and the redshift dependence of the rate per unit comoving volume is contrasted with local estimates in the context of possible cosmic star formation histories and progenitor models.

  12. The influence of hyperon potential on the black-hole-forming failed supernovae

    SciTech Connect

    Nakazato, Ken'ichiro; Sumiyoshi, Kohsuke

    2012-11-12

    We investigate the emergence of hyperons in black-hole-forming failed supernovae, which are caused by the dynamical collapse of nonrotating massive stars. Attractive and repulsive cases are examined for the potential of {Sigma} hyperons to find that it affects the accompanied neutrino emission through the core-collapse dynamics. The neutrino duration time during black hole formation for the repulsive case is {approx}15% longer than that for the attractive case.

  13. Acceleration of cosmic rays in supernova-remnants

    NASA Technical Reports Server (NTRS)

    Dorfi, E. A.; Drury, L. O.

    1985-01-01

    It is commonly accepted that supernova-explosions are the dominant source of cosmic rays up to an energy of 10 to the 14th power eV/nucleon. Moreover, these high energy particles provide a major contribution to the energy density of the interstellar medium (ISM) and should therefore be included in calculations of interstellar dynamic phenomena. For the following the first order Fermi mechanism in shock waves are considered to be the main acceleration mechanism. The influence of this process is twofold; first, if the process is efficient (and in fact this is the cas) it will modify the dynamics and evolution of a supernova-remnant (SNR), and secondly, the existence of a significant high energy component changes the overall picture of the ISM. The complexity of the underlying physics prevented detailed investigations of the full non-linear selfconsistent problem. For example, in the context of the energy balance of the ISM it has not been investigated how much energy of a SN-explosion can be transfered to cosmic rays in a time-dependent selfconsistent model. Nevertheless, a lot of progress was made on many aspects of the acceleration mechanism.

  14. HUBBLE SPIES MOST DISTANT SUPERNOVA EVER SEEN

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Using NASA's Hubble Space Telescope, astronomers pinpointed a blaze of light from the farthest supernova ever seen, a dying star that exploded 10 billion years ago. The detection and analysis of this supernova, called 1997ff, is greatly bolstering the case for the existence of a mysterious form of dark energy pervading the cosmos, making galaxies hurl ever faster away from each other. The supernova also offers the first glimpse of the universe slowing down soon after the Big Bang, before it began speeding up. This panel of images, taken with the Wide Field and Planetary Camera 2, shows the supernova's cosmic neighborhood; its home galaxy; and the dying star itself. Astronomers found this supernova in 1997 during a second look at the northern Hubble Deep Field [top panel], a tiny region of sky first explored by the Hubble telescope in 1995. The image shows the myriad of galaxies Hubble spied when it peered across more than 10 billion years of time and space. The white box marks the area where the supernova dwells. The photo at bottom left is a close-up view of that region. The white arrow points to the exploding star's home galaxy, a faint elliptical. Its redness is due to the billions of old stars residing there. The picture at bottom right shows the supernova itself, distinguished by the white dot in the center. Although this stellar explosion is among the brightest beacons in the universe, it could not be seen directly in the Hubble images. The stellar blast is so distant from Earth that its light is buried in the glow of its host galaxy. To find the supernova, astronomers compared two pictures of the 'deep field' taken two years apart. One image was of the original Hubble Deep Field; the other, the follow-up deep-field picture taken in 1997. Using special computer software, astronomers then measured the light from the galaxies in both images. Noting any changes in light output between the two pictures, the computer identified a blob of light in the 1997 picture

  15. HUBBLE SPIES MOST DISTANT SUPERNOVA EVER SEEN

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Using NASA's Hubble Space Telescope, astronomers pinpointed a blaze of light from the farthest supernova ever seen, a dying star that exploded 10 billion years ago. The detection and analysis of this supernova, called 1997ff, is greatly bolstering the case for the existence of a mysterious form of dark energy pervading the cosmos, making galaxies hurl ever faster away from each other. The supernova also offers the first glimpse of the universe slowing down soon after the Big Bang, before it began speeding up. This panel of images, taken with the Wide Field and Planetary Camera 2, shows the supernova's cosmic neighborhood; its home galaxy; and the dying star itself. Astronomers found this supernova in 1997 during a second look at the northern Hubble Deep Field [top panel], a tiny region of sky first explored by the Hubble telescope in 1995. The image shows the myriad of galaxies Hubble spied when it peered across more than 10 billion years of time and space. The white box marks the area where the supernova dwells. The photo at bottom left is a close-up view of that region. The white arrow points to the exploding star's home galaxy, a faint elliptical. Its redness is due to the billions of old stars residing there. The picture at bottom right shows the supernova itself, distinguished by the white dot in the center. Although this stellar explosion is among the brightest beacons in the universe, it could not be seen directly in the Hubble images. The stellar blast is so distant from Earth that its light is buried in the glow of its host galaxy. To find the supernova, astronomers compared two pictures of the 'deep field' taken two years apart. One image was of the original Hubble Deep Field; the other, the follow-up deep-field picture taken in 1997. Using special computer software, astronomers then measured the light from the galaxies in both images. Noting any changes in light output between the two pictures, the computer identified a blob of light in the 1997 picture

  16. Effect of silicon content on microstructure of low-alloy Q&P-Processed steels

    NASA Astrophysics Data System (ADS)

    Vorel, I.; Jeníček, Š.; Káňa, J.; Ibrahim, K.; Kotěšovec, V.; Mašek, B.

    2017-02-01

    Today’s requirements for the design of functional parts and components demand low weight and, at the same time, high strength. There are several heat treatment methods which can satisfy such requirements. These include TRIP heat treatment, long-time low-temperature austempering, and Q&P processing. It is the Q&P processing which delivers excellent results in terms of mechanical properties and light weight. It relies on stabilising retained austenite through partitioning of carbon between martensite and austenite. The carbon-enriched austenite then becomes a ductile constituent in the otherwise brittle martensitic matrix. A precondition for successful Q&P processing consists in sufficient silicon content in the steel, which precludes precipitation of undesirable cementite. Cementite would otherwise form as a result of enrichment of retained austenite with carbon. To ascertain the usefulness of higher silicon level in steel for Q&P processing, one can compare Q&P processes in steels with various levels of this element

  17. Turbulence-Flame Interactions in Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Aspden, A. J.; Bell, J. B.; Day, M. S.; Woosley, S. E.; Zingale, M.

    2008-12-01

    The large range of time and length scales involved in Type Ia supernovae (SNe Ia) requires the use of flame models. As a prelude to exploring various options for flame models, we consider in this paper high-resolution, three-dimensional simulations of the small-scale dynamics of nuclear flames in the supernova environment in which the details of the flame structure are fully resolved. The range of densities examined, (1-8) × 107 g cm-3, spans the transition from the laminar flamelet regime to the distributed burning regime where small-scale turbulence disrupts the flame. The use of a low Mach number algorithm facilitates the accurate resolution of the thermal structure of the flame and the inviscid turbulent kinetic energy cascade, while implicitly incorporating kinetic energy dissipation at the grid-scale cutoff. For an assumed background of isotropic Kolmogorov turbulence with an energy characteristic of SNe Ia, we find a transition density between 1 and 3 × 107 g cm-3, where the nature of the burning changes qualitatively. By 1 × 107 g cm-3, energy diffusion by conduction and radiation is exceeded, on the flame scale, by turbulent advection. As a result, the effective Lewis number approaches unity. That is, the flame resembles a laminar flame but is turbulently broadened with an effective diffusion coefficient, DT ~ u'l, where u' is the turbulent intensity and l is the integral scale. For the larger integral scales characteristic of a real supernova, the flame structure is predicted to become complex and unsteady. Implications for a possible transition to detonation are discussed.

  18. Utilizing Supernova Remnants as Probes of Explosion Mechanisms and Progenitor Systems

    NASA Astrophysics Data System (ADS)

    Milisavljevic, Dan

    2015-08-01

    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 the various processes that may be taking place deep inside massive stars. Observations of extragalactic supernovae have shed some light on the issue. However, distant supernovae, by nature, appear as unresolved point sources, which severely restricts our ability to extract key properties of the explosion dynamics via detailed knowledge of the three-dimensional kinematics of the expanding ejecta. Progress requires an alternative approach, and to this end there have been successful efforts towards understanding core-collapse supernova explosions through studies of their remnants in our own Milky Way galaxy. Such investigations provide information about the explosion-driven mixing of the progenitor star's chemically distinct layers, the star's mass loss history before explosion, and the fate of its remnant core - all at extremely fine scales. Particularly of note are observations of the young supernova remnant Cassiopeia A, which is the descendant of a massive star that was mostly stripped of its hydrogen envelope. Cassiopeia A's debris field has a bubble-like morphology that may have originated from turbulent mixing processes that encouraged the development of outwardly expanding plumes of radioactive 56Ni-rich ejecta. Important aspects of these observations conflict with sophisticated explosion models and we presently do not have a good understanding of how the 56Ni was mixed. Considering Cassiopeia A's kinematic properties are not unique and likely reflect a common phenomenon of core-collapse supernovae, this conflict represents a big problem that cannot be ignored. Unraveling whether the mixing that we see originates from an asymmetric explosion mechanism or is more tightly associated with a turbulent interior structure will be a challenge, but there is hope.

  19. ASASSN-17co: Discovery of A Supernova in UGC 11128

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Holoien, T. W.-S.; Stanek, K. Z.; Kochanek, C. S.; Brown, J. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Fernandez, J. M.; Kiyota, S.; Koff, R. A.; Post, R. S.

    2017-02-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new supernova in the galaxy UGC 11128.

  20. Supernova Driving. III. Synthetic Molecular Cloud Observations

    NASA Astrophysics Data System (ADS)

    Padoan, Paolo; Juvela, Mika; Pan, Liubin; Haugbølle, Troels; Nordlund, Åke

    2016-08-01

    We present a comparison of molecular clouds (MCs) from a simulation of supernova (SN) driven interstellar medium (ISM) turbulence with real MCs from the Outer Galaxy Survey. The radiative transfer calculations to compute synthetic CO spectra are carried out assuming that the CO relative abundance depends only on gas density, according to four different models. Synthetic MCs are selected above a threshold brightness temperature value, T B,min = 1.4 K, of the J = 1 - 0 12CO line, generating 16 synthetic catalogs (four different spatial resolutions and four CO abundance models), each containing up to several thousands MCs. The comparison with the observations focuses on the mass and size distributions and on the velocity-size and mass-size Larson relations. The mass and size distributions are found to be consistent with the observations, with no significant variations with spatial resolution or chemical model, except in the case of the unrealistic model with constant CO abundance. The velocity-size relation is slightly too steep for some of the models, while the mass-size relation is a bit too shallow for all models only at a spatial resolution dx ≈ 1 pc. The normalizations of the Larson relations show a clear dependence on spatial resolution, for both the synthetic and the real MCs. The comparison of the velocity-size normalization suggests that the SN rate in the Perseus arm is approximately 70% or less of the rate adopted in the simulation. Overall, the realistic properties of the synthetic clouds confirm that SN-driven turbulence can explain the origin and dynamics of MCs.

  1. Burning Thermals in Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Aspden, A. J.; Bell, J. B.; Dong, S.; Woosley, S. E.

    2011-09-01

    We develop a one-dimensional theoretical model for thermals burning in Type Ia supernovae based on the entrainment assumption of Morton, Taylor, and Turner. Extensions of the standard model are required to account for the burning and for the expansion of the thermal due to changes in the background stratification found in the full star. The model is compared with high-resolution three-dimensional numerical simulations, both in a uniform environment and a full-star setting. The simulations in a uniform environment present compelling agreement with the predicted power laws and provide model constants for the full-star model, which then provides excellent agreement with the full-star simulation. The importance of the different components in the model is compared, and are all shown to be relevant. An examination of the effect of initial conditions was then conducted using the one-dimensional model, which would have been infeasible in three dimensions. More mass was burned when the ignition kernel was larger and closer to the center of the star. The turbulent flame speed was found to be important during the early-time evolution of the thermal, but played a diminished role at later times when the evolution is dominated by the large-scale hydrodynamics responsible for entrainment. However, a higher flame speed effectively gave a larger initial ignition kernel and so resulted in more mass burned. This suggests that future studies should focus on the early-time behavior of these thermals (in particular, the transition to turbulence), and that the choice of turbulent flame speed does not play a significant role in the dynamics once the thermal has become established.

  2. BURNING THERMALS IN TYPE ia SUPERNOVAE

    SciTech Connect

    Aspden, A. J.; Bell, J. B.; Dong, S.; Woosley, S. E.

    2011-09-01

    We develop a one-dimensional theoretical model for thermals burning in Type ia supernovae based on the entrainment assumption of Morton, Taylor, and Turner. Extensions of the standard model are required to account for the burning and for the expansion of the thermal due to changes in the background stratification found in the full star. The model is compared with high-resolution three-dimensional numerical simulations, both in a uniform environment and a full-star setting. The simulations in a uniform environment present compelling agreement with the predicted power laws and provide model constants for the full-star model, which then provides excellent agreement with the full-star simulation. The importance of the different components in the model is compared, and are all shown to be relevant. An examination of the effect of initial conditions was then conducted using the one-dimensional model, which would have been infeasible in three dimensions. More mass was burned when the ignition kernel was larger and closer to the center of the star. The turbulent flame speed was found to be important during the early-time evolution of the thermal, but played a diminished role at later times when the evolution is dominated by the large-scale hydrodynamics responsible for entrainment. However, a higher flame speed effectively gave a larger initial ignition kernel and so resulted in more mass burned. This suggests that future studies should focus on the early-time behavior of these thermals (in particular, the transition to turbulence), and that the choice of turbulent flame speed does not play a significant role in the dynamics once the thermal has become established.

  3. Mass measurements in the vicinity of the r p-process and the {nu} p-process paths with the Penning trap facilities JYFLTRAP and SHIPTRAP

    SciTech Connect

    Weber, C.; Elomaa, V.-V.; Aeystoe, J.; Eronen, T.; Hager, U.; Hakala, J.; Jokinen, A.; Kankainen, A.; Moore, I. D.; Penttilae, H.; Rahaman, S.; Rissanen, J.; Saastamoinen, A.; Sonoda, T.; Ferrer, R.; Froehlich, C.; Ackermann, D.; Block, M.; Dworschak, M.; Herfurth, F.

    2008-11-15

    The masses of very neutron-deficient nuclides close to the astrophysical r p- and {nu} p-process paths have been determined with the Penning trap facilities JYFLTRAP at JYFL/Jyvaeskylae and SHIPTRAP at GSI/Darmstadt. Isotopes from yttrium (Z=39) to palladium (Z=46) have been produced in heavy-ion fusion-evaporation reactions. In total, 21 nuclides were studied, and almost half of the mass values were experimentally determined for the first time: {sup 88}Tc, {sup 90-92}Ru, {sup 92-94}Rh, and {sup 94,95}Pd. For the {sup 95}Pd{sup m}, (21/2{sup +}) high-spin state, a first direct mass determination was performed. Relative mass uncertainties of typically {delta}m/m=5x10{sup -8} were obtained. The impact of the new mass values has been studied in {nu} p-process nucleosynthesis calculations. The resulting reaction flow and the final abundances are compared with those obtained with the data of the Atomic Mass Evaluation 2003.

  4. Stellar core collapse and supernova

    SciTech Connect

    Wilson, J.R.; Mayle, R.; Woosley, S.E.; Weaver, T.

    1985-04-01

    Massive stars that end their stable evolution as their iron cores collapse to a neutron star or black hole long been considered good candidates for producing Type II supernovae. For many years the outward propagation of the shock wave produced by the bounce of these iron cores has been studied as a possible mechanism for the explosion. For the most part, the results of these studies have not been particularly encouraging, except, perhaps, in the case of very low mass iron cores or very soft nuclear equations of state. The shock stalls, overwhelmed by photodisintegration and neutrino losses, and the star does not explode. More recently, slow late time heating of the envelope of the incipient neutron star has been found to be capable of rejuvenating the stalled shock and producing an explosion after all. The present paper discusses this late time heating and presents results from numerical calculations of the evolution, core collapse, and subsequent explosion of a number of recent stellar models. For the first time they all, except perhaps the most massive, explode with reasonable choices of input physics. 39 refs., 17 figs., 1 tab.

  5. Supernova Remnant in 3-D

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Click on the image for the movie

    For the first time, a multiwavelength three-dimensional reconstruction of a supernova remnant has been created. This stunning visualization of Cassiopeia A, or Cas A, the result of an explosion approximately 330 years ago, uses data from several telescopes: X-ray data from NASA's Chandra X-ray Observatory, infrared data from NASA's Spitzer Space Telescope and optical data from the National Optical Astronomy Observatory 4-meter telescope at Kitt Peak, Ariz., and the Michigan-Dartmouth-MIT 2.4-meter telescope, also at Kitt Peak. In this visualization, the green region is mostly iron observed in X-rays. The yellow region is a combination of argon and silicon seen in X-rays, optical, and infrared including jets of silicon plus outer debris seen in the optical. The red region is cold debris seen in the infrared. Finally, the blue reveals the outer blast wave, most prominently detected in X-rays.

    Most of the material shown in this visualization is debris from the explosion that has been heated by a shock moving inwards. The red material interior to the yellow/orange ring has not yet encountered the inward moving shock and so has not yet been heated. These unshocked debris were known to exist because they absorb background radio light, but they were only recently discovered in infrared emission with Spitzer. The blue region is composed of gas surrounding the explosion that was heated when it was struck by the outgoing blast wave, as clearly seen in Chandra images.

    To create this visualization, scientists took advantage of both a previously known phenomenon the Doppler effect and a new technology that bridges astronomy and medicine. When elements created inside a supernova, such as iron, silicon and argon, are heated they emit light at certain wavelengths. Material moving towards the observer will have shorter wavelengths and material moving away will have longer

  6. SUPERNOVA FEEDBACK KEEPS GALAXIES SIMPLE

    SciTech Connect

    Chakraborti, Sayan

    2011-05-10

    Galaxies evolve continuously under the influence of self-gravity, rotation, accretion, mergers, and feedback. The currently favored cold dark matter cosmological framework suggests a hierarchical process of galaxy formation, wherein the present properties of galaxies are decided by their individual histories of being assembled from smaller pieces. However, recent studies have uncovered surprising correlations among the properties of galaxies, to the extent of forming a one-parameter set lying on a single fundamental line. It has been argued in the literature that such simplicity is hard to explain within the paradigm of hierarchical galaxy mergers. One of the puzzling results is the simple linear correlation between the neutral hydrogen mass and the surface area, implying that widely different galaxies share very similar neutral hydrogen surface densities. In this work, we show that self-regulated star formation, driven by the competition between gravitational instabilities and mechanical feedback from supernovae, can explain the nearly constant neutral hydrogen surface density across galaxies. We therefore recover the simple scaling relation observed between the neutral hydrogen mass and surface area. This result furthers our understanding of the surprising simplicity in the observed properties of diverse galaxies.

  7. The Supernovae Analysis Application (SNAP)

    NASA Astrophysics Data System (ADS)

    Bayless, Amanda J.; Fryer, Chris L.; Wollaeger, Ryan; Wiggins, Brandon; Even, Wesley; de la Rosa, Janie; Roming, Peter W. A.; Frey, Lucy; Young, Patrick A.; Thorpe, Rob; Powell, Luke; Landers, Rachel; Persson, Heather D.; Hay, Rebecca

    2017-09-01

    The SuperNovae Analysis aPplication (SNAP) is a new tool for the analysis of SN observations and validation of SN models. SNAP consists of a publicly available relational database with observational light curve, theoretical light curve, and correlation table sets with statistical comparison software, and a web interface available to the community. The theoretical models are intended to span a gridded range of parameter space. The goal is to have users upload new SN models or new SN observations and run the comparison software to determine correlations via the website. There are problems looming on the horizon that SNAP is beginning to solve. For example, large surveys will discover thousands of SNe annually. Frequently, the parameter space of a new SN event is unbounded. SNAP will be a resource to constrain parameters and determine if an event needs follow-up without spending resources to create new light curve models from scratch. Second, there is no rapidly available, systematic way to determine degeneracies between parameters, or even what physics is needed to model a realistic SN. The correlations made within the SNAP system are beginning to solve these problems.

  8. Light echoes - Type II supernovae

    NASA Technical Reports Server (NTRS)

    Schaefer, Bradley E.

    1987-01-01

    Type II supernovae (SNs) light curves show a remarkable range of shapes. Data have been collected for the 12 Type II SNs that have light curve information for more than four months past maximum. Contrary to previous reports, it is found that (1) the decay rate after 100 days past maximum varies by almost an order of magnitude and (2) the light curve shapes are not bimodally distributed, but actually form a continuum. In addition, it is found that the extinctions to the SNs are related to the light curve shapes. This implies that the absorbing dust is local to the SNs. The dust is likely to be part of a circumstellar shell emitted by the SN progenitor that Dwek (1983) has used to explain infrared echoes. The optical depth of the shell can get quite large. In such cases, it is found that the photons scattered and delayed by reflection off dust grains will dominate the light curve several months after peak brightness. This 'light echo' offers a straightforward explanation of the diversity of Type II SN light curves.

  9. Diversity in Type Ibn supernovae

    NASA Astrophysics Data System (ADS)

    Hosseinzadeh, Griffin; Valenti, Stefano; Arcavi, Iair; Howell, Dale Andrew; McCully, Curtis; Iptf, Pessto

    2015-01-01

    Type Ibn supernovae (SNe Ibn) are rare explosions of massive stars whose spectra exhibit narrow helium emission lines but no hydrogen lines. The narrow lines are thought to indicate interaction between the SN ejecta and circumstellar material from previous episodes of mass loss. Only a handful of SNe Ibn have been observed, and even fewer have been caught near the time of explosion. However, in the single case where a SN Ibn had multiple observations during the rising phase (iPTF13beo), its light curve exhibited a double peak. Here we present well-sampled multi-band photometry and spectroscopy of another SN Ibn, iPTF14aki, combining data from the intermediate Palomar Transient Factory (iPTF), the Las Cumbres Observatory Global Telescope Network (LCOGT), and the Public ESO Spectroscopic Survey of Transient Objects (PESSTO). We compare this object to other published and previously unpublised SNe Ibn and find that not all such events have a double-peaked light curve. We also discuss constraints on prior episodes of mass loss and the properties of the group as a whole.

  10. Supernova Remnant in 3-D

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Click on the image for the movie

    For the first time, a multiwavelength three-dimensional reconstruction of a supernova remnant has been created. This stunning visualization of Cassiopeia A, or Cas A, the result of an explosion approximately 330 years ago, uses data from several telescopes: X-ray data from NASA's Chandra X-ray Observatory, infrared data from NASA's Spitzer Space Telescope and optical data from the National Optical Astronomy Observatory 4-meter telescope at Kitt Peak, Ariz., and the Michigan-Dartmouth-MIT 2.4-meter telescope, also at Kitt Peak. In this visualization, the green region is mostly iron observed in X-rays. The yellow region is a combination of argon and silicon seen in X-rays, optical, and infrared including jets of silicon plus outer debris seen in the optical. The red region is cold debris seen in the infrared. Finally, the blue reveals the outer blast wave, most prominently detected in X-rays.

    Most of the material shown in this visualization is debris from the explosion that has been heated by a shock moving inwards. The red material interior to the yellow/orange ring has not yet encountered the inward moving shock and so has not yet been heated. These unshocked debris were known to exist because they absorb background radio light, but they were only recently discovered in infrared emission with Spitzer. The blue region is composed of gas surrounding the explosion that was heated when it was struck by the outgoing blast wave, as clearly seen in Chandra images.

    To create this visualization, scientists took advantage of both a previously known phenomenon the Doppler effect and a new technology that bridges astronomy and medicine. When elements created inside a supernova, such as iron, silicon and argon, are heated they emit light at certain wavelengths. Material moving towards the observer will have shorter wavelengths and material moving away will have longer

  11. Iron needles in supernova remnants?

    NASA Astrophysics Data System (ADS)

    Gomez (née Morgan), Haley L.; Dunne, Loretta; Eales, Stephen A.; Gomez, Edward L.; Edmunds, Michael G.

    2005-08-01

    It has been suggested by Dwek that iron needles could explain the submillimetre emission from the Cas A supernova remnant (SNR) with only a very small total mass. We investigate whether a similar model holds for the Kepler SNR, and find that its emission could indeed be explained by a dust mass of less than 10-2Msolar, dependent on the axial ratio l/a of the needles - which we constrain to be less than 700. But the implied needle model for Kepler is inconsistent with that suggested for Cas A since either the needles would have to have a resistivity one or two orders of magnitude greater than those in Cas A or the electron density in Kepler's shocked plasma must be 40 times greater than suggested by X-ray observations. An additional problem with the needle model is that the implied thickness of the needles seems to be implausibly small, if the emission properties are calculated under the usual approximations.

  12. Supernova Feedback in Galaxy Formation

    NASA Astrophysics Data System (ADS)

    Dubois, Y.; Teyssier, R.

    2008-06-01

    The hierarchical model of galaxy formation is known to suffer from the ``over-cooling'' problem: the high efficiency of radiative cooling results in too much baryonic matter in a condensed phase (namely, cold gas or stars) when compared to observations. A solution proposed by many authors (see Springel & Hernquist 2003; Fujita et al. 2004; Rasera & Teyssier 2005) is feedback due to supernova (SN) driven winds or active galactic nuclei. Modeling SN feedback by direct injection of thermal energy usually turns out to be inefficient in galaxy-scale simulations, due to the quasi-instantaneous radiation of the SN energy. To avoid this effect, we have developed a new method to incorporate SN feedback in cosmological simulations: using temporary test particles, we reproduce explicitly a local Sedov blast wave solution in the gas distribution. We have performed several self-consistent runs of isolated Navarro, Frenk, & White (1996, hereafter NFW) halos with radiative cooling, star formation, SN feedback and metal enrichment using the adaptive mesh refinement code RAMSES (Teyssier 2002). We have explored the influence of SN feedback on the formation and the evolution of galaxies with different masses. We have studied the efficiency of the resulting galactic winds, as a function of the mass of the parent halo.

  13. Du Pont Classifications of 2 ASAS-SN Supernovae

    NASA Astrophysics Data System (ADS)

    Shappee, Benjamin J.; Prieto, J. L.; Rich, J.; Madore, B.; Poetrodjojo, Henry; D'Agostino, Joshua

    2016-09-01

    We report optical spectroscopy (range 370-910 nm) of two supernovae discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN; Shappee et al. 2014, ApJ, 788, 48) using the du Pont 2.5-m telescope (+ WFCCD) at Las Campanas Observatory on Aug. 30 and Sep. 1 2016 UT. We performed a cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J.

  14. Du Pont Classifications of 4 ASAS-SN Supernovae

    NASA Astrophysics Data System (ADS)

    Morrell, N.; Shappee, Benjamin J.

    2016-08-01

    We report optical spectroscopy (range 370-910 nm) of four supernovae discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN; Shappee et al. 2014, ApJ, 788, 48) using the du Pont 2.5-m telescope (+ WFCCD) at Las Campanas Observatory on July 31 and Aug. 01 2016 UT. We performed a cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J.

  15. Supernova Registration in Water Cherenkov Veto of Dark Matter Detectors

    NASA Astrophysics Data System (ADS)

    Litvinovich, E. A.; Machulin, I. N.; Pugachev, D. A.; Skorokhvatov, M. D.

    2017-01-01

    Registration of supernova neutrinos is one of the main goals of large underground neutrino detectors. We consider the possibility of using the large water veto tanks of future dark matter experiments as the additional facilities for supernova detection. Simulations were performed for registration of Cherenkov light in 2 kt water veto of Darkside-20k from high energy positrons created by supernova electron antineutrinos via inverse beta decay reaction. Comparison between characteristics of different supernova neutrino detectors are presented.

  16. Dark matter balls help supernovae to explode

    NASA Astrophysics Data System (ADS)

    Froggatt, C. D.; Nielsen, H. B.

    2015-10-01

    As a solution to the well-known problem that the shock wave potentially responsible for the explosion of a supernova actually tends to stall, we propose a new energy source arising from our model for dark matter. Our earlier model proposed that dark matter should consist of cm-large white dwarf-like objects kept together by a skin separating two different sorts of vacua. These dark matter balls or pearls will collect in the middle of any star throughout its lifetime. At some stage during the development of a supernova, the balls will begin to take in neutrons and then other surrounding material. By passing into a ball nucleons fall through a potential of order 10 MeV, causing a severe production of heat — of order 10 foe for a solar mass of material eaten by the balls. The temperature in the iron core will thereby be raised, splitting up the iron into smaller nuclei. This provides a mechanism for reviving the shock wave when it arrives and making the supernova explosion really occur. The onset of the heating due to the dark matter balls would at first stop the collapse of the supernova progenitor. This opens up the possibility of there being two collapses giving two neutrino outbursts, as apparently seen in the supernova SN1987A — one in Mont Blanc and one 4 h 43 min later in both IMB and Kamiokande.

  17. High Rate for Type IC Supernovae

    SciTech Connect

    Muller, R.A.; Marvin-Newberg, H.J.; Pennypacker, Carl R.; Perlmutter, S.; Sasseen, T.P.; Smith, C.K.

    1991-09-01

    Using an automated telescope we have detected 20 supernovae in carefully documented observations of nearby galaxies. The supernova rates for late spiral (Sbc, Sc, Scd, and Sd) galaxies, normalized to a blue luminosity of 10{sup 10} L{sub Bsun}, are 0.4 h{sup 2}, 1.6 h{sup 2}, and 1.1 h{sup 2} per 100 years for SNe type la, Ic, and II. The rate for type Ic supernovae is significantly higher than found in previous surveys. The rates are not corrected for detection inefficiencies, and do not take into account the indications that the Ic supernovae are fainter on the average than the previous estimates; therefore the true rates are probably higher. The rates are not strongly dependent on the galaxy inclination, in contradiction to previous compilations. If the Milky Way is a late spiral, then the rate of Galactic supernovae is greater than 1 per 30 {+-} 7 years, assuming h = 0.75. This high rate has encouraging consequences for future neutrino and gravitational wave observatories.

  18. Supernova hydrodynamics experiments on the Nova laser

    NASA Astrophysics Data System (ADS)

    Kane, J.; Arnett, D.; Remington, B. A.; Glendinning, S. G.; Rubenchik, A.; Drake, R. P.; Fryxell, B. A.; Muller, E.

    1997-12-01

    The critical roles of hydrodynamic instabilities in SN 1987A and in ICF are well known; 2D-3D differences are important in both areas. In a continuing project at Lawrence Livermore National Laboratory (LLNL), the Nova Laser is being used in scaled laboratory experiments of hydrodynamic mixing under supernova-relevant conditions. Numerical simulations of the experiments are being done, using LLNL hydro codes, and astrophysics codes used to model supernovae. Initial investigations with two-layer planar packages having 2D sinusoidal interface perturbations are described in Ap.J. 478, L75 (1997). Early-time simulations done with the LLNL 1D radiation transport code HYADES are mapped into the 2D LLNL code CALE and into the multi-D supernova code PROMETHEUS. Work is underway on experiments comparing interface instability growth produced by 2D sinusoidal versus 3D cross-hatch and axisymmetric cylindrical perturbations. Results of the simulations will be presented and compared with experiment. Implications for interpreting supernova observations and for supernova modelling will be discussed. * Work performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under contract number W-7405-ENG-48.

  19. Fast evolving pair-instability supernovae

    DOE PAGES

    Kozyreva, Alexandra; Gilmer, Matthew; Hirschi, Raphael; ...

    2016-10-06

    With an increasing number of superluminous supernovae (SLSNe) discovered the ques- tion of their origin remains open and causes heated debates in the supernova commu- nity. Currently, there are three proposed mechanisms for SLSNe: (1) pair-instability supernovae (PISN), (2) magnetar-driven supernovae, and (3) models in which the su- pernova ejecta interacts with a circumstellar material ejected before the explosion. Based on current observations of SLSNe, the PISN origin has been disfavoured for a number of reasons. Many PISN models provide overly broad light curves and too reddened spectra, because of massive ejecta and a high amount of nickel. In themore » cur- rent study we re-examine PISN properties using progenitor models computed with the GENEC code. We calculate supernova explosions with FLASH and light curve evolu- tion with the radiation hydrodynamics code STELLA. We find that high-mass models (200 M⊙ and 250 M⊙) at relatively high metallicity (Z=0.001) do not retain hydro- gen in the outer layers and produce relatively fast evolving PISNe Type I and might be suitable to explain some SLSNe. We also investigate uncertainties in light curve modelling due to codes, opacities, the nickel-bubble effect and progenitor structure and composition.« less

  20. Fast evolving pair-instability supernovae

    SciTech Connect

    Kozyreva, Alexandra; Gilmer, Matthew; Hirschi, Raphael; Frohlich, Carla; Blinnikov, Sergey; Wollaeger, Ryan Thomas; Noebauer, Ulrich M.; van Rossum, Daniel R.; Heger, Alexander; Even, Wesley Paul; Waldman, Roni; Tolstov, Alexey; Chatzopoulos, Emmanouil; Sorokina, Elena

    2016-10-06

    With an increasing number of superluminous supernovae (SLSNe) discovered the ques- tion of their origin remains open and causes heated debates in the supernova commu- nity. Currently, there are three proposed mechanisms for SLSNe: (1) pair-instability supernovae (PISN), (2) magnetar-driven supernovae, and (3) models in which the su- pernova ejecta interacts with a circumstellar material ejected before the explosion. Based on current observations of SLSNe, the PISN origin has been disfavoured for a number of reasons. Many PISN models provide overly broad light curves and too reddened spectra, because of massive ejecta and a high amount of nickel. In the cur- rent study we re-examine PISN properties using progenitor models computed with the GENEC code. We calculate supernova explosions with FLASH and light curve evolu- tion with the radiation hydrodynamics code STELLA. We find that high-mass models (200 M⊙ and 250 M⊙) at relatively high metallicity (Z=0.001) do not retain hydro- gen in the outer layers and produce relatively fast evolving PISNe Type I and might be suitable to explain some SLSNe. We also investigate uncertainties in light curve modelling due to codes, opacities, the nickel-bubble effect and progenitor structure and composition.

  1. Scaling supernova hydrodynamics to the laboratory

    SciTech Connect

    Kane, J O; Remington, B A; Arnett, D; Fryxell, B A; Drake, R P

    1998-11-10

    Supernova (SN) 1987A focused attention on the critical role of hydrodynamic instabilities in the evolution of supernovae. To test the modeling of these instabilities, they are attempting to rigorously scale the physics of the laboratory in supernova. The scaling of hydrodynamics on microscopic laser scales to hydrodynamics on the SN-size scales is presented and requirements established. Initial results were reported in [1]. Next the appropriate conditions are generated on the NOVA laser. 10-15 Mbar shock at the interface of a two-layer planar target, which triggers perturbation growth, due to the Richtmyer-Meshkov instability and to the Rayleigh-Taylor instability as the interface decelerates is generated. This scales the hydrodynamics of the He-H interface of a Type II supernova at intermediate times, up to a few x10{sup 3} s. The experiment is modeled using the hydrodynamics codes HYADES and CALE, and the supernova code PROMETHEUS. Results of the experiments and simulations are presented. Analysis of the spike bubble velocities using potential flow theory and Ott thin shell theory is presented, as well as a study of 2D vs. 3D difference in growth at the He-H interface of Sn 1987A.

  2. Supernova experiments on the Nova Laser

    SciTech Connect

    Kane, J.; Arnett, D.; Remington, B.A.; Glendinning, S.G.; Wallace, R.; Rubenchik, A.; Fryxell, B.A.

    1997-12-02

    Supernova (SN) 1987A focused attention on the critical role of hydrodynamic instabilities in the evolution of supernovae. To test the modeling of these instabilities, we are developing laboratory experiments of hydrodynamic mixing under conditions relevant to supernovae. Initial results were reported in [l]. The Nova laser is used to generate a 10-15 Mbar shock at the interface of a two-layer planar target, which triggers perturbation growth, due to the Richtmyer-Meshkov and Rayleigh-Taylor instabilities as the interface decelerates. This resembles the hydrodynamics of the He-H interface of a Type II supernova at intermediate times, up to a few x10{sup 3} s. The experiment is modeled using the hydrodynamics codes HYADES and CALE, and the supernova code PROMETHEUS. Results of the experiments and simulations are presented. New analysis of the bubble velocity is presented, as well as a study of 2D vs. 3D difference in growth at the He-H interface of SN 1987A.

  3. Supernova Experiments on the Nova Laser

    SciTech Connect

    Kane, J.; Arnett, D.; Remington, B. A.; Glendinning, S. G.; Bazan, G.; Drake, R. P.; Fryxell, B. A.

    2000-04-01

    Supernova (SN) 1987A focused attention on the critical role of hydrodynamic instabilities in the evolution of supernovae. To test the modeling of these instabilities, we are developing laboratory experiments of hydrodynamic mixing under conditions relevant to supernovae. Initial results were reported by Kane et al. in a recent paper. The Nova laser is used to generate a 10-15 Mbar shock at the interface of a two-layer planar target, which triggers perturbation growth, due to the Richtmeyer-Meshkov instability, and to the Rayleigh-Taylor instability as the interface decelerates. This resembles the hydrodynamics of the He-H interface of a Type II supernova at intermediate times, up to a few times 10{sup 3} s. The experiment is modeled using the hydrodynamics codes HYADES and CALE, and the supernova code PROMETHEUS. Results of the experiments and simulations are presented. We also present new analysis of the bubble velocity, a study of two-dimensional versus three-dimensional difference in growth at the He-H interface of SN 1987A, and designs for two-dimensional versus three-dimensional hydro experiments. (c) 2000 The American Astronomical Society.

  4. Type Ia Supernovae: Colors, Rates, and Progenitors

    NASA Astrophysics Data System (ADS)

    Heringer, Epson; Pritchet, Chris; Kezwer, Jason; Graham, Melissa L.; Sand, David; Bildfell, Chris

    2017-01-01

    The rate of type Ia supernovae (SNe Ia) in a galaxy depends not only on stellar mass, but also on star formation history (SFH). Here we show that two simple observational quantities (g ‑ r or u ‑ r host galaxy color, and r-band luminosity), coupled with an assumed delay time distribution (DTD) (the rate of SNe Ia as a function of time for an instantaneous burst of star formation), are sufficient to accurately determine a galaxy’s SN Ia rate, with very little sensitivity to the precise details of the SFH. Using this result, we compare observed and predicted color distributions of SN Ia hosts for the MENeaCS cluster supernova survey, and for the SDSS Stripe 82 supernova survey. The observations are consistent with a continuous DTD, without any cutoff. For old progenitor systems, the power-law slope for the DTD is found to be -{1.50}-0.15+0.19. This result favors the double degenerate scenario for SN Ia, though other interpretations are possible. We find that the late-time slopes of the DTD are different at the 1σ level for low and high stretch supernova, which suggest a single degenerate (SD) scenario for the latter. However, due to ambiguity in the current models’ DTD predictions, SD progenitors can neither be confirmed as causing high stretch supernovae nor ruled out from contributing to the overall sample.

  5. Calculated late time spectra of supernovae

    SciTech Connect

    Axelrod, T.S.

    1987-10-30

    We consider here the nebular phase spectra of supernovae whose late time luminosity is provided by the radioactive decay of /sup 56/Ni and /sup 56/Co synthesized in the explosion. A broad variety of supernovae are known or suspected to fall in this category. This includes all SNIa and SNIb, and at least some SNII, in particular SN1987a. At sufficiently late times the expanding supernova becomes basically nebular in character due to its decreasing optical depth. The spectra produced during this stage contain information on the density and abundance structure of the entire supernova, as opposed to spectra near maximum light which are affected only by the outermost layers. A numerical model for nebular spectrum formation is therefore potentially very valuable for answering currently outstanding questions about the post-explosion supernova structure. As an example, we can hope to determine the degree of mixing which occurs between the layers of the ''onion-skin'' abundance structure predicted by current one dimensional explosion calculations. In the sections which follow, such a numerical model is briefly described and then applied to SN1972e, a typical SNIa, SN1985f, an SNIb, and finally to SN1987a. In the case of SN1987a predicted spectra are presented for the wavelength range from 1 to 100 microns at a time 300 days after explosion. 18 refs., 6 figs.

  6. Superluminous supernovae: no threat from eta Carinae.

    PubMed

    Thomas, Brian C; Melott, Adrian L; Fields, Brian D; Anthony-Twarog, Barbara J

    2008-02-01

    Recently, Supernova 2006gy was noted as the most luminous ever recorded, with a total radiated energy of approximately 10(44) Joules. It was proposed that the progenitor may have been a massive evolved star similar to eta Carinae, which resides in our own Galaxy at a distance of about 2.3 kpc. eta Carinae appears ready to detonate. Although it is too distant to pose a serious threat as a normal supernova, and given that its rotation axis is unlikely to produce a gamma-ray burst oriented toward Earth, eta Carinae is about 30,000 times nearer than 2006gy, and we re-evaluate it as a potential superluminous supernova. We have found that, given the large ratio of emission in the optical to the X-ray, atmospheric effects are negligible. Ionization of the atmosphere and concomitant ozone depletion are unlikely to be important. Any cosmic ray effects should be spread out over approximately 10(4) y and similarly unlikely to produce any serious perturbation to the biosphere. We also discuss a new possible effect of supernovae-e-ndocrine disruption induced by blue light near the peak of the optical spectrum. This is a possibility for nearby supernovae at distances too large to be considered "dangerous" for other reasons. However, due to reddening and extinction by the interstellar medium, eta Carinae is unlikely to trigger such effects to any significant degree.

  7. 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.

  8. Analysis of IUE Observations of Supernovae

    NASA Technical Reports Server (NTRS)

    Kirshner, Robert P.

    1996-01-01

    This program supported the analysis of IUE observations of supernovae. One aspect was a Target-of-Opportunity program to observe bright supernovae which was applied to SN 1993J in M81, and another was continuing analysis of the IUE data from SN 1987A. Because of its quick response time, the IUE satellite has continued to provide useful data on the ultraviolet spectra of supernovae. Even after the launch of the Hubble Space Telescope, which has much more powerful ultraviolet spectrometers, the IUE has enabled us to obtain early and frequent measurements of ultraviolet radiation: this information has been folded in with our HST data to create unique observations of supernova which can be interpreted to give powerful constraints on the physical properties of the exploding stars. Our chief result in the present grant period was the completion of a detailed reanalysis of the data on the circumstellar shell of SN 1987A. The presence of narrow high-temperature mission lines from nitrogen-rich gas close to SN 1987A has been the principal observational constraint on the evolution of the supernova's progenitor. Our new analysis shows that the onset of these lines, their rise to maximum, and their subsequent fading can be understood in the context of a model for the photoionization of circumstellar matter.

  9. Turbulence in Type Ia Supernovae Simulations

    NASA Astrophysics Data System (ADS)

    Fisher, Robert

    2012-03-01

    Type Ia supernovae are among the most energetic explosions in the known universe, releasing 10^51 ergs of kinetic energy in their ejecta, with 0.7 solar masses of radioactive Ni-56 synthesized during the explosion. The discovery of the Phillips relation enabled the use of Type Ia supernova (SN Ia) as standardizable cosmological candles, and has ushered in a new era of astronomy leading to the discovery of the acceleration of the universe, leading to the 2011 Nobel Prize in physics. The nature of the Type Ia progenitors, as well as their precise explosion mechanism, remains a subject of active investigation, both observationally as well as theoretically. It is known that the progenitors of Type Ia supernovae are near-Chandrasekhar mass white dwarfs in binary systems, though competing models suggest the companion is either a red giant or main sequence star (the so-called ``single-degenerate channel'') or another white dwarf (the ``double-degenerate channel''). In this talk, I will present recent results of three -dimensional models of the single-degenerate channel of Type Ia supernovae. I will also discuss prospects for modeling the double-degenerate channel of Type Ia supernovae, which have recently enjoyed increased favor from observers and theorists.

  10. Fast evolving pair-instability supernovae

    SciTech Connect

    Kozyreva, Alexandra; Gilmer, Matthew; Hirschi, Raphael; Frohlich, Carla; Blinnikov, Sergey; Wollaeger, Ryan Thomas; Noebauer, Ulrich M.; van Rossum, Daniel R.; Heger, Alexander; Even, Wesley Paul; Waldman, Roni; Tolstov, Alexey; Chatzopoulos, Emmanouil; Sorokina, Elena

    2016-10-06

    With an increasing number of superluminous supernovae (SLSNe) discovered the ques- tion of their origin remains open and causes heated debates in the supernova commu- nity. Currently, there are three proposed mechanisms for SLSNe: (1) pair-instability supernovae (PISN), (2) magnetar-driven supernovae, and (3) models in which the su- pernova ejecta interacts with a circumstellar material ejected before the explosion. Based on current observations of SLSNe, the PISN origin has been disfavoured for a number of reasons. Many PISN models provide overly broad light curves and too reddened spectra, because of massive ejecta and a high amount of nickel. In the cur- rent study we re-examine PISN properties using progenitor models computed with the GENEC code. We calculate supernova explosions with FLASH and light curve evolu- tion with the radiation hydrodynamics code STELLA. We find that high-mass models (200 M⊙ and 250 M⊙) at relatively high metallicity (Z=0.001) do not retain hydro- gen in the outer layers and produce relatively fast evolving PISNe Type I and might be suitable to explain some SLSNe. We also investigate uncertainties in light curve modelling due to codes, opacities, the nickel-bubble effect and progenitor structure and composition.

  11. 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

  12. A solar-type star polluted by calcium-rich supernova ejecta inside the supernova remnant RCW 86

    NASA Astrophysics Data System (ADS)

    Gvaramadze, Vasilii V.; Langer, Norbert; Fossati, Luca; Bock, Douglas C.-J.; Castro, Norberto; Georgiev, Iskren Y.; Greiner, Jochen; Johnston, Simon; Rau, Arne; Tauris, Thomas M.

    2017-06-01

    When a massive star in a binary system explodes as a supernova, its companion star may be polluted with heavy elements from the supernova ejecta. Such pollution has been detected in a handful of post-supernova binaries 1 , but none of them is associated with a supernova remnant. We report the discovery of a binary G star strongly polluted with calcium and other elements at the position of the candidate neutron star [GV2003] N within the young galactic supernova remnant RCW 86. Our discovery suggests that the progenitor of the supernova that produced RCW 86 could have been a moving star, which exploded near the edge of its wind bubble and lost most of its initial mass because of common-envelope evolution shortly before core collapse, and that the supernova explosion might belong to the class of calcium-rich supernovae — faint and fast transients 2,3 , the origin of which is strongly debated 4-6 .

  13. Imagery and spectroscopy of supernova remnants and H-2 regions

    NASA Technical Reports Server (NTRS)

    Dufour, R. J.

    1984-01-01

    Research activities relating to supernova remnants were summarized. The topics reviewed include: progenitor stars of supernova remnants, UV/optical/radio/X-ray imagery of selected regions in the Cygnus Loop, UV/optical spectroscopy of the Cygnus Loop spur, and extragalactic supernova remnant spectra.

  14. 97-ERD-022 final report: Supernova on Nova

    SciTech Connect

    Remington, B A

    1999-03-11

    This is the final year of the 3-year LDRD-ERD involving Lasers, D&NT, Physics, and ILSA to develope astrophysics experiments on intense lasers such as the Nova and Gekko lasers. During this 3 year period, we have developed a highly successful experiment probing the hydrodynamics of the explosion phase of core-collapse supernovae, which occurs during the first ~3 hours after core collapse. This was in collaboration with the Univ. of Arizona and CEA/Saclay. We also developed a very successful experiment to probe the hydrodynamics of the later time, young remnant phase, meaning the first ~10-20 years after core collapse. This was in collaboration with the Univ. of Michigan and Univ. of Colorado. Finally, we developed during the final year an exquisite experiment to probe the dynamics of radiative, high Mach number astrophysical jets, in collaboration with the Univ. of Maryland and Osaka Univ. Each experiment has received very high visibility, with a multitude of publications, both in the technical journals (most importantly, the astrophysical journals) and in the popular press. The attached publication list shows 25 papers published or submitted to technical journals, 5 articles appearing in the popular press (including a cover story of Sky and Telescope), and 65 conference presentations, ~10 of which were invited talks. The most important papers to come out of this effort was a comprehensive theory paper for Ap. J. establishing the rigorous scaling between laboratory laser experiments and the astrophysical subjects of interest: supernovae, supernova remnants, and jets; and a review article for Science covering this emerging subfield of Astrophysics on Intense Lasers. Since there are so many publications that have resulted from this LDRD project, only these two most important papers are attached. The rest are properly referenced, and can be found online or in the library. In anticipation of the closing of the Nova laser, we have successfully proposed transferring the

  15. Possible Progenitor of Special Supernova Type Detected

    NASA Astrophysics Data System (ADS)

    2008-04-01

    Using data from NASA's Chandra X-ray Observatory, scientists have reported the possible detection of a binary star system that was later destroyed in a supernova explosion. The new method they used provides great future promise for finding the detailed origin of these important cosmic events. In an article appearing in the February 14th issue of the journal Nature, Rasmus Voss of the Max Planck Institute for Extraterrestrial Physics in Germany and Gijs Nelemans of Radboud University in the Netherlands searched Chandra images for evidence of a much sought after, but as yet unobserved binary system - one that was about to go supernova. Near the position of a recently detected supernova, they discovered an object in Chandra images taken more than four years before the explosion. Optical image of SN 2007on Optical image of SN 2007on The supernova, known as SN 2007on, was identified as a Type Ia supernova. Astronomers generally agree that Type Ia supernovas are produced by the explosion of a white dwarf star in a binary star system. However, the exact configuration and trigger for the explosion is unclear. Is the explosion caused by a collision between two white dwarfs, or because a white dwarf became unstable by pulling too much material off a companion star? Answering such questions is a high priority because Type Ia supernovas are major sources of iron in the Universe. Also, because of their nearly uniform intrinsic brightness, Type Ia supernova are used as important tools by scientists to study the nature of dark energy and other cosmological issues. People Who Read This Also Read... Oldest Known Objects Are Surprisingly Immature Black Holes Have Simple Feeding Habits Discovery of Most Recent Supernova in Our Galaxy Geriatric Pulsar Still Kicking "Right now these supernovas are used as black boxes to measure distances and derive the rate of expansion of the universe," said Nelemans. "What we're trying to do is look inside the box." If the supernova explosion is

  16. 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).-

  17. Supernovae and Dark Energy -- What's Next?

    NASA Astrophysics Data System (ADS)

    Perlmutter, Saul

    2003-04-01

    The existing supernova measurements of the universe's (accelerating) expansion history have pointed the way to the next generation of experiments. This next generation of supernova measurements must be made with a dramatic step forward in constraints on systematic uncertainties, since the previous measurements already have statistical uncertainties that are close to the current systematics limits. I will show how some recent results set the stage for these advances, and describe a series of ground- and space-based projects and a new satellite experiment (the SuperNova / Acceleration Probe, "SNAP") that promise a systematics-controlled prize: a detailed expansion history of the universe that can teach us about the nature of the mysterious "dark energy" that accelerates the universe.

  18. Supernova Recognition using Support Vector Machines

    SciTech Connect

    Romano, Raquel A.; Aragon, Cecilia R.; Ding, Chris

    2006-10-01

    We introduce a novel application of Support Vector Machines(SVMs) to the problem of identifying potential supernovae usingphotometric and geometric features computed from astronomical imagery.The challenges of this supervised learning application are significant:1) noisy and corrupt imagery resulting in high levels of featureuncertainty,2) features with heavy-tailed, peaked distributions,3)extremely imbalanced and overlapping positiveand negative data sets, and4) the need to reach high positive classification rates, i.e. to find allpotential supernovae, while reducing the burdensome workload of manuallyexamining false positives. High accuracy is achieved viaasign-preserving, shifted log transform applied to features with peaked,heavy-tailed distributions. The imbalanced data problem is handled byoversampling positive examples,selectively sampling misclassifiednegative examples,and iteratively training multiple SVMs for improvedsupernovarecognition on unseen test data. We present crossvalidationresults and demonstrate the impact on a largescale supernova survey thatcurrently uses the SVM decision value to rank-order 600,000 potentialsupernovae each night.

  19. Supernova Science from a "Standard" LSST Cadence

    NASA Astrophysics Data System (ADS)

    Garnavich, P. M.; Smith, R. C.; Miknaitis, G.; Stubbs, C. W.; Suntzeff, N. B.; Preito, J. L.; Pinto, P.

    2004-12-01

    The Large Synoptic Survey Telescope (LSST) will likely have several cadences, but one of the most general will be a cadence which covers a large portion of the available sky repeatedly in a limited number of filters in a short period of time, for example every 3 to 5 nights. Such a cadence is useful not only for identifying and tracking moving sources such as Near Earth Objects (NEOs), but also for identifying and following moderately long-term (month timescale) transient events such as supernovae. Given a sample general cadence, we investigate the number of type Ia and core-collapse supernovae likely to be discovered per year with LSST. We also investigate the resulting light curve and multi-filter sampling and how these data might best be used for studying SN rates, dark energy models and other science programs based on obtaining a large sample of supernovae.

  20. Supernovas y Cosmología

    NASA Astrophysics Data System (ADS)

    Folatelli, G.

    Supernovae are very relevant astrophysical objects because they indicate the violent end of certain stars and because they alter the interstellar medium. But most importantly, they have become an extremely useful tool for measuring cosmological distances. Based on highly precise distances to type Ia supernovae it was possible to find out that the expansion of the universe is currently accelerated. This led to introducing the concept of ``dark energy'' as a dominant and yet unknown component of the cosmos. In this article we will describe the method of distance measurements that leads to the determination of cosmological parameters. We will briefly review the current status of the field with emphasis on the importance of improving our knowledge about the physical nature of supernovae. FULL TEXT IN SPANISH

  1. Supernova Explosions, Nucleosynthesis, and Cosmic Chemical Evolution

    SciTech Connect

    Truran, James W.

    2006-08-25

    The Universe emerged from its first three minutes with a composition consisting of hydrogen, deuterium, 3He, 4He, and 7Li. These isotopes constitute the primordial compositions of galaxies. Within galaxies, the synthesis of heavier elements from carbon through uranium is understood to occur during the normal evolution of stars and in supernova explosions of Types I and II. This history is written in the compositions of the stars and gas in our Milky Way Galaxy and other galaxies. The contributions both from massive stars (M>10 M{center_dot}) and associated Type II supernovae and from Type Ia (thermonuclear) supernovae are particularly noteworthy. We review both the nuclear processes by which this occurs and the compositions of the stellar components of our Galaxy as a function of time which reflect these nucleosynthesis processes. We then discuss how such observations inform us of the nature of the earliest stellar populations and of the abundance history of the Cosmos.

  2. Isothermal blast wave model of supernova remnants

    NASA Technical Reports Server (NTRS)

    Solinger, A.; Buff, J.; Rappaport, S.

    1975-01-01

    The validity of the 'adiabatic' assumption in supernova-remnant calculations is examined, and the alternative extreme of an isothermal blast wave is explored. It is concluded that, because of thermal conductivity, the large temperature gradients predicted by the adiabatic model probably are not maintained in nature. Self-similar solutions to the hydrodynamic equations for an isothermal blast wave have been found and studied. These solutions are then used to determine the relationship between X-ray observations and inferred parameters of supernova remnants. A comparison of the present results with those for the adiabatic model indicates differences which are less than present observational uncertainties. It is concluded that most parameters of supernova remnants inferred from X-ray measurements are relatively insensitive to the specifics of the blast-wave model.

  3. Multidimensional simulations of pair-instability supernovae

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    According to theoretical models, massive stars with masses within the 100-250 M⊙ range should explode as pair-instability supernovae (PISNe). Since the first stars of the Universe are believed to be very massive, these supernovae should play a significant role in the early stages of its history. But these stars represent the last unobserved population, owing to detection limits of current telescopes. In this work we analyze pair-instability supernovae explosions using various numerical codes. We evolve series of the configurations of oxygen cores to establish a range of masses and initial conditions where this type of explosion is possible. We also study the role of possible instabilities in the propagation of shockwaves during the last stage of the explosion. This investigation could help us to predict the observational properties of PISNe for future space and ground telescopes.

  4. 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.

  5. Supernova Explosions, Nucleosynthesis, and Cosmic Chemical Evolution

    NASA Astrophysics Data System (ADS)

    Truran, James W.

    2006-08-01

    The Universe emerged from its first three minutes with a composition consisting of hydrogen, deuterium, 3He, 4He, and 7Li. These isotopes constitute the primordial compositions of galaxies. Within galaxies, the synthesis of heavier elements from carbon through uranium is understood to occur during the normal evolution of stars and in supernova explosions of Types I and II. This history is written in the compositions of the stars and gas in our Milky Way Galaxy and other galaxies. The contributions both from massive stars (M>10 Msolar) and associated Type II supernovae and from Type Ia (thermonuclear) supernovae are particularly noteworthy. We review both the nuclear processes by which this occurs and the compositions of the stellar components of our Galaxy as a function of time which reflect these nucleosynthesis processes. We then discuss how such observations inform us of the nature of the earliest stellar populations and of the abundance history of the Cosmos.

  6. Gamma-producing radioactivities from supernovae

    NASA Astrophysics Data System (ADS)

    Woosley, S. E.; Pinto, Philip A.

    1988-09-01

    The production of three isotopes critical to astronomical γ-ray spectroscopy, 44Ti, 56Co, and 57Co, is briefly reviewed along with the information each contains. Emphasis is placed on SN 1987A, the only Type II supernova likely to be seen in γ-lines for decases to come. The 847 keV line from 56Co decay in this supernova should peak approximately 400 days after its explosion with a flux of about 1×10-3 cm-2 s-1. For comparison, the second best candidate, a Type Ia in the Virgo cluster (20 Mpc) gives a peak flux 100 times smaller than this 100 days after the explosion. 57Co decay in SN 1987A will also present a potentially detectable signal ~1×10-4 cm-2 s-1 in 1989 through 1991. 44Ti, chiefly from Type I supernovae, is a wild card, but may be responsible for the diffuse pair background.

  7. Exploring the Outer Solar System with the ESSENCE Supernova Survey

    SciTech Connect

    Becker, A.C.; Arraki, K.; Kaib, N.A.; Wood-Vasey, W.M.; Aguilera, C.; Blackman, J.W.; Blondin, S.; Challis, P.; Clocchiatti, A.; Covarrubias, R.; Damke, G.; Davis, T.M.; Filippenko, A.V.; Foley, R.J.; Garg, A.; Garnavich, P.M.; Hicken, M.; Jha, S.; Kirshner, R.P.; Krisciunas, K.; Leibundgut, B.; /Munich, Tech. U. /UC, Berkeley /NOAO, Tucson /Washington U., Seattle, Astron. Dept. /Fermilab /Harvard-Smithsonian Ctr. Astrophys. /Harvard U. /Chile U., Santiago /Ohio State U. /Cerro-Tololo InterAmerican Obs. /Harvard U. /Baltimore, Space Telescope Sci. /Johns Hopkins U. /Australian Natl. U., Canberra /Australian Natl. U., Canberra /Cerro-Tololo InterAmerican Obs. /Munich, Tech. U. /Harvard-Smithsonian Ctr. Astrophys. /Harvard U. /Cerro-Tololo InterAmerican Obs. /Texas A-M /Cerro-Tololo InterAmerican Obs.

    2011-11-10

    We report the discovery and orbital determination of 14 trans-Neptunian objects (TNOs) from the ESSENCE Supernova Survey difference imaging data set. Two additional objects discovered in a similar search of the SDSS-II Supernova Survey database were recovered in this effort. ESSENCE repeatedly observed fields far from the solar system ecliptic (-21{sup o} < {beta} < -5{sup o}), reaching limiting magnitudes per observation of I {approx} 23.1 and R {approx} 23.7. We examine several of the newly detected objects in detail, including 2003 UC{sub 414}, which orbits entirely between Uranus and Neptune and lies very close to a dynamical region that would make it stable for the lifetime of the solar system. 2003 SS{sub 422} and 2007 TA{sub 418} have high eccentricities and large perihelia, making them candidate members of an outer class of TNOs. We also report a new member of the 'extended' or 'detached' scattered disk, 2004 VN{sub 112}, and verify the stability of its orbit using numerical simulations. This object would have been visible to ESSENCE for only {approx}2% of its orbit, suggesting a vast number of similar objects across the sky. We emphasize that off-ecliptic surveys are optimal for uncovering the diversity of such objects, which in turn will constrain the history of gravitational influences that shaped our early solar system.

  8. Evolution of Pulsar Wind Nebulae inside Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Temim, T.

    2016-06-01

    Composite supernova remnants (SNRs) are those consisting of both a central pulsar that produces a wind of synchrotron-emitting relativistic particle and a supernova (SN) blast wave that expands into the surrounding interstellar medium (ISM). The evolution of the pulsar wind nebula (PWN) is coupled to the evolution of its host SNR and characterized by distinct stages, from the PWN's early expansion into the unshocked SN ejecta to its late-phase interaction with the SNR reverse shock. I will present an overview of the various evolutionary stages of composite SNRs and show how the signatures of the PWN/SNR interaction can reveal important information about the SNR and PWN dynamics, the SN progenitor and explosion asymmetry, the properties of the SN ejecta and newly-formed dust, particle injection and loss processes, and the eventual escape of energetic particles into the ISM. I will also discuss recent multi-wavelength observations and hydrodynamical modeling of evolved systems in which the PWN interacts with the SNR reverse shock and discuss their implications for our general understanding of the structure and evolution of composite SNRs.

  9. Afterglows of Mildly Relativistic Supernovae: Baryon Loaded Blastwaves

    NASA Astrophysics Data System (ADS)

    Chakraborti, Sayan; Ray, Alak

    2011-08-01

    Relativistic supernovae have been discovered until recently only through their association with long duration Gamma Ray Bursts (GRB). As the ejecta mass is negligible in comparison to the swept up mass, the blastwaves of such explosions are well described by the Blandford-McKee (in the ultra relativistic regime) and Sedov-Taylor (in the non-relativistic regime) solutions during their afterglows. However, the recent discovery of the relativistic supernova SN 2009bb, without a detected GRB, has indicated the possibility of highly baryon loaded mildly relativistic outflows which remains in nearly free expansion phase during the radio afterglow. In this work, we consider the dynamics and emission from a massive, relativistic shell, launched by a Central Engine Driven EXplosion (CEDEX), decelerating adiabatically due to its collision with the pre-explosion circumstellar wind profile of the progenitor. We show that this model explains the observed radio evolution of the prototypical SN 2009bb and demonstrate that SN 2009bb had a highly baryon loaded, mildly relativistic outflow.

  10. Deep Recurrent Neural Networks for Supernovae Classification

    NASA Astrophysics Data System (ADS)

    Charnock, Tom; Moss, Adam

    2017-03-01

    We apply deep recurrent neural networks, which are capable of learning complex sequential information, to classify supernovae (code available at https://github.com/adammoss/supernovae). The observational time and filter fluxes are used as inputs to the network, but since the inputs are agnostic, additional data such as host galaxy information can also be included. Using the Supernovae Photometric Classification Challenge (SPCC) data, we find that deep networks are capable of learning about light curves, however the performance of the network is highly sensitive to the amount of training data. For a training size of 50% of the representational SPCC data set (around 104 supernovae) we obtain a type-Ia versus non-type-Ia classification accuracy of 94.7%, an area under the Receiver Operating Characteristic curve AUC of 0.986 and an SPCC figure-of-merit F 1 = 0.64. When using only the data for the early-epoch challenge defined by the SPCC, we achieve a classification accuracy of 93.1%, AUC of 0.977, and F 1 = 0.58, results almost as good as with the whole light curve. By employing bidirectional neural networks, we can acquire impressive classification results between supernovae types I, II and III at an accuracy of 90.4% and AUC of 0.974. We also apply a pre-trained model to obtain classification probabilities as a function of time and show that it can give early indications of supernovae type. Our method is competitive with existing algorithms and has applications for future large-scale photometric surveys.

  11. Radio Supernovae in the Great Survey Era

    NASA Astrophysics Data System (ADS)

    Lien, Amy; Chakraborty, Nachiketa; Fields, Brian D.; Kemball, Athol

    2011-10-01

    Radio properties of supernova outbursts remain poorly understood despite longstanding campaigns following events discovered at other wavelengths. After ~30 years of observations, only ~50 supernovae have been detected at radio wavelengths, none of which are Type Ia. Even the most radio-loud events are ~104 fainter in the radio than in the optical; to date, such intrinsically dim objects have only been visible in the very local universe. The detection and study of radio supernovae (RSNe) will be fundamentally altered and dramatically improved as the next generation of radio telescopes comes online, including EVLA, ASKAP, and MeerKAT, and culminating in the Square Kilometer Array (SKA); the latter should be >~ 50 times more sensitive than present facilities. SKA can repeatedly scan large (gsim 1 deg2) areas of the sky, and thus will discover RSNe and other transient sources in a new, automatic, untargeted, and unbiased way. We estimate that SKA will be able to detect core-collapse RSNe out to redshift z ~ 5, with an all-redshift rate of ~620 events yr-1 deg-2, assuming a survey sensitivity of 50 nJy and radio light curves like those of SN 1993J. Hence, SKA should provide a complete core-collapse RSN sample that is sufficient for statistical studies of radio properties of core-collapse supernovae. EVLA should find ~160 events yr-1 deg-2 out to redshift z ~ 3, and other SKA precursors should have similar detection rates. We also provided recommendations of the survey strategy to maximize the RSN detections of SKA. This new radio core-collapse supernova sample will complement the detections from the optical searches, such as the LSST, and together provide crucial information on massive star evolution, supernova physics, and the circumstellar medium, out to high redshift. Additionally, SKA may yield the first radio Type Ia detection via follow-up of nearby events discovered at other wavelengths.

  12. First Results from the Nearby Supernova Factory

    NASA Astrophysics Data System (ADS)

    Scalzo, R. A.; Aldering, G.; Lee, B. C.; Loken, S.; Nugent, P.; Perlmutter, S.; Siegrist, J.; Thomas, R. C.; Wang, L.; Wood-Vasey, W. M.; Adam, G.; Bacon, R.; Bonnaud, C.; Capoani, L.; Dubet, D.; Henault, F.; Lantz, B.; Lemonnier, J.-P.; Pecontal, A.; Pecontal, E.; Blanc, N.; Boudoul, G.; Bongard, S.; Castera, A.; Copin, Y.; Gangler, E.; Smadja, G.; Kessler, R.; Antilogus, P.; Astier, P.; Berrelet, E.; Garavini, G.; Gilles, S.; Guevara, L.-A.; Imbault, D.; Juramy, C.; Pain, R.; Taillet, R.; Vincent, D.; Baltay, C.; Rabinovitz, D.; Snyder, J.; Nearby Supernova Factory

    2004-12-01

    The Nearby Supernova Factory (SNfactory) is a project to discover, and study in detail, approximately 300 type Ia supernovae (SNe Ia) in the redshift range 0.03 < z < 0.08. Supernova candidates are found by searching wide-field imaging data from the Near Earth Asteroid Tracking (NEAT) project at JPL, and from the Palomar Consortium (Yale/JPL/Caltech); this ultimately produces a sample of supernovae which is unbiased with respect to host galaxy type. Follow-up observations are performed with the Supernova Integral Field Spectrograph (SNIFS), a novel instrument installed on the University of Hawaii 2.2-meter telescope on Mauna Kea and commissioned in April 2004. By providing time series of flux-calibrated optical spectra taken every two to three nights for each supernova, the SNfactory data set will dramatically improve our understanding of the physics of SNe Ia and reduce the uncertainties in their use as cosmological standard candles. SNIFS observations have been conducted remotely from the United States and France since June 2004, with increasing emphasis on scripting and automation for greater efficiency. This poster reviews the current status of SNIFS and of the SNfactory project and presents its first results after the commissioning of SNIFS. Support for SNfactory is provided in the United States by the DOE Office of Science, the National Science Foundation through the High Performance Wireless Research and Education Network (HPWREN), the Kavli Institute for Cosmological Physics (KICP), and the Gordon and Betty Moore Foundation, and in France by the Centre National de la Recherche Scientifique (CNRS) through the Institut National de Physique Nucleaire et de Physique des Particules (IN2P3), the Institut National des Sciences de l'Univers (INSU) and the Programme National de Cosmologie (PNC).

  13. Tidally-Induced Thermonuclear Supernovae

    SciTech Connect

    Rosswog, S.; Ramirez-Ruiz, E.; Hix, William Raphael

    2009-01-01

    We discuss the results of 3D simulations of tidal disruptions of white dwarfs by moderate-mass black holes as they may exist in the cores of globular clusters or dwarf galaxies. Our simulations follow self-consistently the hydrodynamic and nuclear evolution from the initial parabolic orbit over the disruption to the build-up of an accretion disk around the black hole. For strong enough encounters (pericentre distances smaller than about 1/3 of the tidal radius) the tidal compression is reversed by a shock and finally results in a thermonuclear explosion. These explosions are not restricted to progenitor masses close to the Chandrasekhar limit, we find exploding examples throughout the whole white dwarf mass range. There is, however, a restriction on the masses of the involved black holes: black holes more massive than 2x105M{circle_dot} swallow a typical 0.6M{circle_dot} white dwarf before their tidal forces can overwhelm the star's selfgravity. Therefore, this mechanism is characteristic for black holes of moderate masses. The material that remains bound to the black hole settles into an accretion disk and produces an Xray flare close to the Eddington limit of L{sub Edd} {approx} 10{sup 41}erg/s (Mbh/1000M{circle_dot}), typically lasting for a few months. The combination of a peculiar thermonuclear supernova together with an X-ray flare thus whistle-blows the existence of such moderate-mass black holes. The next generation of wide field space-based instruments should be able to detect such events.

  14. Hard X Rays from Supernova 1993J

    DTIC Science & Technology

    1994-01-01

    extensively observed at many wavelengths and has yielded a wealth of new information about core - collapse supernovae (Wheeler & Filipenko 1994, and references...modelled as the result of a core collapse and subsequent explosion in a red supergiant that had lost almost all of its hydrogen-rich envelope (Nomoto...HARD X RAYS FROM SUPERNOVA 1993J M.D. Leising1, J.D. Kurfess2, D.D. Clayton1, D.A. Grabelsky3, J.E. Grove2, W.N. Johnson2, G.V. Jung4, R.L. Kinzer2

  15. CONDITIONS FOR SUPERNOVAE-DRIVEN GALACTIC WINDS

    SciTech Connect

    Nath, Biman B.; Shchekinov, Yuri E-mail: yus@sfedu.ru

    2013-11-01

    We point out that the commonly assumed condition for galactic outflows, that supernovae (SNe) heating is efficient in the central regions of starburst galaxies, suffers from invalid assumptions. We show that a large filling factor of hot (≥10{sup 6} K) gas is difficult to achieve through SNe heating, irrespective of the SN's initial gas temperature and density, its uniformity, or its clumpiness. We instead suggest that correlated supernovae from OB associations in molecular clouds in the central region can drive powerful outflows if the molecular surface density is >10{sup 3} M {sub ☉} pc{sup –2}.

  16. Nucleosynthesis in Massive Stars and Supernovae

    NASA Astrophysics Data System (ADS)

    Woosley, S. E.; Hoffman, R. D.; Timmes, F. X.; Weaver, T. A.; Thielemann, F.-K.

    1997-02-01

    We briefly summarize some recent work on nucleosynthesis in massive stars and supernovae. Here we explore: 1) the effect of including additional sources of nucleosynthesis besides massive stars into the mixture - especially classical novae and several varieties of Type Ia supernovae; 2) the sensitivity of the results to choices of theoretical nuclear reaction rates in the mass range 28 <= A <= 70; 3) nucleosynthesis above the iron group using a much larger reaction network; and 4) the sensitivity of these results to recent revisions in experimental reaction rates for isotopes A <= 28. For the recently revised rates, 17O is no longer a massive star product.

  17. 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.

  18. Neutrino scattering and flavor transformation in supernovae.

    PubMed

    Cherry, John F; Carlson, J; Friedland, Alexander; Fuller, George M; Vlasenko, Alexey

    2012-06-29

    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.

  19. The infrared emission from supernova condensates

    NASA Technical Reports Server (NTRS)

    Dwek, E.; Werner, M. W.

    1981-01-01

    The possibility of detecting grains formed in supernovae by observations of their emission in the infrared is examined. The basic processes determining the temperature and infrared radiation of grains in supernova environments are analyzed, and the results are used to estimate the infrared emission from the highly metal enriched fast moving knots in Cas A. The predicted fluxes lie within the reach of current ground-based facilities at 10 microns, and their emission should be detectable throughout the infrared band with cryogenic space telescopes.

  20. Progenitor's Signatures in Type Ia Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Chiotellis, A.; Kosenko, D.; Schure, K. M.; Vink, J.

    2013-01-01

    The remnants of Type Ia supernovae (SNe Ia) can provide important clues about their progenitor histories. We discuss two well-observed supernova remnants (SNRs) that are believed to have resulted from SNe Ia, and use various tools to shed light on the possible progenitor histories. We find that Kepler's SNR is consistent with a symbiotic binary progenitor consisting of a white dwarf and an AGB star. Our hydrosimulations can reproduce the observed kinematic and morphological properties. For Tycho's remnant we use the characteristics of the X-ray spectrum and kinematics to show that the ejecta has likely interacted with dense circumstellar gas.

  1. Gamma ray constraints on the galactic supernova rate

    NASA Technical Reports Server (NTRS)

    Hartmann, D.; The, L.-S.; Clayton, D. D.; Leising, M.; Mathews, G.; Woosley, S. E.

    1992-01-01

    Monte Carlo simulations of the expected gamma-ray signatures of galactic supernovae of all types are performed in order to estimate the significance of the lack of a gamma-ray signal due to supernovae occurring during the last millenium. Using recent estimates of nuclear yields, we determine galactic supernova rates consistent with the historic supernova record and the gamma-ray limits. Another objective of these calculations of galactic supernova histories is their application to surveys of diffuse galactic gamma-ray line emission.

  2. Detection of supernova neutrinos at spallation neutron sources

    NASA Astrophysics Data System (ADS)

    Huang, Ming-Yang; Guo, Xin-Heng; Young, Bing-Lin

    2016-07-01

    After considering supernova shock effects, Mikheyev-Smirnov-Wolfenstein effects, neutrino collective effects, and Earth matter effects, the detection of supernova neutrinos at the China Spallation Neutron Source is studied and the expected numbers of different flavor supernova neutrinos observed through various reaction channels are calculated with the neutrino energy spectra described by the Fermi-Dirac distribution and the “beta fit” distribution respectively. Furthermore, the numerical calculation method of supernova neutrino detection on Earth is applied to some other spallation neutron sources, and the total expected numbers of supernova neutrinos observed through different reactions channels are given. Supported by National Natural Science Foundation of China (11205185, 11175020, 11275025, 11575023)

  3. Reducing Zero-point Systematics in Dark Energy Supernova Experiments

    SciTech Connect

    Faccioli, Lorenzo; Kim, Alex G; Miquel, Ramon; Bernstein, Gary; Bonissent, Alain; Brown, Matthew; Carithers, William; Christiansen, Jodi; Connolly, Natalia; Deustua, Susana; Gerdes, David; Gladney, Larry; Kushner, Gary; Linder, Eric; McKee, Shawn; Mostek, Nick; Shukla, Hemant; Stebbins, Albert; Stoughton, Chris; Tucker, David

    2011-04-01

    We study the effect of filter zero-point uncertainties on future supernova dark energy missions. Fitting for calibration parameters using simultaneous analysis of all Type Ia supernova standard candles achieves a significant improvement over more traditional fit methods. This conclusion is robust under diverse experimental configurations (number of observed supernovae, maximum survey redshift, inclusion of additional systematics). This approach to supernova fitting considerably eases otherwise stringent mission cali- bration requirements. As an example we simulate a space-based mission based on the proposed JDEM satellite; however the method and conclusions are general and valid for any future supernova dark energy mission, ground or space-based.

  4. Signatures of pulsars in the light curves of newly formed supernova remnants

    NASA Astrophysics Data System (ADS)

    Kotera, K.; Phinney, E. S.; Olinto, A. V.

    2013-07-01

    We explore the effect of pulsars, in particular those born with millisecond periods, on their surrounding supernova ejectas. While they spin down, fast-spinning pulsars release their tremendous rotational energy in the form of a relativistic magnetized wind that can affect the dynamics and luminosity of the supernova. We estimate the thermal and non-thermal radiations expected from these specific objects, concentrating at times a few years after the onset of the explosion. We find that the bolometric light curves present a high luminosity plateau (that can reach 1043-1044 erg s-1) over a few years. An equally bright TeV gamma-ray emission, and a milder X-ray peak (of the order of 1040-1042 erg s-1) could also appear a few months to a few years after the explosion, as the pulsar wind nebula emerges, depending on the injection parameters. The observations of these signatures by following the emission of a large number of supernovae could have important implications for the understanding of core-collapse supernovae and reveal the nature of the remnant compact object.

  5. Type Ia supernova rate studies from the SDSS-II Supernova Study

    SciTech Connect

    Dilday, Benjamin

    2008-08-01

    The author presents new measurements of the type Ia SN rate from the SDSS-II Supernova Survey. The SDSS-II Supernova Survey was carried out during the Fall months (Sept.-Nov.) of 2005-2007 and discovered ~ 500 spectroscopically confirmed SNe Ia with densely sampled (once every ~ 4 days), multi-color light curves. Additionally, the SDSS-II Supernova Survey has discovered several hundred SNe Ia candidates with well-measured light curves, but without spectroscopic confirmation of type. This total, achieved in 9 months of observing, represents ~ 15-20% of the total SNe Ia discovered worldwide since 1885. The author describes some technical details of the SN Survey observations and SN search algorithms that contributed to the extremely high-yield of discovered SNe and that are important as context for the SDSS-II Supernova Survey SN Ia rate measurements.

  6. Simplified models for the evolution of supernova remnants including particle acceleration

    NASA Astrophysics Data System (ADS)

    Drury, L. O'C.; Markiewicz, W. J.; Voelk, H. J.

    1989-11-01

    A system of coupled ordinary differential equations is presented which models the dynamical evolution of a supernova remnant including the acceleration of the Galactic cosmic rays. In contrast to earlier two-fluid models the closure parameters needed for a hydrodynamic approximation of the cosmic ray 'gas' are not taken as prescribed constants but are estimated dynamically within the model. Diffusive coupling between the outer shock and the remnant interior is introduced; this is shown to be an important moderator of the acceleration as is heating of the thermal plasma by Alfven wave dissipation. For reasonable estimates of the suprathermal particle injection rate into the acceleration process, of the diffusion coefficient appropriate to the accelerated particles, of the coupling between interior and shock, and of wave heating, solutions are found which appear consistent both with observations of young remnants and the idea that the bulk of the Galactic cosmic rays are produced in supernova remnants.

  7. VLBA Reveals Dust-Enshrouded "Supernova Factory"

    NASA Astrophysics Data System (ADS)

    2003-05-01

    Using the National Science Foundation's Very Long Baseline Array (VLBA) radio telescope, astronomers have discovered a newly-exploded star, or supernova, hidden deep in a dust-enshrouded "supernova factory" in a galaxy some 140 million light-years from Earth. "This supernova is likely to be part of a group of super star clusters that produce one such stellar explosion every two years," said James Ulvestad, of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. "We're extremely excited by the tremendous insights into star formation and the early Universe that we may gain by observing this 'supernova factory,'" he added. Ulvestad worked with Susan Neff of NASA's Goddard Space Flight Center in Greenbelt, MD, and Stacy Teng, a graduate student at the University of Maryland, on the project. The scientists presented their findings to the American Astronomical Society's meeting in Nashville, TN. "These super star clusters likely are forming in much the same way that globular clusters formed in the early Universe, and thus provide us with a unique opportunity to learn about how some of the first stars formed billions of years ago," Neff said. The cluster is in an object called Arp 299, a pair of colliding galaxies, where regions of vigorous star formation have been found in past observations. Since 1990, four other supernova explosions have been seen optically in Arp 299. Observations with the NSF's Very Large Array (VLA) earlier showed a region near the nucleus of one of the colliding galaxies which had all the earmarks of prolific star formation. The astronomers focused on this region, prosaically dubbed "Source A," with the VLBA and the NSF's Robert C. Byrd Green Bank Telescope in 2002, and found four objects in this dusty cloud that are likely young supernova remnants. When they observed the region again in February 2003, there was a new, fifth, object located only 7 light-years from one of the previously detected objects. More observations on April 30-May

  8. The ASAS-SN Bright Supernova Catalog - II. 2015

    NASA Astrophysics Data System (ADS)

    Holoien, T. W.-S.; Brown, J. S.; Stanek, K. Z.; Kochanek, C. S.; Shappee, B. J.; Prieto, J. L.; Dong, Subo; Brimacombe, J.; Bishop, D. W.; Basu, U.; Beacom, J. F.; Bersier, D.; Chen, Ping; Danilet, A. B.; Falco, E.; Godoy-Rivera, D.; Goss, N.; Pojmanski, G.; Simonian, G. V.; Skowron, D. M.; Thompson, Todd A.; Woźniak, P. R.; Ávila, C. G.; Bock, G.; Carballo, J.-L. G.; Conseil, E.; Contreras, C.; Cruz, I.; Andújar, J. M. F.; Guo, Zhen; Hsiao, E. Y.; Kiyota, S.; Koff, R. A.; Krannich, G.; Madore, B. F.; Marples, P.; Masi, G.; Morrell, N.; Monard, L. A. G.; Munoz-Mateos, J. C.; Nicholls, B.; Nicolas, J.; Wagner, R. M.; Wiethoff, W. S.

    2017-01-01

    This manuscript presents information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) during 2015, its second full year of operations. The same information is presented for bright (mV ≤ 17), spectroscopically confirmed supernovae discovered by other sources in 2015. As with the first ASAS-SN bright supernova catalog, we also present redshifts and near-UV through IR magnitudes for all supernova host galaxies in both samples. Combined with our previous catalog, this work comprises a complete catalog of 455 supernovae from multiple professional and amateur sources, allowing for population studies that were previously impossible. This is the second of a series of yearly papers on bright supernovae and their hosts from the ASAS-SN team.

  9. Echoes from Ancient supernovae in the Large Magellanic Cloud

    SciTech Connect

    Rest, A; Suntzeff, N B; Olsen, K; Prieto, J L; Smith, R C; Welch, D L; Becker, A; Bergmann, M; Clocchiatti, A; Cook, K; Garg, A; Huber, M; Miknaitis, G; Minniti, D; Nikolaev, S; Stubbs, C

    2005-06-15

    In principle, historical supernovae could still be visible as scattered-light echoes even centuries later [1, 2]. Searches for surface brightness variations using photographic plates have not recovered any echoes in the regions of historical Galactic supernovae [3]. Using differenced images, our SuperMACHO collaboration has discovered three faint new variable surface brightness complexes with high apparent proper motion pointing back to well-defined positions in the Large Magellanic Cloud (LMC). These correspond to three of the six smallest (and likely youngest) supernova remnants believed to be due to thermonuclear (Type Ia) supernovae [4]. A lower limit to the age of these remnants and echoes is 200 years given the lack of any reported LMC supernovae until 1987. The discovery of historical supernova echoes in the LMC suggests that similar echoes for Galactic supernovae such as Tycho, Kepler, Cas A, or SN1006 could be visible using standard image differencing techniques.

  10. The ASAS-SN bright supernova catalogue - II. 2015

    NASA Astrophysics Data System (ADS)

    Holoien, T. W.-S.; Brown, J. S.; Stanek, K. Z.; Kochanek, C. S.; Shappee, B. J.; Prieto, J. L.; Dong, Subo; Brimacombe, J.; Bishop, D. W.; Basu, U.; Beacom, J. F.; Bersier, D.; Chen, Ping; Danilet, A. B.; Falco, E.; Godoy-Rivera, D.; Goss, N.; Pojmanski, G.; Simonian, G. V.; Skowron, D. M.; Thompson, Todd A.; Woźniak, P. R.; Ávila, C. G.; Bock, G.; Carballo, J.-L. G.; Conseil, E.; Contreras, C.; Cruz, I.; Andújar, J. M. F.; Guo, Zhen; Hsiao, E. Y.; Kiyota, S.; Koff, R. A.; Krannich, G.; Madore, B. F.; Marples, P.; Masi, G.; Morrell, N.; Monard, L. A. G.; Munoz-Mateos, J. C.; Nicholls, B.; Nicolas, J.; Wagner, R. M.; Wiethoff, W. S.

    2017-05-01

    This manuscript presents information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) during 2015, its second full year of operations. The same information is presented for bright (mV ≤ 17), spectroscopically confirmed supernovae discovered by other sources in 2015. As with the first ASAS-SN bright supernova catalogue, we also present redshifts and near-ultraviolet through infrared magnitudes for all supernova host galaxies in both samples. Combined with our previous catalogue, this work comprises a complete catalogue of 455 supernovae from multiple professional and amateur sources, allowing for population studies that were previously impossible. This is the second of a series of yearly papers on bright supernovae and their hosts from the ASAS-SN team.

  11. Light echoes from ancient supernovae in the Large Magellanic Cloud.

    PubMed

    Rest, Armin; Suntzeff, Nicholas B; Olsen, Knut; Prieto, Jose Luis; Smith, R Chris; Welch, Douglas L; Becker, Andrew; Bergmann, Marcel; Clocchiatti, Alejandro; Cook, Kem; Garg, Arti; Huber, Mark; Miknaitis, Gajus; Minniti, Dante; Nikolaev, Sergei; Stubbs, Christopher

    2005-12-22

    The light from historical supernovae could in principle still be visible as scattered-light echoes centuries after the explosion. The detection of light echoes could allow us to pinpoint the supernova event both in position and age and, most importantly, permit the acquisition of spectra to determine the 'type' of the supernova centuries after the direct light from the explosion first reached Earth. Although echoes have been discovered around some nearby extragalactic supernovae, targeted searches have not found any echoes in the regions of historical Galactic supernovae. Here we report three faint variable-surface-brightness complexes with high apparent proper motions pointing back to three of the six smallest (and probably youngest) previously catalogued supernova remnants in the Large Magellanic Cloud, which are believed to have been thermonuclear (type Ia) supernovae. Using the distance and apparent proper motions of these echo arcs, we estimate ages of 610 and 410 years for two of them.

  12. The supernova-gamma-ray burst-jet connection.

    PubMed

    Hjorth, Jens

    2013-06-13

    The observed association between supernovae and gamma-ray bursts represents a cornerstone in our understanding of the nature of gamma-ray bursts. The collapsar model provides a theoretical framework for this connection. A key element is the launch of a bipolar jet (seen as a gamma-ray burst). The resulting hot cocoon disrupts the star, whereas the (56)Ni produced gives rise to radioactive heating of the ejecta, seen as a supernova. In this discussion paper, I summarize the observational status of the supernova-gamma-ray burst connection in the context of the 'engine' picture of jet-driven supernovae and highlight SN 2012bz/GRB 120422A--with its luminous supernova but intermediate high-energy luminosity--as a possible transition object between low-luminosity and jet gamma-ray bursts. The jet channel for supernova explosions may provide new insights into supernova explosions in general.

  13. Generalized Spectral Correlations of Type Ia Supernovae from the Nearby Supernova Factory

    NASA Astrophysics Data System (ADS)

    Bailey, Stephen J.; Aldering, G.; Antilogus, P.; Aragon, C.; Baltay, C.; Bongard, S.; Buton, C.; Childress, M.; Chotard, N.; Copin, Y.; Gangler, E.; Loken, S.; Nugent, P.; Pain, R.; Pecontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigaudier, G.; Ripoche, P.; Runge, K.; Scalzo, R.; Smadja, G.; Tao, C.; Thomas, R.; Wu, C.

    2009-01-01

    We present a generalized correlation analysis of type Ia supernova spectra with a focus on spectral features that correlate with absolute magnitude in ways that are not already accounted for by color and lightcurve stretch. The results reveal new spectral correlations beyond those of the classic metrics of feature ratios (RSi, RSiS, RCa, EDCa). These new correlations could be used to improve the calibration of type Ia supernovae for cosmology measurements beyond what is possible with stretch and color alone.

  14. First Confirmed Supernova with the SkyMapper/Zooniverse Supernova Sighting Project

    NASA Astrophysics Data System (ADS)

    Tucker, B. E.; Moller, A.; Armstrong, P.; Mould, J.; Uddin, S.; Muthukrishna, D.; Panther, F. H.; Ruiter, A.; Ridden-Harper, R.; Schmidt, B. P.; Sommer, N. E.; Zhang, B.; Seitenzahl, I.; Baeten, E.; Craggs, A.

    2017-05-01

    We report the classification of a type Ia supernova, SN 2017dxh, discovered in the SkyMapper Transient (SMT) Survey (Scalzo et al. 2017) which utilizes the 268-Mpix camera on the SkyMapper 1.3-m telescope at Siding Spring Observatory near Coonabarabran, NSW, Australia (Keller et al., 2007, PASA, 24, 1). The object was photometrically discovered by citizen scientists as part of the Zooniverse Supernova Sighting Project.

  15. Testing supernova cosmology and progenitor effects with the SDSS-II supernova survey

    NASA Astrophysics Data System (ADS)

    D'Andrea, Christopher Brian

    The study of Type Ia Supernovae, the brilliant explosions of White Dwarfs, has ushered in a new era of observational Cosmology, one in which we have learned that the Universe is not only expanding, but accelerating in its expansion. For further advances to be made in the the field of Supernova Cosmology, future planned surveys will have to understand the systematic differences in these explosions. We use the full 3-year observational data from the Sloan Digital Sky Survey - II Supernova Survey to explore this field. First, we show that the environment a Type Ia Supernova occurs in biases the distance modulus at which current algorithms place them, resulting in a systematic error in derived cosmological parameters. We then investigate the ability Type II-P Supernovae to be used as complements to their brighter cousins as cosmological distance indicators, subject to different progenitor effects and thus different sources of uncertainty. Finally we quantify the diversity in Type II-P Supernovae themselves and the relationship the environment has on their observational properties, and the propensity this might have for biasing distance measurements with these objects.

  16. The ultraviolet properties of supernovae

    NASA Astrophysics Data System (ADS)

    Brown, Peter J.

    2009-09-01

    Ultraviolet (UV) observations of supernovae (SNe) probe an important wavelength region where hot temperatures, extinction, and metallicity have strong effects. In addition, they provide a comparison set against which to compare and better understand rest frame UV observations of high redshift SNe observed in the optical. UV observations, however, are rare due to the need for telescopes above the atmosphere and the difficulty in observing transient objects with space based observatories. Limited observations with space based observatories, primarily the International Ultraviolet Explorer and the Hubble Space Telescope, are reviewed, after which the Ultra-Violet/Optical Telescope (UVOT) on the Swift spacecraft is introduced. With Swift we have observed more SNe than all previous UV missions combined. Case studies of two individual SNe are first presented: SNe 2005am and 2005cs. SN 2005am is the first young SN observed with Swift, and the near-UV (uvw1: central wavelength ~ 2600 λ) light curve is consistent with the previous "template" derived from IUE and HST observations of SNe 1990N and 1992A. SN 2005cs is the first plateau-type II (IIP) with a well observed UV light curve. UVOT observations show a dramatic drop in the UV brightness and shift in the spectral energy distribution from blue to red caused by the dropping temperature and resulting line blanketing in the UV. These case studies demonstrate the information available from the UV data for individual SNe. A photometry method for proper accounting of coincidence loss, aperture corrections, and subtraction of the underlying galaxy is detailed. This method is then applied to a large sample of SNe observed with UVOT. We present 25 light curves and compare SNe by type and across types. The SNe Ia, with a few exceptions, are shown to have very similar light curves in the near UV, whereas, the three SNe Ib/c we have observed are very different. The SNe IIP all have rapidly fading UV light curves, though with

  17. Supernova hydrodynamicas experiments using the Nova laser

    SciTech Connect

    Remington, B.A.; Glendinning, S.G.; Estabrook, K.

    1997-07-01

    We are developing experiments using the Nova laser to investigate (1) compressible nonlinear hydrodynamic mixing relevant to the first few hours of the supernova (SN) explosion and (2) ejecta-ambient plasma interactions relevant to the early SN remnant phase. The experiments and astrophysical implications are discussed.

  18. MHD supernova jets: the missing link

    NASA Technical Reports Server (NTRS)

    Meier, David L.; Nakamura, Masanori

    2003-01-01

    We review recent progress in the theory of jet production, with particular emphasis on the possibility of 1) powerful jets being produced in the first few seconds after collapse of a supernova core and 2)those jets being responsible for the aysmmetric explosion itself.

  19. Multipole expansion method for supernova neutrino oscillations

    SciTech Connect

    Duan, Huaiyu; Shalgar, Shashank E-mail: shashankshalgar@unm.edu

    2014-10-01

    We demonstrate a multipole expansion method to calculate collective neutrino oscillations in supernovae using the neutrino bulb model. We show that it is much more efficient to solve multi-angle neutrino oscillations in multipole basis than in angle basis. The multipole expansion method also provides interesting insights into multi-angle calculations that were accomplished previously in angle basis.

  20. A comparative modeling of supernova 1993J

    NASA Technical Reports Server (NTRS)

    Blinnikov, Sergei; Eastman, Ron; Bartunov, Oleg; Popolitov, Vlad; Woosley, Stan

    1997-01-01

    The light curve of Supernova 1993J is calculated using two computational radiation transport approaches. The two approaches are represented by the computer codes STELLA and EDDINGTON. The emphasis is on the shock breakout and the photometry in the U, B and V bands during the first 120 days of the supernova. The STELLA model includes implicit hydrodynamics and is able to model early supernova evolution before the expansion is homologous. The STELLA model employs multi-group photonics and is able to follow the radiation as it decouples from the matter. The EDDINGTON code uses an algorithm for integrating the transport equation which assumes homologous expansion and uses a finer frequency resolution. The agreement between the two codes is considered to be satisfactory only in the case where compatible physical assumptions are made concerning the opacity. The assumptions are justified. The continuum spectrum for SN 1993J is predicted near the shock breakout to be superior to that predicted by standard single energy group hydrocodes. The uncertainties involved in current time dependent models of supernova light curves are discussed.

  1. Supernova tests of the timescape cosmology

    NASA Astrophysics Data System (ADS)

    Smale, Peter R.; Wiltshire, David L.

    2011-05-01

    The timescape cosmology has been proposed as a viable alternative to homogeneous cosmologies with dark energy. It realizes cosmic acceleration as an apparent effect that arises in calibrating average cosmological parameters in the presence of spatial curvature and gravitational energy gradients that grow large with the growth of inhomogeneities at late epochs. Recently Kwan, Francis and Lewis have claimed that the timescape model provides a relatively poor fit to the Union and Constitution supernovae compilations, as compared to the standard Λ cold dark matter (ΛCDM) model. We show this conclusion is a result of systematic issues in supernova light-curve fitting, and of failing to exclude data below the scale of statistical homogeneity, z≲ 0.033. Using all currently available supernova data sets (Gold07, Union, Constitution, MLCS17, MLCS31, SDSS-II, CSP, Union2), and making cuts at the statistical homogeneity scale, we show that data reduced by the SALT/SALT-II (Spectral Adaptive Light curve Template) fitters provide Bayesian evidence that favours the spatially flat ΛCDM model over the timescape model, whereas data reduced with MLCS2k2 fitters give Bayesian evidence which favours the timescape model over the ΛCDM model. We discuss the questions of extinction and reddening by dust, and of intrinsic colour variations in supernovae which do not correlate with the decay time, and the likely impact these systematics would have in a scenario consistent with the timescape model.

  2. The first seven UK supernova discoveries

    NASA Astrophysics Data System (ADS)

    Hewitt, N.

    2000-04-01

    This paper outlines the early history of amateur patrolling for supernovae from the United Kingdom, describes the methods employed by the patrollers, and provides a detailed description in the words of the observers of the first seven successful discoveries, made between 1996 October and 1998 April.

  3. 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.

  4. GRAVITATIONAL FIELD SHIELDING AND SUPERNOVA EXPLOSIONS

    SciTech Connect

    Zhang, T. X.

    2010-12-20

    A new mechanism for supernova explosions called gravitational field shielding is proposed, in accord with a five-dimensional fully covariant Kaluza-Klein theory with a scalar field that unifies the four-dimensional Einsteinian general relativity and Maxwellian electromagnetic theory. It is shown that a dense compact collapsing core of a star will suddenly turn off or completely shield its gravitational field when the core collapses to a critical density, which is inversely proportional to the square of mass of the core. As the core suddenly turns off its gravity, the extremely large pressure immediately stops the core collapse and pushes the mantle material of supernova moving outward. The work done by the pressure in the expansion can be the order of energy released in a supernova explosion. The gravity will resume and stop the core from a further expansion when the core density becomes less than the critical density. Therefore, the gravitational field shielding leads a supernova to impulsively explode and form a compact object such as a neutron star as a remnant. It works such that a compressed spring will shoot the oscillator out when the compressed force is suddenly removed.

  5. 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.

  6. Essential Ingredients in Core-collapse Supernovae

    DOE PAGES

    Hix, William Raphael; Lentz, E. J.; Endeve, Eirik; ...

    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

  7. 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.

  8. Supernovae and high density nuclear matter

    SciTech Connect

    Kahana, S.

    1986-01-01

    The role of the nuclear equation of state (EOS) in producing prompt supernova explosions is examined. Results of calculations of Baron, Cooperstein, and Kahana incorporating general relativity and a new high density EOS are presented, and the relevance of these calculations to laboratory experiments with heavy ions considered. 31 refs., 6 figs., 2 tabs.

  9. Classification of two LSQ Supernovae with WIFES

    NASA Astrophysics Data System (ADS)

    Hadjiyska, E.; Walker, E. S.; Rabinowitz, D.; Baltay, C.; Ellman, N.; McKinnon, R.; Feindt, U.; Nugent, P.; Childress, M.

    2013-05-01

    We report the classification of two LSQ supernovae (see Hadjiyska et al., ATel #3812) with Wide Field Spectrograph (WiFeS - Dopita et al., 2007, ApSS, 310, 255) on the ANU 2.3m telescope at Siding Spring Observatory, NSW Australia, currently at a 5700-9800A configuration, 1A resolution.

  10. Discovery of Five ASAS-SN Supernovae

    NASA Astrophysics Data System (ADS)

    Marples, P.; Fernandez, J. M.; Brimacombe, J.; Kiyota, S.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Nicholls, B.; Post, R. S.

    2017-07-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii and the 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered several new transient sources.

  11. Discovery of Six ASAS-SN Supernovae

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Stone, G.; Masi, G.; Fernandez, J. M.; Farfan, R. G.; Post, R. S.; Vallely, P.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Nicholls, B.

    2017-08-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii and the 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered several new transient sources.

  12. Discovery of Several ASAS-SN Supernovae

    NASA Astrophysics Data System (ADS)

    Brimacombe, J.; Conseil, E.; Stone, G.; Farfan, R. G.; Vallely, P.; Stanek, K. Z.; Brown, J. S.; Kochanek, C. S.; Shields, J.; Thompson, T. A.; Holoien, T. W.-S.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping

    2017-09-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, and the 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered several new transient sources.

  13. Supernova SN 2014C X-ray

    NASA Image and Video Library

    2017-01-24

    This image from NASA's Chandra X-ray Observatory shows spiral galaxy NGC 7331, center, in a three-color X-ray image. Red, green and blue colors are used for low, medium and high-energy X-rays, respectively. An unusual supernova called SN 2014C has been spotted in this galaxy. http://photojournal.jpl.nasa.gov/catalog/PIA21089

  14. Light Curves of Type IA Supernovae

    NASA Astrophysics Data System (ADS)

    Ford, C. H.; Herbst, W.; Balonek, T. J.; Benson, P. J.; Chromey, F. R.; Ratcliff, S. J.

    1992-05-01

    VRI light curves of five Type Ia supernovae (1991B, 1991N, 1991T, 1991bg, and 1992G) have been obtained with CCDs attached to small telescopes at northeastern sites. The data have been carefully transformed to the standard system using images obtained with the 0.9m telescope at KPNO. The first three supernovae have faded sufficiently that we can carefully correct for the galactic background and, in particular, its effect on the determination of fade rates at late times. SN 1991bg clearly demonstrates that there can be gross differences among Type Ia's in the shape (and maximum brightness) of their light curves (Filippenko et al., preprint). We investigate whether a single "template" can be devised which fits the R and I light curve shapes of the other four supernovae in our sample, and the degree to which each fits the V template of Leibundgut (1988, Ph.D. thesis, U. of Basel). The distinctive secondary maximum seen in I (about 18 days after primary maximum; Balonek et al., preprint) should be useful for distinguishing peculiar Type Ia's like SN 1991bg, and for establishing the time of maximum brightness for supernovae that were discovered up to three weeks afterwards. We thank the W. M. Keck Foundation for their support of the Keck Northeast Astronomy Consortium. This project is an outgrowth of that support.

  15. Einstein Observations of Galactic supernova remnants

    NASA Technical Reports Server (NTRS)

    Seward, Frederick D.

    1990-01-01

    This paper summarizes the observations of Galactic supernova remnants with the imaging detectors of the Einstein Observatory. X-ray surface brightness contours of 47 remnants are shown together with gray-scale pictures. Count rates for these remnants have been derived and are listed for the HRI, IPC, and MPC detectors.

  16. A comparative modeling of supernova 1993J

    NASA Technical Reports Server (NTRS)

    Blinnikov, Sergei; Eastman, Ron; Bartunov, Oleg; Popolitov, Vlad; Woosley, Stan

    1997-01-01

    The light curve of Supernova 1993J is calculated using two computational radiation transport approaches. The two approaches are represented by the computer codes STELLA and EDDINGTON. The emphasis is on the shock breakout and the photometry in the U, B and V bands during the first 120 days of the supernova. The STELLA model includes implicit hydrodynamics and is able to model early supernova evolution before the expansion is homologous. The STELLA model employs multi-group photonics and is able to follow the radiation as it decouples from the matter. The EDDINGTON code uses an algorithm for integrating the transport equation which assumes homologous expansion and uses a finer frequency resolution. The agreement between the two codes is considered to be satisfactory only in the case where compatible physical assumptions are made concerning the opacity. The assumptions are justified. The continuum spectrum for SN 1993J is predicted near the shock breakout to be superior to that predicted by standard single energy group hydrocodes. The uncertainties involved in current time dependent models of supernova light curves are discussed.

  17. 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.

  18. The Cygnus Loop: An Older Supernova Remnant.

    ERIC Educational Resources Information Center

    Straka, William

    1987-01-01

    Describes the Cygnus Loop, one of brightest and most easily studied of the older "remnant nebulae" of supernova outbursts. Discusses some of the historical events surrounding the discovery and measurement of the Cygnus Loop and makes some projections on its future. (TW)

  19. Spectroscopic classification of three supernovae candidates

    NASA Astrophysics Data System (ADS)

    Bose, Subhash; Dong, Subo; Sun, Fengwu; Prieto, Jose L.; Stanek, K. Z.

    2017-08-01

    We report optical spectroscopic observation of supernova candidates ASASSN-17kr (2017gas), ASASSN-17kz (2017gea) and Gaia17bzv (2017fzy) done on UT 2017-08-18, with DBSP mounted on the Hale 5m telescope at Palomar Observatory.

  20. The Cygnus Loop: An Older Supernova Remnant.

    ERIC Educational Resources Information Center

    Straka, William

    1987-01-01

    Describes the Cygnus Loop, one of brightest and most easily studied of the older "remnant nebulae" of supernova outbursts. Discusses some of the historical events surrounding the discovery and measurement of the Cygnus Loop and makes some projections on its future. (TW)

  1. Condensation of dust in supernova ejecta

    NASA Astrophysics Data System (ADS)

    Sarangi, A.; Cherchneff, I.

    Observations in the infrared and submm indicate the presence of molecules and dust in the ejecta of type II-P supernovae. The mass of dust formed in the ejecta of supernovae is still uncertain and highly debated: Infrared observations indicate smaller dust masses (10-5 to 10-3 M ) before 500 days post-explosion, compared to submm observations with Herschel revealing supernova remnants as large reservoirs of cool dust (10-2 to 0.7 M ). We study the ejecta of a typical type II-P supernova with a chemical kinetic approach considering a 15 M progenitor as a benchmark. The synthesis of molecules (e.g., CO, SiO, O2, AlO, SiS, FeS, SiC, SO) and small clusters (e.g., silicates, carbon, metal oxides, metallic clusters etc.) in the gas phase is considered. The clusters form gradually over time in different ejecta zones, small dust masses form in the first 600 days (˜ 10-4 M ), that gradually increase up to ˜ 0.1 M at 1500 days post-explosion. The small clusters condense to form dust grains in the gas phase. The size distributions of different dust components are derived from the study.

  2. Classification of 9 DES supernova by Magellan

    NASA Astrophysics Data System (ADS)

    Challis, P.; Kirshner, R.; Mandel, K.; Avelino, A.; Aldering, G.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Nugent, P.; Perlmutter, S.; Foley, R. J.; Pan, Y.-C.; Casas, R.; Castander, F. J.; Desai, S.; Paech, K.; Smith, R. C.; Schubnell, M.; Kessler, R.; Lasker, J.; Scolnic, D.; Brout, D. J.; Gladney, L.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.; Nichol, R.; Papadopoulos, A.; Childress, M.; D'Andrea, C.; Prajs, S.; Smith, M.; Sullivan, M.; Maartens, R.; Gupta, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.

    2016-09-01

    We report optical spectroscopy of 9 supernovae discovered by the Dark Energy Survey (ATel #4668). The spectra were obtained using LDSS-3C (covering 420-950nm) on the 6.5m Clay telescope at the Las Campanas Observatory.

  3. Ideal bandpasses for type Ia supernova cosmology

    SciTech Connect

    Davis, Tamara M.; Schmidt, Brian P.; Kim, Alex G.

    2005-10-24

    To use type Ia supernovae as standard candles for cosmologywe need accurate broadband magnitudes. In practice the observed magnitudemay differ from the ideal magnitude-redshift relationship either throughintrinsic inhomogeneities in the type Ia supernova population or throughobservational error. Here we investigate how we can choose filterbandpasses to reduce the error caused by both these effects. We find thatbandpasses with large integral fluxes and sloping wings are best able tominimise several sources of observational error, and are also leastsensitive to intrinsic differences in type Ia supernovae. The mostimportant feature of a complete filter set for type Ia supernovacosmology is that each bandpass be a redshifted copy of the first. Wedesign practical sets of redshifted bandpasses that are matched totypical high resistivity CCD and HgCdTe infra-red detector sensitivities.These are designed to minimise systematic error in well observedsupernovae, final designs for specific missions should also considersignal-to-noise requirements and observing strategy. In addition wecalculate how accurately filters need to be calibrated in order toachieve the required photometric accuracy of future supernova cosmologyexperiments such as the SuperNova-Acceleration-Probe (SNAP), which is onepossible realisation of the Joint Dark-Energy mission (JDEM). We considerthe effect of possible periodic miscalibrations that may arise from theconstruction of an interference filter.

  4. KAIT Independent Discovery of Four Recent Supernovae

    NASA Astrophysics Data System (ADS)

    Ross, T. Willie; Channa, Sanyum; Molloy, Jeffrey D.; Zheng, WeiKang; Filippenko, Alexei V.

    2016-03-01

    We report the independent discovery of four recent supernovae with the 0.76-m Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory. All observations were performed with the clear band (close to R) and calibrated to the USNO-B1 catalog.

  5. A 3D View of a Supernova Remnant

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2017-06-01

    Chandra X-ray observations to measure both the knots proper motion in the plane of the sky and their line-of-sight velocity. These two measurements were then combined to build a full 3D map of the motion of the ejecta.3D hydrodynamical simulations of Tycho, stopped at the current epoch. These show that both initially smooth (top) and initially clumpy (bottom) ejecta models are consistent with the current observations of the morphology and dynamics of Tychos ejecta. [Adapted from Williams et al. 2017]Symmetry and ClumpsWilliams and collaborators found that the knots have total velocities that range from 2400 to 6600 km/s. Unlike the forward shock of the supernova, Tychos ejecta display no asymmetries in their motion which suggests that the explosion itself was symmetric. The more likely explanation is a density gradient in the interstellar medium, which could slow the shock wave on one side of the remnant without yet affecting the motion of the clumps of ejecta.As a final exploration, the authors attempt to address the origin of Tychos clumpiness. The fact that some of Tychos ejecta knots precede its outer edge has raised the question of whether the ejecta started out clumpy, or if they began smooth and only clumped during expansion. Williams and collaborators matched the morphological and dynamical data to simulations, demonstrating that neither scenario can be ruled out at this time.This first 3D map of a Type Ia supernova represents an important step in our ability to understand these stellar explosions. The authors suggest that well be able to expand on this map in the future with additional observations from Chandra, as well as with new data from future X-ray observatories that will be able to detect fainter emission.CitationBrian J. Williams et al 2017 ApJ 842 28. doi:10.3847/1538-4357/aa7384

  6. High-Resolution Polarimetry of Supernova Remnant Kesteven 69

    NASA Astrophysics Data System (ADS)

    Wood, C. A.; Mufson, S. L.; Dickel, J. R.

    2008-06-01

    Reported here are high-resolution 6 cm measurements of the adolescent supernova remnant (SNR) Kesteven 69 made with the hybrid BnC configuration of the Very Large Array. Several three-field mosaics of the polarized and total intensity have been used to study this SNR. These investigations lead to a coherent picture of this region. The expanding shock defines an outer rim of high total intensity, suggesting the front is running into large dense clouds with random magnetic field directions. The SNR consists of predominantly of two types of regions, those with high total and relatively weak polarized emission and those with relatively weak total and strong polarized emission. This morphology can be generally explained by the number of clouds with organized magnetic field along the line of sight. Within this SNR there are regions where the field is varying from radial to tangential. As the SN shock encounters clouds, magnetic fields within clouds will strongly affect cloud dynamics.

  7. Supernovae and the origin of the solar system

    NASA Technical Reports Server (NTRS)

    Clayton, D. D.

    1979-01-01

    This review concentrates on recent ideas involving a relationship between the early solar system and supernova explosions. It summarizes briefly the data that has helped inspire those ideas. Because the true relationship is still unknown and generates controversy, the distinct ideas are introduced singly in the historical context of their origins, and the active sense of surprise and controversy is visible. Quotations from pivotal papers are used as part of the exposition. The subject involves equally the isotopic anomalies detected in meteorites and the dynamic events of galactic evolution, nucleosynthesis, and protosolar collapse. Whatever the correct situation is, new connections have been found between the origin of the elements and the formation of the solar system. The objective of this review is to enable interested space scientists to quickly identify the competing points of view and the experiments and theories that have led to them.

  8. No Collective Neutrino Flavor Conversions during the Supernova Accretion Phase

    SciTech Connect

    Chakraborty, Sovan; Mirizzi, Alessandro; Saviano, Ninetta; Tomas, Ricard; Fischer, Tobias

    2011-10-07

    We perform a dedicated study of the supernova (SN) neutrino flavor evolution during the accretion phase, using results from recent neutrino radiation hydrodynamics simulations. In contrast to what was expected in the presence of only neutrino-neutrino interactions, we find that the multiangle effects associated with the dense ordinary matter suppress collective oscillations. The matter suppression implies that neutrino oscillations will start outside the neutrino decoupling region and therefore will have a negligible impact on the neutrino heating and the explosion dynamics. Furthermore, the possible detection of the next galactic SN neutrino signal from the accretion phase, based on the usual Mikheyev-Smirnov-Wolfenstein effect in the SN mantle and Earth matter effects, can reveal the neutrino mass hierarchy in the case that the mixing angle {theta}{sub 13} is not very small.

  9. No collective neutrino flavor conversions during the supernova accretion phase.

    PubMed

    Chakraborty, Sovan; Fischer, Tobias; Mirizzi, Alessandro; Saviano, Ninetta; Tomàs, Ricard

    2011-10-07

    We perform a dedicated study of the supernova (SN) neutrino flavor evolution during the accretion phase, using results from recent neutrino radiation hydrodynamics simulations. In contrast to what was expected in the presence of only neutrino-neutrino interactions, we find that the multiangle effects associated with the dense ordinary matter suppress collective oscillations. The matter suppression implies that neutrino oscillations will start outside the neutrino decoupling region and therefore will have a negligible impact on the neutrino heating and the explosion dynamics. Furthermore, the possible detection of the next galactic SN neutrino signal from the accretion phase, based on the usual Mikheyev-Smirnov-Wolfenstein effect in the SN mantle and Earth matter effects, can reveal the neutrino mass hierarchy in the case that the mixing angle θ(13) is not very small.

  10. Inside the supernova: A powerful convective engine

    NASA Technical Reports Server (NTRS)

    Herant, Marc; Benz, Willy; Hix, W. Raphael; Fryer, Chris L.; Colgate, Stirling A.

    1994-01-01

    We present an extensive study of the inception of supernova explosions by following the evolution of the cores of two massive stars (15 and 25 Solar mass) in multidimension. Our calculations begin at the onset of core collapse and stop several hundred milliseconds after the bounce, at which time successful explosions of the appropriate magnitude have been obtained. Similar to the classical delayed explosion mechanism of Wilson, the explosion is powered by the heating of the envelope due to neutrinos emitted by the protoneutron star as it radiates the gravitational energy liberated by the collapse. However, as was shown by Herant, Benz, & Colgate, this heating generates strong convection outside the neutrinosphere, which we demonstrate to be critical to the explosion. By breaking a purely stratified hydrostatic equilibrium, convection moves the nascent supernova away from a delicate radiative equilibrium between neutrino emission and absorption, Thus, unlike what has been observed in one-dimensional calculations, explosions are rendered quite insensitive to the details of the physical input parameters such as neutrino cross sections or nuclear equation of state parameters. As a confirmation, our comparative one-dimensional calculations with identical microphysics, but in which convection cannot occur, lead to dramatic failures. Guided by our numerical results, we have developed a paradigm for the supernova explosion mechanism. We view a supernova as an open cycle thermodynamic engine in which a reservoir of low-entropy matter (the envelope) is thermally coupled and physically connected to a hot bath (the protoneutron star) by a neutrino flux, and by hydrodynamic instabilities. This paradigm does not invoke new or modified physics over previous treatments, but relies on compellingly straightforward thermodynamic arguments. It provides a robust and self-regulated explosion mechanism to power supernovae that is effective under a wide range of physical parameters.

  11. The Calan/Tololo Supernova Search

    NASA Astrophysics Data System (ADS)

    Maza, J.; Hamuy, M.; Suntzeff, N. B.; Phillips, M. M.; Aviles, R.

    1993-12-01

    In mid-1990, a group of staff members of CTIO and the University of Chile initiated a photographic search on the CTIO Curtis/Schmidt telescope that was designed to discover supernovae (SNe) near maximum light, with the aim to study the physical evolution of the supernova explosion, the environmental factors affecting the occurrence of supernovae, and the general usefulness of this class of objects as distance indicators. By monitoring a large number of fields (45 fields of 25 sq-deg each), the Calan/Tololo survey has yielded about 3 SNe per month to the limit of BMAX <= 19.5 which corresponds to a redshift range of (0.01la zla 0.1). To date, we have found 29 Ia SNe, 2 Type Ic, 15 Type II, and one peculiar SN. From spectroscopy and photometry of these SNe, we have verified that most events were caught before maximum or within a week of maximum light. Once discovered, all SNe were regularly observed on the CTIO 0.9m telescope in the BVRI system to produce light curves down to B ~ 22. The accurate magnitudes of these SNe, measured using psf fitting with DAOPHOT after the careful subtraction of the background galaxy, allow us to explore the range of variations in supernova light curve evolution. As examples, we present the light curves of the SNe 1990af (z=0.05) and 1992aq (z=0.101) which are two of the most distant SNe Ia ever observed through maximum light. A further example is the pair of Type Ia SNe (92bc and 92bo) at z=0.020 which have remarkably different light curve shapes: shapes which are apparently correlated to the intrinsic supernova luminosity at maximum light. This research has been supported by Grant 92/0312 from Fondo Nacional de Ciencias y Tecnología (FONDECYT-Chile).

  12. Scaling supernova hydrodynamics to the laboratory

    SciTech Connect

    Kane, J. O.

    1999-06-01

    Supernova (SN) 1987A focused attention on the critical role of hydrodynamic instabilities in the evolution of supernovae. To test the modeling of these instabilities, we are developing laboratory experiments of hydrodynamic mixing under conditions relevant to supernovae. Initial results were reported in J. Kane et al., Astrophys. J.478, L75 (1997) The Nova laser is used to shock two-layer targets, producing Richtmyer-Meshkov (RM) and Rayleigh-Taylor (RT) instabilities at the interfaces between the layers, analogous to instabilities seen at the interfaces of SN 1987A. Because the hydrodynamics in the laser experiments at intermediate times (3-40 ns) and in SN 1987A at intermediate times (5 s-104 s) are well described by the Euler equations, the hydrodynamics scale between the two regimes. The experiments are modeled using the hydrodynamics codes HYADES and CALE, and the supernova code PROMETHEUS, thus serving as a benchmark for PROMETHEUS. Results of the experiments and simulations are presented. Analysis of the spike and bubble velocities in the experiment using potential flow theory and a modified Ott thin shell theory is presented. A numerical study of 2D vs. 3D differences in instability growth at the O-He and He-H interface of SN 1987A, and the design for analogous laser experiments are presented. We discuss further work to incorporate more features of the SN in the experiments, including spherical geometry, multiple layers and density gradients. Past and ongoing work in laboratory and laser astrophysics is reviewed, including experimental work on supernova remnants (SNRs). A numerical study of RM instability in SNRs is presented.

  13. Inside the supernova: A powerful convective engine

    NASA Technical Reports Server (NTRS)

    Herant, Marc; Benz, Willy; Hix, W. Raphael; Fryer, Chris L.; Colgate, Stirling A.

    1994-01-01

    We present an extensive study of the inception of supernova explosions by following the evolution of the cores of two massive stars (15 and 25 Solar mass) in multidimension. Our calculations begin at the onset of core collapse and stop several hundred milliseconds after the bounce, at which time successful explosions of the appropriate magnitude have been obtained. Similar to the classical delayed explosion mechanism of Wilson, the explosion is powered by the heating of the envelope due to neutrinos emitted by the protoneutron star as it radiates the gravitational energy liberated by the collapse. However, as was shown by Herant, Benz, & Colgate, this heating generates strong convection outside the neutrinosphere, which we demonstrate to be critical to the explosion. By breaking a purely stratified hydrostatic equilibrium, convection moves the nascent supernova away from a delicate radiative equilibrium between neutrino emission and absorption, Thus, unlike what has been observed in one-dimensional calculations, explosions are rendered quite insensitive to the details of the physical input parameters such as neutrino cross sections or nuclear equation of state parameters. As a confirmation, our comparative one-dimensional calculations with identical microphysics, but in which convection cannot occur, lead to dramatic failures. Guided by our numerical results, we have developed a paradigm for the supernova explosion mechanism. We view a supernova as an open cycle thermodynamic engine in which a reservoir of low-entropy matter (the envelope) is thermally coupled and physically connected to a hot bath (the protoneutron star) by a neutrino flux, and by hydrodynamic instabilities. This paradigm does not invoke new or modified physics over previous treatments, but relies on compellingly straightforward thermodynamic arguments. It provides a robust and self-regulated explosion mechanism to power supernovae that is effective under a wide range of physical parameters.

  14. Inside the supernova: A powerful convective engine

    NASA Astrophysics Data System (ADS)

    Herant, Marc; Benz, Willy; Hix, W. Raphael; Fryer, Chris L.; Colgate, Stirling A.

    1994-11-01

    We present an extensive study of the inception of supernova explosions by following the evolution of the cores of two massive stars (15 and 25 Solar mass) in multidimension. Our calculations begin at the onset of core collapse and stop several hundred milliseconds after the bounce, at which time successful explosions of the appropriate magnitude have been obtained. Similar to the classical delayed explosion mechanism of Wilson, the explosion is powered by the heating of the envelope due to neutrinos emitted by the protoneutron star as it radiates the gravitational energy liberated by the collapse. However, as was shown by Herant, Benz, & Colgate, this heating generates strong convection outside the neutrinosphere, which we demonstrate to be critical to the explosion. By breaking a purely stratified hydrostatic equilibrium, convection moves the nascent supernova away from a delicate radiative equilibrium between neutrino emission and absorption, Thus, unlike what has been observed in one-dimensional calculations, explosions are rendered quite insensitive to the details of the physical input parameters such as neutrino cross sections or nuclear equation of state parameters. As a confirmation, our comparative one-dimensional calculations with identical microphysics, but in which convection cannot occur, lead to dramatic failures. Guided by our numerical results, we have developed a paradigm for the supernova explosion mechanism. We view a supernova as an open cycle thermodynamic engine in which a reservoir of low-entropy matter (the envelope) is thermally coupled and physically connected to a hot bath (the protoneutron star) by a neutrino flux, and by hydrodynamic instabilities. This paradigm does not invoke new or modified physics over previous treatments, but relies on compellingly straightforward thermodynamic arguments. It provides a robust and self-regulated explosion mechanism to power supernovae that is effective under a wide range of physical parameters.

  15. Scaling supernova hydrodynamics to the laboratory

    NASA Astrophysics Data System (ADS)

    Kane, J.; Arnett, D.; Remington, B. A.; Glendinning, S. G.; Bazan, G.; Drake, R. P.; Fryxell, B. A.; Teyssier, R.; Moore, K.

    1999-05-01

    Supernova (SN) 1987A focused attention on the critical role of hydrodynamic instabilities in the evolution of supernovae. To test the modeling of these instabilities, we are developing laboratory experiments of hydrodynamic mixing under conditions relevant to supernovae. Initial results were reported in J. Kane et al. [Astrophys. J. 478, L75 (1997) and B. A. Remington et al., Phys. Plasmas 4, 1994 (1997)]. The Nova laser is used to generate a 10-15 Mbar shock at the interface of a two-layer planar target, which triggers perturbation growth due to the Richtmyer-Meshkov instability, and to the Rayleigh-Taylor instability as the interface decelerates. This resembles the hydrodynamics of the He-H interface of a Type II supernova at intermediate times, up to a few ×103 s. The scaling of hydrodynamics on microscopic laser scales to the SN-size scales is presented. The experiment is modeled using the hydrodynamics codes HYADES [J. T. Larson and S. M. Lane, J. Quant. Spect. Rad. Trans. 51, 179 (1994)] and CALE [R. T. Barton, Numerical Astrophysics (Jones and Bartlett, Boston, 1985), pp. 482-497], and the supernova code PROMETHEUS [P. R. Woodward and P. Collela, J. Comp. Phys. 54, 115 (1984)]. Results of the experiments and simulations are presented. Analysis of the spike-and-bubble velocities using potential flow theory and Ott thin-shell theory is presented, as well as a study of 2D versus 3D differences in perturbation growth at the He-H interface of SN 1987A.

  16. Scaling supernova hydrodynamics to the laboratory

    SciTech Connect

    Kane, J.; Arnett, D.; Remington, B.A.; Glendinning, S.G.; Bazan, G.; Drake, R.P.; Fryxell, B.A.; Teyssier, R.

    1999-05-01

    Supernova (SN) 1987A focused attention on the critical role of hydrodynamic instabilities in the evolution of supernovae. To test the modeling of these instabilities, we are developing laboratory experiments of hydrodynamic mixing under conditions relevant to supernovae. Initial results were reported in J. Kane {ital et al.} [Astrophys. J. {bold 478}, L75 (1997) and B. A. Remington {ital et al.}, Phys. Plasmas {bold 4}, 1994 (1997)]. The Nova laser is used to generate a 10{endash}15 Mbar shock at the interface of a two-layer planar target, which triggers perturbation growth due to the Richtmyer{endash}Meshkov instability, and to the Rayleigh{endash}Taylor instability as the interface decelerates. This resembles the hydrodynamics of the He-H interface of a Type II supernova at intermediate times, up to a few {times}10{sup 3}s. The scaling of hydrodynamics on microscopic laser scales to the SN-size scales is presented. The experiment is modeled using the hydrodynamics codes HYADES [J. T. Larson and S. M. Lane, J. Quant. Spect. Rad. Trans. {bold 51}, 179 (1994)] and CALE [R. T. Barton, {ital Numerical Astrophysics} (Jones and Bartlett, Boston, 1985), pp. 482{endash}497], and the supernova code PROMETHEUS [P. R. Woodward and P. Collela, J. Comp. Phys. {bold 54}, 115 (1984)]. Results of the experiments and simulations are presented. Analysis of the spike-and-bubble velocities using potential flow theory and Ott thin-shell theory is presented, as well as a study of 2D versus 3D differences in perturbation growth at the He-H interface of SN 1987A.

  17. Supernova 1987A: 18 Months later

    SciTech Connect

    Schramm, D.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), /approximately/50 kpc away. The supernova star was a massive star of /approximately/15--20M. 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 physicists 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--4 /times/ 10/sup 53/ergs emitted in neutrinos and a temperature, T/sub /bar /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. A neutrino detection, such as that reported earlier in Mt. Blanc, would require more than the rest mass energy of a neutron star to be converted to neutrinos, if it were to have its origin in the LMC. Thus it is probably unrelated to the supernova. The anticipated frequency of collapse events in our Galaxy, will also be discussed with a rate as high as 1/10 year shown to be not unreasonable. 61 refs.

  18. Infrared Light Curves of Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Friedman, Andrew Samuel

    2012-05-01

    This thesis presents the CfAIR2 data set, which includes over 4000 near-Infrared (NIR) JHK8-band measurements of 104 Type Ia Supernovae (SN Ia) observed from 2005-2011 using PAIRITEL, the 1.3-m Peters Automated InfraRed Imaging TELescope at the Fred Lawrence Whipple Observatory (FLWO) on Mount Hopkins, Arizona. While the discovery of dark energy and most subsequent supernova cosmology has been performed using optical and Ultraviolet wavelength observations of SN Ia, a growing body of evidence suggests that NIR SN Ia observations will be crucial for future cosmological studies. Whereas SN Ia observed at optical wavelengths have been shown to be excellent standardizeable candles, using empirical correlations between luminosity, light curve shape, and color, the CfAIR2 data set strengthens the evidence that SN Ia at NIR wavelengths are essentially standard candles, even without correction for light-curve shape or for reddening. CfAIR2 was obtained as part of the CfA Supernova Program, an ongoing multi-wavelength follow-up effort at FLWO designed to observe high-quality, densely sampled light curves and spectra of hundreds of low-redshift SN Ia. CfAIR2 is the largest homogeneously observed and processed NIR data set of its kind to date, nearly tripling the number of individual JHK8-band observations and nearly doubling the set of SN Ia with published NIR light curves in the literature. Matched only by the recently published Carnegie Supernova Project sample, CfAIR2 complements the large and growing set of low-redshift optical and NIR SN Ia observations obtained by the CfA and other programs, making this data set a unique and particularly valuable local universe anchor for future supernova cosmology.

  19. 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.

  20. Moderately luminous Type II supernovae

    NASA Astrophysics Data System (ADS)

    Inserra, C.; Pastorello, A.; Turatto, M.; Pumo, M. L.; Benetti, S.; Cappellaro, E.; Botticella, M. T.; Bufano, F.; Elias-Rosa, N.; Harutyunyan, A.; Taubenberger, S.; Valenti, S.; Zampieri, L.

    2013-07-01

    Context. Core-collapse Supernovae (CC-SNe) descend from progenitors more massive than about 8 M⊙. Because of the young age of the progenitors, the ejecta may eventually interact with the circumstellar medium (CSM) via highly energetic processes detectable in the radio, X-ray, ultraviolet (UV) and, sometimes, in the optical domains. Aims: In this paper we present ultraviolet, optical and near infrared observations of five Type II SNe, namely SNe 2009dd, 2007pk, 2010aj, 1995ad, and 1996W. Together with few other SNe they form a group of moderately luminous Type II events. We investigate the photometric similarities and differences among these bright objects. We also attempt to characterise them by analysing the spectral evolutions, in order to find some traces of CSM-ejecta interaction. Methods: We collected photometry and spectroscopy with several telescopes in order to construct well-sampled light curves and spectral evolutions from the photospheric to the nebular phases. Both photometry and spectroscopy indicate a degree of heterogeneity in this sample. Modelling the data of SNe 2009dd, 2010aj and 1995ad allows us to constrain the explosion parameters and the properties of the progenitor stars. Results: The light curves have luminous peak magnitudes (-16.95 < MB < -18.70). The ejected masses of 56Ni for three SNe span a wide range of values (2.8 × 10-2 M⊙ < M(56Ni)< 1.4 × 10-1 M⊙), while for a fourth (SN 2010aj) we could determine a stringent upper limit (7 × 10-3 M⊙). Clues of interaction, such as the presence of high velocity (HV) features of the Balmer lines, are visible in the photospheric spectra of SNe 2009dd and 1996W. For SN 2007pk we observe a spectral transition from a Type IIn to a standard Type II SN. Modelling the observations of SNe 2009dd, 2010aj and 1995ad with radiation hydrodynamics codes, we infer kinetic plus thermal energies of about 0.2-0.5 foe, initial radii of 2-5 × 1013 cm and ejected masses of ~5.0-9.5 M⊙. Conclusions: These