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.

The role of fission in Supernovae r-process nucleosynthesis

NASA Astrophysics Data System (ADS)

Otsuki, Kaori; Kajino, Toshitaka; Sumiyoshi, Kosuke; Ohta, Masahisa; Mathews, J. Grant

2001-10-01

The r-process elements are presumed to be produced in an explosive environment with short timescale at high entropy, like type-II supernova explosion. Intensive flux of free neutrons are absorbed successively by seed elements to form the nuclear reaction flow on extremely unstable nuclei on the neutron rich side. It would probe our knowledge of the properties of nulei far from the beta stability. It is also important in astronomy since this process forms the long-lived nuclear chronometers Thorium and Uranium that are utilised dating the age of the Milky Way. In our previous work, we showed that the succesful r-process nucleosynthesis can occure above young, hot protoneutron star. Although these long-lived heavy elements are produced comparable amounts to observation in several supernova models which we constructed, fission and alpha-decay were not included there. The fission products could play an important role in setting actinide yields which are used as cosmochronometers. In this talk, we report an infulence of fission on actinide yields and on estimate of Galactic age as well. We also discuss fission yields at lighter elements (Z ~ 50).

Supernova explosions.

NASA Technical Reports Server (NTRS)

Cameron, A. G. W.

1971-01-01

The recent history of theoretical investigations of the supernova mechanism is considered, giving attention also to a number of nuclear physical problems which have yet to be solved in connection with the thermonuclear detonation. A variety of different processes of nucleo-synthesis are expected to occur in association with the supernova explosions. Aspects of the chemical evolution of the galaxy are discussed including the cosmic ray production of lithium, beryllium, and boron in the interstellar medium. Various hypotheses to account for the very large amount of light that comes from a supernova explosion are also examined.

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.

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.

The shock process and light-element production in supernova envelopes

NASA Technical Reports Server (NTRS)

Brown, Lawrence E.; Dearborn, David S.; Schramm, David N.; Larsen, Jon T.; Kurokawa, Shin

1991-01-01

Detailed hydrodynamic modeling of the passage of supernova shocks through the hydrogen enevlopes of blue and red progenitor stars was carried out to explore the sensitivity to model conditions of light element production (specifically Li7 and B-11) which was noted by Dearborn, Schramm, Steigman and Truran (1989) (DSST). It is found that, for stellar models with M is less than or approximately 100 M solar mass, current state of the art supernova shocks do not produce significant light element yields by hydrodynamic processes alone. The dependence of this conclusion on stellar models and on shock strengths is explored. Preliminary implications for Galactic evolution of lithium are discussed, and it is suspected that intermediate mass red giant stars may be the most consistent production site for lithium.

New Hubble Observations of Supernova 1987A Trace Shock Wave

NASA Image and Video Library

2017-12-08

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

Nucleosynthesis in Supernovae

NASA Astrophysics Data System (ADS)

Thielemann, Friedrich-Karl; Isern, Jordi; Perego, Albino; von Ballmoos, Peter

2018-04-01

We present the status and open problems of nucleosynthesis in supernova explosions of both types, responsible for the production of the intermediate mass, Fe-group and heavier elements (with the exception of the main s-process). Constraints from observations can be provided through individual supernovae (SNe) or their remnants (e.g. via spectra and gamma-rays of decaying unstable isotopes) and through surface abundances of stars which witness the composition of the interstellar gas at their formation. With a changing fraction of elements heavier than He in these stars (known as metallicity) the evolution of the nucleosynthesis in galaxies over time can be determined. A complementary way, related to gamma-rays from radioactive decays, is the observation of positrons released in β+-decays, as e.g. from ^{26}Al, ^{44}Ti, ^{56,57}Ni and possibly further isotopes of their decay chains (in competition with the production of e+e- pairs in acceleration shocks from SN remnants, pulsars, magnetars or even of particle physics origin). We discuss (a) the role of the core-collapse supernova explosion mechanism for the composition of intermediate mass, Fe-group (and heavier?) ejecta, (b) the transition from neutron stars to black holes as the final result of the collapse of massive stars, and the relation of the latter to supernovae, faint supernovae, and gamma-ray bursts/hypernovae, (c) Type Ia supernovae and their nucleosynthesis (e.g. addressing the ^{55}Mn puzzle), plus (d) further constraints from galactic evolution, γ-ray and positron observations. This is complemented by the role of rare magneto-rotational supernovae (related to magnetars) in comparison with the nucleosynthesis of compact binary mergers, especially with respect to forming the heaviest r-process elements in galactic evolution.

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.

Supernova Collisions with the Heliosphere

NASA Astrophysics Data System (ADS)

Fields, Brian D.; Athanassiadou, Themis; Johnson, Scott R.

2008-05-01

Nearby supernova explosions—within a few tens of pc of the solar system—have become a subject of intense scrutiny, due to the discovery of live undersea 60Fe from an event 2.8 Myr ago. A key open question concerns the delivery of supernova ejecta to the Earth, in particular penetration of the heliosphere by the supernova remnant (SNR). We present the first systematic numerical hydrodynamical study of the interaction between a supernova blast and the solar wind. Our simulations explore dynamic pressure regimes that are factors >=10 above those in other studies of the heliosphere under exotic conditions, for supernovae exploding at a range of distances through different interstellar environments, and interacting with solar winds of varying strengths. Our results are qualitatively consistent with the structure of the contemporary heliosphere modeled by previous work, but compressed to within the inner solar system. We demonstrate that key characteristics of the resulting heliospheric structure follow simple scaling laws that can be understood in terms of pressure-balance arguments, and which are in agreement with previous work. Our models show that a 10 pc supernova event, incident on a solar-wind outflow with the mean observed properties, compresses the heliopause to just beyond 1 AU. We also demonstrate scenarios where the supernova remnant compresses the heliopause to within 1 AU, in which cases supernova material will be directly deposited on Earth. Since 8 pc marks the nominal "kill radius" for severe biosphere damage, any extinction-level events should have left terrestrial deposits of supernova debris. We conclude with a brief discussion of the effect of our approximations and the impact of additional physics.

Interacting supernovae and supernova impostors

NASA Astrophysics Data System (ADS)

Tartaglia, Leonardo

2016-02-01

Massive stars are thought to end their lives with spectacular explosions triggered by the gravitational collapse of their cores. Interacting supernovae are generally attributed to supernova explosions occurring in dense circumstellar media, generated through mass-loss which characterisie the late phases of the life of their progenitors. In the last two decades, several observational evidences revealed that mass-loss in massive stars may be related to violent eruptions involving their outer layers, such as the luminous blue variables. Giant eruptions of extragalactic luminous blue variables, similar to that observed in Eta Car in the 19th century, are usually labelled 'SN impostors', since they mimic the behaviour of genuine SNe, but are not the final act of the life of the progenitor stars. The mechanisms producing these outbursts are still not understood, although the increasing number of observed cases triggered the efforts of the astronomical community to find possible theoretical interpretations. More recently, a number of observational evidences suggested that also lower-mass stars can experience pre-supernova outbursts, hence becoming supernova impostors. Even more interestingly, there is growing evidence of a connection among massive stars, their outbursts and interacting supernovae. All of this inspired this research, which has been focused in particular on the characterisation of supernova impostors and the observational criteria that may allow us to safely discriminate them from interacting supernovae. Moreover, the discovery of peculiar transients, motivated us to explore the lowest range of stellar masses that may experience violent outbursts. Finally, the quest for the link among massive stars, their giant eruptions and interacting supernovae, led us to study the interacting supernova LSQ13zm, which possibly exploded a very short time after an LBV-like major outburst.

Rayleigh-Taylor mixing in supernova experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swisher, N. C.; Abarzhi, S. I., E-mail: snezhana.abarzhi@gmail.com; Kuranz, C. C.

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 properlymore » 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.« less

Nucleosynthesis in Core-Collapse Supernovae

NASA Astrophysics Data System (ADS)

Stevenson, Taylor Shannon; Viktoria Ohstrom, Eva; Harris, James Austin; Hix, William R.

2018-01-01

The nucleosynthesis which occurs in core-collapse supernovae (CCSN) is one of the most important sources of elements in the universe. Elements from Oxygen through Iron come predominantly from supernovae, and contributions of heavier elements are also possible through processes like the weak r-process, the gamma process and the light element primary process. The composition of the ejecta depends on the mechanism of the explosion, thus simulations of high physical fidelity are needed to explore what elements and isotopes CCSN can contribute to Galactic Chemical Evolution. We will analyze the nucleosynthesis results from self-consistent CCSN simulations performed with CHIMERA, a multi-dimensional neutrino radiation-hydrodynamics code. Much of our understanding of CCSN nucleosynthesis comes from parameterized models, but unlike CHIMERA these fail to address essential physics, including turbulent flow/instability and neutrino-matter interaction. We will present nucleosynthesis predictions for the explosion of a 9.6 solar mass first generation star, relying both on results of the 160 species nuclear reaction network used in CHIMERA within this model and on post-processing with a more extensive network. The lowest mass iron core-collapse supernovae, like this model, are distinct from their more massive brethren, with their explosion mechanism and nucleosynthesis being more like electron capture supernovae resulting from Oxygen-Neon white dwarves. We will highlight the differences between the nucleosynthesis in this model and more massive supernovae. The inline 160 species network is a feature unique to CHIMERA, making this the most sophisticated model to date for a star of this type. We will discuss the need and mechanism to extrapolate the post-processing to times post-simulation and analyze the uncertainties this introduces for supernova nucleosynthesis. We will also compare the results from the inline 160 species network to the post-processing results to study further

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

constrain SN models. We also consider supernova ν-process nucleosynthesis to deduce constraints on the temperature of the various neutrino flavors. We study the effects of neutrino oscillations on the detected neutrino energy spectrum and also show that one might distinguish the equation of state (EoS) as well as the cause of the possible missing luminous supernovae from the detection of supernova relic neutrinos. We also analyze a possible enhanced contribution from failed supernovae leading to a black hole remnant as a solution to the supernova rate problem. We conclude that indeed it might be possible (though difficult) to measure the neutrino temperature, neutrino oscillations, and the EoS and confirm this source of missing luminous supernovae by the detection of the spectrum of relic neutrinos.

Solar r-process-constrained actinide production in neutrino-driven winds of supernovae

NASA Astrophysics Data System (ADS)

Goriely, S.; Janka, H.-Th.

2016-07-01

Long-lived radioactive nuclei play an important role as nucleo-cosmochronometers and as cosmic tracers of nucleosynthetic source activity. In particular, nuclei in the actinide region like thorium, uranium, and plutonium can testify to the enrichment of an environment by the still enigmatic astrophysical sources that are responsible for the production of neutron-rich nuclei by the rapid neutron-capture process (r-process). Supernovae and merging neutron-star (NS) or NS-black hole binaries are considered as most likely sources of the r-nuclei. But arguments in favour of one or the other or both are indirect and make use of assumptions; they are based on theoretical models with remaining simplifications and shortcomings. An unambiguous observational determination of a production event is still missing. In order to facilitate searches in this direction, e.g. by looking for radioactive tracers in stellar envelopes, the interstellar medium or terrestrial reservoirs, we provide improved theoretical estimates and corresponding uncertainty ranges for the actinide production (232Th, 235, 236, 238U, 237Np, 244Pu, and 247Cm) in neutrino-driven winds of core-collapse supernovae. Since state-of-the-art supernova models do not yield r-process viable conditions - but still lack, for example, the effects of strong magnetic fields - we base our investigation on a simple analytical, Newtonian, adiabatic and steady-state wind model and consider the superposition of a large number of contributing components, whose nucleosynthesis-relevant parameters (mass weight, entropy, expansion time-scale, and neutron excess) are constrained by the assumption that the integrated wind nucleosynthesis closely reproduces the Solar system distribution of r-process elements. We also test the influence of uncertain nuclear physics.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miknaitis, Gajus; Pignata, G.; Rest, A.

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 usingmore » 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).« less

Supernova relic neutrinos and the supernova rate problem: Analysis of uncertainties and detectability of ONeMg and failed supernovae

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2014-08-01

average neutrino temperature and constrain SN models. We also consider supernova ν-process nucleosynthesis to deduce constraints on the temperature of the various neutrino flavors. We study the effects of neutrino oscillations on the detected neutrino energy spectrum and also show that one might distinguish the equation of state (EoS) as well as the cause of the possible missing luminous supernovae from the detection of supernova relic neutrinos. We also analyze a possible enhanced contribution from failed supernovae leading to a black hole remnant as a solution to the supernova rate problem. We conclude that indeed it might be possible (though difficult) to measure the neutrino temperature, neutrino oscillations, and the EoS and confirm this source of missing luminous supernovae by the detection of the spectrum of relic neutrinos.« less

Supernova Dust at Sub-micrometer Scales

NASA Astrophysics Data System (ADS)

Nittler, Larry; Stroud, R. M.

2006-06-01

Meteorites contain nanometer to micrometer stardust grains, which formed in pre-solar generations of stars and exhibit large isotopic anomalies that reflect the nuclear processes that occurred in their individual parent stars [1]. Supernovae of Type II have been identified as the sources of much of the stardust, including grains of SiC, Si3N4, graphite and Mg2SiO4. Although, the isotopic compositions of many elements in these grains point unambiguously to supernova nucleosynthesis processes [2], the data require extensive and heterogeneous mixing of disparate nuclear burning zones. A recent study found that individual 200 nm TiC sub-grains within a 12 micron supernova graphite grain have uniform Ti isotopic composition but a range of O isotopic ratios [3]. New microanalysis techniques allow us to correlate the physical microstructures of supernova grains with isotopic composition, e.g., SiC and Si3N4, providing a sub-micron view of condensation processes in supernova ejecta. Results on two SiC grains indicate that micron-sized SiC grains from supernovae consist of assemblages of smaller crystallites with some evidence of radiation and/or shock processing. This is in strong contrast to SiC grains from AGB stars, which are typically single euhedral crystals [4]. The Si, C and N isotopic compositions of the grains are highly uniform, in contrast to the model of [5], which predicts strong isotopic gradients in supernova-derived SiC grains.This work is supported by NASA.[1] Clayton D. D. and Nittler L. R. (2004) ARAA, 42, 39-78.[2] Nittler L. R., et al. (1996) ApJ, 462, L31-34.[3] Stadermann F. J., et al. (2005) GCA, 69, 177-188.[4] Daulton T. L., et al. (2002) Science, 296, 1852-1855.[5] Deneault E. A.-N., et al. (2003) ApJ, 594, 312-325.

Nucleosynthesis during a Thermonuclear Supernova Explosion

NASA Astrophysics Data System (ADS)

Panov, I. V.; Glazyrin, S. I.; Röpke, F. K.; Blinnikov, S. I.

2018-05-01

Supernovae are such bright objects that they can be observed even at high redshifts. Some types of such events, for example, type Ia (thermonuclear), have peculiarities of the light curve, which allows them to be used for cosmological applications. The light curve is determined by the details of the explosion dynamics and nucleosynthesis: in particular, it depends on the amount of iron-peak elements produced during the explosion. We discuss the burning processes in such objects and the peculiarities of turbulence simulations in them, which is needed for a proper hydrodynamic description of the explosion process. A direct nucleosynthesis calculation is performed for the temperature and density profiles derived in the available 3D hydrodynamic explosion simulations. We show that in the supernova progenitor model considered the calculated abundances of elements from carbon to iron-peak elements are in good agreement both with the observations and with the calculations of other authors. At the same time, no r-elements are produced even at the maximum neutron excess for this model ( Y e 0.47) due to the slow evolution of the density and temperature.

Sites that Can Produce Left-handed Amino Acids in the Supernova Neutrino Amino Acid Processing Model

NASA Astrophysics Data System (ADS)

Boyd, Richard N.; Famiano, Michael A.; Onaka, Takashi; Kajino, Toshitaka

2018-03-01

The Supernova Neutrino Amino Acid Processing model, which uses electron anti-neutrinos and the magnetic field from a source object such as a supernova to selectively destroy one amino acid chirality, is studied for possible sites that would produce meteoroids with partially left-handed amino acids. Several sites appear to provide the requisite magnetic field intensities and electron anti-neutrino fluxes. These results have obvious implications for the origin of life on Earth.

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.

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.

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.

Pulsar Wind Bubble Blowout from a Supernova

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blondin, John M.; Chevalier, Roger A., E-mail: blondin@ncsu.edu

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 ismore » 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 10{sup 51} 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.« less

Bolometric Luminosities of Peculiar Type II-P Supernovae: Observational and Theoretical Approaches

NASA Astrophysics Data System (ADS)

Lusk, Jeremy Alexander

2018-01-01

In the three decades since the explosion of SN 1987A, only a handful of other supernovae have been detected which are also thought to originate from blue supergiant progenitors. In this study, we use the five best observed of these supernovae (SNe 1998A, 2000cb, 2006V, 2006au, and 2009E) to examine the bolometric properties of the class through observations and theoretical models. Several techniques for taking photometric observations and inferring bolometric luminosities have been used in the literature. Our newly-improved python package SuperBoL implements many of these techniques. The challenge remains that the true bolometric luminosity of the supernova cannot be directly observed. We must turn to theoretical models in order to examine the validity of the different observationally-based techniques. In this work, we make use of the NLTE generalized atmosphere code PHOENIX to produce synthetic spectra of known luminosity which match the observed supernova spectra. Synthetic photometry of these models is then used as input to SuperBoL to test the different observationally-based bolometric luminosity techniques.

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)

Supernova Fallback onto Magnetars and Propeller-powered Supernovae

NASA Astrophysics Data System (ADS)

Piro, Anthony L.; Ott, Christian D.

2011-08-01

We explore fallback accretion onto newly born magnetars during the supernova of massive stars. Strong magnetic fields (~1015 G) and short spin periods (~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 <~ 5 × 1014 G, accretion causes the magnetar to spin sufficiently rapidly to deform triaxially and produces gravitational waves, but only for ≈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 ≈0.3 M sun, so we expect magnetars born within these types of environments to be more massive than the 1.4 M sun typically associated with neutron stars. The propeller mechanism converts the ~1052 erg of spin energy in the magnetar into the kinetic energy of an outflow, which shock heats the outgoing supernova ejecta during the first ~10-30 s. For a small ~5 M sun hydrogen-poor envelope, this energy creates a brighter, faster evolving supernova with high ejecta velocities ~(1-3) × 104 km s-1 and may appear as a broad-lined Type Ib/c supernova. For a large >~ 10 M sun hydrogen-rich envelope, the result is a bright Type IIP supernova with a plateau luminosity of >~ 1043 erg s-1 lasting for a timescale of ~60-80 days.

Dust in Supernovae and Supernova Remnants I: Formation Scenarios

NASA Astrophysics Data System (ADS)

Sarangi, A.; Matsuura, M.; Micelotta, E. R.

2018-04-01

Supernovae are considered as prime sources of dust in space. Observations of local supernovae over the past couple of decades have detected the presence of dust in supernova ejecta. The reddening of the high redshift quasars also indicate the presence of large masses of dust in early galaxies. Considering the top heavy IMF in the early galaxies, supernovae are assumed to be the major contributor to these large amounts of dust. However, the composition and morphology of dust grains formed in a supernova ejecta is yet to be understood with clarity. Moreover, the dust masses inferred from observations in mid-infrared and submillimeter wavelength regimes differ by two orders of magnitude or more. Therefore, the mechanism responsible for the synthesis of molecules and dust in such environments plays a crucial role in studying the evolution of cosmic dust in galaxies. This review summarises our current knowledge of dust formation in supernova ejecta and tries to quantify the role of supernovae as dust producers in a galaxy.

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.

Searching for Dark Energy with the Whole World's Supernova Dataset |

Science.gov Websites

room at the top for dynamical theories. One of the six new distant supernovae included in the Supernova ) with follow-up observations by the Hubble Space Telescope (bottom). Two views of one of the six new refinements compares ground-based infrared observations (in this case by Japan's Subaru Telescope on Mauna Kea

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).

Evidence for supernova injection into the solar nebula and the decoupling of r-process nucleosynthesis

PubMed Central

Brennecka, Gregory A.; Borg, Lars E.; Wadhwa, Meenakshi

2013-01-01

The isotopic composition of our Solar System reflects the blending of materials derived from numerous past nucleosynthetic events, each characterized by a distinct isotopic signature. We show that the isotopic compositions of elements spanning a large mass range in the earliest formed solids in our Solar System, calcium–aluminum-rich inclusions (CAIs), are uniform, and yet distinct from the average Solar System composition. Relative to younger objects in the Solar System, CAIs contain positive r-process anomalies in isotopes A < 140 and negative r-process anomalies in isotopes A > 140. This fundamental difference in the isotopic character of CAIs around mass 140 necessitates (i) the existence of multiple sources for r-process nucleosynthesis and (ii) the injection of supernova material into a reservoir untapped by CAIs. A scenario of late supernova injection into the protoplanetary disk is consistent with formation of our Solar System in an active star-forming region of the galaxy. PMID:24101483

Evidence for supernova injection into the solar nebula and the decoupling of r-process nucleosynthesis.

PubMed

Brennecka, Gregory A; Borg, Lars E; Wadhwa, Meenakshi

2013-10-22

The isotopic composition of our Solar System reflects the blending of materials derived from numerous past nucleosynthetic events, each characterized by a distinct isotopic signature. We show that the isotopic compositions of elements spanning a large mass range in the earliest formed solids in our Solar System, calcium-aluminum-rich inclusions (CAIs), are uniform, and yet distinct from the average Solar System composition. Relative to younger objects in the Solar System, CAIs contain positive r-process anomalies in isotopes A < 140 and negative r-process anomalies in isotopes A > 140. This fundamental difference in the isotopic character of CAIs around mass 140 necessitates (i) the existence of multiple sources for r-process nucleosynthesis and (ii) the injection of supernova material into a reservoir untapped by CAIs. A scenario of late supernova injection into the protoplanetary disk is consistent with formation of our Solar System in an active star-forming region of the galaxy.

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.

SUPERNOVA FALLBACK ONTO MAGNETARS AND PROPELLER-POWERED SUPERNOVAE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piro, Anthony L.; Ott, Christian D., E-mail: piro@caltech.edu, 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 amore » 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.« less

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

The Perth Automated Supernova Search

NASA Astrophysics Data System (ADS)

Williams, A. J.

1997-12-01

An automated search for supernovae in late spiral galaxies has been established at Perth Observatory, Western Australia. This automated search uses three low-cost PC-clone computers, a liquid nitrogen cooled CCD camera built locally, and a 61-cm telescope automated for the search. The images are all analysed automatically in real-time by routines in Perth Vista, the image processing system ported to the PC architecture for the search system. The telescope control software written for the project, Teljoy, maintains open-loop position accuracy better than 30" of arc after hundreds of jumps over an entire night. Total capital cost to establish and run this supernova search over the seven years of development and operation was around US$30,000. To date, the system has discovered a total of 6 confirmed supernovae, made an independent detection of a seventh, and detected one unconfirmed event assumed to be a supernova. The various software and hardware components of the search system are described in detail, the analysis of the first three years of data is discussed, and results presented. We find a Type Ib/c rate of 0.43 +/- 0.43 SNu, and a Type IIP rate of 0.86 +/- 0.49 SNu, where SNu are 'supernova units', expressed in supernovae per 10^10 solar blue luminosity galaxy per century. These values are for a Hubble constant of 75 km/s per Mpc, and scale as (H0/75)^2. The small number of discoveries has left large statistical uncertainties, but our strategy of frequent observations has reduced systematic errors - altering detection threshold or peak supernova luminosity by +/- 0.5 mag changes estimated rates by only around 20%. Similarly, adoption of different light curve templates for Type Ia and Type IIP supernovae has a minimal effect on the final statistics (2% and 4% change, respectively).

A new supernova light curve modeling program

NASA Astrophysics Data System (ADS)

Jäger, Zoltán; Nagy, Andrea P.; Biro, Barna I.; Vinkó, József

2017-12-01

Supernovae are extremely energetic explosions that highlight the violent deaths of various types of stars. Studying such cosmic explosions may be important because of several reasons. Supernovae play a key role in cosmic nucleosynthesis processes, and they are also the anchors of methods of measuring extragalactic distances. Several exotic physical processes take place in the expanding ejecta produced by the explosion. We have developed a fast and simple semi-analytical code to model the the light curve of core collapse supernovae. This allows the determination of their most important basic physical parameters, like the the radius of the progenitor star, the mass of the ejected envelope, the mass of the radioactive nickel synthesized during the explosion, among others.

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.

Supernova Cosmology Project

Science.gov Websites

Supernova The Supernova Cosmology Project The image above and the movie clips ( QuickTime, or MPEG), show Centaurus A galaxy. The image on the left shows how a supernova appears as it brightens and fades brightness is, from the image at left. The bottom right graph shows how the spectrum of the supernova changes

Highlight on Supernova Early Warning at Daya Bay

NASA Astrophysics Data System (ADS)

Wei, Hanyu

Providing an early warning of supernova burst neutrinos is of importance in studying both supernova dynamics and neutrino physics. The Daya Bay Reactor Neutrino Experiment, with a unique feature of multiple liquid scintillator detectors, is sensitive to the full energy spectrum of supernova burst electron-antineutrinos. By utilizing 8 Antineutrino Detectors (ADs) in the three different experimental halls which are about 1 km's apart from each other, we obtain a powerful and prompt rejection of muon spallation background than single-detector experiments with the same target volume. A dedicated trigger system embedded in the data acquisition system has been installed to allow the detection of a coincidence of neutrino signals of all ADs via an inverse beta-decay (IBD) within a 10-second window, thus providing a robust early warning of a supernova occurrence within the Milky Way. An 8-AD associated supernova trigger table has been established theoretically to tabulate the 8-AD event counts' coincidence vs. the trigger rate. As a result, a golden trigger threshold, i.e. with a false alarm rate < 1/3-months, can be set as low as 6 candidates among the 8 detectors, leading to a 100% detection probability for all 1987A type supernova bursts at the distance to the Milky Way center and a 96% detection probability to those at the edge of the Milky Way.

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

Barium from a mini r-process in supernovae

NASA Technical Reports Server (NTRS)

Heymann, D.

1983-01-01

McCulloch and Wasserburg (1978) have reported nonlinear isotopic anomalies in barium for two Ca-Al-rich inclusions of the Allende carbonaceous chondrite, known as EK-1-4-1 and C-1. In an attempt to account for these anomalies, it has been proposed that Ba from an r-process of nucleosynthesis, containing Ba-135 and Ba-137, was injected into the primeval color system but was not totally homogenized. Questions arise in connection with the relations of Xe isotopes in carbonaceous chondrites. This has prompted Heymann and Dziczkaniec (1979, 1980, 1981) to study the formation of r-Xe, r-Kr, and r-Te by the mini r-process which is thought to occur in the O, Ne-rich shells of Type II supernovae. Lee et al. (1979) have studied the formation of r-Ba, r-Nd, and r-Sm by the same process. Certain differences regarding the approaches used by Lee et al. and by Heymann and Dziczkaniec make it necessary to restudy the work of Lee et al. Attention is given to the survival probabilities of nuclear species of interest, taking into accounts the elements Cs, Ba, I, and Xe.

An explanation of the formation of the peculiar periphery of Tycho's supernova remnant

NASA Astrophysics Data System (ADS)

Fang, Jun; Yu, Huan; Zhang, Li

2018-02-01

Tycho's supernova remnant (SNR) has a periphery that clearly deviates from a spherical shape, based on X-ray and radio observations. The forward shock from the south-east to the north of the remnant has a deformed outline with a depression in the east, although in the west it is generally round and smooth. Moreover, at some locations in the shell, the supernova ejecta is located close to the forward shock, resulting in protrusions. Using 3D hydrodynamical simulations, we studied the dynamical evolution of the supernova ejecta in an inhomogeneous medium and the formation process of the profile of the forward shock. In order to reproduce the peculiar periphery of the remnant, we propose a model in which the supernova ejecta has evolved in a cavity blown by a latitude-dependent outflow. The results indicate that the depression to the east and the protrusion to the south-east on the observed periphery of the remnant can be generally reproduced if we assume a wind bubble driven by an anisotropic wind with a mass-loss rate of ˜10-7 M⊙ yr-1, a pole velocity of ˜100 km s-1, a duration of ˜105 yr prior to the supernova explosion, and a spatial velocity of ˜30 km s-1 of the progenitor with respect to the circumstellar medium. In conclusion, an explanation of the peculiar shape of the periphery of Tycho's SNR is that the supernova ejecta evolved in the cavity driven by a latitude-dependent wind.

Supernovae-generated high-velocity compact clouds

NASA Astrophysics Data System (ADS)

Yalinewich, A.; Beniamini, P.

2018-05-01

Context. A previous study claimed the discovery of an intermediate-mass black hole (IMBH). This hypothetical black hole was invoked in order to explain the high-velocity dispersion in one of several dense molecular clouds near the Galactic center. The same study considered the possibility that this cloud was due to a supernova explosion, but disqualified this scenario because no X-rays were detected. Aims: We here check whether a supernova explosion could have produced that cloud, and whether this explanation is more likely than an IMBH. More specifically, we wish to determine whether a supernova inside a dense molecular cloud would emit in the X-rays. Methods: We have approached this problem from two different directions. First, we performed an analytic calculation to determine the cooling rate by thermal bremsstrahlung and compared this time to the lifetime of the cloud. Second, we estimated the creation rate of these dense clouds in the central molecular zone (CMZ) region near the Galactic center, where they were observed. Based on this rate, we can place lower bounds on the total mass of IMBHs and clouds and compare this to the masses of the components of the CMZ. Results: We find that the cooling time of the supernova remnant inside a molecular cloud is shorter than its dynamical time. This means that the temperature in such a remnant would be much lower than that of a typical supernova remnant. At such a low temperature, the remnant is not expected to emit in the X-rays. We also find that to explain the rate at which such dense clouds are created requires fine-tuning the number of IMBHs. Conclusions: We find the supernova model to be a more likely explanation for the formation of high-velocity compact clouds than an IMBH.

Supernova neutrinos and explosive nucleosynthesis

NASA Astrophysics Data System (ADS)

Kajino, T.; Aoki, W.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Mathews, G. J.; Nakamura, K.; Shibagaki, S.; Suzuki, T.

2014-05-01

Core-collapse supernovae eject huge amount of flux of energetic neutrinos. We studied the explosive nucleosyn-thesis in supernovae and found that several isotopes 7Li, 11B, 92Nb, 138La and 180Ta 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 θ13, simultaneously. There is recent evidence that SiC X grains from the Murchison meteorite may contain supernova-produced light elements 11B and 7Li encapsulated in the presolar grains. Combining the recent experimental constraints on θ13, 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.

Three Great Eyes on Kepler's Supernova Remnant

NASA Technical Reports Server (NTRS)

2004-01-01

<p/> [figure removed for brevity, see original site] Composite <p/> [figure removed for brevity, see original site] [figure removed for brevity, see original site] Chandra X-Ray Data (blue) Chandra X-Ray Data (green)Hubble Telescope (visible-light)Spitzer Telescope (infrared) <p/> NASA's three Great Observatories -- the Hubble Space Telescope, the Spitzer Space Telescope, and the Chandra X-ray Observatory -- joined forces to probe the expanding remains of a supernova, called Kepler's supernova remnant, first seen 400 years ago by sky watchers, including astronomer Johannes Kepler. <p/> The combined image unveils a bubble-shaped shroud of gas and dust that is 14 light-years wide and is expanding at 4 million miles per hour (2,000 kilometers per second). Observations from each telescope highlight distinct features of the supernova remnant, a fast-moving shell of iron-rich material from the exploded star, surrounded by an expanding shock wave that is sweeping up interstellar gas and dust. <p/> Each color in this image represents a different region of the electromagnetic spectrum, from X-rays to infrared light. These diverse colors are shown in the panel of photographs below the composite image. The X-ray and infrared data cannot be seen with the human eye. By color-coding those data and combining them with Hubble's visible-light view, astronomers are presenting a more complete picture of the supernova remnant. <p/> Visible-light images from the Hubble telescope (colored yellow) reveal where the supernova shock wave is slamming into the densest regions of surrounding gas. The bright glowing knots are dense clumps from instabilities that form behind the shock wave. The Hubble data also show thin filaments of gas that look like rippled sheets seen edge-on. These filaments reveal where the shock wave is encountering lower-density, more uniform interstellar material. <p/> The Spitzer telescope shows microscopic dust particles (colored red) that have been heated by the

How high energy fluxes may affect Rayleigh–Taylor instability growth in young supernova remnants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuranz, Carolyn C.; Park, Hye -Sook; Huntington, Channing M.

Here, energy-transport effects can alter the structure that develops as a supernova evolves into a supernova remnant. The Rayleigh–Taylor instability is thought to produce structure at the interface between the stellar ejecta and the circumstellar matter, based on simple models and hydrodynamic simulations. Here we report experimental results from the National Ignition Facility to explore how large energy fluxes, which are present in supernovae, affect this structure. We observed a reduction in Rayleigh–Taylor growth. In analyzing the comparison with supernova SN1993J, a Type II supernova, we found that the energy fluxes produced by heat conduction appear to be larger thanmore » the radiative energy fluxes, and large enough to have dramatic consequences. No reported astrophysical simulations have included radiation and heat conduction self-consistently in modeling supernova remnants and these dynamics should be noted in the understanding of young supernova remnants.« less

How high energy fluxes may affect Rayleigh–Taylor instability growth in young supernova remnants

DOE PAGES

Kuranz, Carolyn C.; Park, Hye -Sook; Huntington, Channing M.; ...

2018-04-19

Here, energy-transport effects can alter the structure that develops as a supernova evolves into a supernova remnant. The Rayleigh–Taylor instability is thought to produce structure at the interface between the stellar ejecta and the circumstellar matter, based on simple models and hydrodynamic simulations. Here we report experimental results from the National Ignition Facility to explore how large energy fluxes, which are present in supernovae, affect this structure. We observed a reduction in Rayleigh–Taylor growth. In analyzing the comparison with supernova SN1993J, a Type II supernova, we found that the energy fluxes produced by heat conduction appear to be larger thanmore » the radiative energy fluxes, and large enough to have dramatic consequences. No reported astrophysical simulations have included radiation and heat conduction self-consistently in modeling supernova remnants and these dynamics should be noted in the understanding of young supernova remnants.« less

r-process nucleosynthesis in dynamic helium-burning environments

NASA Technical Reports Server (NTRS)

Cowan, J. J.; Cameron, A. G. W.; Truran, J. W.

1985-01-01

The results of an extended examination of r-process nucleosynthesis in helium-burning enviroments are presented. Using newly calculated nuclear rates, dynamical r-process calculations have been made of thermal runaways in helium cores typical of low-mass stars and in the helium zones of stars undergoing supernova explosions. These calculations show that, for a sufficient flux of neutrons produced by the C-13 neutron source, r-process nuclei in solar proportions can be produced. The conditions required for r-process production are found to be 10 to the 20th-10 to the 21st neutrons per cubic centimeter for times of 0.01-0.1 s and neutron number densities in excess of 10 to the 19th per cubic centimeter for times of about 1 s. The amount of C-13 required is found to be exceedingly high - larger than is found to occur in any current stellar evolutionary model. It is thus unlikely that these helium-burning environments are responsible for producing the bulk of the r-process elements seen in the solar system.

X-ray spectroscopic observations and modeling of supernova remnants

NASA Technical Reports Server (NTRS)

Shull, J. M.

1981-01-01

The X-ray observations of young remnants and their theoretical interpretation are described. A number of questions concerning the nature of the blast wave interaction with the interstellar gas and grains and of atomic processes in these hot plasmas are considered. It is concluded that future X-ray spectrometers with high collecting area, moderate spectral resolution and good spatial resolution can make important contributions to the understanding of supernova remnants in the Milky Way and neighboring galaxies and of their role in the global chemical and dynamical evolution of the interstellar medium.

Nucleosynthesis in Thermonuclear Supernovae

NASA Astrophysics Data System (ADS)

Seitenzahl, Ivo Rolf; Townsley, Dean M.

The explosion energy of thermonuclear (type Ia) supernovae is derived from the difference in nuclear binding energy liberated in the explosive fusion of light "fuel" nuclei, predominantly carbon and oxygen, into more tightly bound nuclear "ash" dominated by iron and silicon group elements. The very same explosive thermonuclear fusion event is also one of the major processes contributing to the nucleosynthesis of the heavy elements, in particular the iron-group elements. For example, most of the iron and manganese in the sun and its planetary system were produced in thermonuclear supernovae. Here, we review the physics of explosive thermonuclear burning in carbon-oxygen white dwarf material and the methodologies utilized in calculating predicted nucleosynthesis from hydrodynamic explosion models. While the dominant explosion scenario remains unclear, many aspects of the nuclear combustion and nucleosynthesis are common to all models and must occur in some form in order to produce the observed yields. We summarize the predicted nucleosynthetic yields for existing explosion models, placing particular emphasis on characteristic differences in the nucleosynthetic signatures of the different suggested scenarios leading to type Ia supernovae. Following this, we discuss how these signatures compare with observations of several individual supernovae, remnants, and the composition of material in our galaxy and galaxy clusters.

Supernova 1987A in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Kafatos, Minas; Michalitsianos, Andrew G.

2006-11-01

Foreword; Acknowledgements; Workshop participants; 1. Images and spectrograms of Sanduleak - 69º202, the SN 1987a progenitor N. R. Walborn; 2. The progenitor of SN 1987A G. Sonneborn; 3. Another supernova with a blue progenitor C. M. Gaskell and W. C. Keel; 4. Optical and infrared observations of SN 1987A from Cerro Tololo Inter-American Observatory M. M. Phillips; 5. SN 1987A: observational results obtained at ESO I. J. Danziger, P. Bouchet, R. A. E. Fosbury, C. Gouiffes, L. B. Lucy, A. F. M. Moorwood, E. Oliva and F. Rufener; 6. Observations of SN 1987A at the South African Astronomical Observatory (SAAO) M. W. Feast; 7. Observations of SN 1987A at the Anglo-Australian Telescope W. J. Couch; 8. Linear polarimetric study of SN 1987A A. Clocchiatti, M. Méndez, O. Benvenuto, C. Feinstein, H. Marraco, B. García and N. Morrell; 9. Infrared spectroscopy of SN 1987A from the NASA Kuiper Airborne Observatory H. P. Larson, S. Drapatz, M. J. Mumma and H. A. Weaver; 10. Radio observations of SN 1987A N. Bartel et al.; 11. Ultraviolet observations of SN 1987A: clues to mass loss R. P. Kirshner; 12. On the energetics of SN 1987A N. Panagia; 13. On the nature and apparent uniqueness of SN 1987A A. V. Filippenko; 14. A comparison of the SN 1987A light curve with other type II supernovae, and the detectability of similar supernovae M. F. Schmitz and C. M. Gaskell; 15. P-Cygni features and photospheric velocities L. Bildsten and J. C. L. Wang; 16. The Neutrino burst from SN 1987A detected in the Mont Blanc LSD experiment M. Aglietta et al.; 17. Toward observational neutrino astrophysics M. Koshiba; 18. The discovery of neutrinos from SN 1987A with the IMB detector J. Matthews; 19. Peering into the abyss: the neutrinos from SN 1987A A. Burrows; 20. Phenomenological analysis of neutrino emission from SN 1987A J. N. Bahcall, D. N. Spergel and W. H. Press; 21. Mass determination of neutrinos H. Y. Chiu; 22. Neutrino transport in a type II supernova D. C. Ellison, P. M. Giovanoni

OXYGEN-RICH SUPERNOVA REMNANT IN THE LARGE MAGELLANIC CLOUD

NASA Technical Reports Server (NTRS)

2002-01-01

chemical composition of this nuclear- processed material, and thereby test theories of stellar evolution. The image shows a region of the remnant 50 light-years across. The supernova explosion should have been visible from Earth's southern hemisphere around 1,000 B.C., but there are no known historical records that chronicle what would have appeared as a 'new star' in the heavens. This 'true color' picture was made by superposing images taken on 9-10 August 1994 in three of the strongest optical emission lines: singly ionized sulfur (red), doubly ionized oxygen (green), and singly ionized oxygen (blue). Photo credit: Jon A. Morse (STScI) and NASA Investigating team: William P. Blair (PI; JHU), Michael A. Dopita (MSSSO), Robert P. Kirshner (Harvard), Knox S. Long (STScI), Jon A. Morse (STScI), John C. Raymond (SAO), Ralph S. Sutherland (UC-Boulder), and P. Frank Winkler (Middlebury). Image files in GIF and JPEG format may be accessed via anonymous ftp from oposite.stsci.edu in /pubinfo: GIF: /pubinfo/GIF/N132D.GIF JPEG: /pubinfo/JPEG/N132D.jpg The same images are available via World Wide Web from links in URL http://www.stsci.edu/public.html.

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.

High-Energy Cosmic Rays from Supernovae

NASA Astrophysics Data System (ADS)

Morlino, Giovanni

Cosmic rays are charged relativistic particles that reach the Earth with extremely high energies, providing striking evidence of the existence of effective accelerators in the Universe. Below an energy around ˜ 1017 eV, cosmic rays are believed to be produced in the Milky Way, while above that energy, their origin is probably extragalactic. In the early 1930s, supernovae were already identified as possible sources for the galactic component of cosmic rays. After the 1970s this idea has gained more and more credibility, thanks to the development of the diffusive shock acceleration theory, which provides a robust theoretical framework for particle energization in astrophysical environments. Afterward, mostly in recent years, much observational evidence has been gathered in support of this framework, converting a speculative idea in a real paradigm. In this chapter the basic pillars of this paradigm will be illustrated. This includes the acceleration mechanism, the nonlinear effects produced by accelerated particles onto the shock dynamics needed to reach the highest energies, the escape process from the sources, and the transportation of cosmic rays through the Galaxy. The theoretical picture will be corroborated by discussing several observations which support the idea that supernova remnants are effective cosmic ray factories.

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

Design, characterization, and sensitivity of the supernova trigger system at Daya Bay

NASA Astrophysics Data System (ADS)

Wei, Hanyu; Lebanowski, Logan; Li, Fei; Wang, Zhe; Chen, Shaomin

2016-02-01

Providing an early warning of galactic supernova explosions from neutrino signals is important in studying supernova dynamics and neutrino physics. A dedicated supernova trigger system has been designed and installed in the data acquisition system at Daya Bay and integrated into the worldwide Supernova Early Warning System (SNEWS). Daya Bay's unique feature of eight identically-designed detectors deployed in three separate experimental halls makes the trigger system naturally robust against cosmogenic backgrounds, enabling a prompt analysis of online triggers and a tight control of the false-alert rate. The trigger system is estimated to be fully sensitive to 1987A-type supernova bursts throughout most of the Milky Way. The significant gain in sensitivity of the eight-detector configuration over a mass-equivalent single detector is also estimated. The experience of this online trigger system is applicable to future projects with spatially distributed detectors.

Evolution of Supernova Remnants

NASA Astrophysics Data System (ADS)

Arbutina, B.

2017-12-01

This book, both a monograph and a graduate textbook, is based on my original research and partly on the materials prepared earlier for the 2007 and 2008 IARS Astrophysics Summer School in Istanbul, AstroMundus course 'Supernovae and Their Remnants' that was held for the first time in 2011 at the Department of Astronomy, Faculty of Mathematics, University of Belgrade, and a graduate course 'Evolution of Supernova Remnants' that I teach at the aforementioned university. The first part Supernovae (introduction, thermonuclear supernovae, core-collapse supernovae) provides introductory information and explains the classification and physics of supernova explosions, while the second part Supernova remnants (introduction, shock waves, cosmic rays and particle acceleration, magnetic fields, synchrotron radiation, hydrodynamic and radio evolution of supernova remnants), which is the field I work in, is more detailed in scope i.e. technical/mathematical. Special attention is paid to details of mathematical derivations that often cannot be found in original works or available literature. Therefore, I believe it can be useful to both, graduate students and researchers interested in the field.

The shock process and light element production in supernovae envelopes. Ph.D. Thesis - Chicago Univ.

NASA Technical Reports Server (NTRS)

Brown, Lawrence E.; Dearborn, David S.; Schramm, David N.; Larsen, Jon T.; Kurokawa, Shin

1990-01-01

Detailed hydrodynamic modeling of the passage of supernova shocks through the hydrogen envelopes of blue and red progenitor stars was carried out to explore the sensitivity to model conditions of light element production (specifically Li-7 and B-11) which was noted by Dearborn, Schramm, Steigman and Truran (1989) (DSST). It is found that, for stellar models with M is less than or approximately 100 M solar mass, current state of the art supernova shocks do not produce significant light element yields by hydrodynamic processes alone. The dependence of this conclusion on stellar models and on shock strengths is explored. Preliminary implications for Galactic evolution of lithium are discussed, and it is suspected that intermediate mass red giant stars may be the most consistent production site for lithium.

Semi-supervised learning for photometric supernova classification

NASA Astrophysics Data System (ADS)

Richards, Joseph W.; Homrighausen, Darren; Freeman, Peter E.; Schafer, Chad M.; Poznanski, Dovi

2012-01-01

We present a semi-supervised method for photometric supernova typing. Our approach is to first use the non-linear dimension reduction technique diffusion map to detect structure in a data base of supernova light curves and subsequently employ random forest classification on a spectroscopically confirmed training set to learn a model that can predict the type of each newly observed supernova. We demonstrate that this is an effective method for supernova typing. As supernova numbers increase, our semi-supervised method efficiently utilizes this information to improve classification, a property not enjoyed by template-based methods. Applied to supernova data simulated by Kessler et al. to mimic those of the Dark Energy Survey, our methods achieve (cross-validated) 95 per cent Type Ia purity and 87 per cent Type Ia efficiency on the spectroscopic sample, but only 50 per cent Type Ia purity and 50 per cent efficiency on the photometric sample due to their spectroscopic follow-up strategy. To improve the performance on the photometric sample, we search for better spectroscopic follow-up procedures by studying the sensitivity of our machine-learned supernova classification on the specific strategy used to obtain training sets. With a fixed amount of spectroscopic follow-up time, we find that, despite collecting data on a smaller number of supernovae, deeper magnitude-limited spectroscopic surveys are better for producing training sets. For supernova Ia (II-P) typing, we obtain a 44 per cent (1 per cent) increase in purity to 72 per cent (87 per cent) and 30 per cent (162 per cent) increase in efficiency to 65 per cent (84 per cent) of the sample using a 25th (24.5th) magnitude-limited survey instead of the shallower spectroscopic sample used in the original simulations. When redshift information is available, we incorporate it into our analysis using a novel method of altering the diffusion map representation of the supernovae. Incorporating host redshifts leads to a 5

POLYCYCLIC AROMATIC HYDROCARBON PROCESSING IN THE BLAST WAVE OF THE SUPERNOVA REMNANT N132D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tappe, A.; Rho, J.; Boersma, C.

2012-08-01

We present Spitzer Infrared Spectrograph 14-36 {mu}m mapping observations of the supernova remnant N132D in the Large Magellanic Cloud. This study focuses on the processing of polycyclic aromatic hydrocarbons (PAHs) that we previously identified in the southern blast wave. The mid-infrared spectra show strong continuum emission from shock-heated dust and a unique, nearly featureless plateau in the 15-20 {mu}m region, which we attribute to PAH molecules. The typical PAH emission bands observed in the surrounding interstellar medium ahead of the blast wave disappear, which indicates shock processing of PAH molecules. The PAH plateau appears most strongly at the outer edgemore » of the blast wave and coincides with diffuse X-ray emission that precedes the brightest X-ray and optical filaments. This suggests that PAH molecules in the surrounding medium are swept up and processed in the hot gas of the blast wave shock, where they survive the harsh conditions long enough to be detected. We also observe a broad emission feature at 20 {mu}m appearing with the PAH plateau. We speculate that this feature is either due to FeO dust grains or connected to the processing of PAHs in the supernova blast wave shock.« less

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

NASA Astrophysics Data System (ADS)

Plewa, Tomasz; Handy, Timothy; Odrzywolek, Andrzej

2014-09-01

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

Supernova Cosmology Project

Science.gov Websites

Supernova Survey: An Intensive HST Survey for z>1 Type Ia Supernovae by Targeting Galaxy Clusters Survey new survey strategy to discover and study high redshift Type Ia supernovae (SNe Ia) using the Hubble improvement in the efficiency of finding SNe compared to an HST field survey and a factor of three improvement

Supernova Cosmology Project

Science.gov Websites

Space Telescope Cluster Supernova Survey: II. The Type Ia Supernova Rate in High-Redshift Galaxy /abs/0809.1648 Constraining Dust and Color Variations of High-z SNe Using NICMOS on the Hubble Space /0804.4142 A New Determination of the High-Redshift Type Ia Supernova Rates with the Hubble Space Telescope

STRESS Counting Supernovae

NASA Astrophysics Data System (ADS)

Botticella, M. T.; Cappellaro, E.; Riello, M.; Greggio, L.; Benetti, S.; Patat, F.; Turatto, M.; Altavilla, G.; Pastorello, A.; Valenti, S.; Zampieri, L.; Harutyunyan, A.; Pignata, G.; Taubenberger, S.

2008-12-01

The rate of occurrence of supernovae (SNe) is linked to some of the basic ingredients of galaxy evolution, such as the star formation rate, the chemical enrichment and feedback processes. SN rates at intermediate redshift and their dependence on specific galaxy properties have been investigated in the Southern inTermediate Redshift ESO Supernova Search (STRESS). The rate of core collapse SNe (CC SNe) at a redshift of around 0.25 is found to be a factor two higher than the local value, whereas the SNe Ia rate remains almost constant. SN rates in red and blue galaxies were also measured and it was found that the SNe Ia rate seems to be constant in galaxies of different colour, whereas the CC SN rate seems to peak in blue galaxies, as in the local Universe.

On the Induced Gravitational Collapse Scenario of Gamma-ray Bursts Associated with Supernovae

NASA Astrophysics Data System (ADS)

Becerra, L.; Bianco, C. L.; Fryer, C. L.; Rueda, J. A.; Ruffini, R.

2016-12-01

Following the induced gravitational collapse (IGC) paradigm of gamma-ray bursts (GRBs) associated with type Ib/c supernovae, we present numerical simulations of the explosion of a carbon-oxygen (CO) core in a binary system with a neutron-star (NS) companion. The supernova ejecta trigger a hypercritical accretion process onto the NS thanks to a copious neutrino emission and the trapping of photons within the accretion flow. We show that temperatures of 1-10 MeV develop near the NS surface, hence electron-positron annihilation into neutrinos becomes the main cooling channel leading to accretion rates of 10-9-{10}-1 {M}⊙ s-1 and neutrino luminosities of 1043-1052 erg s-1 (the shorter the orbital period the higher the accretion rate). We estimate the maximum orbital period, {P}\\max , as a function of the NS initial mass, up to which the NS companion can reach by hypercritical accretion the critical mass for gravitational collapse leading to black hole formation. We then estimate the effects of the accreting and orbiting NS companion onto a novel geometry of the supernova ejecta density profile. We present the results of a 1.4× {10}7 particle simulation which show that the NS induces accentuated asymmetries in the ejecta density around the orbital plane. We elaborate on the observables associated with the above features of the IGC process. We apply this framework to specific GRBs: we find that X-ray flashes (XRFs) and binary-driven hypernovae are produced in binaries with P\\gt {P}\\max and P\\lt {P}\\max , respectively. We analyze in detail the case of XRF 060218.

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.

ANTIMATTER PRODUCTION IN SUPERNOVA REMNANTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kachelriess, M.; Ostapchenko, S.; Tomas, R.

2011-06-01

We calculate the energy spectra of cosmic rays (CRs) and their secondaries produced in a supernova remnant (SNR) taking into account the time dependence of the SNR shock. We model the trajectories of charged particles as a random walk with a prescribed diffusion coefficient, accelerating the particles at each shock crossing. Secondary production by CRs colliding with gas is included as a Monte Carlo process. We find that SNRs produce less antimatter than suggested previously: the positron/electron ratio F{sub e}{sup +}/F{sub e}{sup +}{sub +e}{sup -} and the antiproton/proton ratio F{sub p-bar/}F{sub p-bar+p} are a few percent and few x 10{supmore » -5}, respectively. Moreover, the obtained positron/electron ratio decreases with energy, while the antiproton/proton ratio rises at most by a factor of two above 10 GeV.« less

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.

Exposing Hierarchical Parallelism in the FLASH Code for Supernova Simulation on Summit and Other Architectures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Papatheodore, Thomas L.; Messer, Bronson

Since roughly 100 million years after the big bang, the primordial elements hydrogen (H), helium (He), and lithium (Li) have been synthesized into heavier elements by thermonuclear reactions inside of the stars. The change in stellar composition resulting from these reactions causes stars to evolve over the course of their lives. Although most stars burn through their nuclear fuel and end their lives quietly as inert, compact objects, whereas others end in explosive deaths. These stellar explosions are called supernovae and are among the most energetic events known to occur in our universe. Supernovae themselves further process the matter ofmore » their progenitor stars and distribute this material into the interstellar medium of their host galaxies. In the process, they generate ∼1051 ergs of kinetic energy by sending shock waves into their surroundings, thereby contributing to galactic dynamics as well.« less

Peculiar Supernovae

NASA Astrophysics Data System (ADS)

Milisavljevic, Dan; Margutti, Raffaella

2018-06-01

What makes a supernova truly "peculiar?" In this review we attempt to address this question by tracing the history of the use of "peculiar" as a descriptor of non-standard supernovae back to the original binary spectroscopic classification of Type I vs. Type II proposed by Minkowski (Publ. Astron. Soc. Pac., 53:224, 1941). A handful of noteworthy examples are highlighted to illustrate a general theme: classes of supernovae that were once thought to be peculiar are later seen as logical branches of standard events. This is not always the case, however, and we discuss ASASSN-15lh as an example of a transient with an origin that remains contentious. We remark on how late-time observations at all wavelengths (radio-through-X-ray) that probe 1) the kinematic and chemical properties of the supernova ejecta and 2) the progenitor star system's mass loss in the terminal phases preceding the explosion, have often been critical in understanding the nature of seemingly unusual events.

The Supernova Spectropolarimetry (SNSPOL) Project; Probing the Geometry of Supernova Explosions

NASA Astrophysics Data System (ADS)

Williams, George Grant; Leonard, Douglas; Smith, Nathan; Smith, Paul; Milne, Peter; Hoffman, Jennifer L.; Bilinski, Christopher

2018-01-01

In recent years, evidence has grown that most supernovae exhibit departures from spherical symmetry. These results, together with full three-dimensional modeling, are exposing the possibility that asymmetries are not simply an observable feature of some supernovae, but may, in fact, be a necessity of the explosion mechanism itself. However, with the exception of SN 1987A, a supernova photosphere cannot be resolved through direct imaging from ground or space. Only the powerful technique of polarimetry can directly probe asymmetries on those spatial scales. Spectropolarimetry enhances the power of this technique by revealing wavelength-dependent variations that may result from differences in the geometrical distributions of the various ionic species. Multi-epoch observations over several months can be used to follow the evolution of these asymmetries as a supernova evolves and its photosphere recedes through the ejecta. The Supernova Spectropolarimetry (SNSPOL) Project aims to study the predominance and characteristics of asymmetries in all types of supernovae by decoding their complex, time-dependent polarimetric behavior. This is accomplished through multi-epoch observations using the CCD Imaging/Spectropolarimeter (SPOL) on the 61” Kuiper, the 90” Bok, and the 6.5-m MMT telescopes. During the past six years, the SNSPOL Project has observed more than 95 supernovae, approximately 2/3 of which have been observed at multiple epochs. Here we present a summary of the project, its current status, and a few selected results.

The properties of the progenitor, neutron star, and pulsar wind in the supernova remnant Kes 75

NASA Astrophysics Data System (ADS)

Gelfand, J. D.; Slane, P. O.; Temim, T.

2014-03-01

By studying composite supernova remnants (SNRs), remnants which contain a pulsar wind nebula (PWN), it is possible to estimate physical properties of the progenitor explosion, central neutron star, and its pulsar wind that are difficult to measure directly. This is best done by fitting the dynamical and broadband spectral properties of a PWN with an evolutionary model for a PWN inside an SNR. We apply such a model to the composite SNR Kes 75, whose associated pulsar PSR J1846-0258 is thought to have an extremely strong surface magnetic field. If ˜ 3 M_⊙ of mass was ejected in the supernova, our model suggests a normal or slightly subenergetic supernova in a low density environment. Additionally, for the measured pre-outburst braking index of p=2.65, our model prefers an age of {˜ 430} years and an initial spin period P_0 ˜ 0.2 s. Lastly, the magnetization of the pulsar wind and energy spectrum of particles injected at the termination shock are similar to those observed from other PWNe powered by less magnetized neutron stars. While further study is needed to verify these results, they are nominally inconsistent with strong neutron star magnetic fields resulting from very fast initial rotation.

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.

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.

Pair production of helicity-flipped neutrinos in supernovae

NASA Technical Reports Server (NTRS)

Perez, Armando; Gandhi, Raj

1989-01-01

The emissivity was calculated for the pair production of helicity-flipped neutrinos, in a way that can be used in supernova calculations. Also presented are simple estimates which show that such process can act as an efficient energy-loss mechanism in the shocked supernova core, and this fact is used to extract neutrino mass limits from SN 1987A neutrino observations.

Active-sterile neutrino conversion: consequences for the r-process and supernova neutrino detection

NASA Astrophysics Data System (ADS)

Fetter, J.; McLaughlin, G. C.; Balantekin, A. B.; Fuller, G. M.

2003-02-01

We examine active-sterile neutrino conversion in the late time post-core-bounce supernova environment. By including the effect of feedback on the Mikheyev-Smirnov-Wolfenstein (MSW) conversion potential, we obtain a large range of neutrino mixing parameters which produce a favorable environment for the r-process. We look at the signature of this effect in the current generation of neutrino detectors now coming on line. We also investigate the impact of the neutrino-neutrino forward-scattering-induced potential on the MSW conversion.

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.

r-Process nucleosynthesis from three-dimensional jet-driven core-collapse supernovae with magnetic misalignments

NASA Astrophysics Data System (ADS)

Halevi, Goni; Mösta, Philipp

2018-06-01

We investigate r-process nucleosynthesis in three-dimensional general relativistic magnetohydrodynamic simulations of jet-driven supernovae resulting from rapidly rotating, strongly magnetized core-collapse. We explore the effect of misaligning the pre-collapse magnetic field with respect to the rotation axis by performing four simulations: one aligned model and models with 15°, 30°, and 45° misalignments. The simulations we present employ a microphysical finite-temperature equation of state and a leakage scheme that captures the overall energetics and lepton number exchange due to post-bounce neutrino emission and absorption. We track the thermodynamic properties of the ejected material with Lagrangian tracer particles and analyse its composition with the nuclear reaction network SKYNET. By using different neutrino luminosities in post-processing the tracer data with SKYNET, we constrain the impact of uncertainties in neutrino luminosities. We find that, for the aligned model considered here, the use of an approximate leakage scheme results in neutrino luminosity uncertainties corresponding to a factor of 100-1000 uncertainty in the abundance of third peak r-process elements. Our results show that for misalignments of 30° or less, r-process elements are robustly produced as long as neutrino luminosities are reasonably low (≲ 5 × 1052 erg s-1). For a more extreme misalignment of 45°, we find the production of r-process elements beyond the second peak significantly reduced. We conclude that robust r-process nucleosynthesis in magnetorotational supernovae requires a progenitor stellar core with a large poloidal magnetic field component that is at least moderately (within ˜30°) aligned with the rotation axis.

Light Curves of the Type II-P Supernova SN 2017eaw: The First 200 Days

NASA Astrophysics Data System (ADS)

Tsvetkov, D. Yu.; Shugarov, S. Yu.; Volkov, I. M.; Pavlyuk, N. N.; Vozyakova, O. V.; Shatsky, N. I.; Nikiforova, A. A.; Troitsky, I. S.; Troitskaya, Yu. V.; Baklanov, P. V.

2018-05-01

We present the results of our UBVRI photometry for the type II-P supernova SN 2017eaw in NGC6946 obtained fromMay 14 to December 7, 2017, at several telescopes, including the 2.5-m telescope at the CaucasusHigh-Altitude Observatory of the SAIMSU. The dates andmagnitudes atmaximumlight and the light-curve parameters have been determined. The color evolution, extinction, and peak luminosity of SN 2017eaw are discussed. The results of our preliminary radiation-gasdynamic simulations of its light curves with the STELLA code describe satisfactorily the UBVRI observational data.

A Study of the Type II-Plateau Supernova SN 2014cx

NASA Astrophysics Data System (ADS)

Flatland, Kelsi; Leonard, Douglas Christopher; Williams, George Grant; Smith, Paul S.; Bilinski, Christopher; Dessart, Luc; Gonzalez, Luis; Hoffman, Jennifer L.; Huk, Leah; Milne, Peter; Smith, Nathan

2015-08-01

The type II-plateau (II-P) class of supernova is the most commonly observed type of core-collapse event, and yet the basic characteristics of this class are still being defined (e.g. Pejcha & Prieto 2015). Here we add to the growing sample of type II-P events with well-sampled data from observations of SN 2014cx. SN 2014cx was independently discovered on September 2, 2014 UT by Nakano et al. (2014; CBET 3963) and Holoien et al. (2014; ATEL 6436) in the nearby (d ~ 20.7 Mpc, Tully 1988) SBd galaxy NGC 337. It was classified as a young Type II supernova through spectra taken within a day of discovery at both optical (Nakano et al. 2014) and near-infrared (Morrell et al. 2014; ATEL 6442) wavelengths. Later (Andrews et al. 2015; ATEL 7084), it was photometrically determined to be specifically a type II-P supernova, indicating the core-collapse event of a progenitor that had a large hydrogen envelope (Pejcha & Prieto 2015). We initiated a photometric and spectropolarimetric campaign to follow SN 2014cx; over a five month period following the supernova's discovery, we obtained optical images using the 1-meter telescope at Mount Laguna Observatory as part of the MOunt LAguna SUpernova Survey (MOLASUS), and spectra as part of the SuperNova SpectroPOLarimetry project (SNSPOL). Here we present the initial analysis of the photometry and spectroscopy obtained as part of this campaign. We acknowledge support from NSF grants AST-1009571 and AST-1210311, under which part of this research was carried out.

A Study of the Type II-Plateau Supernova SN 2014cx

NASA Astrophysics Data System (ADS)

Flatland, Kelsi; Leonard, Douglas C.; Williams, Grant; Smith, Paul S.; Bilinski, Christopher; Gonzalez, Luis; Hoffman, Jennifer L.; Huk, Leah N.; Milne, Peter; Smith, Nathan; Supernova Spectropolarimetry Project

2016-06-01

The type II-plateau (II-P) class of supernova is the most commonly observed type of core-collapse event, and yet the basic characteristics of this class are still being defined (e.g. Pejcha & Prieto 2015). Here we add to the growing sample of type II-P events with well-sampled data from observations of SN 2014cx. SN 2014cx was independently discovered on September 2, 2014 UT by Nakano et al. (2014; CBET 3963) and Holoien et al. (2014; ATEL 6436) in the nearby (d ~ 20.7 Mpc, Tully 1988) SBd galaxy NGC 337. It was classified as a young Type II supernova through spectra taken within a day of discovery at both optical (Nakano et al. 2014) and near-infrared (Morrell et al. 2014; ATEL 6442) wavelengths. Later (Andrews et al. 2015; ATEL 7084), it was photometrically determined to be specifically a type II-P supernova, indicating the core-collapse event of a progenitor that had a large hydrogen envelope (Pejcha & Prieto 2015). We initiated a photometric and spectropolarimetric campaign to follow SN 2014cx; over a five month period following the supernova's discovery, we obtained optical images using the 1-meter telescope at Mount Laguna Observatory as part of the MOunt LAguna SUpernova Survey (MOLASUS), and spectra as part of the SuperNova SpectroPOLarimetry project (SNSPOL). Here we present the analysis of the photometry and spectroscopy obtained as part of this campaign. We acknowledge support from NSF grants AST-1009571 and AST-1210311, under which part of this research was carried out.

Effects of neutrino oscillations on nucleosynthesis and neutrino signals for an 18 M⊙ supernova model

NASA Astrophysics Data System (ADS)

Wu, Meng-Ru; Qian, Yong-Zhong; Martínez-Pinedo, Gabriel; Fischer, Tobias; Huther, Lutz

2015-03-01

In this paper, we explore the effects of neutrino flavor oscillations on supernova nucleosynthesis and on the neutrino signals. Our study is based on detailed information about the neutrino spectra and their time evolution from a spherically symmetric supernova model for an 18 M⊙ progenitor. We find that collective neutrino oscillations are not only sensitive to the detailed neutrino energy and angular distributions at emission, but also to the time evolution of both the neutrino spectra and the electron density profile. We apply the results of neutrino oscillations to study the impact on supernova nucleosynthesis and on the neutrino signals from a Galactic supernova. We show that in our supernova model, collective neutrino oscillations enhance the production of rare isotopes 138La and 180Ta but have little impact on the ν p -process nucleosynthesis. In addition, the adiabatic Mikheyev-Smirnov-Wolfenstein flavor transformation, which occurs in the C /O and He shells of the supernova, may affect the production of light nuclei such as 7Li and 11B. For the neutrino signals, we calculate the rate of neutrino events in the Super-Kamiokande detector and in a hypothetical liquid argon detector. Our results suggest the possibility of using the time profiles of the events in both detectors, along with the spectral information of the detected neutrinos, to infer the neutrino mass hierarchy.

On the induced gravitational collapse scenario of gamma-ray bursts associated with supernovae

DOE PAGES

Becerra, L.; Bianco, C. L.; Fryer, C. L.; ...

2016-12-10

Following the induced gravitational collapse (IGC) paradigm of gamma-ray bursts (GRBs) associated with type Ib/c supernovae, we present numerical simulations of the explosion of a carbon–oxygen (CO) core in a binary system with a neutron-star (NS) companion. The supernova ejecta trigger a hypercritical accretion process onto the NS thanks to a copious neutrino emission and the trapping of photons within the accretion flow. We show that temperatures of 1–10 MeV develop near the NS surface, hence electron–positron annihilation into neutrinos becomes the main cooling channel leading to accretion rates of 10–9–more » $${10}^{-1}\\,{M}_{\\odot }$$ s–1 and neutrino luminosities of 10 43–10 52 erg s –1 (the shorter the orbital period the higher the accretion rate). We estimate the maximum orbital period, $${P}_{\\max },$$ as a function of the NS initial mass, up to which the NS companion can reach by hypercritical accretion the critical mass for gravitational collapse leading to black hole formation. We then estimate the effects of the accreting and orbiting NS companion onto a novel geometry of the supernova ejecta density profile. We present the results of a $$1.4\\times {10}^{7}$$ particle simulation which show that the NS induces accentuated asymmetries in the ejecta density around the orbital plane. We elaborate on the observables associated with the above features of the IGC process. We apply this framework to specific GRBs: we find that X-ray flashes (XRFs) and binary-driven hypernovae are produced in binaries with $$P\\gt {P}_{\\max }$$ and $$P\\lt {P}_{\\max },$$ respectively. As a result, we analyze in detail the case of XRF 060218.« less

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

Type Ia Supernova Cosmology

NASA Astrophysics Data System (ADS)

Leibundgut, B.; Sullivan, M.

2018-03-01

The primary agent for Type Ia supernova cosmology is the uniformity of their appearance. We present the current status, achievements and uncertainties. The Hubble constant and the expansion history of the universe are key measurements provided by Type Ia supernovae. They were also instrumental in showing time dilation, which is a direct observational signature of expansion. Connections to explosion physics are made in the context of potential improvements of the quality of Type Ia supernovae as distance indicators. The coming years will see large efforts to use Type Ia supernovae to characterise dark energy.

Supernova Cosmology Project

Science.gov Websites

, 2014 The Supernova Cosmology Project and High-Z Team share the 2015 Breakthrough Prize in Fundamental Perlmutter, leader of the international Supernova Cosmology Project, and principal investigator of the

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

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

The SuperNova Integral Field Spectrograph

NASA Astrophysics Data System (ADS)

Aldering, Gregory S.; Supernova Factory, Nearby

2007-05-01

The SuperNova Integral Field Spectrograph (SNIFS) is operated at the University of Hawaii 2.2 meter telescope on Mauna Kea by the Nearby Supernova Factory. The IFU has a 6x6 arcsecond field of view, and the combined blue and red channels simultaneously cover the full optical (320-1000 nm) spectral range. SNIFS was designed to allow spectrophotometry of supernovae under both photometric and non-photometric conditions. SNIFS is operated entirely remotely, in a quasi-automated mode, from as nearby as Hilo, Hawaii and as far away as Paris, France. Being mounted at the south bent Cassegrain focus of the UH 2.2-m, SNIFS is always available, either for regular Nearby Supernova Factory observations, or any of a range of programs conducted by astronomers at the University of Hawaii Institute for Astronomy. We illustrate some of the unique features of SNIFS and some of the science programs that have been undertaken using it. This work is supported in part by the Director, Office of Science, Office of High Energy and Nuclear Physics, of the U.S. Department of Energy under Contracts No. DE-FG0-92ER40704, by a grant from the Gordon & Betty Moore Foundation, and in France by CNRS/IN2P3, CNRS/INSU and PNC.

Nuclear astrophysics of supernovae

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 itmore » 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.« less

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

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foglizzo, Thierry; Kazeroni, Rémi; Guilet, Jérôme

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

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 .

Recent Hubble Space Telescope Imaging of the Light Echoes of Supernova 2014J in M 82 and Supernova 2016adj in Centaurus A

NASA Astrophysics Data System (ADS)

Lawrence, Stephen S.; Hyder, Ali; Sugerman, Ben; Crotts, Arlin P. S.

2017-06-01

We report on our ongoing use of Hubble Space Telescope (HST) imaging to monitor the scattered light echoes of recent heavily-extincted supernovae in two nearby, albeit unusual, galaxies.Supernova 2014J was a highly-reddened Type Ia supernova that erupted in the nearby irregular star-forming galaxy M 82 in 2014 January. It was discovered to have light echo by Crotts (2016) in early epoch HST imaging and has been further described by Yang, et al. (2017) based on HST imaging through late 2014. Our ongoing monitoring in the WFC3 F438W, F555W, and F814W filters shows that, consistent with Crotts (2106) and Yang, et al. (2017), throughout 2015 and 2016 the main light echo arc expanded through a dust complex located approximately 230 pc in the foreground of the supernova. This main light echo has, however, faded dramatically in our most recent HST imaging from 2017 March. The supernova itself has also faded to undetectable levels by 2017 March.Supernova 2016adj is a highly-reddened core-collapse supernova that erupted inside the unusual dust lane of the nearby giant elliptical galaxy Centaurus A (NGC 5128) in 2016 February. It was discovered to have a light echo by Sugerman & Lawrence (2016) in early epoch HST imaging in 2016 April. Our ongoing monitoring in the WFC3 F438W, F547M, and F814W filters shows a slightly elliptical series of light echo arc segments hosted by a tilted dust complex ranging approximately 150--225 pc in the foreground of the supernova. The supernova itself has also faded to undetectable levels by 2017 April.References: Crotts, A. P. S., ApJL, 804, L37 (2016); Yang et al., ApJ, 834, 60 (2017); Sugerman, B. and Lawrence, S., ATel #8890 (2016).

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.

Uncertainties in the production of p nuclides in thermonuclear supernovae determined by Monte Carlo variations

NASA Astrophysics Data System (ADS)

Nishimura, N.; Rauscher, T.; Hirschi, R.; Murphy, A. St J.; Cescutti, G.; Travaglio, C.

2018-03-01

Thermonuclear supernovae originating from the explosion of a white dwarf accreting mass from a companion star have been suggested as a site for the production of p nuclides. Such nuclei are produced during the explosion, in layers enriched with seed nuclei coming from prior strong s processing. These seeds are transformed into proton-richer isotopes mainly by photodisintegration reactions. Several thousand trajectories from a 2D explosion model were used in a Monte Carlo approach. Temperature-dependent uncertainties were assigned individually to thousands of rates varied simultaneously in post-processing in an extended nuclear reaction network. The uncertainties in the final nuclear abundances originating from uncertainties in the astrophysical reaction rates were determined. In addition to the 35 classical p nuclides, abundance uncertainties were also determined for the radioactive nuclides 92Nb, 97, 98Tc, 146Sm, and for the abundance ratios Y(92Mo)/Y(94Mo), Y(92Nb)/Y(92Mo), Y(97Tc)/Y(98Ru), Y(98Tc)/Y(98Ru), and Y(146Sm)/Y(144Sm), important for Galactic Chemical Evolution studies. Uncertainties found were generally lower than a factor of 2, although most nucleosynthesis flows mainly involve predicted rates with larger uncertainties. The main contribution to the total uncertainties comes from a group of trajectories with high peak density originating from the interior of the exploding white dwarf. The distinction between low-density and high-density trajectories allows more general conclusions to be drawn, also applicable to other simulations of white dwarf explosions.

Red-Supergiant and Supernova Rate Problems: Implication for the Relic Supernova Neutrino Spectrum

NASA Astrophysics Data System (ADS)

Hidaka, J.; Kajino, T.; Mathews, G. J.

2016-08-01

Direct observations of core-collapse supernovae (SNe) and their red supergiant (RSG) progenitors suggest that the upper mass limit of RSGs may be only about 16.5{--}18{M}⊙ , while the standard theoretical value is as much as 25{M}⊙ . We investigate the possibility that RSGs with m\\gt 16.5{--}18{M}⊙ end their lives as failed supernovae (fSNe) and analyze their contribution to the relic supernova neutrino spectrum. We show that adopting this mass limit simultaneously solves both the RSG problem and the supernova rate problem. In addition, energetic neutrinos that originated from fSNe are sensitive to the explosion mechanism, and in particular, to the nuclear equation of state (EOS). We show that this solution to the RSG problem might also be used to constrain the EOS for failed supernovae.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 SNmore » 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.« less

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.

Large-scale Instability during Gravitational Collapse with Neutrino Transport and a Core-Collapse Supernova

NASA Astrophysics Data System (ADS)

Aksenov, A. G.; Chechetkin, V. M.

2018-04-01

Most of the energy released in the gravitational collapse of the cores of massive stars is carried away by neutrinos. Neutrinos play a pivotal role in explaining core-collape supernovae. Currently, mathematical models of the gravitational collapse are based on multi-dimensional gas dynamics and thermonuclear reactions, while neutrino transport is considered in a simplified way. Multidimensional gas dynamics is used with neutrino transport in the flux-limited diffusion approximation to study the role of multi-dimensional effects. The possibility of large-scale convection is discussed, which is interesting both for explaining SN II and for setting up observations to register possible high-energy (≳10MeV) neutrinos from the supernova. A new multi-dimensional, multi-temperature gas dynamics method with neutrino transport is presented.

Stardust from Supernovae and Its Isotopes

NASA Astrophysics Data System (ADS)

Hoppe, Peter

Primitive solar system materials, namely, meteorites, interplanetary dust particles, and cometary matter contain small quantities of nanometer- to micrometer-sized refractory dust grains that exhibit large isotopic abundance anomalies. These grains are older than our solar system and have been named "presolar grains." They formed in the winds of red giant and asymptotic giant stars and in the ejecta of stellar explosions, i.e., represent a sample of stardust that can be analyzed in terrestrial laboratories for isotopic compositions and other properties. The inventory of presolar grains is dominated by grains from red giant and asymptotic giant branch stars. Presolar grains from supernovae form a minor but important subpopulation. Supernova (SN) minerals identified to date include silicon carbide, graphite, silicon nitride, oxides, and silicates. Isotopic studies of major, minor, and trace elements in these dust grains have provided detailed insights into nucleosynthetic and mixing processes in supernovae and how dust forms in these violent environments.

MAGNETAR-POWERED SUPERNOVAE IN TWO DIMENSIONS. I. SUPERLUMINOUS SUPERNOVAE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Ke-Jung; Woosley, S. E.; Sukhbold, Tuguldur, E-mail: ken.chen@nao.ac.jp

2016-11-20

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 bymore » 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.« less

Outflows from Compact Objects in Supernovae and Novae

NASA Astrophysics Data System (ADS)

Vlasov, Andrey Dmitrievich

Originally thought of as a constant and unchanging place, the Universe is full of dramas of stars emerging, dying, eating each other, colliding, etc. One of the first transient phenomena noticed were called novae (the name means "new" in Latin). Years later, supernovae were discovered. Despite their names, both novae and supernovae are events in relatively old stars, with supernovae marking the point of stellar death. Known for thousands of years, supernovae and novae remain among the most studied events in our Universe. Supernovae strongly influence the circumstellar medium, enriching it with heavy elements and shocking it, facilitating star formation. Cosmic rays are believed to be accelerated in shocks from supernovae, with small contribution possibly coming from novae. Even though the basic physics of novae is understood, many questions remain unanswered. These include the geometry of the ejecta, why some novae are luminous radio or gamma-ray sources and others are not, what is the ultimate fate of recurrent novae, etc. Supernova explosions are the primary sources of elements heavier than hydrogen and helium. The elements up to nuclear masses A around 100 can form through successive nuclear fusion in the cores of stars starting with hydrogen. Beyond iron, the fusion becomes endothermic instead of exothermic. In addition, for these nuclear masses the temperatures required to overcome the Coulomb barriers are so high that the nuclei are dissociated into alpha particles and free nucleons. Hence all elements heavier than A around 100 should have formed by some other means. These heavier nuclear species are formed by neutron capture on seed nuclei close to or heavier than iron-group nuclei. Depending on the ratio between neutron-capture timescale and beta-decay timescale, neutron-capture processes are called rapid or slow (r- and s-processes, respectively). The s-process, which occurs near the valley of stable isotopes, terminates at Bi (Z=83), because after Bi

Neutrino nucleosynthesis in core-collapse Supernova explosions

NASA Astrophysics Data System (ADS)

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

2018-01-01

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

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

Early chemo-dynamical evolution of dwarf galaxies deduced from enrichment of r-process elements

NASA Astrophysics Data System (ADS)

Hirai, Yutaka; Ishimaru, Yuhri; Saitoh, Takayuki R.; Fujii, Michiko S.; Hidaka, Jun; Kajino, Toshitaka

2017-04-01

The abundance of elements synthesized by the rapid neutron-capture process (r-process elements) of extremely metal-poor (EMP) stars in the Local Group galaxies gives us clues to clarify the early evolutionary history of the Milky Way halo. The Local Group dwarf galaxies would have similarly evolved with building blocks of the Milky Way halo. However, how the chemo-dynamical evolution of the building blocks affects the abundance of r-process elements is not yet clear. In this paper, we perform a series of simulations using dwarf galaxy models with various dynamical times and total mass, which determine star formation histories. We find that galaxies with dynamical times longer than 100 Myr have star formation rates less than 10-3 M⊙ yr-1 and slowly enrich metals in their early phase. These galaxies can explain the observed large scatters of r-process abundance in EMP stars in the Milky Way halo regardless of their total mass. On the other hand, the first neutron star merger appears at a higher metallicity in galaxies with a dynamical time shorter than typical neutron star merger times. The scatters of r-process elements mainly come from the inhomogeneity of the metals in the interstellar medium whereas the scatters of α-elements are mostly due to the difference in the yield of each supernova. Our results demonstrate that the future observations of r-process elements in EMP stars will be able to constrain the early chemo-dynamical evolution of the Local Group galaxies.

The impact of different interstellar medium structures on the dynamical evolution of supernova remnants

NASA Astrophysics Data System (ADS)

Wang, Yueyang; Bao, Biwen; Yang, Chuyuan; Zhang, Li

2018-05-01

The dynamical properties of supernova remnants (SNRs) evolving with different interstellar medium structures are investigated through performing extensive two-dimensional magnetohydrodynamic (MHD) simulations in the cylindrical symmetry. Three cases of different interstellar medium structures are considered: the uniform medium, the turbulent medium and the cloudy medium. Large-scale density and magnetic fluctuations are calculated and mapped into the computational domain before simulations. The clouds are set by random distribution in advance. The above configuration allows us to study the time-dependent dynamical properties and morphological evolution of the SNR evolving with different ambient structures, along with the development of the instabilities at the contact discontinuity. Our simulation results indicate that remnant morphology deviates from symmetry if the interstellar medium contains clouds or turbulent density fluctuations. In the cloudy medium case, interactions between the shock wave and clouds lead to clouds' fragmentation. The magnetic field can be greatly enhanced by stretching field lines with a combination of instabilities while the width of amplification region is quite different among the three cases. Moreover, both the width of amplification region and the maximum magnetic-field strength are closely related to the clouds' density.

KamLAND Sensitivity to Neutrinos from Pre-supernova Stars

NASA Astrophysics Data System (ADS)

Asakura, K.; Gando, A.; Gando, Y.; Hachiya, T.; Hayashida, S.; Ikeda, H.; Inoue, K.; Ishidoshiro, K.; Ishikawa, T.; Ishio, S.; Koga, M.; Matsuda, S.; Mitsui, T.; Motoki, D.; Nakamura, K.; Obara, S.; Oura, T.; Shimizu, I.; Shirahata, Y.; Shirai, J.; Suzuki, A.; Tachibana, H.; Tamae, K.; Ueshima, K.; Watanabe, H.; Xu, B. D.; Kozlov, A.; Takemoto, Y.; Yoshida, S.; Fushimi, K.; Piepke, A.; Banks, T. I.; Berger, B. E.; Fujikawa, B. K.; O'Donnell, T.; Learned, J. G.; Maricic, J.; Matsuno, S.; Sakai, M.; Winslow, L. A.; Efremenko, Y.; Karwowski, H. J.; Markoff, D. M.; Tornow, W.; Detwiler, J. A.; Enomoto, S.; Decowski, M. P.; KamLAND Collaboration

2016-02-01

In the late stages of nuclear burning for massive stars (M > 8 M⊙), the production of neutrino-antineutrino pairs through various processes becomes the dominant stellar cooling mechanism. As the star evolves, the energy of these neutrinos increases and in the days preceding the supernova a significant fraction of emitted electron anti-neutrinos exceeds the energy threshold for inverse beta decay on free hydrogen. This is the golden channel for liquid scintillator detectors because the coincidence signature allows for significant reductions in background signals. We find that the kiloton-scale liquid scintillator detector KamLAND can detect these pre-supernova neutrinos from a star with a mass of 25 M⊙ at a distance less than 690 pc with 3σ significance before the supernova. This limit is dependent on the neutrino mass ordering and background levels. KamLAND takes data continuously and can provide a supernova alert to the community.

Calculating Galactic Distances Through Supernova Light Curve Analysis (Abstract)

NASA Astrophysics Data System (ADS)

Glanzer, J.

2018-06-01

(Abstract only) The purpose of this project is to experimentally determine the distance to the galaxy M101 by using data that were taken on the type Ia supernova SN 2011fe at the Paul P. Feder Observatory. Type Ia supernovae are useful for determining distances in astronomy because they all have roughly the same luminosity at the peak of their outburst. Comparing the apparent magnitude to the absolute magnitude allows a measurement of the distance. The absolute magnitude is estimated in two ways: using an empirical relationship from the literature between the rate of decline and the absolute magnitude, and using sncosmo, a PYTHON package used for supernova light curve analysis that fits model light curves to the photometric data.

NASA's Hubble Sees A New Supernova Remnant Light Up

NASA Image and Video Library

2011-06-10

NASA image release June 10, 2011 Astronomers using NASA's Hubble Space Telescope are witnessing the unprecedented transition of a supernova to a supernova remnant, where light from an exploding star in a neighboring galaxy, the Large Magellanic Cloud, reached Earth in February 1987. Named Supernova 1987A, it was the closest supernova explosion witnessed in almost 400 years. The supernova's close proximity to Earth has allowed astronomers to study it in detail as it evolves. Now, the supernova debris, which has faded over the years, is brightening. This means that a different power source has begun to light the debris. The debris of SN 1987A is beginning to impact the surrounding ring, creating powerful shock waves that generate X-rays observed with NASA's Chandra X-ray Observatory. Those X-rays are illuminating the supernova debris and shock heating is making it glow in visible light. The results are being reported in the June 9, 2011, issue of the journal Nature by a team including Robert Kirshner of the Harvard-Smithsonian Center for Astrophysics (CfA), who leads a long-term study of SN 1987A with Hubble. Since its launch in 1990, the Hubble telescope has provided a continuous record of the changes in SN 1987A. Credit: NASA, ESA, and P. Challis (Harvard-Smithsonian Center for Astrophysics) NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Join us on Facebook Find us on Instagram

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.

Supernova Neutrino Opacity from Nucleon-Nucleon Bremsstrahlung and Related Processes

NASA Astrophysics Data System (ADS)

Hannestad, Steen; Raffelt, Georg

1998-11-01

Elastic scattering on nucleons, νN --> Nν, is the dominant supernova (SN) opacity source for μ and τ neutrinos. The dominant energy- and number-changing processes were thought to be νe- --> e-ν and νν¯<-->e+e- until Suzuki showed that the bremsstrahlung process νν¯NN<-->NN was actually more important. We find that for energy exchange, the related ``inelastic scattering process'' νNN<-->NNν is even more effective by about a factor of 10. A simple estimate implies that the νμ and ντ spectra emitted during the Kelvin-Helmholtz cooling phase are much closer to that of ν¯e than had been thought previously. To facilitate a numerical study of the spectra formation we derive a scattering kernel that governs both bremsstrahlung and inelastic scattering and give an analytic approximation formula. We consider only neutron-neutron interactions; we use a one-pion exchange potential in Born approximation, nonrelativistic neutrons, and the long-wavelength limit, simplifications that appear justified for the surface layers of an SN core. We include the pion mass in the potential, and we allow for an arbitrary degree of neutron degeneracy. Our treatment does not include the neutron-proton process and does not include nucleon-nucleon correlations. Our perturbative approach applies only to the SN surface layers, i.e., to densities below about 1014 g cm-3.

The Core-Collapse Supernova-Black Hole Connection

NASA Astrophysics Data System (ADS)

O'Connor, Evan

The death of a massive star is typically associated with a bright optical transient known as a core-collapse supernova. However, there is growing evidence that not all massive stars end their lives with a brillant optical display, but rather in a whimper. These failed supernovae, or unnovae, result from the central engine failing to turn the initial implosion of the iron core into an explosion that launches the supernova shock wave, unbinds the majority of the star, and creates the supernova as we know it. In these unnovae, the failure of the central engine is soon followed by the collapse of the would-be neutron star into a stellar mass black hole. Instead of the bright optical display following successful supernovae, little to no optical emission is expected from typical failed supernovae as most of the material quietly accretes onto the black hole. This makes the hunt for failed supernovae difficult. In this chapter for the Handbook of Supernovae, I present the growing observational evidence for failed supernovae and discuss the current theoretical understanding of how and in what stars the supernova central engine fails.

Neutron stars in supernova remnants and beyond

NASA Astrophysics Data System (ADS)

Gvaramadze, V.

We propose a new approach for studying the neutron star/supernova remnant associations, based on the idea that the supernova remnants can be products of an off-centered supernova explosion in a preexisting bubble created by the wind of a moving massive star. A cavity supernova explosion of a moving star results in a considerable offset of the neutron star birth-place from the geometrical center of the supernova remnant. Therefore: a) the high transverse velocities inferred for a number of neutron stars through their association with supernova remnants can be reduced; b) the proper motion vector of a neutron star should not necessarily point away from the geometrical center of the associated supernova remnant. Taking into account these two facts allow us to enlarge the circle of possible neutron star/supernova remnant associations, and could significantly affect the results of previous studies of associations. The possibilities of our approach are illustrated with some examples. We also show that the concept of an off-centered cavity supernova explosion could be used to explain the peculiar structures of a number of supernova remnants and for searches for stellar remnants possibly associated with them.

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.

Supernovae, supernebulae, and nucleosynthesis

NASA Astrophysics Data System (ADS)

Wheeler, J. Craig; Harkness, Robert P.; Barkat, Zalman; Swartz, Douglas

1986-10-01

Supernova atmosphere calculations continue to show that variants of previously calculated carbon-deflagration models provide a good representation of the maximum light spectra of classical type Ia supernovae including the ultraviolet deficit. Careful consideration of the conditions leading to central thermonuclear runaway of degenerate carbon shows that runaway can, however, lead to detonation and direct conflict with observations. As witnessed by the spectra of type Ib supernovae, massive stars are expected to be the primary source of oxygen. Estimates of the absolute production of oxygen in massive stars suggest that if all stars more massive than ≡12 M_sun; explode as supernovae, oxygen would be overproduced in the solar neighborhood, an effect exacerbated by the recent increase in the reaction rate for 12C(α, γ)16O.

KamLAND Sensitivity to Neutrinos from Pre-Supernova Stars

DOE PAGES

Asakura, K.; Gando, A.; Gando, Y.; ...

2016-02-10

In the late stages of nuclear burning for massive stars (M > 8 M ⊙), the production of neutrino-antineutrino pairs through various processes becomes the dominant stellar cooling mechanism. Furthermore, as the star evolves, the energy of these neutrinos increases and in the days preceding the supernova a significant fraction of emitted electron anti-neutrinos exceeds the energy threshold for inverse beta decay on free hydrogen. This is the golden channel for liquid scintillator detectors because the coincidence signature allows for significant reductions in background signals. Here, we find that the kiloton-scale liquid scintillator detector KamLAND can detect these pre-supernova neutrinosmore » from a star with a mass of 25 M ⊙ at a distance less than 690 pc with 3σ significance before the supernova. This limit is dependent on the neutrino mass ordering and background levels. KamLAND takes data continuously and can provide a supernova alert to the community.« less

A surge of light at the birth of a supernova.

PubMed

Bersten, M C; Folatelli, G; García, F; Van Dyk, S D; Benvenuto, O G; Orellana, M; Buso, V; Sánchez, J L; Tanaka, M; Maeda, K; Filippenko, A V; Zheng, W; Brink, T G; Cenko, S B; de Jaeger, T; Kumar, S; Moriya, T J; Nomoto, K; Perley, D A; Shivvers, I; Smith, N

2018-02-21

It is difficult to establish the properties of massive stars that explode as supernovae. The electromagnetic emission during the first minutes to hours after the emergence of the shock from the stellar surface conveys important information about the final evolution and structure of the exploding star. However, the unpredictable nature of supernova events hinders the detection of this brief initial phase. Here we report the serendipitous discovery of a newly born, normal type IIb supernova (SN 2016gkg), which reveals a rapid brightening at optical wavelengths of about 40 magnitudes per day. The very frequent sampling of the observations allowed us to study in detail the outermost structure of the progenitor of the supernova and the physics of the emergence of the shock. We develop hydrodynamical models of the explosion that naturally account for the complete evolution of the supernova over distinct phases regulated by different physical processes. This result suggests that it is appropriate to decouple the treatment of the shock propagation from the unknown mechanism that triggers the explosion.

A surge of light at the birth of a supernova

NASA Astrophysics Data System (ADS)

Bersten, M. C.; Folatelli, G.; García, F.; van Dyk, S. D.; Benvenuto, O. G.; Orellana, M.; Buso, V.; Sánchez, J. L.; Tanaka, M.; Maeda, K.; Filippenko, A. V.; Zheng, W.; Brink, T. G.; Cenko, S. B.; de Jaeger, T.; Kumar, S.; Moriya, T. J.; Nomoto, K.; Perley, D. A.; Shivvers, I.; Smith, N.

2018-02-01

It is difficult to establish the properties of massive stars that explode as supernovae. The electromagnetic emission during the first minutes to hours after the emergence of the shock from the stellar surface conveys important information about the final evolution and structure of the exploding star. However, the unpredictable nature of supernova events hinders the detection of this brief initial phase. Here we report the serendipitous discovery of a newly born, normal type IIb supernova (SN 2016gkg), which reveals a rapid brightening at optical wavelengths of about 40 magnitudes per day. The very frequent sampling of the observations allowed us to study in detail the outermost structure of the progenitor of the supernova and the physics of the emergence of the shock. We develop hydrodynamical models of the explosion that naturally account for the complete evolution of the supernova over distinct phases regulated by different physical processes. This result suggests that it is appropriate to decouple the treatment of the shock propagation from the unknown mechanism that triggers the explosion.

The first ten years of Swift supernovae

NASA Astrophysics Data System (ADS)

Brown, Peter J.; Roming, Peter W. A.; Milne, Peter A.

2015-09-01

The Swift Gamma Ray Burst Explorer has proven to be an incredible platform for studying the multiwavelength properties of supernova explosions. In its first ten years, Swift has observed over three hundred supernovae. The ultraviolet observations reveal a complex diversity of behavior across supernova types and classes. Even amongst the standard candle type Ia supernovae, ultraviolet observations reveal distinct groups. When the UVOT data is combined with higher redshift optical data, the relative populations of these groups appear to change with redshift. Among core-collapse supernovae, Swift discovered the shock breakout of two supernovae and the Swift data show a diversity in the cooling phase of the shock breakout of supernovae discovered from the ground and promptly followed up with Swift. Swift observations have resulted in an incredible dataset of UV and X-ray data for comparison with high-redshift supernova observations and theoretical models. Swift's supernova program has the potential to dramatically improve our understanding of stellar life and death as well as the history of our universe.

Low-z Type Ia Supernova Calibration

NASA Astrophysics Data System (ADS)

Hamuy, Mario

The discovery of acceleration and dark energy in 1998 arguably constitutes one of the most revolutionary discoveries in astrophysics in recent years. This paradigm shift was possible thanks to one of the most traditional cosmological tests: the redshift-distance relation between galaxies. This discovery was based on a differential measurement of the expansion rate of the universe: the current one provided by nearby (low-z) type Ia supernovae and the one in the past measured from distant (high-z) supernovae. This paper focuses on the first part of this journey: the calibration of the type Ia supernova luminosities and the local expansion rate of the universe, which was made possible thanks to the introduction of digital CCD (charge-coupled device) digital photometry. The new technology permitted us in the early 1990s to convert supernovae as precise tools to measure extragalactic distances through two key surveys: (1) the "Tololo Supernova Program" which made possible the critical discovery of the "peak luminosity-decline rate" relation for type Ia supernovae, the key underlying idea today behind precise cosmology from supernovae, and (2) the Calán/Tololo project which provided the low - z type Ia supernova sample for the discovery of acceleration.

Gamma-ray transfer and energy deposition in supernovae

NASA Technical Reports Server (NTRS)

Swartz, Douglas A.; Sutherland, Peter G.; Harkness, Robert P.

1995-01-01

Solutions to the energy-independent (gray) radiative transfer equations are compared to results of Monte Carlo simulations of the Ni-56 and Co-56 decay gamma-ray energy deposition in supernovae. The comparison shows that an effective, purely absorptive, gray opacity, kappa(sub gamma) approximately (0. 06 +/- 0.01)Y(sub e) sq cm/g, where Y is the total number of electrons per baryon, accurately describes the interaction of gamma-rays with the cool supernova gas and the local gamma-ray energy deposition within the gas. The nature of the gamma-ray interaction process (dominated by Compton scattering in the relativistic regime) creates a weak dependence of kappa(sub gamma) on the optical thickness of the (spherically symmetric) supernova atmosphere: The maximum value of kappa(sub gamma) applies during optically thick conditions when individual gamma-rays undergo multiple scattering encounters and the lower bound is reached at the phase characterized by a total Thomson optical depth to the center of the atmosphere tau(sub e) approximately less than 1. Gamma-ray deposition for Type Ia supernova models to within 10% for the epoch from maximum light to t = 1200 days. Our results quantitatively confirm that the quick and efficient solution to the gray transfer problem provides an accurate representation of gamma-ray energy deposition for a broad range of supernova conditions.

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.

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

The influence of collective neutrino oscillations on a supernova r process

NASA Astrophysics Data System (ADS)

Duan, Huaiyu; Friedland, Alexander; McLaughlin, Gail C.; Surman, Rebecca

2011-03-01

Recently, it has been demonstrated that neutrinos in a supernova oscillate collectively. This process occurs much deeper than the conventional matter-induced Mikheyev-Smirnov-Wolfenstein effect and hence may have an impact on nucleosynthesis. In this paper we explore the effects of collective neutrino oscillations on the r-process, using representative late-time neutrino spectra and outflow models. We find that accurate modeling of the collective oscillations is essential for this analysis. As an illustration, the often-used 'single-angle' approximation makes grossly inaccurate predictions for the yields in our setup. With the proper multiangle treatment, the effect of the oscillations is found to be less dramatic, but still significant. Since the oscillation patterns are sensitive to the details of the emitted fluxes and the sign of the neutrino mass hierarchy, so are the r-process yields. The magnitude of the effect also depends sensitively on the astrophysical conditions—in particular on the interplay between the time when nuclei begin to exist in significant numbers and the time when the collective oscillation begins. A more definitive understanding of the astrophysical conditions, and accurate modeling of the collective oscillations for those conditions, is necessary.

Cosmic Ray Production in Supernovae

NASA Astrophysics Data System (ADS)

Bykov, A. M.; Ellison, D. C.; Marcowith, A.; Osipov, S. M.

2018-02-01

We give a brief review of the origin and acceleration of cosmic rays (CRs), emphasizing the production of CRs at different stages of supernova evolution by the first-order Fermi shock acceleration mechanism. We suggest that supernovae with trans-relativistic outflows, despite being rather rare, may accelerate CRs to energies above 10^{18} eV over the first year of their evolution. Supernovae in young compact clusters of massive stars, and interaction powered superluminous supernovae, may accelerate CRs well above the PeV regime. We discuss the acceleration of the bulk of the galactic CRs in isolated supernova remnants and re-acceleration of escaped CRs by the multiple shocks present in superbubbles produced by associations of OB stars. The effects of magnetic field amplification by CR driven instabilities, as well as superdiffusive CR transport, are discussed for nonthermal radiation produced by nonlinear shocks of all speeds including trans-relativistic ones.

The End of Days -- Chandra Catches X-ray Glow From Supernova

NASA Astrophysics Data System (ADS)

1999-12-01

Through a combination of serendipity and skill, scientists have used NASA's Chandra X-ray Observatory to capture a rare glimpse of X-radiation from the early phases of a supernova, one of the most violent events in nature. Although more than a thousand supernovas have been observed by optical astronomers, the early X-ray glow from the explosions has been detected in less than a dozen cases. The Chandra observations were made under the direction of a team of scientists from the Massachusetts Institute of Technology (MIT) in Cambridge, led by Walter Lewin and his graduate student, Derek Fox. When combined with simultaneous observations by radio and optical telescopes, the X-ray observations tell about the thickness of the shell that was blown off, its density, its speed, and how much material was shed by the star before it exploded. Chandra observed an X-ray glow from SN1999em with the total power of 50,000 suns. Ten days later it observed the supernova for another nine hours, and found that the X rays had faded to half their previous intensity. The optical luminosity, which had the brightness of 200 million suns, had faded somewhat less. No radio emission was detected at any time. With this information, the MIT group and their colleagues are already piecing together a picture of the catastrophic explosion. Observations by optical astronomers showed that SN1999em was a Type II supernova produced by the collapse of the core of a star ten or more times as massive as the Sun. The intense heat generated in the collapse produces a cataclysmic rebound that sends high speed debris flying outward at speeds in excess of 20 million miles per hour. The debris crashes into matter shed by the former star before the explosion. This awesome collision generates shock waves that heat expanding debris to three million degrees. The X-ray glow from this hot gas was detected by Chandra and gives astrophysicists a better understanding of the dynamics of the explosion, as well as the

Diagnostics of the Supernova Engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fryer, Chris L.; Ellinger, Carola; Young, Patrick A.

The standard engine behind core-collapse supernovae is continuously evolving with increasingly detailed models. At this time, most simulations focus on an engine invoking turbulence above the proto-neutron star, sometimes termed the “convection-enhanced” engine. Finally, we review this engine and why it has become the standard for normal supernovae, focusing on a wide set of observations that provide insight into the supernova engine.

Diagnostics of the Supernova Engine

DOE PAGES

Fryer, Chris L.; Ellinger, Carola; Young, Patrick A.; ...

2017-10-17

The standard engine behind core-collapse supernovae is continuously evolving with increasingly detailed models. At this time, most simulations focus on an engine invoking turbulence above the proto-neutron star, sometimes termed the “convection-enhanced” engine. Finally, we review this engine and why it has become the standard for normal supernovae, focusing on a wide set of observations that provide insight into the supernova engine.

Evidence for the Stochastic Acceleration of Secondary Antiprotons by Supernova Remnants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cholis, Ilias; Hooper, Dan; Linden, Tim

2017-01-16

The antiproton-to-proton ratio in the cosmic-ray spectrum is a sensitive probe of new physics. Using recent measurements of the cosmic-ray antiproton and proton fluxes in the energy range of 1-1000 GeV, we study the contribution to themore » $$\\bar{p}/p$$ ratio from secondary antiprotons that are produced and subsequently accelerated within individual supernova remnants. We consider several well-motivated models for cosmic-ray propagation in the interstellar medium and marginalize our results over the uncertainties related to the antiproton production cross section and the time-, charge-, and energy-dependent effects of solar modulation. We find that the increase in the $$\\bar{p}/p$$ ratio observed at rigidities above $$\\sim$$ 100 GV cannot be accounted for within the context of conventional cosmic-ray propagation models, but is consistent with scenarios in which cosmic-ray antiprotons are produced and subsequently accelerated by shocks within a given supernova remnant. In light of this, the acceleration of secondary cosmic rays in supernova remnants is predicted to substantially contribute to the cosmic-ray positron spectrum, accounting for a significant fraction of the observed positron excess.« less

Neutrino signal from pair-instability supernovae

NASA Astrophysics Data System (ADS)

Wright, Warren P.; Gilmer, Matthew S.; Fröhlich, Carla; Kneller, James P.

2017-11-01

A very massive star with a carbon-oxygen core in the range of 64M ⊙supernova. Pair-instability supernovae are candidates for superluminous supernovae due to the prodigious amounts of radioactive elements they create. While the basic mechanism for the explosion is understood, how a star reaches a state is not, and thus observations of a nearby pair-instability supernova would allow us to test current models of stellar evolution at the extreme of stellar masses. Much will be sought within the electromagnetic radiation we detect from such a supernova but we should not forget that the neutrinos from a pair-instability supernova contain unique signatures of the event that unambiguously identify this type of explosion. We calculate the expected neutrino flux at Earth from two, one-dimensional pair-instability supernova simulations which bracket the mass range of stars which explode by this mechanism taking into account the full time and energy dependence of the neutrino emission and the flavor evolution through the outer layers of the star. We calculate the neutrino signals in five different detectors chosen to represent present or near future designs. We find the more massive progenitors explode as pair-instability supernova which can easily be detected in multiple different neutrino detectors at the "standard" supernova distance of 10 kpc producing several events in DUNE, JUNO, and Super-Kamiokande, while the lightest progenitors produce only a handful of events (if any) in the same detectors. The proposed Hyper-Kamiokande detector would detect neutrinos from a large pair-instability supernova as far as ˜50 kpc allowing it to reach the Megallanic Clouds and the several very high mass stars known to exist there.

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.

The binary progenitor of Tycho Brahe's 1572 supernova.

PubMed

Ruiz-Lapuente, Pilar; Comeron, Fernando; Méndez, Javier; Canal, Ramon; Smartt, Stephen J; Filippenko, Alexei V; Kurucz, Robert L; Chornock, Ryan; Foley, Ryan J; Stanishev, Vallery; Ibata, Rodrigo

2004-10-28

The brightness of type Ia supernovae, and their homogeneity as a class, makes them powerful tools in cosmology, yet little is known about the progenitor systems of these explosions. They are thought to arise when a white dwarf accretes matter from a companion star, is compressed and undergoes a thermonuclear explosion. Unless the companion star is another white dwarf (in which case it should be destroyed by the mass-transfer process itself), it should survive and show distinguishing properties. Tycho's supernova is one of only two type Ia supernovae observed in our Galaxy, and so provides an opportunity to address observationally the identification of the surviving companion. Here we report a survey of the central region of its remnant, around the position of the explosion, which excludes red giants as the mass donor of the exploding white dwarf. We found a type G0-G2 star, similar to our Sun in surface temperature and luminosity (but lower surface gravity), moving at more than three times the mean velocity of the stars at that distance, which appears to be the surviving companion of the supernova.

Understanding Core-Collapse Supernovae

NASA Astrophysics Data System (ADS)

Hix, W. R.; Lentz, E. J.; Baird, M.; Messer, O. E. B.; Mezzacappa, A.; Lee, C.-T.; Bruenn, S. W.; Blondin, J. M.; Marronetti, P.

2010-03-01

Our understanding of core-collapse supernovae continues to improve as better microphysics is included in increasingly realistic neutrino-radiationhydrodynamic simulations. Recent multi-dimensional models with spectral neutrino transport, which slowly develop successful explosions for a range of progenitors between 12 and 25 solar mass, 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 progresses on both the macroscopic and microscopic effects that affect core-collapse supernovae are discussed.

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.

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.

Detection of Neutrinos from Galactic and Cosmic Supernovae

NASA Astrophysics Data System (ADS)

Beacom, John

2010-11-01

Detecting neutrinos is the key to understanding core-collapse supernovae, but this is notoriously difficult due to the small interaction cross section of neutrinos and the low frequency of supernovae. The prospects for detecting Galactic supernovae depend almost completely on the probability of a fluctuation from the low supernova rate; the detection aspects are largely under control. The prospects for detecting Cosmic supernovae instead depend almost completely on the detection aspects, especially regarding reducing detector backgrounds; the supernova rate and neutrino flux of the universe are now rather well measured or predicted. After decades of effort and patience, we have good reasons to anticipate that detecting supernova neutrinos is within reach.

Active-Site Hydration and Water Diffusion in Cytochrome P450cam: A Highly Dynamic Process

PubMed Central

Miao, Yinglong; Baudry, Jerome

2011-01-01

Long-timescale molecular dynamics simulations (300 ns) are performed on both the apo- (i.e., camphor-free) and camphor-bound cytochrome P450cam (CYP101). Water diffusion into and out of the protein active site is observed without biased sampling methods. During the course of the molecular dynamics simulation, an average of 6.4 water molecules is observed in the camphor-binding site of the apo form, compared to zero water molecules in the binding site of the substrate-bound form, in agreement with the number of water molecules observed in crystal structures of the same species. However, as many as 12 water molecules can be present at a given time in the camphor-binding region of the active site in the case of apo-P450cam, revealing a highly dynamic process for hydration of the protein active site, with water molecules exchanging rapidly with the bulk solvent. Water molecules are also found to exchange locations frequently inside the active site, preferentially clustering in regions surrounding the water molecules observed in the crystal structure. Potential-of-mean-force calculations identify thermodynamically favored trans-protein pathways for the diffusion of water molecules between the protein active site and the bulk solvent. Binding of camphor in the active site modifies the free-energy landscape of P450cam channels toward favoring the diffusion of water molecules out of the protein active site. PMID:21943431

An Open Catalog for Supernova Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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 parsingmore » 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.« less

Detectability of galactic supernova neutrinos coherently scattered on xenon nuclei in XMASS

NASA Astrophysics Data System (ADS)

Abe, K.; Hiraide, K.; Ichimura, K.; Kishimoto, Y.; Kobayashi, K.; Kobayashi, M.; Moriyama, S.; Nakagawa, K.; Nakahata, M.; Norita, T.; Ogawa, H.; Sekiya, H.; Takachio, O.; Takeda, A.; Yamashita, M.; Yang, B. S.; Kim, N. Y.; Kim, Y. D.; Tasaka, S.; Liu, J.; Martens, K.; Suzuki, Y.; Fujita, R.; Hosokawa, K.; Miuchi, K.; Oka, N.; Onishi, Y.; Takeuchi, Y.; Kim, Y. H.; Lee, J. S.; Lee, K. B.; Lee, M. K.; Fukuda, Y.; Itow, Y.; Kegasa, R.; Kobayashi, K.; Masuda, K.; Takiya, H.; Uchida, H.; Nishijima, K.; Fujii, K.; Murayama, I.; Nakamura, S.; Xmass Collaboration

2017-03-01

The coherent elastic neutrino-nucleus scattering (CEvNS) plays a crucial role at the final evolution of stars. The detection of it would be of importance in astroparticle physics. Among all available neutrino sources, galactic supernovae give the highest neutrino flux in the MeV range. Among all liquid xenon dark matter experiments, XMASS has the largest sensitive volume and light yield. The possibility to detect galactic supernova via the CEvNS-process on xenon nuclei in the current XMASS detector was investigated. The total number of events integrated in about 18 s after the explosion of a supernova 10 kpc away from the Earth was expected to be from 3.5 to 21.1, depending on the supernova model used to predict the neutrino flux, while the number of background events in the same time window was measured to be negligible. All lead to very high possibility to detect CEvNS experimentally for the first time utilizing the combination of galactic supernovae and the XMASS detector. In case of a supernova explosion as close as Betelgeuse, the total observable events can be more than ∼ 104, making it possible to distinguish different supernova models by examining the evolution of neutrino event rate in XMASS.

Neutrino Emission from Supernovae

NASA Astrophysics Data System (ADS)

Janka, Hans-Thomas

Supernovae are the most powerful cosmic sources of MeV neutrinos. These elementary particles play a crucial role when the evolution of a massive star is terminated by the collapse of its core to a neutron star or a black hole and the star explodes as supernova. The release of electron neutrinos, which are abundantly produced by electron captures, accelerates the catastrophic infall and causes a gradual neutronization of the stellar plasma by converting protons to neutrons as dominant constituents of neutron star matter. The emission of neutrinos and antineutrinos of all flavors carries away the gravitational binding energy of the compact remnant and drives its evolution from the hot initial to the cold final state. The absorption of electron neutrinos and antineutrinos in the surroundings of the newly formed neutron star can power the supernova explosion and determines the conditions in the innermost supernova ejecta, making them an interesting site for the nucleosynthesis of iron-group elements and trans-iron nuclei.

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.

Diffuse remnants of supernova explosions of moving massive stars

NASA Astrophysics Data System (ADS)

Gvaramadze, V. V.

The modification of the ambient interstellar medium by the wind of massive stars (the progenitors of most of supernovae) results in that the structure and evolution of diffuse supernova remnants (SNRs) significantly deviate from those derived from standard models of SNRs based of the Sedov-Taylor solution. The stellar proper motion and the regular interstellar magnetic field affect the symmetry of the processed medium and cause the SNR to be non-spherically-symmetric. We show that taking into account these effects allows us to explain the diverse morphologies of the known SNRs (the particular attention is paid to the elongated axisymmetric SNRs and the SNRs consisting of two partially overlapping shells) and to infer the ``true" supernova explosion sites in some peculiar SNRs (therefore to search for new neutron stars associated with them).

NASA Scientists Witness a Supernova Cosmic Rite of Passage

NASA Astrophysics Data System (ADS)

2005-11-01

Scientists using NASA's Chandra X-ray Observatory have witnessed a cosmic rite of passage, the transition from a supernova to a supernova remnant, a process that has never been seen in much detail until now, leaving it poorly defined. A supernova is a massive star explosion; the remnant is the beautiful glowing shell that evolves afterwards. When does a supernova become supernova remnant? When does the shell appear and what powers its radiant glow? A science team led by Dr. Stefan Immler of NASA's Goddard Space Flight Center, Greenbelt, Md., has taken a fresh look at a supernova that exploded in 1970, called SN 1970G, just off the handle of the Big Dipper. This is the oldest supernova ever seen by X-ray telescopes. Chandra X-ray Image of SN 1970G Chandra X-ray Image of SN 1970G "Some astronomers have thought there's a moment when the supernova remnant magically turns on years after the supernova itself has faded away, when the shock wave of the explosion finally hits and lights up the interstellar medium," said Immler. "By contrast, our results show that a new supernova quickly and seamlessly evolves into a supernova remnant. The star's own debris, and not the interstellar medium gas, fuels the remnant." These results appear in The Astrophysical Journal, co-authored by Dr. Kip Kuntz, also of Goddard. They support previous Chandra observations of SN 1987A by Dr. Sangwook Park of Penn State. Using new data from Chandra and archived data from the European-led ROSAT and XMM-Newton observatories, Immler and Kuntz pieced together how SN 1970G evolved over the years. They found telltale signs of a supernova remnant - bright X-ray light - yet no evidence of interstellar gas, even across a distance around the site of the explosion 35 times larger than our solar system. Instead, the material that is heated by the supernova shock to glow in X-ray light, what we call the remnant, is from the stellar wind of the star itself and not distant gas in the interstellar medium. This

Supernova 2007bi as a pair-instability explosion.

PubMed

Gal-Yam, A; Mazzali, P; Ofek, E O; Nugent, P E; Kulkarni, S R; Kasliwal, M M; Quimby, R M; Filippenko, A V; Cenko, S B; Chornock, R; Waldman, R; Kasen, D; Sullivan, M; Beshore, E C; Drake, A J; Thomas, R C; Bloom, J S; Poznanski, D; Miller, A A; Foley, R J; Silverman, J M; Arcavi, I; Ellis, R S; Deng, J

2009-12-03

Stars with initial masses such that 10M[symbol: see text] supernova. By contrast, extremely massive stars with M(initial) >or= 140M[symbol: see text] (if such exist) develop oxygen cores with masses, M(core), that exceed 50M[symbol: see text], where high temperatures are reached at relatively low densities. Conversion of energetic, pressure-supporting photons into electron-positron pairs occurs before oxygen ignition and leads to a violent contraction which triggers a nuclear explosion that unbinds the star in a pair-instability supernova. Transitional objects with 100M[symbol: see text] < M(initial) < 140M[symbol: see text] may end up as iron-core-collapse supernovae following violent mass ejections, perhaps as a result of brief episodes of pair instability, and may already have been identified. Here we report observations of supernova SN 2007bi, a luminous, slowly evolving object located within a dwarf galaxy. We estimate the exploding core mass to be M(core) approximately 100M[symbol: see text], in which case theory unambiguously predicts a pair-instability supernova. We show that >3M[symbol: see text] of radioactive (56)Ni was synthesized during the explosion and that our observations are well fitted by models of pair-instability supernovae. This indicates that nearby dwarf galaxies probably host extremely massive stars, above the apparent Galactic stellar mass limit, which perhaps result from processes similar to those that created the first stars in the Universe.

X-ray emission from reverse-shocked ejecta in supernova remnants

NASA Technical Reports Server (NTRS)

Cioffi, Denis F.; Mckee, Christopher F.

1990-01-01

A simple physical model of the dynamics of a young supernova remnant is used to derive a straightforward kinematical description of the reverse shock. With suitable approximations, formulae can then be developed to give the X-ray emission of the reverse-shocked ejecta. The results are found to agree favorably with observations of SN1006.

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

New prospects for detecting high-energy neutrinos from nearby supernovae

NASA Astrophysics Data System (ADS)

Murase, Kohta

2018-04-01

Neutrinos from supernovae (SNe) are crucial probes of explosive phenomena at the deaths of massive stars and neutrino physics. High-energy neutrinos are produced through hadronic processes by cosmic rays, which are accelerated during interaction between the supernova (SN) ejecta and circumstellar material (CSM). Recent observations of extragalactic SNe have revealed that a dense CSM is commonly expelled by the progenitor star. We provide new quantitative predictions of time-dependent high-energy neutrino emission from diverse types of SNe. We show that IceCube and KM3Net can detect ˜103 events from a SN II-P (and ˜3 ×105 events from a SN IIn) at a distance of 10 kpc. The new model also enables us to critically optimize the time window for dedicated searches for nearby SNe. A successful detection will give us a multienergy neutrino view of SN physics and new opportunities to study neutrino properties, as well as clues to the cosmic-ray origin. GeV-TeV neutrinos may also be seen by KM3Net, Hyper-Kamiokande, and PINGU.

SUPERNOVAE, NEUTRON STARS, AND TWO KINDS OF NEUTRINO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chiu, H.Y.

1962-08-15

The role of neutrinos in the core of a star that has undergone a supernova explosion is discussed. The existence of neutron stars, the Schwarzchild singularity in general relativity, and the meaning of conservation of baryons in the neighborhood of a Schwarzchild singularity are also considered. The problem of detection of neutron stars is discussed. It is concluded that neutron stars are the most plausible alternative for the remnant of the core of a supernova. The neutrino emission processes are divided into two groups: the neutrino associated with the meson (mu) and the production of electron neutrinos. (C.E.S.)

The ASAS-SN bright supernova catalogue - III. 2016

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.; Bose, S.; Beacom, J. F.; Bersier, D.; Chen, Ping; Chomiuk, L.; Falco, E.; Godoy-Rivera, D.; Morrell, N.; Pojmanski, G.; Shields, J. V.; Strader, J.; Stritzinger, M. D.; Thompson, Todd A.; Woźniak, P. R.; Bock, G.; Cacella, P.; Conseil, E.; Cruz, I.; Fernandez, J. M.; Kiyota, S.; Koff, R. A.; Krannich, G.; Marples, P.; Masi, G.; Monard, L. A. G.; Nicholls, B.; Nicolas, J.; Post, R. S.; Stone, G.; Wiethoff, W. S.

2017-11-01

This catalogue summarizes information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) and all other bright (mpeak ≤ 17), spectroscopically confirmed supernovae discovered in 2016. We then gather the near-infrared through ultraviolet magnitudes of all host galaxies and the offsets of the supernovae from the centres of their hosts from public data bases. We illustrate the results using a sample that now totals 668 supernovae discovered since 2014 May 1, including the supernovae from our previous catalogues, with type distributions closely matching those of the ideal magnitude limited sample from Li et al. This is the third of a series of yearly papers on bright supernovae and their hosts from the ASAS-SN team.

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.

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).

Supernovae Discovery Efficiency

NASA Astrophysics Data System (ADS)

John, Colin

2018-01-01

Abstract:We present supernovae (SN) search efficiency measurements for recent Hubble Space Telescope (HST) surveys. Efficiency is a key component to any search, and is important parameter as a correction factor for SN rates. To achieve an accurate value for efficiency, many supernovae need to be discoverable in surveys. This cannot be achieved from real SN only, due to their scarcity, so fake SN are planted. These fake supernovae—with a goal of realism in mind—yield an understanding of efficiency based on position related to other celestial objects, and brightness. To improve realism, we built a more accurate model of supernovae using a point-spread function. The next improvement to realism is planting these objects close to galaxies and of various parameters of brightness, magnitude, local galactic brightness and redshift. Once these are planted, a very accurate SN is visible and discoverable by the searcher. It is very important to find factors that affect this discovery efficiency. Exploring the factors that effect detection yields a more accurate correction factor. Further inquires into efficiency give us a better understanding of image processing, searching techniques and survey strategies, and result in an overall higher likelihood to find these events in future surveys with Hubble, James Webb, and WFIRST telescopes. After efficiency is discovered and refined with many unique surveys, it factors into measurements of SN rates versus redshift. By comparing SN rates vs redshift against the star formation rate we can test models to determine how long star systems take from the point of inception to explosion (delay time distribution). This delay time distribution is compared to SN progenitors models to get an accurate idea of what these stars were like before their deaths.

High Redshift Supernova Search

Science.gov Websites

;on schedule." Before-and-after pictures (and Hubble Space Telescope picture) of a high-redshift High Redshift Supernova Search Home Page of the Supernova Cosmology Project This is the Lawrence Foretell Fate of the Universe." Pictures from the ground and from the Hubble Space Telescope: [PDF

Models for Supernovae and Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Woosley, Stan

Supernovae and gamma-ray bursts are the brightest stellar mass explosions in the universe. As such, they serve as cosmic beacons for probing cosmic structure and diagnosing the properties of stars and the universe when it was young. They also produce black holes and neutron stars, interesting in themselves as laboratories where exotic physics comes into play, and they make the elements from which life arises. Consequently, supernovae and gamma-ray bursts are subject to intense study by many NASA missions. We propose focused studies in five areas of supernova research that are directly relevant to NASA's missions, especially SWIFT, HST, JWST, and planning for WFIRST. Our specific topics are a) models for Type Ia supernovae; b) extreme supernovae and first supernovae; c) magnetar-powered supernovae; d) ultra-long duration gamma-ray bursts; and e) shock breakout in supernovae. These phenomena all have in common their importance to NASA missions and the fact that they can be studied using similar tools - computer codes that do radiation hydrodynamics. Our two principal codes, KEPLER (one-dimension) and CASTRO (one to three dimensions), have been honed to the task by years of supernova modeling, and have some unique capabilities. Type Ia supernovae have long been of interest to NASA, but their importance has increased lately because of their utility in determining cosmic distances and because a string of recent observational breakthroughs has severely limited their progenitors. Responding to these developments, we propose to focus on a class of model we have previously neglected, the merger of two white dwarfs. The mergers will be studied with KEPLER and CASTRO in one and two dimensions, and the spectra and light curves determined. The library of model results will be useful in interpreting the results of present NASA missions and planning new ones. A second important area of investigation will be the study of first generation stars and the supernovae that they produce

Detection of a Very Bright Source Close to the LMC Supernova SN 1987A: Erratum

NASA Astrophysics Data System (ADS)

Nisenson, P.; Papaliolios, C.; Karovska, M.; Noyes, R.

1988-01-01

In the Letter "Detection of a Very Bright Source Close to the LMC Supernova SN 1987A" by P. Nisenson, C. Papaliolios, M. Karovska, and R. Noyes (1987 Ap. J. [Letters], 320, L15), two of the figure labels for Figure 1 were inadvertently transposed in the production process. A corrected version of the figure appears as Plate L4. The Journal regrets the error.

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

A faint type of supernova from a white dwarf with a helium-rich companion.

PubMed

Perets, H B; Gal-Yam, A; Mazzali, P A; Arnett, D; Kagan, D; Filippenko, A V; Li, W; Arcavi, I; Cenko, S B; Fox, D B; Leonard, D C; Moon, D-S; Sand, D J; Soderberg, A M; Anderson, J P; James, P A; Foley, R J; Ganeshalingam, M; Ofek, E O; Bildsten, L; Nelemans, G; Shen, K J; Weinberg, N N; Metzger, B D; Piro, A L; Quataert, E; Kiewe, M; Poznanski, D

2010-05-20

Supernovae are thought to arise from two different physical processes. The cores of massive, short-lived stars undergo gravitational core collapse and typically eject a few solar masses during their explosion. These are thought to appear as type Ib/c and type II supernovae, and are associated with young stellar populations. In contrast, the thermonuclear detonation of a carbon-oxygen white dwarf, whose mass approaches the Chandrasekhar limit, is thought to produce type Ia supernovae. Such supernovae are observed in both young and old stellar environments. Here we report a faint type Ib supernova, SN 2005E, in the halo of the nearby isolated galaxy, NGC 1032. The 'old' environment near the supernova location, and the very low derived ejected mass ( approximately 0.3 solar masses), argue strongly against a core-collapse origin. Spectroscopic observations and analysis reveal high ejecta velocities, dominated by helium-burning products, probably excluding this as a subluminous or a regular type Ia supernova. We conclude that it arises from a low-mass, old progenitor, likely to have been a helium-accreting white dwarf in a binary. The ejecta contain more calcium than observed in other types of supernovae and probably large amounts of radioactive (44)Ti.

The distant type Ia supernova rate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pain, R.; Fabbro, S.; Sullivan, M.

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 = 1more » 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.« less

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.

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.

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.

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.

Molecular dynamics for dense matter

NASA Astrophysics Data System (ADS)

Maruyama, Toshiki; Watanabe, Gentaro; Chiba, Satoshi

2012-08-01

We review a molecular dynamics method for nucleon many-body systems called quantum molecular dynamics (QMD), and our studies using this method. These studies address the structure and the dynamics of nuclear matter relevant to neutron star crusts, supernova cores, and heavy-ion collisions. A key advantage of QMD is that we can study dynamical processes of nucleon many-body systems without any assumptions about the nuclear structure. First, we focus on the inhomogeneous structures of low-density nuclear matter consisting not only of spherical nuclei but also of nuclear "pasta", i.e., rod-like and slab-like nuclei. We show that pasta phases can appear in the ground and equilibrium states of nuclear matter without assuming nuclear shape. Next, we show our simulation of compression of nuclear matter which corresponds to the collapsing stage of supernovae. With the increase in density, a crystalline solid of spherical nuclei changes to a triangular lattice of rods by connecting neighboring nuclei. Finally, we discuss fragment formation in expanding nuclear matter. Our results suggest that a generally accepted scenario based on the liquid-gas phase transition is not plausible at lower temperatures.

Multidimensional simulations of core-collapse supernovae with CHIMERA

NASA Astrophysics Data System (ADS)

Lentz, Eric J.; Bruenn, S. W.; Yakunin, K.; Endeve, E.; Blondin, J. M.; Harris, J. A.; Hix, W. R.; Marronetti, P.; Messer, O. B.; Mezzacappa, A.

2014-01-01

Core-collapse supernovae are driven by a multidimensional neutrino radiation hydrodynamic (RHD) engine, and full simulation requires at least axisymmetric (2D) and ultimately symmetry-free 3D RHD simulation. We present recent and ongoing work with our multidimensional RHD supernova code CHIMERA to understand the nature of the core-collapse explosion mechanism and its consequences. Recently completed simulations of 12-25 solar mass progenitors(Woosley & Heger 2007) in well resolved (0.7 degrees in latitude) 2D simulations exhibit robust explosions meeting the observationally expected explosion energy. We examine the role of hydrodynamic instabilities (standing accretion shock instability, neutrino driven convection, etc.) on the explosion dynamics and the development of the explosion energy. Ongoing 3D and 2D simulations examine the role that simulation resolution and the removal of the imposed axisymmetry have in the triggering and development of an explosion from stellar core collapse. Companion posters will explore the gravitational wave signals (Yakunin et al.) and nucleosynthesis (Harris et al.) of our simulations.

Observing the Next Galactic Supernova with the NOvA Detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vasel, Justin A.; Sheshukov, Andrey; Habig, Alec

The next galactic core-collapse supernova will deliver a wealth of neutrinos which for the first time we are well-situated to measure. These explosions produce neutrinos with energies between 10 and 100 MeV over a period of tens of seconds. Galactic supernovae are relatively rare events, occurring with a frequency of just a few per century. It is therefore essential that all neutrino detectors capable of detecting these neutrinos are ready to trigger on this signal when it occurs. This poster describes a data-driven trigger which is designed to detect the neutrino signal from a galactic core-collapse supernova with the NOvAmore » detectors. The trigger analyzes 5ms blocks of detector activity and applies background rejection algorithms to detect the signal time structure over the background. This background reduction is an essential part of the process, as the NOvA detectors are designed to detect neutrinos from Fermilab's NuMI beam which have an average energy of 2GeV--well above the average energy of supernova neutrinos.« less

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.

The Carnegie Supernova Project: The Low-Redshift Survey

NASA Astrophysics Data System (ADS)

Hamuy, Mario; Folatelli, Gastón; Morrell, Nidia I.; Phillips, Mark M.; Suntzeff, Nicholas B.; Persson, S. E.; Roth, Miguel; Gonzalez, Sergio; Krzeminski, Wojtek; Contreras, Carlos; Freedman, Wendy L.; Murphy, D. C.; Madore, Barry F.; Wyatt, P.; Maza, José; Filippenko, Alexei V.; Li, Weidong; Pinto, P. A.

2006-01-01

Supernovae are essential to understanding the chemical evolution of the universe. Type Ia supernovae also provide the most powerful observational tool currently available for studying the expansion history of the universe and the nature of dark energy. Our basic knowledge of supernovae comes from the study of their photometric and spectroscopic properties. However, the presently available data sets of optical and near-infrared light curves of supernovae are rather small and/or heterogeneous, and employ photometric systems that are poorly characterized. Similarly, there are relatively few supernovae whose spectral evolution has been well sampled, both in wavelength and phase, with precise spectrophotometric observations. The low-redshift portion of the Carnegie Supernova Project (CSP) seeks to remedy this situation by providing photometry and spectrophotometry of a large sample of supernovae taken on telescope/filter/detector systems that are well understood and well characterized. During a 5 year program that began in 2004 September, we expect to obtain high-precision u'g'r'i'BVYJHKs light curves and optical spectrophotometry for about 250 supernovae of all types. In this paper we provide a detailed description of the CSP survey observing and data reduction methodology. In addition, we present preliminary photometry and spectra obtained for a few representative supernovae during the first observing campaign.

NEW EQUATIONS OF STATE IN SIMULATIONS OF CORE-COLLAPSE SUPERNOVAE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hempel, M.; Liebendoerfer, M.; Fischer, T.

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 themore » 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.« less

TESTING THE ROLE OF SNe Ia FOR GALACTIC CHEMICAL EVOLUTION OF p-NUCLEI WITH TWO-DIMENSIONAL MODELS AND WITH s-PROCESS SEEDS AT DIFFERENT METALLICITIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Travaglio, C.; Gallino, R.; Rauscher, T.

2015-01-20

The bulk of p isotopes is created in the ''gamma processes'' mainly by sequences of photodisintegrations and beta decays in explosive conditions in Type Ia supernovae (SNIa) or in core collapse supernovae (ccSN). The contribution of different stellar sources to the observed distribution of p-nuclei in the solar system is still under debate. We explore single degenerate Type Ia supernovae in the framework of two-dimensional SNIa delayed-detonation explosion models. Travaglio et al. discussed the sensitivity of p-nuclei production to different SNIa models, i.e., delayed detonations of different strength, deflagrations, and the dependence on selected s-process seed distributions. Here we present amore » detailed study of p-process nucleosynthesis occurring in SNIa with s-process seeds at different metallicities. Based on the delayed-detonation model DDT-a of TRV11, we analyze the dependence of p-nucleosynthesis on the s-seed distribution obtained from different strengths of the {sup 13}C pocket. We also demonstrate that {sup 208}Pb seed alone changes the p-nuclei production considerably. The heavy-s seeds (140 ≤A < 208) contribute with about 30%-40% to the total light-p nuclei production up to {sup 132}Ba (with the exception of {sup 94}Mo and {sup 130}Ba, to which the heavy-s seeds contribute with about 15% only). Using a Galactic chemical evolution code from Travaglio et al., we study the contribution of SNIa to the solar stable p-nuclei. We find that explosions of Chandrasekhar-mass single degenerate systems produce a large amount of p-nuclei in our Galaxy, both in the range of light (A ≤ 120) and heavy p-nuclei, at almost flat average production factors (within a factor of about three). We discussed in details p-isotopes such as {sup 94}Mo with a behavior diverging from the average, which we attribute to uncertainties in the nuclear data or in SNIa modeling. Li et al. find that about 70% of all SNeIa are normal events. If these are explained in the

The secondary supernova machine: Gravitational compression, stored Coulomb energy, and SNII displays

NASA Astrophysics Data System (ADS)

Clayton, Donald D.; Meyer, Bradley S.

2016-04-01

Radioactive power for several delayed optical displays of core-collapse supernovae is commonly described as having been provided by decays of 56Ni nuclei. This review analyses the provenance of that energy more deeply: the form in which that energy is stored; what mechanical work causes its storage; what conservation laws demand that it be stored; and why its release is fortuitously delayed for about 106 s into a greatly expanded supernova envelope. We call the unifying picture of those energy transfers the secondary supernova machine owing to its machine-like properties; namely, mechanical work forces storage of large increases of nuclear Coulomb energy, a positive energy component within new nuclei synthesized by the secondary machine. That positive-energy increase occurs despite the fusion decreasing negative total energy within nuclei. The excess of the Coulomb energy can later be radiated, accounting for the intense radioactivity in supernovae. Detailed familiarity with this machine is the focus of this review. The stored positive-energy component created by the machine will not be reduced until roughly 106 s later by radioactive emissions (EC and β +) owing to the slowness of weak decays. The delayed energy provided by the secondary supernova machine is a few × 1049 erg, much smaller than the one percent of the 1053 erg collapse that causes the prompt ejection of matter; however, that relatively small stored energy is vital for activation of the late displays. The conceptual basis of the secondary supernova machine provides a new framework for understanding the energy source for late SNII displays. We demonstrate the nuclear dynamics with nuclear network abundance calculations, with a model of sudden compression and reexpansion of the nuclear gas, and with nuclear energy decompositions of a nuclear-mass law. These tools identify excess Coulomb energy, a positive-energy component of the total negative nuclear energy, as the late activation energy. If the

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.

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

Constraining the Origin and Heating Mechanism of Dust in Type IIn Supernovae

NASA Astrophysics Data System (ADS)

Fox, Ori; Skrutskie, Michael; Chevalier, Roger; Moseley, Samuel Harvey

2011-05-01

More than any other supernova subclass, Type IIn supernovae tend to exhibit late-time (>100 days) infrared emission from warm dust. Identifying the origin and heating mechanism of the dust provides an important probe of the supernova explosion, circumstellar environment, and progenitor system. Yet mid-infrared observations, which span the peak of the thermal emission, are rare. Two years ago, we executed a warm Spitzer survey (P60122) of sixty-eight Type IIn events from the past ten years. The survey uncovered nine supernovae with unreported late-time infrared excesses, in some cases more than 5 years post-explosion. From this single epoch of data, and ground-based optical data, we have determined the likely origin of the mid-infrared emission to be pre-existing dust that is continuously heated by optical emission generated by ongoing circumstellar interaction between the forward shock and circumstellar medium. Furthermore, we noticed an emerging trend suggests these supernovae ``turn off'' at ~1000-2000 days post-discovery once the forward shock overruns the dust shell. Now is the ideal time to build upon this work with a second epoch of observations, which will be necessary to constrain our models. If we catch even a single supernova turning off between the first and second epochs of observation, we will be able to both measure the size of the circumstellar dust shell and characterize of the supernova progenitor system. We can obtain all the necessary data in only 9.3 hours of observation. Our team has extensive experience in infrared supernovae observations. We have already published two papers on one Type IIn supernovae (SN 2005ip) and authored two successful proposal for Spitzer observations of this subclass. This is an ideal application for the Spitzer warm mission, as the 3.6 and 4.5 micron bands span the peak of the thermal emission and provide the necessary constraints on the dust temperature, mass, and luminosity.

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.

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.

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.

Inside supernova 1987A

NASA Technical Reports Server (NTRS)

Mccray, Richard; Shull, J. Michael; Sutherland, Peter

1987-01-01

The future evolution of the electromagnetic spectrum of the supernova 1987A is considered. It is shown that conventional models for supernova explosions predict that within several months a spectacular display of X-rays and UV emission lines will be seen from SN 1987A as the envelope expands to reveal the inner debris of the explosion. Two likely scenarios are considered: first, that the debris produces strong gamma rays from radioactive Co-56, and second, that an X-ray-emitting pulsar exists at the center. It is also predicted that a bright infrared echo will soon appear as a result of reprocessing of the optical/ultraviolet light by circumstellar grains; the luminosity of this echo can provide a sensitive test of the mass-loss history of the supernova progenitor.

Broad-band emission properties of central engine powered supernova ejecta interacting with a circumstellar medium

NASA Astrophysics Data System (ADS)

Suzuki, Akihiro; Maeda, Keiichi

2018-04-01

We investigate broad-band emission from supernova ejecta powered by a relativistic wind from a central compact object. A recent two-dimensional hydrodynamic simulation studying the dynamical evolution of supernova ejecta with a central energy source has revealed that outermost layers of the ejecta are accelerated to mildly relativistic velocities because of the breakout of a hot bubble driven by the energy injection. The outermost layers decelerate as they sweep a circumstellar medium surrounding the ejecta, leading to the formation of the forward and reverse shocks propagating in the circumstellar medium and the ejecta. While the ejecta continue to release the internal energy as thermal emission from the photosphere, the energy dissipation at the forward and reverse shock fronts gives rise to non-thermal emission. We calculate light curves and spectral energy distributions of thermal and non-thermal emission from central engine powered supernova ejecta embedded in a steady stellar wind with typical mass loss rates for massive stars. The light curves are compared with currently available radio and X-ray observations of hydrogen-poor superluminous supernovae, as well as the two well-studied broad-lined Ic supernovae, 1998bw and 2009bb, which exhibit bright radio emission indicating central engine activities. We point out that upper limits on radio luminosities of nearby superluminous supernovae may indicate the injected energy is mainly converted to thermal radiation rather than creating mildly relativistic flows owing to photon diffusion time scales comparable to the injection time scale.

The Foundation Supernova Survey: motivation, design, implementation, and first data release

NASA Astrophysics Data System (ADS)

Foley, Ryan J.; Scolnic, Daniel; Rest, Armin; Jha, S. W.; Pan, Y.-C.; Riess, A. G.; Challis, P.; Chambers, K. C.; Coulter, D. A.; Dettman, K. G.; Foley, M. M.; Fox, O. D.; Huber, M. E.; Jones, D. O.; Kilpatrick, C. D.; Kirshner, R. P.; Schultz, A. S. B.; Siebert, M. R.; Flewelling, H. A.; Gibson, B.; Magnier, E. A.; Miller, J. A.; Primak, N.; Smartt, S. J.; Smith, K. W.; Wainscoat, R. J.; Waters, C.; Willman, M.

2018-03-01

The Foundation Supernova Survey aims to provide a large, high-fidelity, homogeneous, and precisely calibrated low-redshift Type Ia supernova (SN Ia) sample for cosmology. The calibration of the current low-redshift SN sample is the largest component of systematic uncertainties for SN cosmology, and new data are necessary to make progress. We present the motivation, survey design, observation strategy, implementation, and first results for the Foundation Supernova Survey. We are using the Pan-STARRS telescope to obtain photometry for up to 800 SNe Ia at z ≲ 0.1. This strategy has several unique advantages: (1) the Pan-STARRS system is a superbly calibrated telescopic system, (2) Pan-STARRS has observed 3/4 of the sky in grizyP1 making future template observations unnecessary, (3) we have a well-tested data-reduction pipeline, and (4) we have observed ˜3000 high-redshift SNe Ia on this system. Here, we present our initial sample of 225 SN Ia grizP1 light curves, of which 180 pass all criteria for inclusion in a cosmological sample. The Foundation Supernova Survey already contains more cosmologically useful SNe Ia than all other published low-redshift SN Ia samples combined. We expect that the systematic uncertainties for the Foundation Supernova Sample will be two to three times smaller than other low-redshift samples. We find that our cosmologically useful sample has an intrinsic scatter of 0.111 mag, smaller than other low-redshift samples. We perform detailed simulations showing that simply replacing the current low-redshift SN Ia sample with an equally sized Foundation sample will improve the precision on the dark energy equation-of-state parameter by 35 per cent, and the dark energy figure of merit by 72 per cent.

The shocking development of lithium (and boron) in supernovae

NASA Technical Reports Server (NTRS)

Dearborn, David S. P.; Schramm, David N.; Steigman, Gary; Truran, James

1989-01-01

It is shown that significant amounts of Li-7 and B-11 are produced in Type 2 supernovae. The synthesis of these rare elements occurs as the supernova shock traverses the base of the hydrogen envelope burning He-3 to masses 7 and 11 via alpha capture. The yields in this process are sufficient to account for the difference in lithium abundance observed between Pop 2 and Pop 1 stars. Since lithium (and boron) would, in this manner, be created in the same stars that produce the bulk of the heavy elements, the lithium abundance even in old Pop 1 stars would be high (as observed). The B-11 production may remedy the long-standing problem of the traditional spallation scenario to account for the observed isotopic ratio of boron. Observational consequences of this mechanism are discussed, including the evolution of lithium and boron isotope ratios in the Galaxy and the possible use of the boron yields to constrain the number of blue progenitor Type 2 supernovae.

Cosmic rays from supernovae and comments on the Vela X pre-supernova

NASA Technical Reports Server (NTRS)

Cameron, A. G. W.

1971-01-01

A possible history of the production of elements in the galaxy is presented, based on assumptions about the end points of stellar evolution and of the general evolution of the galaxy. A wide range of quantities involving the relative abundances of nucleosynthesis products observed in the solar system, and various galactic quantities such as the current rate of supernova production and the present gas content of the galaxy, were considered. These assumptions were utilized in a computer program in which the gas content of the galaxy is gradually turned into stars. The stars are continually enriched in the products of nucleosynthesis as they approach the ends of their evolutionary lifetimes. It is suggested that supernova explosions are associated with the mass range of about 4-8 solar masses. Possible theories on the type of stellar explosive event represented by the Vela supernova are discussed.

ASASSN-18bt: Discovery of A Probable, Bright Supernova in a Kepler Supernova Field

NASA Astrophysics Data System (ADS)

Brown, Jon S.; Stanek, K. Z.; Vallely, P.; Kochanek, C. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Brimacombe, J.

2018-02-01

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 transient source, most likely a supernova, in the galaxy UGC 04780, which is being monitored by Kepler between Dec 7 2017 and Feb 25, 2018.

Models of bright nickel-free supernovae from stripped massive stars with circumstellar shells

NASA Astrophysics Data System (ADS)

Kleiser, Io K. W.; Kasen, Daniel; Duffell, Paul C.

2018-04-01

The nature of an emerging class of rapidly fading supernovae (RFSNe) - characterized by their short-lived light-curve duration, but varying widely in peak brightness - remains puzzling. Whether the RFSNe arise from low-mass thermonuclear eruptions on white dwarfs or from the core collapse of massive stars is still a matter of dispute. We explore the possibility that the explosion of hydrogen-free massive stars could produce bright but rapidly fading transients if the effective pre-supernova radii are large and if little or no radioactive nickel is ejected. The source of radiation is then purely due to shock cooling. We study this model of RFSNe using spherically symmetric hydrodynamics and radiation transport calculations of the explosion of stripped stars embedded in helium-dominated winds or shells of various masses and extent. We present a parameter study showing how the properties of the circumstellar envelopes affect the dynamics of the explosion and can lead to a diversity of light curves. We also explore the dynamics of the fallback of the innermost stellar layers, which might be able to remove radioactive nickel from the ejecta, making the rapid decline in the late-time light curve possible. We provide scaling relations that describe how the duration and luminosity of these events depend on the supernova kinetic energy and the mass and radius of the circumstellar material.

The ASAS-SN Bright Supernova Catalog – II. 2015

DOE PAGES

Holoien, T. W. -S.; Brown, J. S.; Stanek, K. Z.; ...

2017-01-16

Here, this paper 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 themore » second of a series of yearly papers on bright supernovae and their hosts from the ASAS-SN team.« less

The ASAS-SN Bright Supernova Catalog – II. 2015

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holoien, T. W. -S.; Brown, J. S.; Stanek, K. Z.

Here, this paper 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 themore » second of a series of yearly papers on bright supernovae and their hosts from the ASAS-SN team.« less

The ASAS-SN bright supernova catalogue – III. 2016

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holoien, T. W. -S.; Brown, J. S.; Stanek, K. Z.

In this catalogue we summarize information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) and all other bright (m peak ≤ 17), spectroscopically confirmed supernovae discovered in 2016. We then gather the near-infrared through ultraviolet magnitudes of all host galaxies and the offsets of the supernovae from the centres of their hosts from public data bases. We illustrate the results using a sample that now totals 668 supernovae discovered since 2014 May 1, including the supernovae from our previous catalogues, with type distributions closely matching those of the ideal magnitude limited sample from Li et al.more » This is then the third of a series of yearly papers on bright supernovae and their hosts from the ASAS-SN team.« less

The ASAS-SN bright supernova catalogue – III. 2016

DOE PAGES

Holoien, T. W. -S.; Brown, J. S.; Stanek, K. Z.; ...

2017-08-18

In this catalogue we summarize information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) and all other bright (m peak ≤ 17), spectroscopically confirmed supernovae discovered in 2016. We then gather the near-infrared through ultraviolet magnitudes of all host galaxies and the offsets of the supernovae from the centres of their hosts from public data bases. We illustrate the results using a sample that now totals 668 supernovae discovered since 2014 May 1, including the supernovae from our previous catalogues, with type distributions closely matching those of the ideal magnitude limited sample from Li et al.more » This is then the third of a series of yearly papers on bright supernovae and their hosts from the ASAS-SN team.« less

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)

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.

Toward an efficient Photometric Supernova Classifier

NASA Astrophysics Data System (ADS)

McClain, Bradley

2018-01-01

The Sloan Digital Sky Survey Supernova Survey (SDSS) discovered more than 1,000 Type Ia Supernovae, yet less than half of these have spectroscopic measurements. As wide-field imaging telescopes such as The Dark Energy Survey (DES) and the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) discover more supernovae, the need for accurate and computationally cheap photometric classifiers increases. My goal is to use a photometric classification algorithm based on Sncosmo, a python library for supernova cosmology analysis, to reclassify previously identified Hubble SN and other non-spectroscopically confirmed surveys. My results will be compared to other photometric classifiers such as PSNID and STARDUST. In the near future, I expect to have the algorithm validated with simulated data, optimized for efficiency, and applied with high performance computing to real data.

Supernova explosions in magnetized, primordial dark matter haloes

NASA Astrophysics Data System (ADS)

Seifried, D.; Banerjee, R.; Schleicher, D.

2014-05-01

The first supernova explosions are potentially relevant sources for the production of the first large-scale magnetic fields. For this reason, we present a set of high-resolution simulations studying the effect of supernova explosions on magnetized, primordial haloes. We focus on the evolution of an initially small-scale magnetic field formed during the collapse of the halo. We vary the degree of magnetization, the halo mass, and the amount of explosion energy in order to account for expected variations as well as to infer systematical dependences of the results on initial conditions. Our simulations suggest that core collapse supernovae with an explosion energy of 1051 erg and more violent pair instability supernovae with 1053 erg are able to disrupt haloes with masses up to about 106 and 107 M⊙, respectively. The peak of the magnetic field spectra shows a continuous shift towards smaller k-values, i.e. larger length scales, over time reaching values as low as k = 4. On small scales, the magnetic energy decreases at the cost of the energy on large scales resulting in a well-ordered magnetic field with a strength up to ˜10-8 G depending on the initial conditions. The coherence length of the magnetic field inferred from the spectra reaches values up to 250 pc in agreement with those obtained from autocorrelation functions. We find the coherence length to be as large as 50 per cent of the radius of the supernova bubble. Extrapolating this relation to later stages, we suggest that significantly strong magnetic fields with coherence lengths as large as 1.5 kpc could be created. We discuss possible implications of our results on processes like recollapse of the halo, first galaxy formation, and the magnetization of the intergalactic medium.

Shocked Clouds in the Vela Supernova Remnant

NASA Technical Reports Server (NTRS)

Nichols, Joy S.; Slavin, Jonathan D.

2004-01-01

Unusually strong high-excitation C I has been detected in eleven lines of sight through the Vela supernova remnant by means of UV absorption-line studies of IUE data. Most of these lines of sight lie near the western edge of the X-ray bright region of the supernova remnant in a spatially distinct band approximately 1deg by 4deg oriented approximately north/south. The high-excitation C I (denoted C I*) is interpreted as evidence of a complex of shocked dense clouds inside the supernova remnant, due to the high pressures indicated in this region. To further analyze the properties of this region of C I*, we present new HIRES-processed IRAS data of the entire Vela SNR. A temperature map calculated from the HIRES IRAS data, based on a two-component dust model, reveals the signature of hot dust at several locations in the SNR. The hot dust is anti-correlated spatially with X-ray emission as revealed by ROSAT, as would be expected for a dusty medium interacting with a shock wave. The regions of hot dust are strongly correlated with optical filaments, supporting a scenario of dense clouds interior to the SNR that have been shocked and are now cooling behind the supernova blast wave. With few exceptions, the lines of sight to the strong C I* pass through regions of hot dust and optical filaments. Possible mechanisms for the production of the anomalously large columns of C I and C I* are discussed. Dense clouds on the back western hemisphere of the remnant may explain the relatively low X-ray emission in the western portion of the Vela supernova remnant due to the slower forward shock velocity in regions where the shock has encountered the dense clouds. An alternate explanation for the presence of neutral, excited state, and ionized species along the same line of sight may be a magnetic precusor that heats and compresses the gas ahead of the shock.

Neutron Stars in Supernova Remnants and Beyond

NASA Astrophysics Data System (ADS)

Gvaramadze, V. V.

We discuss a concept of off-centred cavity supernova explosion as applied to neutron star/supernova remnant associations and show how this concept could be used to preclude the anti-humane decapitating the Duck (G5.4-1.2 + G5.27-0.9) and dismembering the Swan (Cygnus Loop), as well as to search for a stellar remnant associated with the supernova remnant RCW86.

Interacting supernovae and supernova impostors. LSQ13zm: an outburst heralds the death of a massive star

DOE PAGES

Tartaglia, L.; Pastorello, A.; Sullivan, M.; ...

2016-03-23

Here we report photometric and spectroscopic observations of the optical transient LSQ13zm. Historical data reveal the presence of an eruptive episode (that we label as ‘2013a’) followed by a much brighter outburst (‘2013b’) three weeks later, that we argue to be the genuine supernova explosion. This sequence of events closely resemble those observed for SN 2010mc and (in 2012) SN 2009ip. Furthermore, the absolute magnitude reached by LSQ13zm during 2013a (MR = -14.87 ± 0.25 mag) is comparable with those of supernova impostors, while that of the 2013b event (M R = -18.46 ± 0.21 mag) is consistent with thosemore » of interacting supernovae. Our spectra reveal the presence of a dense and structured circumstellar medium, probably produced through numerous pre-supernova mass-loss events. In addition, we find evidence for high-velocity ejecta, with a fraction of gas expelled at more than 20 000 km s -1. The spectra of LSQ13zm show remarkable similarity with those of well-studied core-collapse supernovae. From the analysis of the available photometric and spectroscopic data, we conclude that we first observed the last event of an eruptive sequence from a massive star, likely a Luminous Blue Variable, which a short time later exploded as a core-collapse supernova. Our detailed analysis of archival images suggests that the host galaxy is a star-forming Blue Dwarf Compact Galaxy.« less

Interacting supernovae and supernova impostors. LSQ13zm: an outburst heralds the death of a massive star

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tartaglia, L.; Pastorello, A.; Sullivan, M.

Here we report photometric and spectroscopic observations of the optical transient LSQ13zm. Historical data reveal the presence of an eruptive episode (that we label as ‘2013a’) followed by a much brighter outburst (‘2013b’) three weeks later, that we argue to be the genuine supernova explosion. This sequence of events closely resemble those observed for SN 2010mc and (in 2012) SN 2009ip. Furthermore, the absolute magnitude reached by LSQ13zm during 2013a (MR = -14.87 ± 0.25 mag) is comparable with those of supernova impostors, while that of the 2013b event (M R = -18.46 ± 0.21 mag) is consistent with thosemore » of interacting supernovae. Our spectra reveal the presence of a dense and structured circumstellar medium, probably produced through numerous pre-supernova mass-loss events. In addition, we find evidence for high-velocity ejecta, with a fraction of gas expelled at more than 20 000 km s -1. The spectra of LSQ13zm show remarkable similarity with those of well-studied core-collapse supernovae. From the analysis of the available photometric and spectroscopic data, we conclude that we first observed the last event of an eruptive sequence from a massive star, likely a Luminous Blue Variable, which a short time later exploded as a core-collapse supernova. Our detailed analysis of archival images suggests that the host galaxy is a star-forming Blue Dwarf Compact Galaxy.« less

NORMAL TYPE Ia SUPERNOVAE FROM VIOLENT MERGERS OF WHITE DWARF BINARIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pakmor, R.; Kromer, M.; Taubenberger, S.

2012-03-15

One of the most important questions regarding the progenitor systems of Type Ia supernovae (SNe Ia) is whether mergers of two white dwarfs can lead to explosions that reproduce observations of normal events. Here we present a fully three-dimensional simulation of a violent merger of two carbon-oxygen white dwarfs with masses of 0.9 M{sub Sun} and 1.1 M{sub Sun} combining very high resolution and exact initial conditions. A well-tested combination of codes is used to study the system. We start with the dynamical inspiral phase and follow the subsequent thermonuclear explosion under the plausible assumption that a detonation forms inmore » the process of merging. We then perform detailed nucleosynthesis calculations and radiative transfer simulations to predict synthetic observables from the homologously expanding supernova ejecta. We find that synthetic color light curves of our merger, which produces about 0.62 M{sub Sun} of {sup 56}Ni, show good agreement with those observed for normal SNe Ia in all wave bands from U to K. Line velocities in synthetic spectra around maximum light also agree well with observations. We conclude that violent mergers of massive white dwarfs can closely resemble normal SNe Ia. Therefore, depending on the number of such massive systems available these mergers may contribute at least a small fraction to the observed population of normal SNe Ia.« less

Oscillation effects and time variation of the supernova neutrino signal

NASA Astrophysics Data System (ADS)

Kneller, James P.; McLaughlin, Gail C.; Brockman, Justin

2008-02-01

The neutrinos detected from the next galactic core-collapse supernova will contain valuable information on the internal dynamics of the explosion. One mechanism leading to a temporal evolution of the neutrino signal is the variation of the induced neutrino flavor mixing driven by changes in the density profile. With one and two-dimensional hydrodynamical simulations we identify the behavior and properties of prominent features of the explosion. Using these results we demonstrate the time variation of the neutrino crossing probabilities due to changes in the Mikheyev-Smirnov-Wolfenstein (MSW) neutrino transformations as the star explodes by using the S-matrix—Monte Carlo—approach to neutrino propagation. After adopting spectra for the neutrinos emitted from the proto-neutron star we calculate for a galactic supernova the evolution of the positron spectra within a water Cerenkov detector and find that this signal allows us to probe of a number of explosion features.

Dance into the fire: dust survival inside supernova remnants

NASA Astrophysics Data System (ADS)

Micelotta, Elisabetta R.; Dwek, Eli; Slavin, Jonathan D.

2016-06-01

Core collapse supernovae (CCSNe) are important sources of interstellar dust, potentially capable of producing 1 M_{⊙}) of dust in their explosively expelled ejecta. However, unlike other dust sources, the dust has to survive the passage of the reverse shock, generated by the interaction of the supernova blast wave with its surrounding medium. Knowledge of the net amount of dust produced by CCSNe is crucial for understanding the origin and evolution of dust in the local and high-redshift universe. Our goal is to identify the dust destruction mechanisms in the ejecta, and derive the net amount of dust that survives the passage of the reverse shock. To do so, we have developed analytical models for the evolution of a supernova blast wave and of the reverse shock, and the simultaneous processing of the dust inside the cavity of the supernova remnant. We have applied our models to the special case of the clumpy ejecta of the remnant of Cassiopeia A (Cas A), assuming that the dust (silicates and carbon grains) resides in cool oxygen-rich ejecta clumps which are uniformly distributed within the remnant and surrounded by a hot X-ray emitting plasma (smooth ejecta). The passage of the reverse shock through the clumps gives rise to a relative gas-grain motion and also destroys the clumps. While residing in the ejecta clouds, dust is processed via kinetic sputtering, which is terminated either when the grains escape the clumps, or when the clumps are destroyed by the reverse shock. In either case, grain destruction proceeds thereafter by thermal sputtering in the hot shocked smooth ejecta. We find that 12 and 16 percent of silicate and carbon dust, respectively, survive the passage of the reverse shock by the time the shock has reached the center of the remnant. These fractions depend on the morphology of the ejecta and the medium into which the remnant is expanding, as well as the composition and size distribution of the grains that formed in the ejecta. Results will

Bridging the gap: from massive stars to supernovae.

PubMed

Maund, Justyn R; Crowther, Paul A; Janka, Hans-Thomas; Langer, Norbert

2017-10-28

Almost since the beginning, massive stars and their resultant supernovae have played a crucial role in the Universe. These objects produce tremendous amounts of energy and new, heavy elements that enrich galaxies, encourage new stars to form and sculpt the shapes of galaxies that we see today. The end of millions of years of massive star evolution and the beginning of hundreds or thousands of years of supernova evolution are separated by a matter of a few seconds, in which some of the most extreme physics found in the Universe causes the explosive and terminal disruption of the star. Key questions remain unanswered in both the studies of how massive stars evolve and the behaviour of supernovae, and it appears the solutions may not lie on just one side of the explosion or the other or in just the domain of the stellar evolution or the supernova astrophysics communities. The need to view massive star evolution and supernovae as continuous phases in a single narrative motivated the Theo Murphy international scientific meeting 'Bridging the gap: from massive stars to supernovae' at Chicheley Hall, UK, in June 2016, with the specific purpose of simultaneously addressing the scientific connections between theoretical and observational studies of massive stars and their supernovae, through engaging astronomers from both communities.This article is part of the themed issue 'Bridging the gap: from massive stars to supernovae'. © 2017 The Author(s).

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.

Supernova brightening from chameleon-photon mixing

DOE Office of Scientific and Technical Information (OSTI.GOV)

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. Chameleonsmore » 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.« less

Unusual Supernovae and Alternative Power Sources

NASA Astrophysics Data System (ADS)

Kasen, Daniel

Recent observations have revealed a diverse class of peculiar supernovae, among them transients that are extremely luminous and unusually dim, or that evolve remarkably rapidly or slowly over time. The light curves of some of these events cannot be powered by ordinary energy sources such as the decay of radioactive isotopes. This chapter begins with a brief description of certain types of unusual supernovae and then reviews the basic physics of supernova light curves, deriving in a pedagogical way the analytic scalings that characterize the peak brightness and duration. After illustrating that ordinary power sources cannot explain all of the observed events, we turn to theoretical ideas involving less common mechanisms, such as energy injection from a long-lived central engine (a rapidly rotating magnetar or an accreting black hole). We conclude by speculating how alternative power sources may be manifest in observations of the assorted classes of peculiar supernovae.

The supernova - supernova remnant connection through multi-dimensional magnetohydrodynamic modeling

NASA Astrophysics Data System (ADS)

Orlando, S.; Miceli, M.; Petruk, O.; Ono, M.

2017-10-01

Supernova remnants (SNRs) are diffuse extended sources often characterized by a rather complex morphology and a highly non-uniform distribution of ejecta. General consensus is that such a morphology reflects, on one hand, pristine structures and features of the progenitor supernova (SN) explosion and, on the other hand, the early interaction of the SN blast wave with the inhomogeneous circumstellar medium (CSM) formed in the latest stages of the progenitor star's evolution. Deciphering X-ray observations of SNRs, therefore, might open the possibility to reconstruct the ejecta structure as it was soon after the SN explosion and the structure and geometry of the medium immediately surrounding the progenitor star. This requires accurate and detailed models which describe the evolution from the on-set of the SN to the full remnant development and which connect the X-ray emission properties of the remnants to the progenitor SNe. Here we show how multi-dimensional SN-SNR magnetohydrodynamic models have been very effective in deciphering X-ray observations of SNR Cassiopeia A and SN 1987A. This has allowed us to unveil the average structure of ejecta in the immediate aftermath of the SN explosion and to constrain the 3D pre-supernova structure and geometry of the environment surrounding the progenitor SN.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morozova, Viktoriya; Renzo, Mathieu; Ott, Christian D.

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

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

A common explosion mechanism for type Ia supernovae.

PubMed

Mazzali, Paolo A; Röpke, Friedrich K; Benetti, Stefano; Hillebrandt, Wolfgang

2007-02-09

Type Ia supernovae, the thermonuclear explosions of white dwarf stars composed of carbon and oxygen, were instrumental as distance indicators in establishing the acceleration of the universe's expansion. However, the physics of the explosion are debated. Here we report a systematic spectral analysis of a large sample of well-observed type Ia supernovae. Mapping the velocity distribution of the main products of nuclear burning, we constrain theoretical scenarios. We find that all supernovae have low-velocity cores of stable iron-group elements. Outside this core, nickel-56 dominates the supernova ejecta. The outer extent of the iron-group material depends on the amount of nickel-56 and coincides with the inner extent of silicon, the principal product of incomplete burning. The outer extent of the bulk of silicon is similar in all supernovae, having an expansion velocity of approximately 11,000 kilometers per second and corresponding to a mass of slightly over one solar mass. This indicates that all the supernovae considered here burned similar masses and suggests that their progenitors had the same mass. Synthetic light-curve parameters and three-dimensional explosion simulations support this interpretation. A single explosion scenario, possibly a delayed detonation, may thus explain most type Ia supernovae.

Prompt directional detection of galactic supernova by combining large liquid scintillator neutrino detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fischer, V.; Chirac, T.; Lasserre, T., E-mail: vincent.fischer@cea.fr, E-mail: tchirac@gmail.fr, E-mail: thierry.lasserre@cea.fr

2015-08-01

Core-collapse supernovae produce an intense burst of electron antineutrinos in the few-tens-of-MeV range. Several Large Liquid Scintillator-based Detectors (LLSD) are currently operated worldwide, being very effective for low energy antineutrino detection through the Inverse Beta Decay (IBD) process. In this article, we develop a procedure for the prompt extraction of the supernova location by revisiting the details of IBD kinematics over the broad energy range of supernova neutrinos. Combining all current scintillator-based detector, we show that one can locate a canonical supernova at 10 kpc with an accuracy of 45 degrees (68% C.L.). After the addition of the next generationmore » of scintillator-based detectors, the accuracy could reach 12 degrees (68% C.L.), therefore reaching the performances of the large water Čerenkov neutrino detectors. We also discuss a possible improvement of the SuperNova Early Warning System (SNEWS) inter-experiment network with the implementation of a directionality information in each experiment. Finally, we discuss the possibility to constrain the neutrino energy spectrum as well as the mass of the newly born neutron star with the LLSD data.« less

Prompt directional detection of galactic supernova by combining large liquid scintillator neutrino detectors

NASA Astrophysics Data System (ADS)

Fischer, V.; Chirac, T.; Lasserre, T.; Volpe, C.; Cribier, M.; Durero, M.; Gaffiot, J.; Houdy, T.; Letourneau, A.; Mention, G.; Pequignot, M.; Sibille, V.; Vivier, M.

2015-08-01

Core-collapse supernovae produce an intense burst of electron antineutrinos in the few-tens-of-MeV range. Several Large Liquid Scintillator-based Detectors (LLSD) are currently operated worldwide, being very effective for low energy antineutrino detection through the Inverse Beta Decay (IBD) process. In this article, we develop a procedure for the prompt extraction of the supernova location by revisiting the details of IBD kinematics over the broad energy range of supernova neutrinos. Combining all current scintillator-based detector, we show that one can locate a canonical supernova at 10 kpc with an accuracy of 45 degrees (68% C.L.). After the addition of the next generation of scintillator-based detectors, the accuracy could reach 12 degrees (68% C.L.), therefore reaching the performances of the large water Čerenkov neutrino detectors. We also discuss a possible improvement of the SuperNova Early Warning System (SNEWS) inter-experiment network with the implementation of a directionality information in each experiment. Finally, we discuss the possibility to constrain the neutrino energy spectrum as well as the mass of the newly born neutron star with the LLSD data.

How supernovae became the basis of observational cosmology

NASA Astrophysics Data System (ADS)

Pruzhinskaya, Maria Victorovna; Lisakov, Sergey Mikhailovich

2016-12-01

This paper is dedicated to the discovery of one of the most important relationships in supernova cosmology - the relation between the peak luminosity of Type Ia supernovae and their luminosity decline rate after maximum light. The history of this relationship is quite long and interesting. The relationship was independently discovered by the American statistician and astronomer Bert Woodard Rust and the Soviet astronomer Yury Pavlovich Pskovskii in the 1970s. Using a limited sample of Type I supernovae they were able to show that the brighter the supernova is, the slower its luminosity declines after maximum. Only with the appearance of CCD cameras could Mark Phillips re-inspect this relationship on a new level of accuracy using a better sample of supernovae. His investigations confirmed the idea proposed earlier by Rust and Pskovskii.

Preview of a Forthcoming Supernova

NASA Image and Video Library

2017-12-08

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

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

NASA Astrophysics Data System (ADS)

Plewa, Tomasz; Handy, Timothy; Odrzywolek, Andrzej

2014-03-01

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

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.

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

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

Modeling Type II-P/II-L Supernovae Interacting with Recent Episodic Mass Ejections from Their Presupernova Stars with MESA and SNEC

NASA Astrophysics Data System (ADS)

Das, Sanskriti; Ray, Alak

2017-12-01

We show how dense, compact, discrete shells of circumstellar gas immediately outside of red supergiants affect the optical light curves of Type II-P/II-L supernovae (SNe), using the example of SN 2013ej. Earlier efforts in the literature had used an artificial circumstellar medium (CSM) stitched to the surface of an evolved star that had not gone through a phase of late-stage heavy mass loss, which, in essence, is the original source of the CSM. In contrast, we allow enhanced mass-loss rate from the modeled star during the 16O and 28Si burning stages and construct the CSM from the resulting mass-loss history in a self-consistent way. Once such evolved pre-SN stars are exploded, we find that the models with early interaction between the shock and the dense CSM reproduce light curves far better than those without that mass loss and, hence, having no nearby dense CSM. The required explosion energy for the progenitors with a dense CSM is reduced by almost a factor of two compared to those without the CSM. Our model, with a more realistic CSM profile and presupernova and explosion parameters, fits observed data much better throughout the rise, plateau, and radioactive tail phases as compared to previous studies. This points to an intermediate class of supernovae between Type II-P/II-L and Type II-n SNe with the characteristics of simultaneous UV and optical peak, slow decline after peak, and a longer plateau.

Preparatory studies for the WFIRST supernova cosmology measurements

NASA Astrophysics Data System (ADS)

Perlmutter, Saul

In the context of the WFIRST-AFTA Science Definition Team we developed a first version of a supernova program, described in the WFIRST-AFTA SDT report. This program uses the imager to discover supernova candidates and an Integral Field Spectrograph (IFS) to obtain spectrophotometric light curves and higher signal to noise spectra of the supernovae near peak to better characterize the supernovae and thus minimize systematic errors. While this program was judged a robust one, and the estimates of the sensitivity to the cosmological parameters were felt to be reliable, due to limitation of time the analysis was clearly limited in depth on a number of issues. The goal of this proposal is to further develop this program and refine the estimates of the sensitivities to the cosmological parameters using more sophisticated systematic uncertainty models and covariance error matrices that fold in more realistic data concerning observed populations of SNe Ia as well as more realistic instrument models. We propose to develop analysis algorithms and approaches that are needed to build, optimize, and refine the WFIRST instrument and program requirements to accomplish the best supernova cosmology measurements possible. We plan to address the following: a) Use realistic Supernova populations, subclasses and population drift. One bothersome uncertainty with the supernova technique is the possibility of population drift with redshift. We are in a unique position to characterize and mitigate such effects using the spectrophotometric time series of real Type Ia supernovae from the Nearby Supernova Factory (SNfactory). Each supernova in this sample has global galaxy measurements as well as additional local environment information derived from the IFS spectroscopy. We plan to develop methods of coping with this issue, e.g., by selecting similar subsamples of supernovae and allowing additional model flexibility, in order to reduce systematic uncertainties. These studies will allow us to

An optical supernova associated with the X-ray flash XRF 060218.

PubMed

Pian, E; Mazzali, P A; Masetti, N; Ferrero, P; Klose, S; Palazzi, E; Ramirez-Ruiz, E; Woosley, S E; Kouveliotou, C; Deng, J; Filippenko, A V; Foley, R J; Fynbo, J P U; Kann, D A; Li, W; Hjorth, J; Nomoto, K; Patat, F; Sauer, D N; Sollerman, J; Vreeswijk, P M; Guenther, E W; Levan, A; O'Brien, P; Tanvir, N R; Wijers, R A M J; Dumas, C; Hainaut, O; Wong, D S; Baade, D; Wang, L; Amati, L; Cappellaro, E; Castro-Tirado, A J; Ellison, S; Frontera, F; Fruchter, A S; Greiner, J; Kawabata, K; Ledoux, C; Maeda, K; Møller, P; Nicastro, L; Rol, E; Starling, R

2006-08-31

Long-duration gamma-ray bursts (GRBs) are associated with type Ic supernovae that are more luminous than average and that eject material at very high velocities. Less-luminous supernovae were not hitherto known to be associated with GRBs, and therefore GRB-supernovae were thought to be rare events. Whether X-ray flashes--analogues of GRBs, but with lower luminosities and fewer gamma-rays--can also be associated with supernovae, and whether they are intrinsically 'weak' events or typical GRBs viewed off the axis of the burst, is unclear. Here we report the optical discovery and follow-up observations of the type Ic supernova SN 2006aj associated with X-ray flash XRF 060218. Supernova 2006aj is intrinsically less luminous than the GRB-supernovae, but more luminous than many supernovae not accompanied by a GRB. The ejecta velocities derived from our spectra are intermediate between these two groups, which is consistent with the weakness of both the GRB output and the supernova radio flux. Our data, combined with radio and X-ray observations, suggest that XRF 060218 is an intrinsically weak and soft event, rather than a classical GRB observed off-axis. This extends the GRB-supernova connection to X-ray flashes and fainter supernovae, implying a common origin. Events such as XRF 060218 are probably more numerous than GRB-supernovae.

Eta Carinae: An Astrophysical Laboratory to Study Conditions During the Transition Between a Pseudo-Supernova and a Supernova

NASA Astrophysics Data System (ADS)

McKinnon, Darren; Gull, T. R.; Madura, T.

2014-01-01

A major puzzle in the studies of supernovae is the pseudo-supernova, or the near-supernovae state. It has been found to precede, in timespans ranging from months to years, a number of recently-detected distant supernovae. One explanation of these systems is that a member of a massive binary underwent a near-supernova event shortly before the actual supernova phenomenon. Luckily, we have a nearby massive binary, Eta Carinae, that provides an astrophysical laboratory of a near-analog. The massive, highly-eccentric, colliding-wind binary star system survived a non-terminal stellar explosion in the 1800's, leaving behind the incredible bipolar, 10"x20" Homunculus nebula. Today, the interaction of the binary stellar winds 1") is resolvable by the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope (HST). Using HST/STIS, several three-dimensional (3D) data cubes (2D spatial, 1D velocity) have been obtained at selected phases during Eta Carinae's 5.54-year orbital cycle. The data cubes were collected by mapping the central 1-2" at 0.05" intervals with a 52"x0.1" aperture. Selected forbidden lines, that form in the colliding wind regions, provide information on electron density of the shocked regions, the ionization by the hot secondary companion of the primary wind and how these regions change with orbital phase. By applying various analysis techniques to these data cubes, we can compare and measure temporal changes due to the interactions between the two massive winds. The observations, when compared to current 3D hydrodynamic models, provide insight on Eta Carinae's recent mass-loss history, important for determining the current and future states of this likely nearby supernova progenitor.

Neutrino astronomy with supernova neutrinos

NASA Astrophysics Data System (ADS)

Brdar, Vedran; Lindner, Manfred; Xu, Xun-Jie

2018-04-01

Modern neutrino facilities will be able to detect a large number of neutrinos from the next Galactic supernova. We investigate the viability of the triangulation method to locate a core-collapse supernova by employing the neutrino arrival time differences at various detectors. We perform detailed numerical fits in order to determine the uncertainties of these time differences for the cases when the core collapses into a neutron star or a black hole. We provide a global picture by combining all the relevant current and future neutrino detectors. Our findings indicate that in the scenario of a neutron star formation, supernova can be located with precision of 1.5 and 3.5 degrees in declination and right ascension, respectively. For the black hole scenario, sub-degree precision can be reached.

A comparison of models for supernova remnants including cosmic rays

NASA Astrophysics Data System (ADS)

Kang, Hyesung; Drury, L. O'C.

1992-11-01

A simplified model which can follow the dynamical evolution of a supernova remnant including the acceleration of cosmic rays without carrying out full numerical simulations has been proposed by Drury, Markiewicz, & Voelk in 1989. To explore the accuracy and the merits of using such a model, we have recalculated with the simplified code the evolution of the supernova remnants considered in Jones & Kang, in which more detailed and accurate numerical simulations were done using a full hydrodynamic code based on the two-fluid approximation. For the total energy transferred to cosmic rays the two codes are in good agreement, the acceleration efficiency being the same within a factor of 2 or so. The dependence of the results of the two codes on the closure parameters for the two-fluid approximation is also qualitatively similar. The agreement is somewhat degraded in those cases where the shock is smoothed out by the cosmic rays.

How to See a Recently Discovered Supernova

ScienceCinema

Nugent, Peter

2017-12-12

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/

How to See a Recently Discovered Supernova

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nugent, Peter

2011-08-31

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:more » http://newscenter.lbl.gov/feature-stories/2011/08/25/supernova/« less

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

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.

Supernova Cosmology Inference with Probabilistic Photometric Redshifts (SCIPPR)

NASA Astrophysics Data System (ADS)

Peters, Christina; Malz, Alex; Hlozek, Renée

2018-01-01

The Bayesian Estimation Applied to Multiple Species (BEAMS) framework employs probabilistic supernova type classifications to do photometric SN cosmology. This work extends BEAMS to replace high-confidence spectroscopic redshifts with photometric redshift probability density functions, a capability that will be essential in the era the Large Synoptic Survey Telescope and other next-generation photometric surveys where it will not be possible to perform spectroscopic follow up on every SN. We present the Supernova Cosmology Inference with Probabilistic Photometric Redshifts (SCIPPR) Bayesian hierarchical model for constraining the cosmological parameters from photometric lightcurves and host galaxy photometry, which includes selection effects and is extensible to uncertainty in the redshift-dependent supernova type proportions. We create a pair of realistic mock catalogs of joint posteriors over supernova type, redshift, and distance modulus informed by photometric supernova lightcurves and over redshift from simulated host galaxy photometry. We perform inference under our model to obtain a joint posterior probability distribution over the cosmological parameters and compare our results with other methods, namely: a spectroscopic subset, a subset of high probability photometrically classified supernovae, and reducing the photometric redshift probability to a single measurement and error bar.

UBVRIz Light Curves of 51 Type II Supernovae

NASA Astrophysics Data System (ADS)

Galbany, Lluís; Hamuy, Mario; Phillips, Mark M.; Suntzeff, Nicholas B.; Maza, José; de Jaeger, Thomas; Moraga, Tania; González-Gaitán, Santiago; Krisciunas, Kevin; Morrell, Nidia I.; Thomas-Osip, Joanna; Krzeminski, Wojtek; González, Luis; Antezana, Roberto; Wishnjewski, Marina; McCarthy, Patrick; Anderson, Joseph P.; Gutiérrez, Claudia P.; Stritzinger, Maximilian; Folatelli, Gastón; Anguita, Claudio; Galaz, Gaspar; Green, Elisabeth M.; Impey, Chris; Kim, Yong-Cheol; Kirhakos, Sofia; Malkan, Mathew A.; Mulchaey, John S.; Phillips, Andrew C.; Pizzella, Alessandro; Prosser, Charles F.; Schmidt, Brian P.; Schommer, Robert A.; Sherry, William; Strolger, Louis-Gregory; Wells, Lisa A.; Williger, Gerard M.

2016-02-01

We present a compilation of UBVRIz light curves of 51 type II supernovae discovered during the course of four different surveys during 1986-2003: the Cerro Tololo Supernova Survey, the Calán/Tololo Supernova Program (C&T), the Supernova Optical and Infrared Survey (SOIRS), and the Carnegie Type II Supernova Survey (CATS). The photometry is based on template-subtracted images to eliminate any potential host galaxy light contamination, and calibrated from foreground stars. This work presents these photometric data, studies the color evolution using different bands, and explores the relation between the magnitude at maximum brightness and the brightness decline parameter (s) from maximum light through the end of the recombination phase. This parameter is found to be shallower for redder bands and appears to have the best correlation in the B band. In addition, it also correlates with the plateau duration, being shorter (longer) for larger (smaller) s values.

Investigating the Origin of the Supernova Remnant W49B

NASA Astrophysics Data System (ADS)

Crum, Ryan Matthew; Frank, Kari A.; Dwarkadas, Vikram; Burrows, David N.

2018-01-01

W49B is a Galactic supernova remnant whose origin is still debated. Is it the remains of an unusual asymmetric Type 1a supernova or of a jet-driven core collapse supernova? Using the X-ray analysis method, Smoothed Particle Inference (SPI), we dig deeper into understanding the complex properties of SNR W49B. We do this by characterizing the temperatures and abundance ratios throughout the remnant. We will compare the results with a wide variety of supernova nucleosynthesis models in order to constrain the mechanism behind this unusual supernova remnant.

The Carnegie Supernova Project I. Photometry data release of low-redshift stripped-envelope supernovae

NASA Astrophysics Data System (ADS)

Stritzinger, M. D.; Anderson, J. P.; Contreras, C.; Heinrich-Josties, E.; Morrell, N.; Phillips, M. M.; Anais, J.; Boldt, L.; Busta, L.; Burns, C. R.; Campillay, A.; Corco, C.; Castellon, S.; Folatelli, G.; González, C.; Holmbo, S.; Hsiao, E. Y.; Krzeminski, W.; Salgado, F.; Serón, J.; Torres-Robledo, S.; Freedman, W. L.; Hamuy, M.; Krisciunas, K.; Madore, B. F.; Persson, S. E.; Roth, M.; Suntzeff, N. B.; Taddia, F.; Li, W.; Filippenko, A. V.

2018-02-01

The first phase of the Carnegie Supernova Project (CSP-I) was a dedicated supernova follow-up program based at the Las Campanas Observatory that collected science data of young, low-redshift supernovae between 2004 and 2009. Presented in this paper is the CSP-I photometric data release of low-redshift stripped-envelope core-collapse supernovae. The data consist of optical (uBgVri) photometry of 34 objects, with a subset of 26 having near-infrared (YJH) photometry. Twenty objects have optical pre-maximum coverage with a subset of 12 beginning at least five days prior to the epoch of B-band maximum brightness. In the near-infrared, 17 objects have pre-maximum observations with a subset of 14 beginning at least five days prior to the epoch of J-band maximum brightness. Analysis of this photometric data release is presented in companion papers focusing on techniques to estimate host-galaxy extinction and the light-curve and progenitor star properties of the sample. The analysis of an accompanying visual-wavelength spectroscopy sample of 150 spectra will be the subject of a future paper. Based on observations collected at Las Campanas Observatory.Tables 2-8 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/609/A134

Magnetar-powered Supernovae in Two Dimensions. II. Broad-line Supernovae Ic

NASA Astrophysics Data System (ADS)

Chen, Ke-Jung; Moriya, Takashi J.; Woosley, Stan; Sukhbold, Tuguldur; Whalen, Daniel J.; Suwa, Yudai; Bromm, Volker

2017-04-01

Nascent neutron stars (NSs) with millisecond periods and magnetic fields in excess of 1016 Gauss can drive highly energetic and asymmetric explosions known as magnetar-powered supernovae. These exotic explosions are one theoretical interpretation for supernovae Ic-BL, which are sometimes associated with long gamma-ray bursts. Twisted magnetic field lines extract the rotational energy of the NS and release it as a disk wind or a jet with energies greater than 1052 erg over ˜20 s. What fraction of the energy of the central engine go into the wind and the jet remain unclear. We have performed two-dimensional hydrodynamical simulations of magnetar-powered supernovae (SNe) driven by disk winds and jets with the CASTRO code to investigate the effect of the central engine on nucleosynthetic yields, mixing, and light curves. We find that these explosions synthesize less than 0.05 {M}⊙ of {}56{Ni} and that this mass is not very sensitive to central engine type. The morphology of the explosion can provide a powerful diagnostic of the properties of the central engine. In the absence of a circumstellar medium, these events are not very luminous, with peak bolometric magnitudes of {M}b˜ -16.5 due to low {}56{Ni} production.

DISCOVERY OF X-RAY EMISSION FROM SUPERNOVA 1970G WITH CHANDRA: FILLING THE VOID BETWEEN SUPERNOVAE AND SUPERNOVA REMNANTS

NASA Technical Reports Server (NTRS)

Immler, Stefan; Kuntz, K. D.

2005-01-01

We report the discovery of X-ray emission from SN 1970G in M101, 35 yr after its outburst, using deep X-ray imaging with the Chundra X-Ray Observatory. The Chandra ACIS spectrum shows that the emission is soft (52 keV) and characteristic of the reverse-shock region. The X-ray luminosity, Lo,,, = (1.1 3 0.2) x lo3# ergs s-1, is likely caused by the interaction of the supernova shock with dense circumstellar matter. If the material was deposited by the stellar wind from the progenitor, a mass-loss rate of M = (2.6 ? 0.4) x M, yr-I (v,/lO km s-I) is inferred. Utilizing the high-resolution Chandra ACIS data of SN 1970G and its environment, we reconstruct the X-ray lightcurve from previous ROSAT HRI, PSPC, and XMM-Newton EPIC observations, and find a best-fit linear rate of decline of L cc t-# with index s = 2.7 t 0.9 over a period of -20-35 yr after the outburst. As the oldest supernova detected in X-rays, SN 1970G allows, for the first time, direct observation of the transition from a supenova to its supernova remnant phase.

Acquiring information about neutrino parameters by detecting supernova neutrinos

NASA Astrophysics Data System (ADS)

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

2010-08-01

We consider the supernova shock effects, the Mikheyev-Smirnov-Wolfenstein effects, the collective effects, and the Earth matter effects in the detection of type II supernova neutrinos on the Earth. It is found that the event number of supernova neutrinos depends on the neutrino mass hierarchy, the neutrino mixing angle θ13, and neutrino masses. Therefore, we propose possible methods to identify the mass hierarchy and acquire information about θ13 and neutrino masses by detecting supernova neutrinos. We apply these methods to some current neutrino experiments.

The impact of vorticity waves on the shock dynamics in core-collapse supernovae

NASA Astrophysics Data System (ADS)

Huete, César; Abdikamalov, Ernazar; Radice, David

2018-04-01

Convective perturbations arising from nuclear shell burning can play an important role in propelling neutrino-driven core-collapse supernova explosions. In this work, we analyse the impact of vorticity waves on the shock dynamics, and subsequently on the post-shock flow, using the solution of the linear hydrodynamics equations. As a result of the interaction with the shock wave, vorticity waves increase their kinetic energy, and a new set of entropic and acoustic waves is deposited in the post-shock region. These perturbations interact with the neutrino-driven turbulent convection that develops in that region. Although both vorticity and acoustic waves inject non-radial motion into the gain region, the contribution of the acoustic waves is found to be negligibly small in comparison to that of the vorticity waves. On the other hand, entropy waves become buoyant and trigger more convection. Using the concept of critical neutrino luminosity, we assess the impact of these modes on the explosion conditions. While the direct injection of non-radial motion reduces the critical neutrino luminosity by ˜ 12 per cent for typical problem parameters, the buoyancy-driven convection triggered by entropy waves reduces the critical luminosity by ˜ 17-24 per cent, which approximately agrees with the results of three-dimensional neutrino-hydrodynamics simulations. Finally, we discuss the limits of validity of the assumptions employed.

ASASSN-15no: the Supernova that plays hide-and-seek

NASA Astrophysics Data System (ADS)

Benetti, S.; Zampieri, L.; Pastorello, A.; Cappellaro, E.; Pumo, M. L.; Elias-Rosa, N.; Ochner, P.; Terreran, G.; Tomasella, L.; Taubenberger, S.; Turatto, M.; Morales-Garoffolo, A.; Harutyunyan, A.; Tartaglia, L.

2018-05-01

We report the results of our follow-up campaign of the peculiar supernova ASASSN-15no, based on optical data covering ˜300 d of its evolution. Initially the spectra show a pure blackbody continuum. After few days, the HeI λλ 5876 transition appears with a P-Cygni profile and an expansion velocity of about 8700 km s-1. Fifty days after maximum, the spectrum shows signs typically seen in interacting supernovae. A broad (FWHM ˜ 8000 km s-1) Hα becomes more prominent with time until ˜150 d after maximum and quickly declines later on. At these phases Hαstarts to show an intermediate component, which together with the blue pseudo-continuum are clues that the ejecta begin to interact with the circumstellar medium (CSM). The spectra at the latest phases look very similar to the nebular spectra of stripped-envelope SNe. The early part (the first 40 d after maximum) of the bolometric curve, which peaks at a luminosity intermediate between normal and superluminous supernovae, is well reproduced by a model in which the energy budget is essentially coming from ejecta recombination and 56Ni decay. From the model, we infer a mass of the ejecta Mej = 2.6 M⊙; an initial radius of the photosphere R0 = 2.1 × 1014 cm; and an explosion energy Eexpl = 0.8 × 1051 erg. A possible scenario involves a massive and extended H-poor shell lost by the progenitor star a few years before explosion. The shell is hit, heated, and accelerated by the supernova ejecta. The accelerated shell+ejecta rapidly dilutes, unveiling the unperturbed supernova spectrum below. The outer ejecta start to interact with a H-poor external CSM lost by the progenitor system about 9-90 yr before the explosion.

Diffuse neutrino supernova background as a cosmological test

NASA Astrophysics Data System (ADS)

Barranco, J.; Bernal, A.; Delepine, D.

2018-05-01

The future detection and measurement of the diffuse neutrino supernova background will provide us with information about supernova neutrino emission and the cosmic core-collapse supernova rate. Little has been said about the information that this measurement could give us about the expansion history of the Universe. The purpose of this article is to study the change of the predicted diffuse supernova neutrino background as a function of the cosmological model. In particular, we study three different models: the Λ–Cold Dark Matter model, the Logotropic universe and a bulk viscous matter-dominated universe. By fitting the free parameters of each model with the supernova Ia probe, we calculate the predicted number of events in these three models. We found that the spectra and number of events for the Λ–Cold dark matter model and the Logotropic model are almost indistinguishable, while a bulk viscous matter-dominated cosmological model predicts more events.

UBVRIz LIGHT CURVES OF 51 TYPE II SUPERNOVAE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galbany, Lluis; Hamuy, Mario; Jaeger, Thomas de

We present a compilation of UBVRIz light curves of 51 type II supernovae discovered during the course of four different surveys during 1986–2003: the Cerro Tololo Supernova Survey, the Calán/Tololo Supernova Program (C and T), the Supernova Optical and Infrared Survey (SOIRS), and the Carnegie Type II Supernova Survey (CATS). The photometry is based on template-subtracted images to eliminate any potential host galaxy light contamination, and calibrated from foreground stars. This work presents these photometric data, studies the color evolution using different bands, and explores the relation between the magnitude at maximum brightness and the brightness decline parameter (s) frommore » maximum light through the end of the recombination phase. This parameter is found to be shallower for redder bands and appears to have the best correlation in the B band. In addition, it also correlates with the plateau duration, being shorter (longer) for larger (smaller) s values.« less

OGLE-2014-SN-073 as a fallback accretion powered supernova

NASA Astrophysics Data System (ADS)

Moriya, Takashi J.; Terreran, Giacomo; Blinnikov, Sergei I.

2018-03-01

We investigate the possibility that the energetic Type II supernova OGLE-2014-SN-073 is powered by a fallback accretion following the failed explosion of a massive star. Taking massive hydrogen-rich supernova progenitor models, we estimate the fallback accretion rate and calculate the light-curve evolution of supernovae powered by the fallback accretion. We find that such fallback accretion powered models can reproduce the overall observational properties of OGLE-2014-SN-073. It may imply that some failed explosions could be observed as energetic supernovae like OGLE-2014-SN-073 instead of faint supernovae as previously proposed.

zBEAMS: a unified solution for supernova cosmology with redshift uncertainties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, Ethan; Lochner, Michelle; Bassett, Bruce A.

Supernova cosmology without spectra will be an important component of future surveys such as LSST. This lack of supernova spectra results in uncertainty in the redshifts which, if ignored, leads to significantly biased estimates of cosmological parameters. Here we present a hierarchical Bayesian formalism— zBEAMS—that addresses this problem by marginalising over the unknown or uncertain supernova redshifts to produce unbiased cosmological estimates that are competitive with supernova data with spectroscopically confirmed redshifts. zBEAMS provides a unified treatment of both photometric redshifts and host galaxy misidentification (occurring due to chance galaxy alignments or faint hosts), effectively correcting the inevitable contamination inmore » the Hubble diagram. Like its predecessor BEAMS, our formalism also takes care of non-Ia supernova contamination by marginalising over the unknown supernova type. We illustrate this technique with simulations of supernovae with photometric redshifts and host galaxy misidentification. A novel feature of the photometric redshift case is the important role played by the redshift distribution of the supernovae.« less

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

Measurements of Amplified Magnetic Field and Cosmic-Ray Content in Supernova Remnants

NASA Astrophysics Data System (ADS)

Uchiyama, Yasunobu

Supernova explosions drive collisionless shocks in the interstellar (or circumstellar) medium. Such shocks are mediated by plasma waves, resulting in the shock transition on a scale much smaller than the collisional mean free path. Galactic cosmic rays are widely considered to be accelerated at collisionless shocks in supernova remnants via diffusive shock acceleration. New high-energy data coming from the X-ray and gamma-ray satellites and from imaging air Cerenkov telescopes are making possible to study physics of particle acceleration at supernova shocks, such as magnetic field amplification which is considered to be realized as part of shock acceleration process and the energy content of cosmic-ray particles in the supernova shell. In particular, GeV observations with the Fermi Gamma-ray Space Telescope offer the prime means to establish the origin of the gamma-rays, and to measure the cosmic-ray content. Moreover they provide a new opportunity to learn about how particle acceleration responds to environ-mental effects. I will present recent observational results from the Chandra and Suzaku X-ray satellites and new results from the LAT onboard Fermi, and discuss their implications to the origin of galactic cosmic rays.

Dynamics of quadruple systems composed of two binaries: stars, white dwarfs, and implications for Ia supernovae

NASA Astrophysics Data System (ADS)

Fang, Xiao; Thompson, Todd A.; Hirata, Christopher M.

2018-05-01

We investigate the long-term secular dynamics and Lidov-Kozai (LK) eccentricity oscillations of quadruple systems composed of two binaries at quadrupole and octupole orders in the perturbing Hamiltonian. We show that the fraction of systems reaching high eccentricities is enhanced relative to triple systems, over a broader range of parameter space. We show that this fraction grows with time, unlike triple systems evolved at quadrupole order. This is fundamentally because with their additional degrees of freedom, quadruple systems do not have a maximal set of commuting constants of the motion, even in secular theory at quadrupole order. We discuss these results in the context of star-star and white dwarf-white dwarf (WD) binaries, with emphasis on WD-WD mergers and collisions relevant to the Type Ia supernova problem. For star-star systems, we find that more than 30 per cent of systems reach high eccentricity within a Hubble time, potentially forming triple systems via stellar mergers or close binaries. For WD-WD systems, taking into account general relativistic and tidal precession and dissipation, we show that the merger rate is enhanced in quadruple systems relative to triple systems by a factor of 3.5-10, and that the long-term evolution of quadruple systems leads to a delay-time distribution ˜1/t for mergers and collisions. In gravitational wave-driven mergers of compact objects, we classify the mergers by their evolutionary patterns in phase space and identify a regime in about 8 per cent of orbital shrinking mergers, where eccentricity oscillations occur on the general relativistic precession time-scale, rather than the much longer LK time-scale. Finally, we generalize previous treatments of oscillations in the inner binary eccentricity (evection) to eccentric mutual orbits. We assess the merger rate in quadruple and triple systems and the implications for their viability as progenitors of stellar mergers and Type Ia supernovae.

From Supernovae to Neutron Stars

NASA Astrophysics Data System (ADS)

Suwa, Yudai

A core-collapse supernova is a generation site of a neutron star as well as one of the largest explosions in the universe. This article gives a brief overview of the studies on supernova explosion mechanism. Basic picture of the explosion mechanism, the method to solve neutrino transfer equation, the impact of the nuclear equation of state on the explosion, and long-term simulation of neutron star evolution from the onset of the explosion are presented.

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'.

Characterizing Dark Energy Through Supernovae

NASA Astrophysics Data System (ADS)

Davis, Tamara M.; Parkinson, David

Type Ia supernovae are a powerful cosmological probe that gave the first strong evidence that the expansion of the universe is accelerating. Here we provide an overview of how supernovae can go further to reveal information about what is causing the acceleration, be it dark energy or some modification to our laws of gravity. We first review the methods of statistical inference that are commonly used, making a point of separating parameter estimation from model selection. We then summarize the many different approaches used to explain or test the acceleration, including parametric models (like the standard model, ΛCDM), nonparametric models, dark fluid models such as quintessence, and extensions to standard gravity. Finally, we also show how supernova data can be used beyond the Hubble diagram, to give information on gravitational lensing and peculiar velocities that can be used to distinguish between models that predict the same expansion history.

Late formation of silicon carbide in type II supernovae

PubMed Central

Liu, Nan; Nittler, Larry R.; Alexander, Conel M. O’D.; Wang, Jianhua

2018-01-01

We have found that individual presolar silicon carbide (SiC) dust grains from supernovae show a positive correlation between 49Ti and 28Si excesses, which is attributed to the radioactive decay of the short-lived (t½ = 330 days) 49V to 49Ti in the inner highly 28Si-rich Si/S zone. The 49V-49Ti chronometer shows that these supernova SiC dust grains formed at least 2 years after their parent stars exploded. This result supports recent dust condensation calculations that predict a delayed formation of carbonaceous and SiC grains in supernovae. The astronomical observation of continuous buildup of dust in supernovae over several years can, therefore, be interpreted as a growing addition of C-rich dust to the dust reservoir in supernovae. PMID:29376119

Discovery of Most Recent Supernova in Our Galaxy

NASA Astrophysics Data System (ADS)

2008-05-01

The most recent supernova in our Galaxy has been discovered by tracking the rapid expansion of its remains. This result, using NASA's Chandra X-ray Observatory and NRAO's Very Large Array (VLA), has implications for understanding how often supernovas explode in the Milky Way galaxy. The supernova explosion occurred about 140 years ago, making it the most recent supernova in the Milky Way as measured in Earth's time frame. Previously, the last known galactic supernova occurred around 1680, based on studying the expansion of its remnant Cassiopeia A. X-ray Image Radio and X-ray Images The recent supernova explosion was not seen in optical light about 140 years ago because it occurred close to the center of the Galaxy, and is embedded in a dense field of gas and dust. This made it about a trillion times fainter, in optical light, than an unobscured supernova. However, the supernova remnant it caused, G1.9+0.3, is now seen in X-ray and radio images. "We can see some supernova explosions with optical telescopes across half of the Universe, but when they're in this murk we can miss them in our own cosmic backyard," said Stephen Reynolds of North Carolina State University, who led the Chandra study. "Fortunately, the expanding gas cloud from the explosion shines brightly in radio waves and X-rays for thousands of years. X-ray and radio telescopes can see through all that obscuration and show us what we've been missing." Astronomers regularly observe supernovas in other galaxies like ours, and based on those rates, estimate that about three should explode every century in our Milky Way, although these estimates have large margins of error. People Who Read This Also Read... Milky Way's Super-efficient Particle Accelerators Caught in The Act Oldest Known Objects Are Surprisingly Immature Action Replay of Powerful Stellar Explosion Milky Way’s Giant Black Hole Awoke from Slumber 300 Years Ago "If the supernova rate estimates are correct, there should be the remnants of

The VLT Measures the Shape of a Type Ia Supernova

NASA Astrophysics Data System (ADS)

2003-08-01

1448 and SN 2001el (DSS and NTT/EMMI). PR Photo 24b/03 : Optical spectrum of SN 2001el and fractional polarisation (VLT/FORS) Supernova explosions and cosmic distances During Type Ia supernova events, remnants of stars with an initial mass of up to a few times that of the Sun (so-called "white dwarf stars") explode, leaving nothing behind but a rapidly expanding cloud of "stardust". Type Ia supernovae are apparently quite similar to one another. This provides them a very useful role as "standard candles" that can be used to measure cosmic distances. Their peak brightness rivals that of their parent galaxy, hence qualifying them as prime cosmic yardsticks. Astronomers have exploited this fortunate circumstance to study the expansion history of our Universe. They recently arrived at the fundamental conclusion that the Universe is expanding at an accelerating rate, cf. ESO PR 21/98, December 1998 (see also the Supernova Acceleration Probe web page). The explosion of a white dwarf star In the most widely accepted models of Type Ia supernovae the pre-explosion white dwarf star orbits a solar-like companion star, completing a revolution every few hours. Due to the close interaction, the companion star continuously loses mass, part of which is picked up (in astronomical terminology: "accreted") by the white dwarf. A white dwarf represents the penultimate stage of a solar-type star. The nuclear reactor in its core has run out of fuel a long time ago and is now inactive. However, at some point the mounting weight of the accumulating material will have increased the pressure inside the white dwarf so much that the nuclear ashes in there will ignite and start burning into even heavier elements. This process very quickly becomes uncontrolled and the entire star is blown to pieces in a dramatic event. An extremely hot fireball is seen that often outshines the host galaxy. The shape of the explosion Although all supernovae of Type Ia have quite similar properties, it has never been

Type Ia supernovae: explosions and progenitors

NASA Astrophysics Data System (ADS)

Kerzendorf, Wolfgang Eitel

2011-08-01

Supernovae are the brightest explosions in the universe. Supernovae in our Galaxy, rare and happening only every few centuries, have probably been observed since the beginnings of mankind. At first they were interpreted as religious omens but in the last half millennium they have increasingly been used to study the cosmos and our place in it. Tycho Brahe deduced from his observations of the famous supernova in 1572, that the stars, in contrast to the widely believe Aristotelian doctrine, were not immutable. More than 400 years after Tycho made his paradigm changing discovery using SN 1572, and some 60 years after supernovae had been identified as distant dying stars, two teams changed the view of the world again using supernovae. The found that the Universe was accelerating in its expansion, a conclusion that could most easily be explained if more than 70% of the Universe was some previously un-identified form of matter now often referred to as `Dark Energy'. Beyond their prominent role as tools to gauge our place in the Universe, supernovae themselves have been studied well over the past 75 years. We now know that there are two main physical causes of these cataclysmic events. One of these channels is the collapse of the core of a massive star. The observationally motivated classes Type II, Type Ib and Type Ic have been attributed to these events. This thesis, however is dedicated to the second group of supernovae, the thermonuclear explosions of degenerate carbon and oxygen rich material and lacking hydrogen - called Type Ia supernovae (SNe Ia). White dwarf stars are formed at the end of a typical star's life when nuclear burning ceases in the core, the outer envelope is ejected, with the degenerate core typically cooling for eternity. Theory predicts that such stars will self ignite when close to 1.38 Msun (called the Chandrasekhar Mass). Most stars however leave white dwarfs with 0.6 Msun, and no star leaves a remnant as heavy as 1.38 M! sun, which suggests

Neutrino flavor instabilities in a time-dependent supernova model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abbar, Sajad; Duan, Huaiyu

2015-10-19

In this study, a dense neutrino medium such as that inside a core-collapse supernova can experience collective flavor conversion or oscillations because of the neutral-current weak interaction among the neutrinos. This phenomenon has been studied in a restricted, stationary supernova model which possesses the (spatial) spherical symmetry about the center of the supernova and the (directional) axial symmetry around the radial direction. Recently it has been shown that these spatial and directional symmetries can be broken spontaneously by collective neutrino oscillations. In this letter we analyze the neutrino flavor instabilities in a time-dependent supernova model. Our results show that collectivemore » neutrino oscillations start at approximately the same radius in both the stationary and time-dependent supernova models unless there exist very rapid variations in local physical conditions on timescales of a few microseconds or shorter. Our results also suggest that collective neutrino oscillations can vary rapidly with time in the regimes where they do occur which need to be studied in time-dependent supernova models.« less

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.

Supernova neutrino detection in LZ

NASA Astrophysics Data System (ADS)

Khaitan, D.

2018-02-01

In the first 10 seconds of a core-collapse supernova, almost all of its progenitor's gravitational potential, O(1053 ergs), is carried away in the form of neutrinos. These neutrinos, with O(10 MeV) kinetic energy, can interact via coherent elastic neutrino-nucleus scattering (CEνNS) depositing O(1 keV) in detectors. In this work we describe the performances of low-background dark matter detectors, such as LUX-ZEPLIN (LZ), optimized for detecting low-energy depositions, in detecting these neutrino interactions. For instance, a 27 Msolar supernova at 10 kpc is expected to produce ~350 neutrino interactions in the 7-tonne liquid xenon active volume of LZ. Based on the LS220 EoS neutrino flux model for a SN, the Noble Element Simulation Technique (NEST), and predicted CEνNS cross-sections for xenon, to study energy deposition and detection of SN neutrinos in LZ. We simulate the response of the LZ data acquisition system (DAQ) and demonstrate its capability and limitations in handling this interaction rate. We present an overview of the LZ detector, focusing on the benefits of liquid xenon for supernova neutrino detection. We discuss energy deposition and detector response simulations and their results. We present an analysis technique to reconstruct the total number of neutrinos and the time of the supernova core bounce.

The All-Sky Automated Survey for Supernovae

NASA Astrophysics Data System (ADS)

Bersier, D.

2016-12-01

This is an overview of the All-Sky Automated Survey for SuperNovae - ASAS-SN. We briefly present the hardware and capabilities of the survey and describe the most recent science results, in particular tidal disruption events and supernovae, including the brightest SN ever found.

Observational Evidence for High Neutronization in Supernova Remnants: Implications for Type Ia Supernova Progenitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martínez-Rodríguez, Héctor; Badenes, Carles; Andrews, Brett

The physical process whereby a carbon–oxygen white dwarf explodes as a Type Ia supernova (SN Ia) remains highly uncertain. The degree of neutronization in SN Ia ejecta holds clues to this process because it depends on the mass and the metallicity of the stellar progenitor, and on the thermodynamic history prior to the explosion. We report on a new method to determine ejecta neutronization using Ca and S lines in the X-ray spectra of Type Ia supernova remnants (SNRs). Applying this method to Suzaku data of Tycho, Kepler , 3C 397, and G337.2−0.7 in the Milky Way, and N103B inmore » the Large Magellanic Cloud, we find that the neutronization of the ejecta in N103B is comparable to that of Tycho and Kepler , which suggests that progenitor metallicity is not the only source of neutronization in SNe Ia. We then use a grid of SN Ia explosion models to infer the metallicities of the stellar progenitors of our SNRs. The implied metallicities of 3C 397, G337.2−0.7, and N103B are major outliers compared to the local stellar metallicity distribution functions, indicating that progenitor metallicity can be ruled out as the origin of neutronization for these SNRs. Although the relationship between ejecta neutronization and equivalent progenitor metallicity is subject to uncertainties stemming from the {sup 12}C + {sup 16}O reaction rate, which affects the Ca/S mass ratio, our main results are not sensitive to these details.« less

Amplification and polarization of supernovae by gravitational lensing

NASA Technical Reports Server (NTRS)

Schneider, P.; Wagoner, Robert V.

1987-01-01

The gravitational lensing of supernovae by individual masses which could comprise the dark matter is analyzed. Detailed predictions of the amplification and polarization are presented, including effects of a galactic environment. Their time dependence is produced by the expansion of the supernovae beam within the lens. The fraction of supernovae which might thus be identified as being lensed in surveys at proposed limiting magnitudes is estimated. These two effects could provide the only known unique signature of microlensing.

Production of light elements and 98Tc through the ν-process with the neutrino oscillation in supernova explosion

NASA Astrophysics Data System (ADS)

Ko, Heamin; Kusakabe, Motohiko; Cheoun, Myung-Ki; Kwak, Kyujin; Kim, Kyungsik

2018-04-01

Stars ending with core collapse supernovae (SNe) emit a tremendous number of neutrinos during their explosions. While these neutrinos pass through each layer of the stars, they react with the nuclides in the progenitor. Although the neutrino cross sections are very small, its huge flux is high enough to react with nuclides to change their abundances. We consider this ν-process, by which abundances of some elements may be explained exclusively by this neutrino process. One of the candidates is 98Tc. In this study, we check the ν-process contributions due to the neutrino reactions. In this calculation we also include the neutrino oscillation effect in the matter with varying density, so called MSW effect, not only for 98Tc production but also 4He and 12C destruction, which occurs at first in the He/C layer in the present model.

Effect of Supernovae on the Local Interstellar Material

NASA Astrophysics Data System (ADS)

Frisch, Priscilla; Dwarkadas, Vikram V.

A range of astronomical data indicates that ancient supernovae created the galactic environment of the Sun and sculpted the physical properties of the interstellar medium near the heliosphere. In this paper, we review the characteristics of the local interstellar medium that have been affected by supernovae. The kinematics, magnetic field, elemental abundances, and configuration of the nearest interstellar material support the view that the Sun is at the edge of the Loop I superbubble, which has merged into the low-density Local Bubble. The energy source for the higher temperature X-ray-emitting plasma pervading the Local Bubble is uncertain. Winds from massive stars and nearby supernovae, perhaps from the Sco-Cen association, may have contributed radioisotopes found in the geologic record and galactic cosmic ray population. Nested supernova shells in the Orion and Sco-Cen regions suggest spatially distinct sites of episodic star formation. The heliosphere properties vary with the pressure of the surrounding interstellar cloud. A nearby supernova would modify this pressure equilibrium and thereby severely disrupt the heliosphere as well as the local interstellar medium.

The ROTSE Supernova Verification Project (RSVP): Status and Early Discoveries

NASA Astrophysics Data System (ADS)

Yuan, Fang; Akerlof, C.; Quimby, R.; Aretakis, J.; McKay, T.; Miller, J. M.; Rykoff, E. S.; Swan, H. F.; Wheeler, J. C.

2007-12-01

The goal of the ROTSE Supernova Verification Project is the discovery of nearby supernova shortly after shock breakout followed by multi-epoch spectral observations as the lightcurves evolve. The very early spectra effectively constrain the progenitor properties and explosion models, but only a few such observations exist for SN Ia. The sequence of spectral observations reveals deeper and deeper layers of the explosion over time that can be used to construct a detailed picture of the burning process. This program follows the concept of the Texas Supernova Search initiated and executed successfully by Robert Quimby using ROTSE-IIIb at McDonald Observatory. To enlarge the discovery rate, we have developed image subtraction code to be installed on all four ROTSE-III telescopes. By monitoring selected fields nightly to a typical limiting magnitude of 18.5, ROTSE-III is able to discover a nearby supernova earlier than many similar searches. The expected discovery rate is 3 per month at one dedicated site. Since August 2007, our pipeline has been fully operational on ROTSE-IIIb and has discovered 5 supernovae, 3 of which we reported as ATELs and CBETs while the remaining two were found concurrently and reported by others. Among these, SN 2007if is a particularly interesting example of an apparent SN Ia involving the destruction of a super-Chandrasekhar mass system. Its spectrum closely matches that of SN 2003fg which was the first such case that has been observed. Our photometry data show a lightcurve that is a factor of 2 overluminous for a SN Ia, consistent with this interpretation. This work has been supported by NASA grants NNG-04WC41G and NNX-07AF02G.

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

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.

Resonant Spin-Flavor Conversion of Supernova Neutrinos

NASA Astrophysics Data System (ADS)

Ando, Shin'ichiro; Sato, K.

2003-07-01

We investigate resonant spin-flavor (RSF) conversions of supernova neutrinos which are induced by the interaction of neutrino magnetic moment and supernova magnetic fields. With a new diagram we propose, it is found that four conversions occur in supernovae, two are induced by the RSF effect and two by the pure Mikheyev-Smirnov-Wolfenstein (MSW) effect. The realistic numerical calculation of neutrino conversions indicates that the RSF-induced νe ↔ ντ tran¯ -12 9 -1 sition occurs efficiently, when µν > 10 µB (B0 /5 × 10 G) , where B0 is the strength of the magnetic field at the surface of iron core. We also evaluate the energy spectrum as a function of µν B0 at the super-Kamiokande detector using the calculated conversion probabilities, and find that the spectral deformation might have possibility to provide useful information on the neutrino magnetic moment as well as the magnetic field strength in supernovae.

Red supergiants as supernova progenitors.

PubMed

Davies, Ben

2017-10-28

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'. © 2017 The Author(s).

Light-curve and spectral properties of ultra-stripped core-collapse supernovae

NASA Astrophysics Data System (ADS)

Moriya, Takashi J.

2017-11-01

We discuss light-curve and spectral properties of ultra-stripped core-collapse supernovae. Ultra-stripped supernovae are supernovae with ejecta masses of only ~0.1M ⊙ whose progenitors lose their envelopes due to binary interactions with their compact companion stars. We follow the evolution of an ultra-stripped supernova progenitor until core collapse and perform explosive nucleosynthesis calculations. We then synthesize light curves and spectra of ultra-stripped supernovae based on the nucleosynthesis results. We show that ultra-stripped supernovae synthesize ~0.01M ⊙ of the radioactive 56Ni, and their typical peak luminosity is around 1042 erg s-1 or -16 mag. Their typical rise time is 5 - 10 days. By comparing synthesized and observed spectra, we find that SN 2005ek and some of so-called calcium-rich gap transients like PTF10iuv may be related to ultra-stripped supernovae.

Are supernova remnants quasi-parallel or quasi-perpendicular accelerators

NASA Technical Reports Server (NTRS)

Spangler, S. R.; Leckband, J. A.; Cairns, I. H.

1989-01-01

Observations of shock waves in the solar system which show a pronounced difference in the plasma wave and particle environment depending on whether the shock is propagating along or perpendicular to the interplanetary magnetic field are discussed. Theories for particle acceleration developed for quasi-parallel and quasi-perpendicular shocks, when extended to the interstellar medium suggest that the relativistic electrons in radio supernova remnants are accelerated by either the Q parallel or Q perpendicular mechanisms. A model for the galactic magnetic field and published maps of supernova remnants were used to search for a dependence of structure on the angle Phi. Results show no tendency for the remnants as a whole to favor the relationship expected for either mechanism, although individual sources resemble model remnants of one or the other acceleration process.

Suzaku Finds "Fossil" Fireballs from Supernovae

NASA Image and Video Library

2017-12-08

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...

Dust in a Type Ia Supernova Progenitor: Spitzer Spectroscopy of Kepler's Supernova Remnant

NASA Technical Reports Server (NTRS)

Williams, Brian J.; Borkowski, Kazimierz; Reynolds, Stephen P.; Ghavamian, Parviz; Blair, William P.; Long, Knox S.; Sankrit, Ravi

2012-01-01

Characterization of the relatively poorly-understood progenitor systems of Type Ia supernovae is of great importance in astrophysics, particularly given the important cosmological role that these supernovae play. Kepler's Supernova Remnant, the result of a Type Ia supernova, shows evidence for an interaction with a dense circumstellar medium (CSM), suggesting a single-degenerate progenitor system. We present 7.5-38 micron IR spectra of the remnant, obtained with the Spitzer Space Telescope, dominated by emission from warm dust. Broad spectral features at 10 and 18 micron, consistent with various silicate particles, are seen throughout. These silicates were likely formed in the stellar outflow from the progenitor system during the AGB stage of evolution, and imply an oxygen-rich chemistry. In addition to silicate dust, a second component, possibly carbonaceous dust, is necessary to account for the short-wavelength IRS and IRAC data. This could imply a mixed chemistry in the atmosphere of the progenitor system. However, non-spherical metallic iron inclusions within silicate grains provide an alternative solution. Models of collisionally-heated dust emission from fast shocks (> 1000 km/s) propagating into the CSM can reproduce the majority of the emission associated with non-radiative filaments, where dust temperatures are approx 80-100 K, but fail to account for the highest temperatures detected, in excess of 150 K. We find that slower shocks (a few hundred km/s) into moderate density material (n(sub o) approx 50-100 / cubic cm) are the only viable source of heating for this hottest dust. We confirm the finding of an overall density gradient, with densities in the north being an order of magnitude greater than those in the south.

Supernova remnant evolution in wind bubbles: A closer look at Kes 27

NASA Astrophysics Data System (ADS)

Dwarkadas, V. V.; Dewey, D.

2013-03-01

Massive Stars (>8M⊙) lose mass in the form of strong winds. These winds accumulate around the star, forming wind-blown bubbles. When the star explodes as a supernova (SN), the resulting shock wave expands within this wind-blown bubble, rather than the interstellar medium. The properties of the resulting remnant, its dynamics and kinematics, the morphology, and the resulting evolution, are shaped by the structure and properties of the wind-blown bubble. In this article we focus on Kes 27, a supernova remnant (SNR) that has been proposed by [1] to be evolving in a wind-blown bubble, explore its properties, and investigate whether the X-Ray properties could be ascribed to evolution of a SNR in a wind-blown bubble. Our initial model does not support the scenario proposed by [1], due to the fact that the reflected shock is expanding into much lower densities.

Dual-Ratiometric Fluorescent Nanoprobe for Visualizing the Dynamic Process of pH and Superoxide Anion Changes in Autophagy and Apoptosis.

PubMed

Yang, Limin; Chen, Yuanyuan; Yu, Zhengze; Pan, Wei; Wang, Hongyu; Li, Na; Tang, Bo

2017-08-23

Autophagy and apoptosis are closely associated with various pathological and physiological processes in cell cycles. Investigating the dynamic changes of intracellular active molecules in autophagy and apoptosis is of great significance for clarifying their inter-relationship and regulating mechanism in many diseases. In this study, we develop a dual-ratiometric fluorescent nanoprobe for quantitatively differentiating the dynamic process of superoxide anion (O 2 •- ) and pH changes in autophagy and apoptosis in HeLa cells. A rhodamine B-loaded mesoporous silica core was used as the reference, and fluorescence probes for pH and O 2 •- measurement were doped in the outer layer shell of SiO 2 . Then, chitosan and triphenylphosphonium were modified on the surface of SiO 2 . The experimental results showed that the nanoprobe is able to simultaneously and precisely visualize the changes of mitochondrial O 2 •- and pH in HeLa cells. The kinetics data revealed that the changes of pH and O 2 •- during autophagy and apoptosis in HeLa cells were significantly different. The pH value was decreased at the early stage of apoptosis and autophagy, whereas the O 2 •- level was enhanced at the early stage of apoptosis and almost unchanged at the initial stage of autophagy. At the late stage of apoptosis and autophagy, the concentration of O 2 •- was increased, whereas the pH was decreased at the late stage of autophagy and almost unchanged at the late stage of apoptosis. We hope that the present results provide useful information for studying the effects of O 2 •- and pH in autophagy and apoptosis in various pathological conditions and diseases.

Discovery of the Most Distant Supernovae and the Quest for {Omega}

DOE R&D Accomplishments Database

Goldhaber, G.; Perlmutter, S.; Gabi, S.; Goobar, A.; Kim, A.; Kim, M.; Pain, R.; Pennypacker, C.; Small, I.; Boyle, B.

1994-05-01

A search for cosmological supernovae has discovered a number of a type Ia supernovae. In particular, one at z = 0.458 is the most distant supernovae yet observed. There is strong evidence from measurements of nearby type Ia supernovae that they can be considered as "standard candles". The authors plan to use these supernovae to measure the deceleration in the general expansion of the universe. The aim of their experiment is to try and observe and measure about 30 such distant supernovae in order to obtain a measurement of the deceleration parameter q{sub o} which is related to {Omega}. Here {Omega} is the ratio of the density of the universe to the critical density, and they expect a measurement with an accuracy of about 30%.

Aspherical Supernovae and Oblique Shock Breakout

NASA Astrophysics Data System (ADS)

Afsariardchi, Niloufar; Matzner, Christopher D.

2017-02-01

In an aspherical supernova explosion, shock emergence is not simultaneous and non-radial flows develop near the stellar surface. Oblique shock breakouts tend to be easily developed in compact progenitors like stripped-envelop core collapse supernovae. According to Matzner et al. (2013), non-spherical explosions develop non-radial flows that alters the observable emission and radiation of a supernova explosion. These flows can limit ejecta speed, change the distribution of matter and heat of the ejecta, suppress the breakout flash, and most importantly engender collisions outside the star. We construct a global numerical FLASH hydrodynamic simulation in a two dimensional spherical coordinate, focusing on the non-relativistic, adiabatic limit in a polytropic envelope to see how these fundamental differences affect the early light curve of core-collapse SNe.

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.

The Carnegie Supernova Project: Intrinsic colors of type Ia supernovae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burns, Christopher R.; Persson, S. E.; Freedman, Wendy L.

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 rangemore » 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.« less

ASPHERICITY, INTERACTION, AND DUST IN THE TYPE II-P/II-L SUPERNOVA 2013EJ IN MESSIER 74

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mauerhan, Jon C.; Graham, Melissa L.; Filippenko, Alexei V.

2017-01-10

SN 2013ej is a well-studied core-collapse supernova (SN) that stemmed from a directly identified red supergiant (RSG) progenitor in galaxy M74. The source exhibits signs of substantial geometric asphericity, X-rays from persistent interaction with circumstellar material (CSM), thermal emission from warm dust, and a light curve that appears intermediate between supernovae of Types II-P and II-L. The proximity of this source motivates a close inspection of these physical characteristics and their potential interconnection. We present multiepoch spectropolarimetry of SN 2013ej during the first 107 days and deep optical spectroscopy and ultraviolet through infrared photometry past ∼800 days. SN 2013ej exhibitsmore » the strongest and most persistent continuum and line polarization ever observed for a SN of its class during the recombination phase. Modeling indicates that the data are consistent with an oblate ellipsoidal photosphere, viewed nearly edge-on and probably augmented by optical scattering from circumstellar dust. We suggest that interaction with an equatorial distribution of CSM, perhaps the result of binary evolution, is responsible for generating the photospheric asphericity. Relatedly, our late-time optical imaging and spectroscopy show that asymmetric CSM interaction is ongoing, and the morphology of broad H α emission from shock-excited ejecta provides additional evidence that the geometry of the interaction region is ellipsoidal. Alternatively, a prolate ellipsoidal geometry from an intrinsically bipolar explosion is also a plausible interpretation of the data but would probably require a ballistic jet of radioactive material capable of penetrating the hydrogen envelope early in the recombination phase. Finally, our latest space-based optical imaging confirms that the late interaction-powered light curve dropped below the stellar progenitor level, confirming the RSG star’s association with the explosion.« less

Supernova nucleosynthesis and the physics of neutrino oscillation

NASA Astrophysics Data System (ADS)

Kajino, Toshitaka

2012-11-01

We studied the explosive nucleosynthesis in core-collapse supernovae and found that several isotopes of rare elements like 7Li, 11B, 138La, 180Ta and others are predominantly produced by the neutrino interactions with several abundant nuclei. These isotopes are strongly affected by the neutrino flavor oscillation due to the MSW (Mikheyev-Smirnov-Wolfenstein) effect. We here first study how to know the suitable average 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 neutrino oscillation effects on their abundances, and propose a new novel method to determine the neutrino oscillation parameters, θ13 and mass hierarchy, simultaneously. There is recent evidence that some SiC X grains from the Murchison meteorite may contain supernova-produced neutrino-process 11B and 7Li encapsulated in the grains. Combining the recent experimental constraints on θ13, we show that although the uncertainties are still large, our method hints at a marginal preference for an inverted neutrino mass hierarchy for the first time.

Unraveling HIV protease flaps dynamics by Constant pH Molecular Dynamics simulations.

PubMed

Soares, Rosemberg O; Torres, Pedro H M; da Silva, Manuela L; Pascutti, Pedro G

2016-08-01

The active site of HIV protease (HIV-PR) is covered by two flaps. These flaps are known to be essential for the catalytic activity of the HIV-PR, but their exact conformations at the different stages of the enzymatic pathway remain subject to debate. Understanding the correct functional dynamics of the flaps might aid the development of new HIV-PR inhibitors. It is known that, the HIV-PR catalytic efficiency is pH-dependent, likely due to the influence of processes such as charge transfer and protonation/deprotonation of ionizable residues. Several Molecular Dynamics (MD) simulations have reported information about the HIV-PR flaps. However, in MD simulations the protonation of a residue is fixed and thus it is not possible to study the correlation between conformation and protonation state. To address this shortcoming, this work attempts to capture, through Constant pH Molecular Dynamics (CpHMD), the conformations of the apo, substrate-bound and inhibitor-bound HIV-PR, which differ drastically in their flap arrangements. The results show that the HIV-PR flaps conformations are defined by the protonation of the catalytic residues Asp25/Asp25' and that these residues are sensitive to pH changes. This study suggests that the catalytic aspartates can modulate the opening of the active site and substrate binding. Copyright © 2016 Elsevier Inc. All rights reserved.

Bridging the gap: from massive stars to supernovae

PubMed Central

Crowther, Paul A.; Janka, Hans-Thomas; Langer, Norbert

2017-01-01

Almost since the beginning, massive stars and their resultant supernovae have played a crucial role in the Universe. These objects produce tremendous amounts of energy and new, heavy elements that enrich galaxies, encourage new stars to form and sculpt the shapes of galaxies that we see today. The end of millions of years of massive star evolution and the beginning of hundreds or thousands of years of supernova evolution are separated by a matter of a few seconds, in which some of the most extreme physics found in the Universe causes the explosive and terminal disruption of the star. Key questions remain unanswered in both the studies of how massive stars evolve and the behaviour of supernovae, and it appears the solutions may not lie on just one side of the explosion or the other or in just the domain of the stellar evolution or the supernova astrophysics communities. The need to view massive star evolution and supernovae as continuous phases in a single narrative motivated the Theo Murphy international scientific meeting ‘Bridging the gap: from massive stars to supernovae’ at Chicheley Hall, UK, in June 2016, with the specific purpose of simultaneously addressing the scientific connections between theoretical and observational studies of massive stars and their supernovae, through engaging astronomers from both communities. This article is part of the themed issue ‘Bridging the gap: from massive stars to supernovae’. PMID:28923995

Gamma-line emission from radioactivities produced in supernovae

NASA Technical Reports Server (NTRS)

Woosley, S. E.; Timmes, F. X.

1997-01-01

The major targets for the gamma ray spectroscopy of supernovae are reviewed. The principle benefit of such observations is the insight provided into the mechanisms of supernova explosions, the distribution and nature of star forming regions in our Galaxy, and the history of the nucleosynthesis of our Galaxy. The emphasis is on two short lived species, Co-56 and Ti-44 which may be seen in individual events and two longer lived species, Al-26 and Fe-60, which can be seen as the cumulative production of many supernovae.

Initial statistics from the Perth Automated Supernova Search

NASA Astrophysics Data System (ADS)

Williams, A. J.

1997-08-01

The Perth Automated Supernova Search uses the 61-cm PLAT (Perth Lowell Automated Telescope) at Perth Observatory, Western Australia. Since 1993 January 1, five confirmed supernovae have been found by the search. The analysis of the first three years of data is discussed, and preliminary results presented. We find a Type Ib/c rate of 0.43 +/- 0.43 SNu, and a Type IIP rate of 0.86 +/- 0.49 SNu, where SNu are 'supernova units'. These values are for a Hubble constant of 75 km per sec per Mpc.

Constraining the Origin and Heating Mechanism of Dust in Type IIn Supernovae

NASA Astrophysics Data System (ADS)

Fox, Ori; Skrutskie, Michael; Filippenko, Alex

2012-12-01

More than any other supernova subclass, Type IIn supernovae tend to exhibit late-time (>1 year) infrared emission from warm dust. Identifying the origin and heating mechanism of the dust provides an important probe of the supernova explosion, circumstellar environment, and progenitor system. Yet mid-infrared observations, which span the peak of the thermal emission, are rare. Three years ago, we executed a warm Spitzer survey (P60122) that uncovered a unique sample of ten supernovae with unreported late-time infrared excesses, in some cases more than 5 years post-explosion. The data from this single epoch are most consistent with a pre-existing dust shell that is continuously heated by visible and/or X-ray emission generated by ongoing shock interaction. Furthermore, the lack of any detections beyond ~2000 days suggests the dust is destroyed once the forward shock overruns the pre-existing shell. The actual shell sizes remain unknown, however, since the derived blackbody radii offer only lower limits. Last year, we obtained second epoch observations of these ten re-discovered SNe IIn (plus the well-studied Type IIn SN 2010jl). The project aimed for non-detections to constrain the light-curve ``turn-off'' times and, thereby, the shell sizes and progenitor mass-loss models. Only two SNe (2005gn and 2008J), however, went undetected. The other nine SNe remain bright at mid-IR wavelengths, which means the dust shell radii are larger than expected. Here we propose continued monitoring of these nine SNe IIn to constrain the size of the circumstellar dust shell and characterize the supernova progenitor system. We can obtain all the necessary data in only 6.1 hours of observation.

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.

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.

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

PubMed

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

2009-06-04

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

Bounds on the Coupling of the Majoron to Light Neutrinos from Supernova Cooling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farzan, Yasaman

2002-12-02

We explore the role of Majoron (J) emission in the supernova cooling process, as a source of upper bound on the neutrino-Majoron coupling. We show that the strongest upper bound on the coupling to {nu}{sub 3} comes from the {nu}{sub e}{nu}{sub e} {yields} J process in the core of a supernova. We also find bounds on diagonal couplings of the Majoron to {nu}{sub {mu}({tau})}{nu}{sub {mu}({tau})} and on off-diagonal {nu}{sub e}{nu}{sub {mu}({tau})} couplings in various regions of the parameter space. We discuss the evaluation of cross-section for four-particle interactions ({nu}{nu} {yields} JJ and {nu}J {yields} {nu}J). We show that these aremore » typically dominated by three-particle sub-processes and do not give new independent constraints.« less

A unified model of supernova driven by magnetic monopoles

NASA Astrophysics Data System (ADS)

Peng, Qiu-He; Liu, Jing-Jing; Chou, Chih-Kang

2017-12-01

In this paper, we first discuss a series of important but puzzling physical mechanisms concerning the energy source, various kinds of core collapsed supernovae explosion mechanisms during central gravitational collapse in astrophysics. We also discuss the puzzle of possible association of γ -ray burst with gravitational wave perturbation, the heat source for the molten interior of the core of the Earth and finally the puzzling problem of the cooling of white dwarfs. We then make use of the estimations for the space flux of magnetic monopoles (hereafter MMs) and nucleon decay induced by MMs (called the Rubakov-Callen (RC) effect) to obtain the luminosity due to the RC effect. In terms of the formula for this RC luminosity, we present a unified treatment for the heat source of the Earth's core, the energy source for the white dwarf interior, various kinds of core collapsed supernovae (Type II Supernova (SNII), Type Ib Supernova (SNIb), Type Ic Supernova (SNIc), Super luminous supernova (SLSN)), and the production mechanism for γ -ray burst. This unified model can also be used to reasonably explain the possible association of the short γ -ray burst detected by the Fermi γ -ray Burst Monitoring Satellite (GBM) with the LIGO gravitational wave event GW150914 in September 2015.

Polarisation Spectral Synthesis For Type Ia Supernova Explosion Models

NASA Astrophysics Data System (ADS)

Bulla, Mattia

2017-02-01

Despite their relevance across a broad range of astrophysical research topics, Type Ia supernova explosions are still poorly understood and answers to the questions of when, why and how these events are triggered remain unclear. In this respect, polarisation offers a unique opportunity to discriminate between the variety of possible scenarios. The observational evidence that Type Ia supernovae are associated with rather low polarisation signals (smaller than a few per cent) places strong constraints for models and calls for modest asphericities in the progenitor system and/or explosion mechanism.The goal of this thesis is to assess the validity of contemporary Type Ia supernova explosion models by testing whether their predicted polarisation signatures can account for the small signals usually observed. To this end, we have implemented and tested an innovative Monte Carlo scheme in the radiative transfer code artis. Compared to previous Monte Carlo approaches, this technique produces synthetic observables (light curves, flux and polarisation spectra) with a substantial reduction in the Monte Carlo noise and therefore in the required computing time. This improvement is particularly crucial for our study as we aim to extract very weak polarisation signals, comparable to those detected in Type Ia supernovae. We have also demonstrated the applicability of this method to other classes of supernovae via a preliminary study of the first spectropolarimetry observations of superluminous supernovae.Using this scheme, we have calculated synthetic spectropolarimetry for three multi-dimensional explosion models recently proposed as promising candidates to explain Type Ia supernovae. Our findings highlight the power of spectropolarimetry in testing and discriminating between different scenarios. While all the three models predict light curves and flux spectra that are similar to each others and reproduce those observed in Type Ia supernovae comparably well, polarisation does

Efficient implementation of constant pH molecular dynamics on modern graphics processors.

PubMed

Arthur, Evan J; Brooks, Charles L

2016-09-15

The treatment of pH sensitive ionization states for titratable residues in proteins is often omitted from molecular dynamics (MD) simulations. While static charge models can answer many questions regarding protein conformational equilibrium and protein-ligand interactions, pH-sensitive phenomena such as acid-activated chaperones and amyloidogenic protein aggregation are inaccessible to such models. Constant pH molecular dynamics (CPHMD) coupled with the Generalized Born with a Simple sWitching function (GBSW) implicit solvent model provide an accurate framework for simulating pH sensitive processes in biological systems. Although this combination has demonstrated success in predicting pKa values of protein structures, and in exploring dynamics of ionizable side-chains, its speed has been an impediment to routine application. The recent availability of low-cost graphics processing unit (GPU) chipsets with thousands of processing cores, together with the implementation of the accurate GBSW implicit solvent model on those chipsets (Arthur and Brooks, J. Comput. Chem. 2016, 37, 927), provide an opportunity to improve the speed of CPHMD and ionization modeling greatly. Here, we present a first implementation of GPU-enabled CPHMD within the CHARMM-OpenMM simulation package interface. Depending on the system size and nonbonded force cutoff parameters, we find speed increases of between one and three orders of magnitude. Additionally, the algorithm scales better with system size than the CPU-based algorithm, thus allowing for larger systems to be modeled in a cost effective manner. We anticipate that the improved performance of this methodology will open the door for broad-spread application of CPHMD in its modeling pH-mediated biological processes. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Identification of the central compact object in the young supernova remnant 1E 0102.2-7219

NASA Astrophysics Data System (ADS)

Vogt, Frédéric P. A.; Bartlett, Elizabeth S.; Seitenzahl, Ivo R.; Dopita, Michael A.; Ghavamian, Parviz; Ruiter, Ashley J.; Terry, Jason P.

2018-04-01

Oxygen-rich young supernova remnants1 are valuable objects for probing the outcome of nucleosynthetic processes in massive stars, as well as the physics of supernova explosions. Observed within a few thousand years after the supernova explosion2, these systems contain fast-moving oxygen-rich and hydrogen-poor filaments visible at optical wavelengths: fragments of the progenitor's interior expelled at a few thousand kilometres per second during the supernova explosion. Here we report the identification of the compact object in the supernova remnant 1E 0102.2-7219 in reprocessed Chandra X-ray Observatory data, enabled by the discovery of a ring-shaped structure visible primarily in optical recombination lines of Ne i and O i. The optical ring has a radius of (2.10 ± 0.35)″ ≡ (0.63 ± 0.11) pc, and is expanding at a velocity of 90 .5-30+40 km s-1. It surrounds an X-ray point source with an intrinsic X-ray luminosity Li (1.2-2.0 keV) = (1.4 ± 0.2) × 1033 erg s-1. The energy distribution of the source indicates that this object is an isolated neutron star: a central compact object akin to those present in the Cas A3-5 and Pup A6 supernova remnants, and the first of its kind to be identified outside of our Galaxy.

Identification of the central compact object in the young supernova remnant 1E 0102.2-7219

NASA Astrophysics Data System (ADS)

Vogt, Frédéric P. A.; Bartlett, Elizabeth S.; Seitenzahl, Ivo R.; Dopita, Michael A.; Ghavamian, Parviz; Ruiter, Ashley J.; Terry, Jason P.

2018-06-01

Oxygen-rich young supernova remnants1 are valuable objects for probing the outcome of nucleosynthetic processes in massive stars, as well as the physics of supernova explosions. Observed within a few thousand years after the supernova explosion2, these systems contain fast-moving oxygen-rich and hydrogen-poor filaments visible at optical wavelengths: fragments of the progenitor's interior expelled at a few thousand kilometres per second during the supernova explosion. Here we report the identification of the compact object in the supernova remnant 1E 0102.2-7219 in reprocessed Chandra X-ray Observatory data, enabled by the discovery of a ring-shaped structure visible primarily in optical recombination lines of Ne i and O i. The optical ring has a radius of (2.10 ± 0.35)″ ≡ (0.63 ± 0.11) pc, and is expanding at a velocity of 90 .5-30+40 km s-1. It surrounds an X-ray point source with an intrinsic X-ray luminosity Li (1.2-2.0 keV) = (1.4 ± 0.2) × 1033 erg s-1. The energy distribution of the source indicates that this object is an isolated neutron star: a central compact object akin to those present in the Cas A3-5 and Pup A6 supernova remnants, and the first of its kind to be identified outside of our Galaxy.

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

PubMed

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

2015-12-17

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

The detectability of supernovae against elliptical galactic disks.

NASA Astrophysics Data System (ADS)

Pearce, E. C.

A 75 cm telescope has been automated with a Prime 300 mini-computer to search approximately 250 galaxies per hour for young supernovae. The high-speed star-location and comparison algorithms used in the Digitized Astronomy Supernova Search (DASS) system is described.

Regulation of the X-ray luminosity of clusters of galaxies by cooling and supernova feedback.

PubMed

Voit, G M; Bryan, G L

2001-11-22

Clusters of galaxies are thought to contain about ten times as much dark matter as baryonic matter. The dark component therefore dominates the gravitational potential of a cluster, and the baryons confined by this potential radiate X-rays with a luminosity that depends mainly on the gas density in the cluster's core. Predictions of the X-rays' properties based on models of cluster formation do not, however, agree with the observations. If the models ignore the condensation of cooling gas into stars and feedback from the associated supernovae, they overestimate the X-ray luminosity because the density of the core gas is too high. An early episode of uniformly distributed supernova feedback could rectify this by heating the uncondensed gas and therefore making it harder to compress into the core, but such a process seems to require an implausibly large number of supernovae. Here we show how radiative cooling of intergalactic gas and subsequent supernova heating conspire to eliminate highly compressible low-entropy gas from the intracluster medium. This brings the core entropy and X-ray luminosities of clusters into agreement with the observations, in a way that depends little on the efficiency of supernova heating in the early Universe.

VLA radio upper limit on Type IIn Supernova 2008S

NASA Astrophysics Data System (ADS)

Chandra, Poonam; Soderberg, Alicia

2008-02-01

Poonam Chandra and Alicia Soderberg report on behalf of a larger collaboration: We observed type IIn supernova SN 2008S (CBET 1234) with the Very Large Array (VLA) on 2008, February 10.62 UT. We do not detect any radio emission at the supernova position (CBET 1234). The flux density at the supernova position is -62 +/- 36 uJy.

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.

Observational Constraints on the Nature of the Dark Energy: First Cosmological Results From the ESSENCE Supernova Survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood-Vasey, W.Michael; Miknaitis, G.; Stubbs, C.W.

We present constraints on the dark energy equation-of-state parameter, w = P/({rho}c{sup 2}), using 60 Type Ia supernovae (SNe Ia) from the ESSENCE supernova survey. We derive a set of constraints on the nature of the dark energy assuming a flat Universe. By including constraints on ({Omega}{sub M}, w) from baryon acoustic oscillations, we obtain a value for a static equation-of-state parameter w = -1.05{sub -0.12}{sup +0.13} (stat 1{sigma}) {+-} 0.13 (sys) and {Omega}{sub M} = 0.274{sub -0.020}{sup +0.033} (stat 1{sigma}) with a best-fit {chi}{sup 2}/DoF of 0.96. These results are consistent with those reported by the Super-Nova Legacy Surveymore » in a similar program measuring supernova distances and redshifts. We evaluate sources of systematic error that afflict supernova observations and present Monte Carlo simulations that explore these effects. Currently, the largest systematic currently with the potential to affect our measurements is the treatment of extinction due to dust in the supernova host galaxies. Combining our set of ESSENCE SNe Ia with the SuperNova Legacy Survey SNe Ia, we obtain a joint constraint of w = -1.07{sub -0.09}{sup +0.09} (stat 1{sigma}) {+-} 0.13 (sys), {Omega}{sub M} = 0.267{sub -0.018}{sup +0.028} (stat 1{sigma}) with a best-fit {chi}{sup 2}/DoF of 0.91. The current SNe Ia data are fully consistent with a cosmological constant.« less

Tight Coupling of Astrocyte pH Dynamics to Epileptiform Activity Revealed by Genetically Encoded pH Sensors.

PubMed

Raimondo, Joseph V; Tomes, Hayley; Irkle, Agnese; Kay, Louise; Kellaway, Lauriston; Markram, Henry; Millar, Robert P; Akerman, Colin J

2016-06-29

Astrocytes can both sense and shape the evolution of neuronal network activity and are known to possess unique ion regulatory mechanisms. Here we explore the relationship between astrocytic intracellular pH dynamics and the synchronous network activity that occurs during seizure-like activity. By combining confocal and two-photon imaging of genetically encoded pH reporters with simultaneous electrophysiological recordings, we perform pH measurements in defined cell populations and relate these to ongoing network activity. This approach reveals marked differences in the intracellular pH dynamics between hippocampal astrocytes and neighboring pyramidal neurons in rodent in vitro models of epilepsy. With three different genetically encoded pH reporters, astrocytes are observed to alkalinize during epileptiform activity, whereas neurons are observed to acidify. In addition to the direction of pH change, the kinetics of epileptiform-associated intracellular pH transients are found to differ between the two cell types, with astrocytes displaying significantly more rapid changes in pH. The astrocytic alkalinization is shown to be highly correlated with astrocytic membrane potential changes during seizure-like events and mediated by an electrogenic Na(+)/HCO3 (-) cotransporter. Finally, comparisons across different cell-pair combinations reveal that astrocytic pH dynamics are more closely related to network activity than are neuronal pH dynamics. This work demonstrates that astrocytes exhibit distinct pH dynamics during periods of epileptiform activity, which has relevance to multiple processes including neurometabolic coupling and the control of network excitability. Dynamic changes in intracellular ion concentrations are central to the initiation and progression of epileptic seizures. However, it is not known how changes in intracellular H(+) concentration (ie, pH) differ between different cell types during seizures. Using recently developed pH-sensitive proteins, we

New method for enhanced efficiency in detection of gravitational waves from supernovae using coherent network of detectors

NASA Astrophysics Data System (ADS)

Mukherjee, S.; Salazar, L.; Mittelstaedt, J.; Valdez, O.

2017-11-01

Supernovae in our universe are potential sources of gravitational waves (GW) that could be detected in a network of GW detectors like LIGO and Virgo. Core-collapse supernovae are rare, but the associated gravitational radiation is likely to carry profuse information about the underlying processes driving the supernovae. Calculations based on analytic models predict GW energies within the detection range of the Advanced LIGO detectors, out to tens of Mpc for certain types of signals e.g. coalescing binary neutron stars. For supernovae however, the corresponding distances are much less. Thus, methods that can improve the sensitivity of searches for GW signals from supernovae are desirable, especially in the advanced detector era. Several methods have been proposed based on various likelihood-based regulators that work on data from a network of detectors to detect burst-like signals (as is the case for signals from supernovae) from potential GW sources. To address this problem, we have developed an analysis pipeline based on a method of noise reduction known as the harmonic regeneration noise reduction (HRNR) algorithm. To demonstrate the method, sixteen supernova waveforms from the Murphy et al. 2009 catalog have been used in presence of LIGO science data. A comparative analysis is presented to show detection statistics for a standard network analysis as commonly used in GW pipelines and the same by implementing the new method in conjunction with the network. The result shows significant improvement in detection statistics.

High energy neutrinos from gamma-ray bursts with precursor supernovae.

PubMed

Razzaque, Soebur; Mészáros, Peter; Waxman, Eli

2003-06-20

The high energy neutrino signature from proton-proton and photo-meson interactions in a supernova remnant shell ejected prior to a gamma-ray burst provides a test for the precursor supernova, or supranova, model of gamma-ray bursts. Protons in the supernova remnant shell and photons entrapped from a supernova explosion or a pulsar wind from a fast-rotating neutron star remnant provide ample targets for protons escaping the internal shocks of the gamma-ray burst to interact and produce high energy neutrinos. We calculate the expected neutrino fluxes, which can be detected by current and future experiments.

Broad-line Type Ic supernova SN 2014ad

NASA Astrophysics Data System (ADS)

Sahu, D. K.; Anupama, G. C.; Chakradhari, N. K.; Srivastav, S.; Tanaka, Masaomi; Maeda, Keiichi; Nomoto, Ken'ichi

2018-04-01

We present optical and ultraviolet photometry and low-resolution optical spectroscopy of the broad-line Type Ic supernova SN 2014ad in the galaxy PGC 37625 (Mrk 1309), covering the evolution of the supernova during -5 to +87 d with respect to the date of maximum in the B band. A late-phase spectrum obtained at +340 d is also presented. With an absolute V-band magnitude at peak of MV = -18.86 ± 0.23 mag, SN 2014ad is fainter than supernovae associated with gamma ray bursts (GRBs), and brighter than most of the normal and broad-line Type Ic supernovae without an associated GRB. The spectral evolution indicates that the expansion velocity of the ejecta, as measured using the Si II line, is as high as ˜33 500 km s-1 around maximum, while during the post-maximum phase it settles at ˜15 000 km s-1. The expansion velocity of SN 2014ad is higher than that of all other well-observed broad-line Type Ic supernovae except for the GRB-associated SN 2010bh. The explosion parameters, determined by applying Arnett's analytical light-curve model to the observed bolometric light-curve, indicate that it was an energetic explosion with a kinetic energy of ˜(1 ± 0.3) × 1052 erg and a total ejected mass of ˜(3.3 ± 0.8) M⊙, and that ˜0.24 M⊙ of 56Ni was synthesized in the explosion. The metallicity of the host galaxy near the supernova region is estimated to be ˜0.5 Z⊙.

The effect of cosmic-ray acceleration on supernova blast wave dynamics

NASA Astrophysics Data System (ADS)

Pais, M.; Pfrommer, C.; Ehlert, K.; Pakmor, R.

2018-05-01

Non-relativistic shocks accelerate ions to highly relativistic energies provided that the orientation of the magnetic field is closely aligned with the shock normal (quasi-parallel shock configuration). In contrast, quasi-perpendicular shocks do not efficiently accelerate ions. We model this obliquity-dependent acceleration process in a spherically expanding blast wave setup with the moving-mesh code AREPO for different magnetic field morphologies, ranging from homogeneous to turbulent configurations. A Sedov-Taylor explosion in a homogeneous magnetic field generates an oblate ellipsoidal shock surface due to the slower propagating blast wave in the direction of the magnetic field. This is because of the efficient cosmic ray (CR) production in the quasi-parallel polar cap regions, which softens the equation of state and increases the compressibility of the post-shock gas. We find that the solution remains self-similar because the ellipticity of the propagating blast wave stays constant in time. This enables us to derive an effective ratio of specific heats for a composite of thermal gas and CRs as a function of the maximum acceleration efficiency. We finally discuss the behavior of supernova remnants expanding into a turbulent magnetic field with varying coherence lengths. For a maximum CR acceleration efficiency of about 15 per cent at quasi-parallel shocks (as suggested by kinetic plasma simulations), we find an average efficiency of about 5 per cent, independent of the assumed magnetic coherence length.

An extremely luminous X-ray outburst at the birth of a supernova

NASA Astrophysics Data System (ADS)

Soderberg, A. M.; Berger, E.; Page, K. L.; Schady, P.; Parrent, J.; Pooley, D.; Wang, X.-Y.; Ofek, E. O.; Cucchiara, A.; Rau, A.; Waxman, E.; Simon, J. D.; Bock, D. C.-J.; Milne, P. A.; Page, M. J.; Barentine, J. C.; Barthelmy, S. D.; Beardmore, A. P.; Bietenholz, M. F.; Brown, P.; Burrows, A.; Burrows, D. N.; Byrngelson, G.; Cenko, S. B.; Chandra, P.; Cummings, J. R.; Fox, D. B.; Gal-Yam, A.; Gehrels, N.; Immler, S.; Kasliwal, M.; Kong, A. K. H.; Krimm, H. A.; Kulkarni, S. R.; Maccarone, T. J.; Mészáros, P.; Nakar, E.; O'Brien, P. T.; Overzier, R. A.; de Pasquale, M.; Racusin, J.; Rea, N.; York, D. G.

2008-05-01

Massive stars end their short lives in spectacular explosions-supernovae-that synthesize new elements and drive galaxy evolution. Historically, supernovae were discovered mainly through their `delayed' optical light (some days after the burst of neutrinos that marks the actual event), preventing observations in the first moments following the explosion. As a result, the progenitors of some supernovae and the events leading up to their violent demise remain intensely debated. Here we report the serendipitous discovery of a supernova at the time of the explosion, marked by an extremely luminous X-ray outburst. We attribute the outburst to the `break-out' of the supernova shock wave from the progenitor star, and show that the inferred rate of such events agrees with that of all core-collapse supernovae. We predict that future wide-field X-ray surveys will catch each year hundreds of supernovae in the act of exploding.

An extremely luminous X-ray outburst at the birth of a supernova.

PubMed

Soderberg, A M; Berger, E; Page, K L; Schady, P; Parrent, J; Pooley, D; Wang, X-Y; Ofek, E O; Cucchiara, A; Rau, A; Waxman, E; Simon, J D; Bock, D C-J; Milne, P A; Page, M J; Barentine, J C; Barthelmy, S D; Beardmore, A P; Bietenholz, M F; Brown, P; Burrows, A; Burrows, D N; Bryngelson, G; Byrngelson, G; Cenko, S B; Chandra, P; Cummings, J R; Fox, D B; Gal-Yam, A; Gehrels, N; Immler, S; Kasliwal, M; Kong, A K H; Krimm, H A; Kulkarni, S R; Maccarone, T J; Mészáros, P; Nakar, E; O'Brien, P T; Overzier, R A; de Pasquale, M; Racusin, J; Rea, N; York, D G

2008-05-22

Massive stars end their short lives in spectacular explosions--supernovae--that synthesize new elements and drive galaxy evolution. Historically, supernovae were discovered mainly through their 'delayed' optical light (some days after the burst of neutrinos that marks the actual event), preventing observations in the first moments following the explosion. As a result, the progenitors of some supernovae and the events leading up to their violent demise remain intensely debated. Here we report the serendipitous discovery of a supernova at the time of the explosion, marked by an extremely luminous X-ray outburst. We attribute the outburst to the 'break-out' of the supernova shock wave from the progenitor star, and show that the inferred rate of such events agrees with that of all core-collapse supernovae. We predict that future wide-field X-ray surveys will catch each year hundreds of supernovae in the act of exploding.

An earlier explosion date for the Crab Nebula supernova

NASA Astrophysics Data System (ADS)

Abt, Helmut A.; Fountain, John W.

2018-04-01

The Chinese first reported the Crab Nebula supernova on 1054 July 5. Ecclesiastical documents from the near east reported it in April and May of 1054. More than 33 petroglyphs made by Native Americans in the US and Mexico are consistent with sightings both before and after conjunction with the Sun on 1054 May 27. We found a petroglyph showing the new star close to Venus and the Moon, which occurred on 1054 April 12 and April 13, respectively. Collins et al., using the four historical dates, derived a light curve that is like that of a Type Ia supernova. The only remaining problem with this identification is that this supernova was near maximum light for 85 d, which is unlike the behavior of any known supernova.

The Progenitor Systems and Explosion Mechanisms of Supernovae

NASA Astrophysics Data System (ADS)

Milisavljevic, D.

2013-10-01

Supernovae are among the most powerful explosions in the universe. They affect the energy balance, global structure, and chemical make-up of galaxies, they produce neutron stars, black holes, and some gamma-ray bursts, and they have been used as cosmological yardsticks to detect the accelerating expansion of the universe. Fundamental properties of these cosmic engines, however, remain uncertain. In this review we discuss the progress made over the last two decades in understanding supernova progenitor systems and explosion mechanisms. We also comment on anticipated future directions of research and highlight alternative methods of investigation using young supernova remnants.

The past, present and future supernova threat to Earth's biosphere

NASA Astrophysics Data System (ADS)

Beech, Martin

2011-12-01

A brief review of the threat posed to Earth's biosphere via near-by supernova detonations is presented. The expected radiation dosage, cosmic ray flux and expanding blast wave collision effects are considered, and it is argued that a typical supernova must be closer than ˜10-pc before any appreciable and potentially harmful atmosphere/biosphere effects are likely to occur. In contrast, the critical distance for Gamma-ray bursts is of order 1-kpc. In spite of the high energy effects potentially involved, the geological record provides no clear-cut evidence for any historic supernova induced mass extinctions and/or strong climate change episodes. This, however, is mostly a reflection of their being numerous possible (terrestrial and astronomical) forcing mechanisms acting upon the biosphere and the difficulty of distinguishing between competing scenarios. Key to resolving this situation, it is suggested, is the development of supernova specific extinction and climate change linked ecological models. Moving to the future, we estimate that over the remaining lifetime of the biosphere (˜2 Gyr) the Earth might experience 1 GRB and 20 supernova detonations within their respective harmful threat ranges. There are currently at least 12 potential pre-supernova systems within 1-kpc of the Sun. Of these systems IK Pegasi is the closest Type Ia pre-supernova candidate and Betelgeuse is the closest potential Type II supernova candidate. We review in some detail the past, present and future behavior of these two systems. Developing a detailed evolutionary model we find that IK Pegasi will likely not detonate until some 1.9 billion years hence, and that it affords absolutely no threat to Earth's biosphere. Betelgeuse is the closest, reasonably well understood, pre-supernova candidate to the Sun at the present epoch, and may undergo detonation any time within the next several million years. The stand-off distance of Betelgeuse at the time of its detonation is estimated to fall

Can pair-instability supernova models match the observations of superluminous supernovae?

NASA Astrophysics Data System (ADS)

Kozyreva, Alexandra; Blinnikov, S.

2015-12-01

An increasing number of so-called superluminous supernovae (SLSNe) are discovered. It is believed that at least some of them with slowly fading light curves originate in stellar explosions induced by the pair instability mechanism. Recent stellar evolution models naturally predict pair instability supernovae (PISNe) from very massive stars at wide range of metallicities (up to Z = 0.006, Yusof et al.). In the scope of this study, we analyse whether PISN models can match the observational properties of SLSNe with various light-curve shapes. Specifically, we explore the influence of different degrees of macroscopic chemical mixing in PISN explosive products on the resulting observational properties. We artificially apply mixing to the 250 M⊙ PISN evolutionary model from Kozyreva et al. and explore its supernova evolution with the one-dimensional radiation hydrodynamics code STELLA. The greatest success in matching SLSN observations is achieved in the case of an extreme macroscopic mixing, where all radioactive material is ejected into the hydrogen-helium outer layer. Such an extreme macroscopic redistribution of chemicals produces events with faster light curves with high photospheric temperatures and high photospheric velocities. These properties fit a wider range of SLSNe than non-mixed PISN model. Our mixed models match the light curves, colour temperature, and photospheric velocity evolution of two well-observed SLSNe PTF12dam and LSQ12dlf. However, these models' extreme chemical redistribution may be hard to realize in massive PISNe. Therefore, alternative models such as the magnetar mechanism or wind-interaction may still to be favourable to interpret rapidly rising SLSNe.

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

Neutrinos from type Ia supernovae: The gravitationally confined detonation scenario

NASA Astrophysics Data System (ADS)

Wright, Warren P.; Kneller, James P.; Ohlmann, Sebastian T.; Röpke, Friedrich K.; Scholberg, Kate; Seitenzahl, Ivo R.

2017-02-01

Despite their use as cosmological distance indicators and their importance in the chemical evolution of galaxies, the unequivocal identification of the progenitor systems and explosion mechanism of normal type Ia supernovae (SNe Ia) remains elusive. The leading hypothesis is that such a supernova is a thermonuclear explosion of a carbon-oxygen white dwarf, but the exact explosion mechanism is still a matter of debate. Observation of a galactic SN Ia would be of immense value in answering the many open questions related to these events. One potentially useful source of information about the explosion mechanism and progenitor is the neutrino signal because the neutrinos from the different mechanisms possess distinct spectra as a function of time and energy. In this paper, we compute the expected neutrino signal from a gravitationally confined detonation (GCD) explosion scenario for a SN Ia and show how the flux at Earth contains features in time and energy unique to this scenario. We then calculate the expected event rates in the Super-K, Hyper-K, JUNO, DUNE, and IceCube detectors and find both Hyper-K and IceCube will see a few events for a GCD supernova at 1 kpc or closer, while Super-K, JUNO, and DUNE will see events if the supernova is closer than ˜0.3 kpc . The distance and detector criteria needed to resolve the time and spectral features arising from the explosion mechanism, neutrino production, and neutrino oscillation processes are also discussed. The neutrino signal from the GCD is then compared with the signal from a deflagration-to-detonation transition (DDT) explosion model computed previously. We find the overall event rate is the most discriminating feature between the two scenarios followed by the event rate time structure. Using the event rate in the Hyper-K detector alone, the DDT can be distinguished from the GCD at 2 σ if the distance to the supernova is less than 2.3 kpc for a normal mass ordering and 3.6 kpc for an inverted ordering.

X-Ray Illumination of the Ejecta of Supernova 1987A

NASA Technical Reports Server (NTRS)

Larsson, J.; Fransson, C.; Oestlin, G.; Groeningsson, P.; Jerkstrand, A.; Kozma, C.; Sollerman, J.; Challis, P.; Kirshner, R. P.; Chevalier, R. A.;

Probing Late-Stage Stellar Evolution through Robotic Follow-Up of Nearby Supernovae

NASA Astrophysics Data System (ADS)

Hosseinzadeh, Griffin

2018-01-01

Many of the remaining uncertainties in stellar evolution can be addressed through immediate and long-term photometry and spectroscopy of supernovae. The early light curves of thermonuclear supernovae can contain information about the nature of the binary companion to the exploding white dwarf. Spectra of core-collapse supernovae can reveal material lost by massive stars in their final months to years. Thanks to a revolution in technology—robotic telescopes, high-speed internet, machine learning—we can now routinely discover supernovae within days of explosion and obtain well-sampled follow-up data for months and years. Here I present three major results from the Global Supernova Project at Las Cumbres Observatory that take advantage of these technological advances. (1) SN 2017cbv is a Type Ia supernova discovered within a day of explosion. Early photometry shows a bump in the U-band relative to previously observed Type Ia light curves, possibly indicating the presence of a nondegenerate binary companion. (2) SN 2016bkv is a low-luminosity Type IIP supernova also caught very young. Narrow emission lines in the earliest spectra indicate interaction between the ejecta and a dense shell of circumstellar material, previously observed only in the brightest Type IIP supernovae. (3) Type Ibn supernovae are a rare class that interact with hydrogen-free circumstellar material. An analysis of the largest-yet sample of this class has found that their light curves are much more homogeneous and faster-evolving than their hydrogen-rich counterparts, Type IIn supernovae, but that their maximum-light spectra are more diverse.

A Search for High-Energy Gamma-Rays from Supernova SN1987A.

NASA Astrophysics Data System (ADS)

Waldron, Liam Edwin

1992-01-01

The Australian Defence Force Academy (ADFA) balloon -borne gamma-ray astronomy telescope was flown successfully from Alice Springs Australia twice during 1987 and 1988 (flights 87-2-19 and 88-1-5) with the aim of measuring the gamma-ray flux, in the energy range 50 to 500 MeV, from Supernova SN1987A in the Large Magellanic Cloud. The two flights corresponded to day 55 and day 407 respectively of remnant evolution. The instrument was complemented by a hard X-ray proportional counter, designed and constructed by the Istituto di Astrofisica Spaziale, CNR, Frascati Italy, and sensitive to the 10 to 250 KeV energy range. In this thesis, an account is given of the physical processes responsible for the production of gamma-rays astrophysical environments and their relation to supernovae and cosmic-rays. A description is then given of the main features of the gamma-ray telescope and its principle of operation, the most important part of the telescope being a spark-chamber used to determine the direction of arrival of incident gamma-rays. Data obtained during each flight was recorded as spark-chamber tacks on photographic film. A detailed account of the methods of subsequent data reduction and analysis, as carried out by the author, are given. The principal results of this work were that 3-sigma upper limits to the gamma-ray flux from Supernova SN1987A of 2.2 times 10^ {-5} photons cm^{ -2} s^{-1} and 3.4 times 10^{-5} photons cm^{-2} s^ {-1} were obtained for days 55 and 407 of remnant evolution respectively, these limits being somewhat lower than previously reported in the literature from a preliminary analysis of the data. The above two upper limits are consistent with Supernova SN1987A being an atypical Type-II supernova. That is, the progenitor was a blue, rather than a red, supergiant. The limits are compared with theoretical predictions related to current models of gamma-ray emission from young Type -II supernovae.

Progress Report on the Berkeley/Anglo-Australian Observatory High-redshift Supernova Search

DOE R&D Accomplishments Database

Goldhaber, G.; Perlmutter, S.; Pennypacker, C.; Marvin, H.; Muller, R. A.; Couch, W.; Boyle, B.

1990-11-01

There are two main efforts related to supernovae in progress at Berkeley. The first is an automated supernova search for nearby supernovae, which was already discussed by Carl Pennypacker at this conference. The second is a search for distant supernovae, in the z = 0.3 to 0.5 region, aimed at measuring {Omega}. It is the latter that I want to discuss in this paper.

Supernova Cosmology Without Spectroscopy

NASA Astrophysics Data System (ADS)

Johnson, Elizabeth; Scolnic, Daniel; Kessler, Rick; Rykoff, Eli; Rozo, Eduardo

2018-01-01

Present and future supernovae (SN) surveys face several challenges: the ability to acquire redshifts of either the SN or its host galaxy, the ability to classify a SN without a spectrum, and unknown relations between SN luminosity and host galaxy type. We present here a new approach that addresses these challenges. From the large sample of SNe discovered and measured by the Dark Energy Survey (DES), we cull the sample to only supernovae (SNe) located in luminous red galaxies (LRGs). For these galaxies, photometric redshift estimates are expected to be accurate to a standard deviation of 0.02x(1+z). In addition, only Type Ia Supernovae are expected to exist in these galaxies, thereby providing a pure SNIa sample. Furthermore, we can combine this high-redshift sample with a low-redshift SN sample of only SNe located in LRGs, thereby producing a sample that is less sensitive to host galaxy relations because the host galaxy demographic is consistent across the redshift range. We find that the current DES sample has ~250 SNe in LRGs, a similar amount to current SNIa samples used to measure cosmological parameters. We present our method to produce a photometric-only Hubble diagram and measure cosmological parameters. Finally, we discuss systematic uncertainties from this approach, and forecast constraints from this method for LSST, which should have a sample roughly 200 times as large.

Powerful Nearby Supernova Caught By Web

NASA Astrophysics Data System (ADS)

2008-09-01

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

VizieR Online Data Catalog: Berkeley supernova Ia program. II. (Silverman+, 2012)

NASA Astrophysics Data System (ADS)

Silverman, J. M.; Kong, J. J.; Filippenko, A. V.

2013-08-01

In this second paper in a series, we present measurements of spectral features of 432 low-redshift (z<0.1) optical spectra of 261 Type Ia supernovae (SNe Ia) within 20d of maximum brightness. The data were obtained from 1989 to the end of 2008 as part of the Berkeley Supernova Ia Program (BSNIP) and are presented in BSNIP I by Silverman et al. (J/MNRAS/425/1789). We describe in detail our method of automated, robust spectral feature definition and measurement which expands upon similar previous studies. Using this procedure, we attempt to measure expansion velocities, pseudo-equivalent widths (pEWs), spectral feature depths and fluxes at the centre and endpoints of each of nine major spectral feature complexes. (10 data files).

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.

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.

The ASAS-SN bright supernova catalogue – I. 2013–2014

DOE PAGES

Holoien, T. W. -S.; Stanek, K. Z.; Kochanek, C. S.; ...

2016-09-12

We present basic statistics for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) during its first year-and-a-half of operations, spanning 2013 and 2014. We also present the same information for all other bright (m V ≤ 17), spectroscopically confirmed supernovae discovered from 2014 May 1 through the end of 2014, providing a comparison to the ASAS-SN sample starting from the point where ASAS-SN became operational in both hemispheres. In addition, we present collected redshifts and near-UV through IR magnitudes, where available, for all host galaxies of the bright supernovae in both samples. This work represents a comprehensivemore » catalogue of bright supernovae and their hosts from multiple professional and amateur sources, allowing for population studies that were not previously possible because the all-sky emphasis of ASAS-SN redresses many previously existing biases. In particular, ASAS-SN systematically finds bright supernovae closer to the centres of host galaxies than either other professional surveys or amateurs, a remarkable result given ASAS-SN's poorer angular resolution. In conclusion, this is the first of a series of yearly papers on bright supernovae and their hosts that will be released by the ASAS-SN team.« less

Ultra-Bright Optical Transients Are Linked With Type Ic Supernovae

DTIC Science & Technology

2010-11-20

Station, Flagstaff, AZ 86001, USA Received 2010 August 16; accepted 2010 September 9; published 2010 October 25 ABSTRACT Recent searches by unbiased...wide-field surveys have uncovered a group of extremely luminous optical transients. The initial discoveries of SN 2005ap by the Texas Supernova Search ...supernova searches (e.g., the Texas Supernova Search ) or all-sky surveys, such as the Panoramic Survey Telescope & Rapid Response System (Pan-STARRS), the

Neutrino-pair emission from nuclear de-excitation in core-collapse supernova simulations

NASA Astrophysics Data System (ADS)

Fischer, T.; Langanke, K.; Martínez-Pinedo, G.

2013-12-01

We study the impact of neutrino-pair production from the de-excitation of highly excited heavy nuclei on core-collapse supernova simulations, following the evolution up to several 100 ms after core bounce. Our study is based on the agile-boltztransupernova code, which features general relativistic radiation hydrodynamics and accurate three-flavor Boltzmann neutrino transport in spherical symmetry. In our simulations the nuclear de-excitation process is described in two different ways. At first we follow the approach proposed by Fuller and Meyer [Astrophys. J.AJLEEY0004-637X10.1086/170317 376, 701 (1991)], which is based on strength functions derived in the framework of the nuclear Fermi-gas model of noninteracting nucleons. Second, we parametrize the allowed and forbidden strength distributions in accordance with measurements for selected nuclear ground states. We determine the de-excitation strength by applying the Brink hypothesis and detailed balance. For both approaches, we find that nuclear de-excitation has no effect on the supernova dynamics. However, we find that nuclear de-excitation is the leading source for the production of electron antineutrinos as well as heavy-lepton-flavor (anti)neutrinos during the collapse phase. At sufficiently high densities, the associated neutrino spectra are influenced by interactions with the surrounding matter, making proper simulations of neutrino transport important for the determination of the neutrino-energy loss rate. We find that, even including nuclear de-excitations, the energy loss during the collapse phase is overwhelmingly dominated by electron neutrinos produced by electron capture.

VizieR Online Data Catalog: UBVRIz light curves of 51 Type II supernovae (Galbany+, 2016)

NASA Astrophysics Data System (ADS)

Galbany, L.; Hamuy, M.; Phillips, M. M.; Suntzeff, N. B.; Maza, J.; de Jaeger, T.; Moraga, T.; Gonzalez-Gaitan, S.; Krisciunas, K.; Morrell, N. I.; Thomas-Osip, J.; Krzeminski, W.; Gonzalez, L.; Antezana, R.; Wishnjewski, M.; McCarthy, P.; Anderson, J. P.; Gutierrez, C. P.; Stritzinger, M.; Folatelli, G.; Anguita, C.; Galaz, G.; Green, E. M.; Impey, C.; Kim, Y.-C.; Kirhakos, S.; Malkan, M. A.; Mulchaey, J. S.; Phillips, A. C.; Pizzella, A.; Prosser, C. F.; Schmidt, B. P.; Schommer, R. A.; Sherry, W.; Strolger, L.-G.; Wells, L. A.; Williger, G. M.

2016-08-01

This paper presents a sample of multi-band, visual-wavelength light curves of 51 type II supernovae (SNe II) observed from 1986 to 2003 in the course of four different surveys: the Cerro Tololo Supernova Survey, the Calan Tololo Supernova Program (C&T), the Supernova Optical and Infrared Survey (SOIRS), and the Carnegie Type II Supernovae Survey (CATS). Near-infrared photometry and optical spectroscopy of this set of SNe II will be published in two companion papers. A list of the SNe II used in this study is presented in Table1. The first object in our list is SN 1986L and it is the only SN observed with photoelectric techniques (by M.M.P and S.K., using the Cerro Tololo Inter-American Observatory (CTIO) 0.9m equipped with a photometer and B and V filters). The remaining SNe were observed using a variety of telescopes equipped with CCD detectors and UBV(RI)KCz filters (see Table5). The magnitudes for the photometric sequences of the 51 SNe II are listed in Table4. In every case, these sequences were derived from observations of Landolt standards (see Appendix D in Hamuy et al. 2001ApJ...558..615H for the definition of the z band and Stritzinger et al. 2002AJ....124.2100S for the description of the z-band standards). Table5 lists the resulting UBVRIz magnitudes for the 51 SNe. (3 data files).

CRTS SNhunt: The First Five Years of Supernova Discoveries

NASA Astrophysics Data System (ADS)

Howerton, Stanley C.

2017-01-01

CRTS SNhunt: The First Five Years of Supernova Discoveries is a compilation of all supernova and supernova-like discoveries from the first five operational years of the supernova search SNhunt which is one project in the larger Catalina Real-Time Transient Survey (CRTS). SNhunt is perhaps one of the last traditional large-scale searches in which a person compares an image with a reference frame. This kind of search is time consuming as there is not a computer to narrow down the possibilities. The only help is a subtraction frame which shows differences between the two images. Images came from the Catalina Sky Survey, Mount Lemmon Survey, and Siding Spring Survey. Most of the discoveries were by the author. For many, a confirmation or a follow-up image is included. Where possible, a light curve was also created.

The evolution of supernova remnants in different galactic environments, and its effects on supernova statistics

NASA Technical Reports Server (NTRS)

Kafatos, M.; Sofia, S.; Bruhweiler, F.; Gull, T. R.

1980-01-01

Examination of the interaction between supernova (SN) ejecta and the various environments in which the explosive event might occur shows that only a small fraction of the many SNs produce observable supernova remnants (SNRs). This fraction, which is found to depend weakly upon the lower mass limit of the SN progenitors, and more strongly on the specfic characteristics of the associated interstellar medium, decreases from approximately 15 percent near the galctic center to 10 percent at Rgal approximately 10 kpc and drops nearly to zero for Rgal 15 kpc. Generally, whether a SNR is detectable is determined by the density of the ambient interstellar medium in which it is embeeede. The presence of large, low density cavities arpund stellar associations due to the combined effects of stellar winds and supernova shells strongly suggests that a large portion of the detectable SNRs have runway stars as their progenitors. These results explain the differences between the substantially larger SN rates in the galaxy derived both from pulsar statistics and from observations of SN events in external galaxies, when compared to the substantially smaller SN rates derived form galactic SNR statistics.

Influence of pH on dynamics of microbial enhanced oil recovery processes using biosurfactant producing Pseudomonas putida: Mathematical modelling and numerical simulation.

PubMed

Sivasankar, P; Suresh Kumar, G

2017-01-01

In present work, the influence of reservoir pH conditions on dynamics of microbial enhanced oil recovery (MEOR) processes using Pseudomonas putida was analysed numerically from the developed mathematical model for MEOR processes. Further, a new strategy to improve the MEOR performance has also been proposed. It is concluded from present study that by reversing the reservoir pH from highly acidic to low alkaline condition (pH 5-8), flow and mobility of displaced oil, displacement efficiency, and original oil in place (OOIP) recovered gets significantly enhanced, resulting from improved interfacial tension (IFT) reduction by biosurfactants. At pH 8, maximum of 26.1% of OOIP was recovered with higher displacement efficiency. The present study introduces a new strategy to increase the recovery efficiency of MEOR technique by characterizing the biosurfactants for IFT min /IFT max values for different pH conditions and subsequently, reversing the reservoir pH conditions at which the IFT min /IFT max value is minimum. Copyright © 2016 Elsevier Ltd. All rights reserved.

THE CLUSTER LENSING AND SUPERNOVA SURVEY WITH HUBBLE: AN OVERVIEW

DOE Office of Scientific and Technical Information (OSTI.GOV)

Postman, Marc; Coe, Dan; Bradley, Larry

2012-04-01

The Cluster Lensing And Supernova survey with Hubble (CLASH) is a 524-orbit Multi-Cycle Treasury Program to use the gravitational lensing properties of 25 galaxy clusters to accurately constrain their mass distributions. The survey, described in detail in this paper, will definitively establish the degree of concentration of dark matter in the cluster cores, a key prediction of structure formation models. The CLASH cluster sample is larger and less biased than current samples of space-based imaging studies of clusters to similar depth, as we have minimized lensing-based selection that favors systems with overly dense cores. Specifically, 20 CLASH clusters are solelymore » X-ray selected. The X-ray-selected clusters are massive (kT > 5 keV) and, in most cases, dynamically relaxed. Five additional clusters are included for their lensing strength ({theta}{sub Ein} > 35'' at z{sub s} = 2) to optimize the likelihood of finding highly magnified high-z (z > 7) galaxies. A total of 16 broadband filters, spanning the near-UV to near-IR, are employed for each 20-orbit campaign on each cluster. These data are used to measure precise ({sigma}{sub z} {approx} 0.02(1 + z)) photometric redshifts for newly discovered arcs. Observations of each cluster are spread over eight epochs to enable a search for Type Ia supernovae at z > 1 to improve constraints on the time dependence of the dark energy equation of state and the evolution of supernovae. We present newly re-derived X-ray luminosities, temperatures, and Fe abundances for the CLASH clusters as well as a representative source list for MACS1149.6+2223 (z 0.544).« less

Improvement of the Performance of an Electrocoagulation Process System Using Fuzzy Control of pH.

PubMed

Demirci, Yavuz; Pekel, Lutfiye Canan; Altinten, Ayla; Alpbaz, Mustafa

2015-12-01

The removal efficiencies of electrocoagulation (EC) systems are highly dependent on the initial value of pH. If an EC system has an acidic influent, the pH of the effluent increases during the treatment process; conversely, if such a system has an alkaline influent, the pH of the effluent decreases during the treatment process. Thus, changes in the pH of the wastewater affect the efficiency of the EC process. In this study, we investigated the dynamic effects of pH. To evaluate approaches for preventing increases in the pH of the system, the MATLAB/Simulink program was used to develop and evaluate an on-line computer-based system for pH control. The aim of this work was to study Proportional-Integral-Derivative (PID) control and fuzzy control of the pH of a real textile wastewater purification process using EC. The performances and dynamic behaviors of these two control systems were evaluated based on determinations of COD, colour, and turbidity removal efficiencies.

Interacting Supernovae: Types IIn and Ibn

NASA Astrophysics Data System (ADS)

Smith, Nathan

Supernovae that show evidence of strong shock interaction between their ejecta and pre-existing slower circumstellar material (CSM) constitute an interesting, diverse, and still poorly understood category of explosive transients. The chief reason they are extremely interesting is because they tell us that in a subset of stellar deaths, the progenitor star becomes wildly unstable in the years, decades, or centuries before explosion. This is something that has not been included in standard stellar evolution models but may significantly change the end product and yield of that evolution and complicates our attempts to map SNe to their progenitors. Another reason they are interesting is because CSM interaction is an efficient engine for making bright transients, allowing superluminous transients to arise from normal SN explosion energy, and transients of normal supernova luminosity to arise from sub-energetic explosions or low radioactivity yield. CSM interaction shrouds the fast ejecta in bright shock emission, obscuring our view of the underlying explosion, and the radiation hydrodynamics is challenging to model. The CSM interaction may also be highly nonspherical, perhaps linked to binary interaction in the progenitor system. In some cases, these complications make it difficult to tell the difference between a core-collapse and thermonuclear explosion or to discern between a nonterminal eruption, failed supernova, or weak supernova. Efforts to uncover the physical parameters of individual events and connections to progenitor stars make this a rapidly evolving topic that challenges paradigms of stellar evolution.

The neutron capture process in the He shell in core-collapse supernovae: Presolar silicon carbide grains as a diagnostic tool for nuclear astrophysics

NASA Astrophysics Data System (ADS)

Pignatari, Marco; Hoppe, Peter; Trappitsch, Reto; Fryer, Chris; Timmes, F. X.; Herwig, Falk; Hirschi, Raphael

2018-01-01

Carbon-rich presolar grains are found in primitive meteorites, with isotopic measurements to date suggesting a core-collapse supernovae origin site for some of them. This holds for about 1-2% of presolar silicon carbide (SiC) grains, so-called Type X and C grains, and about 30% of presolar graphite grains. Presolar SiC grains of Type X show anomalous isotopic signatures for several elements heavier than iron compared to the solar abundances: most notably for strontium, zirconium, molybdenum, ruthenium and barium. We study the nucleosynthesis of zirconium and molybdenum isotopes in the He-shell of three core-collapse supernovae models of 15, 20 and 25 M⊙ with solar metallicity, and compare the results to measurements of presolar grains. We find the stellar models show a large scatter of isotopic abundances for zirconium and molybdenum, but the mass averaged abundances are qualitatively similar to the measurements. We find all models show an excess of 96Zr relative to the measurements, but the model abundances are affected by the fractionation between Sr and Zr since a large contribution to 90Zr is due to the radiogenic decay of 90Sr. Some supernova models show excesses of 95,97Mo and depletion of 96Mo relative to solar. The mass averaged distribution from these models shows an excess of 100Mo, but this may be alleviated by very recent neutron-capture cross section measurements. We encourage future explorations to assess the impact of the uncertainties in key neutron-capture reaction rates that lie along the n-process path.

Search for Type Ia supernova NUV-optical subclasses

NASA Astrophysics Data System (ADS)

Cinabro, David; Scolnic, Daniel; Kessler, Richard; Li, Ashley; Miller, Jake

2017-04-01

In response to a recently reported observation of evidence for two classes of Type Ia supernovae (SNe Ia) distinguished by their brightness in the rest-frame near-ultraviolet (NUV), we search for the phenomenon in publicly available light-curve data. We use the SNANA supernova analysis package to simulate SN Ia light curves in the Sloan Digital Sky Survey (SDSS) Supernova Search and the Supernova Legacy Survey (SNLS) with a model of two distinct ultraviolet classes of SNe Ia and a conventional model with a single broad distribution of SN-Ia ultraviolet brightnesses. We compare simulated distributions of rest-frame colours with these two models to those observed in 158 SNe Ia in the SDSS and SNLS data. The SNLS sample of 99 SNe Ia is in clearly better agreement with a model with one class of SN Ia light curves and shows no evidence for distinct NUV sub-classes. The SDSS sample of 59 SNe Ia with poorer colour resolution does not distinguish between the two models.

Super-AGB Stars and their Role as Electron Capture Supernova Progenitors

NASA Astrophysics Data System (ADS)

Doherty, Carolyn L.; Gil-Pons, Pilar; Siess, Lionel; Lattanzio, John C.

2017-11-01

We review the lives, deaths and nucleosynthetic signatures of intermediate-mass stars in the range ≈6-12 M⊙, which form super-AGB stars near the end of their lives. The critical mass boundaries both between different types of massive white dwarfs (CO, CO-Ne, ONe), and between white dwarfs and supernovae, are examined along with the relative fraction of super-AGB stars that end life either as an ONe white dwarf or as a neutron star (or an ONeFe white dwarf), after undergoing an electron capture supernova event. The contribution of the other potential single-star channel to electron-capture supernovae, that of the failed massive stars, is also discussed. The factors that influence these different final fates and mass limits, such as composition, rotation, the efficiency of convection, the nuclear reaction rates, mass-loss rates, and third dredge-up efficiency, are described. We stress the importance of the binary evolution channels for producing electron-capture supernovae. Recent nucleosynthesis calculations and elemental yield results are discussed and a new set of s-process heavy element yields is presented. The contribution of super-AGB star nucleosynthesis is assessed within a Galactic perspective, and the (super-)AGB scenario is considered in the context of the multiple stellar populations seen in globular clusters. A brief summary of recent works on dust production is included. Last, we conclude with a discussion of the observational constraints and potential future advances for study into these stars on the low mass/high mass star boundary.

Self-similar dynamic converging shocks - I. An isothermal gas sphere with self-gravity

NASA Astrophysics Data System (ADS)

Lou, Yu-Qing; Shi, Chun-Hui

2014-07-01

We explore novel self-similar dynamic evolution of converging spherical shocks in a self-gravitating isothermal gas under conceivable astrophysical situations. The construction of such converging shocks involves a time-reversal operation on feasible flow profiles in self-similar expansion with a proper care for the increasing direction of the specific entropy. Pioneered by Guderley since 1942 but without self-gravity so far, self-similar converging shocks are important for implosion processes in aerodynamics, combustion, and inertial fusion. Self-gravity necessarily plays a key role for grossly spherical structures in very broad contexts of astrophysics and cosmology, such as planets, stars, molecular clouds (cores), compact objects, planetary nebulae, supernovae, gamma-ray bursts, supernova remnants, globular clusters, galactic bulges, elliptical galaxies, clusters of galaxies as well as relatively hollow cavity or bubble structures on diverse spatial and temporal scales. Large-scale dynamic flows associated with such quasi-spherical systems (including collapses, accretions, fall-backs, winds and outflows, explosions, etc.) in their initiation, formation, and evolution are likely encounter converging spherical shocks at times. Our formalism lays an important theoretical basis for pertinent astrophysical and cosmological applications of various converging shock solutions and for developing and calibrating numerical codes. As examples, we describe converging shock triggered star formation, supernova explosions, and void collapses.

A kinematic study of 0509-67.5, the second youngest supernova remnant in the Large Magellanic Cloud, and its astrophysical implications

NASA Astrophysics Data System (ADS)

Hovey, Luke

2016-05-01

Supernova remnants are the lasting interactions of shock waves that develop in the wake of supernovae. These remnants, especially those in our galaxy and our companion galaxies, allow us to study supernovae for thousands of years after the initial stellar explosions. Remnants that are formed from Ia supernovae, which are the explosions and complete annihilation of white dwarf stars, are of particular interest due to the explosions' value as standard candles in cosmological studies. The shock waves in these young supernova remnants offer an unparalleled look into the physical processes that take place there, especially since these shocks are often simpler to study than shocks with strong radiative components that are present in remnants that are formed from the core-collapse supernovae of massive stars. I will detail the work of my kinematic study of the second youngest remnant in the Large Magellanic Cloud, 0509--67.5, which has been confirmed to be the result of a Ia supernova. Chapter 2 details the proper motion measurements made on the forward shock of this remnant, which has led to many key results. I was able to use the results of ii the global shock speed in the remnant to measure the density of neutral hydrogen in the ambient medium into which these shocks expand. In addition, I use the measurements of the shock speed for select portions of the forward shock to search for signatures of efficient cosmic-ray acceleration. Hydrodynamic simulations are then employed to constrain the age and ambient medium density of 0509--67.5, as well as to place limits on the compression factor at the immediate location of the blast wave. Chapter 3 uses the proper motion results from chapter 2 to determine possible asymmetries in the expansion of the remnant for the eastern and western limbs. These measurements are then used as constraints in hydrodynamic simulations to assess the possible dynamical offset of the explosion site compared to the geometric center of 0509

MISSING BLACK HOLES UNVEIL THE SUPERNOVA EXPLOSION MECHANISM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belczynski, Krzysztof; Wiktorowicz, Grzegorz; Fryer, Chris L.

2012-09-20

It is firmly established that the stellar mass distribution is smooth, covering the range 0.1-100 M{sub Sun }. It is to be expected that the masses of the ensuing compact remnants correlate with the masses of their progenitor stars, and thus it is generally thought that the remnant masses should be smoothly distributed from the lightest white dwarfs to the heaviest black holes (BHs). However, this intuitive prediction is not borne out by observed data. In the rapidly growing population of remnants with observationally determined masses, a striking mass gap has emerged at the boundary between neutron stars (NSs) andmore » BHs. The heaviest NSs reach a maximum of two solar masses, while the lightest BHs are at least five solar masses. Over a decade after the discovery, the gap has become a significant challenge to our understanding of compact object formation. We offer new insights into the physical processes that bifurcate the formation of remnants into lower-mass NSs and heavier BHs. Combining the results of stellar modeling with hydrodynamic simulations of supernovae, we both explain the existence of the gap and also put stringent constraints on the inner workings of the supernova explosion mechanism. In particular, we show that core-collapse supernovae are launched within 100-200 ms of the initial stellar collapse, implying that the explosions are driven by instabilities with a rapid (10-20 ms) growth time. Alternatively, if future observations fill in the gap, this will be an indication that these instabilities develop over a longer (>200 ms) timescale.« less

Neutrinos, supernovae, and the origin of the heavy elements

NASA Astrophysics Data System (ADS)

Qian, YongZhong

2018-04-01

Stars of 8-100 M ⊙ end their lives as core-collapse supernovae (SNe). In the process they emit a powerful burst of neutrinos, produce a variety of elements, and leave behind either a neutron star or a black hole. The wide mass range for SN progenitors results in diverse neutrino signals, explosion energies, and nucleosynthesis products. A major mechanism to produce nuclei heavier than iron is rapid neutron capture, or the r process. This process may be connected to SNe in several ways. A brief review is presented on current understanding of neutrino emission, explosion, and nucleosynthesis of SNe.

Nuclear weak interactions, supernova nucleosynthesis and neutrino oscillation

NASA Astrophysics Data System (ADS)

Kajino, Toshitaka

2013-07-01

We study the nuclear weak response in light-to-heavy mass nuclei and calculate neutrino-nucleus cross sections. We apply these cross sections to the explosive nucleosynthesis in core-collapse supernovae and find that several isotopes of rare elements 7Li, 11B, 138La, 180Ta and several others are predominantly produced by the neutrino-process nucleosynthesis. We discuss how to determine the suitable neutrino spectra of three different flavors and their anti-particles 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. Light-mass nuclei like 7Li and 11B, which are produced in outer He-layer, are strongly affected by the neutrino flavor oscillation due to the MSW (Mikheyev-Smirnov-Wolfenstein) effect, while heavy-mass nuclei like 138La, 180Ta and r-process elements, which are produced in the inner O-Ne-Mg layer or the atmosphere of proto-neutron star, are likely to be free from the MSW effect. Using such a different nature of the neutrino-process nucleosynthesis, we study the neutrino oscillation effects on their abundances, and propose a new novel method to determine the unknown neutrino oscillation parameters, θ13 and mass hierarchy, simultaneously. There is recent evidence that some SiC X grains from the Murchison meteorite may contain supernova-produced neutrino-process 11B and 7Li encapsulated in the grains. Combining the recent experimental constraints on θ13, we show that although the uncertainties are still large, our method hints at a marginal preference for an inverted neutrino mass hierarchy for the first time.

Implications for Post-processing Nucleosynthesis of Core-collapse Supernova Models with Lagrangian Particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, J. Austin; Hix, W. Raphael; Chertkow, Merek A.

In this paper, we investigate core-collapse supernova (CCSN) nucleosynthesis with self-consistent, axisymmetric (2D) simulations performed using the neutrino hydrodynamics code Chimera. Computational costs have traditionally constrained the evolution of the nuclear composition within multidimensional CCSN models to, at best, a 14-species α-network capable of tracking onlymore » $$(\\alpha ,\\gamma )$$ reactions from 4He to 60Zn. Such a simplified network limits the ability to accurately evolve detailed composition and neutronization or calculate the nuclear energy generation rate. Lagrangian tracer particles are commonly used to extend the nuclear network evolution by incorporating more realistic networks into post-processing nucleosynthesis calculations. However, limitations such as poor spatial resolution of the tracer particles; inconsistent thermodynamic evolution, including misestimation of expansion timescales; and uncertain determination of the multidimensional mass cut at the end of the simulation impose uncertainties inherent to this approach. Finally, we present a detailed analysis of the impact of such uncertainties for four self-consistent axisymmetric CCSN models initiated from solar-metallicity, nonrotating progenitors of 12, 15, 20, and 25 $${M}_{\\odot }$$ and evolved with the smaller α-network to more than 1 s after the launch of an explosion.« less

Implications for Post-processing Nucleosynthesis of Core-collapse Supernova Models with Lagrangian Particles

DOE PAGES

Harris, J. Austin; Hix, W. Raphael; Chertkow, Merek A.; ...

2017-06-26

In this paper, we investigate core-collapse supernova (CCSN) nucleosynthesis with self-consistent, axisymmetric (2D) simulations performed using the neutrino hydrodynamics code Chimera. Computational costs have traditionally constrained the evolution of the nuclear composition within multidimensional CCSN models to, at best, a 14-species α-network capable of tracking onlymore » $$(\\alpha ,\\gamma )$$ reactions from 4He to 60Zn. Such a simplified network limits the ability to accurately evolve detailed composition and neutronization or calculate the nuclear energy generation rate. Lagrangian tracer particles are commonly used to extend the nuclear network evolution by incorporating more realistic networks into post-processing nucleosynthesis calculations. However, limitations such as poor spatial resolution of the tracer particles; inconsistent thermodynamic evolution, including misestimation of expansion timescales; and uncertain determination of the multidimensional mass cut at the end of the simulation impose uncertainties inherent to this approach. Finally, we present a detailed analysis of the impact of such uncertainties for four self-consistent axisymmetric CCSN models initiated from solar-metallicity, nonrotating progenitors of 12, 15, 20, and 25 $${M}_{\\odot }$$ and evolved with the smaller α-network to more than 1 s after the launch of an explosion.« less

Implications for Post-processing Nucleosynthesis of Core-collapse Supernova Models with Lagrangian Particles

NASA Astrophysics Data System (ADS)

Harris, J. Austin; Hix, W. Raphael; Chertkow, Merek A.; Lee, C. T.; Lentz, Eric J.; Messer, O. E. Bronson

2017-07-01

We investigate core-collapse supernova (CCSN) nucleosynthesis with self-consistent, axisymmetric (2D) simulations performed using the neutrino hydrodynamics code Chimera. Computational costs have traditionally constrained the evolution of the nuclear composition within multidimensional CCSN models to, at best, a 14-species α-network capable of tracking only (α ,γ ) reactions from 4He to 60Zn. Such a simplified network limits the ability to accurately evolve detailed composition and neutronization or calculate the nuclear energy generation rate. Lagrangian tracer particles are commonly used to extend the nuclear network evolution by incorporating more realistic networks into post-processing nucleosynthesis calculations. However, limitations such as poor spatial resolution of the tracer particles inconsistent thermodynamic evolution, including misestimation of expansion timescales and uncertain determination of the multidimensional mass cut at the end of the simulation impose uncertainties inherent to this approach. We present a detailed analysis of the impact of such uncertainties for four self-consistent axisymmetric CCSN models initiated from solar-metallicity, nonrotating progenitors of 12, 15, 20, and 25 {M}⊙ and evolved with the smaller α-network to more than 1 s after the launch of an explosion.

Shedding light on the Type Ia supernova extinction puzzle: dust location found

NASA Astrophysics Data System (ADS)

Bulla, M.; Goobar, A.; Dhawan, S.

2018-06-01

The colour evolution of reddened Type Ia supernovae can place strong constraints on the location of dust and help address the question of whether the observed extinction stems from the interstellar medium or from circumstellar material surrounding the progenitor. Here we analyse BV photometry of 48 reddened Type Ia supernovae from the literature and estimate the dust location from their B - V colour evolution. We find a time-variable colour excess E(B - V) for 15 supernovae in our sample and constrain dust to distances between 0.013 and 45 pc (4 × 1016 - 1020 cm). For the remaining supernovae, we obtain a constant E(B - V) evolution and place lower limits on the dust distance from the explosion. In all the 48 supernovae, the inferred dust location is compatible with an interstellar origin for the extinction. This is corroborated by the observation that supernovae with relatively nearby dust (≲ 1 pc) are located close to the center of their host galaxy, in high-density dusty regions where interactions between the supernova radiation and interstellar clouds close by are likely to occur. For supernovae showing time-variable E(B - V), we identify a potential preference for low RV values, unusually strong sodium absorption and blue-shifted and time-variable absorption features. Within the interstellar framework, this brings evidence to a proposed scenario where cloud-cloud collisions induced by the supernova radiation pressure can shift the grain size distribution to smaller values and enhance the abundance of sodium in the gaseous phase.

Simulations of Supernova Shock Breakout

NASA Astrophysics Data System (ADS)

Frey, Lucille; Fryer, C. L.; Hungerford, A. L.

2009-01-01

Massive stars at the end of their lives release huge amounts of energy in supernova explosions which can be detected across cosmological distances. Even if prior observations exist, such distances make supernova progenitors difficult to identify. Very early observations of supernovae give us a rare view of these short-lived stars immediately before core collapse. Several recently observed X-ray and UV bursts associated with supernova have been interpreted as shock breakout observations. When the radiation-dominated shock wave from core collapse approaches the stellar surface, the optical depth of the plasma ahead of the shock decreases until the radiation can escape in a burst. If a dense wind is present, the shock breaks out beyond the stellar surface. Occurring days or weeks before the optical light from radioactive decay peaks, shock breakout radiation can be used to determine the radius of the progenitor star or its recent mass loss history. Whether the durations and spectra of the observed X-ray and UV bursts match those expected for shock breakout is currently being debated. A similar phenomenon would occur when the shockwave interacts with gas shells such as those ejected by luminous blue variable outbursts. Full radiation-hydrodynamics calculations are necessary to reproduce the behavior of the radiation-dominated shock and shock breakout. We use a radiation-hydrodynamics code with adaptive mesh refinement to follow the motion of the shock wave with high resolution. We run a suite of one dimensional simulations using binary and single progenitors with a range of mass loss histories, wind velocities and explosion energies. These simulations will better constrain the properties of the progenitor star and its environment that can be derived from shock breakout observations. This work was funded in part under the auspices of the U.S. Dept. of Energy, and supported by its contract W-7405-ENG-36 to Los Alamos National Laboratory.

Hubble Monitors Supernova In Nearby Galaxy M82

NASA Image and Video Library

2014-02-26

This is a Hubble Space Telescope composite image of a supernova explosion designated SN 2014J in the galaxy M82. At a distance of approximately 11.5 million light-years from Earth it is the closest supernova of its type discovered in the past few decades. The explosion is categorized as a Type Ia supernova, which is theorized to be triggered in binary systems consisting of a white dwarf and another star — which could be a second white dwarf, a star like our sun, or a giant star. Astronomers using a ground-based telescope discovered the explosion on January 21, 2014. This Hubble photograph was taken on January 31, as the supernova approached its peak brightness. The Hubble data are expected to help astronomers refine distance measurements to Type Ia supernovae. In addition, the observations could yield insights into what kind of stars were involved in the explosion. Hubble’s ultraviolet-light sensitivity will allow astronomers to probe the environment around the site of the supernova explosion and in the interstellar medium of the host galaxy. Because of their consistent peak brightness, Type Ia supernovae are among the best tools to measure distances in the universe. They were fundamental to the 1998 discovery of the mysterious acceleration of the expanding universe. A hypothesized repulsive force, called dark energy, is thought to cause the acceleration. Among the other major NASA space-based observatories used in the M82 viewing campaign are Spitzer Space Telescope, Chandra X-ray Observatory, Nuclear Spectroscopic Telescope Array (NuSTAR), Fermi Gamma-ray Space Telescope, Swift Gamma Ray Burst Explorer, and the Stratospheric Observatory for Infrared Astronomy (SOFIA). Image Credit: NASA, ESA, A. Goobar (Stockholm University), and the Hubble Heritage Team (STScI/AURA) NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics

The Los Alamos Supernova Light Curve Project: Current Projects and Future Directions

NASA Astrophysics Data System (ADS)

Wiggins, Brandon Kerry; Los Alamos Supernovae Research Group

2015-01-01

The Los Alamos Supernova Light Curve Project models supernovae in the ancient and modern universe to determine the luminosities of observability of certain supernovae events and to explore the physics of supernovae in the local universe. The project utilizes RAGE, Los Alamos' radiation hydrodynamics code to evolve the explosions of progenitors prepared in well-established stellar evolution codes. RAGE allows us to capture events such as shock breakout and collisions of ejecta with shells of material which cannot be modeled well in other codes. RAGE's dumps are then ported to LANL's SPECTRUM code which uses LANL's OPLIB opacities database to calculate light curves and spectra. In this paper, we summarize our recent work in modeling supernovae.

A Model of the Vela Supernova Remnant

NASA Astrophysics Data System (ADS)

Gvaramadze, Vasilii

2000-10-01

A model of the Vela supernova remnant (SNR) based on a cavity explosion of a supernova (SN) star is proposed. It is suggested that the general structure of the remnant is determined by the interaction of the SN blast wave with a massive shell created by the SN progenitor (15-20 M_solar) star. A possible origin of the nebula of hard X-ray emission detected around the Vela pulsar is discussed.

A luminous, blue progenitor system for the type Iax supernova 2012Z

NASA Astrophysics Data System (ADS)

McCully, Curtis; Jha, Saurabh W.; Foley, Ryan J.; Bildsten, Lars; Fong, Wen-Fai; Kirshner, Robert P.; Marion, G. H.; Riess, Adam G.; Stritzinger, Maximilian D.

2014-08-01

Type Iax supernovae are stellar explosions that are spectroscopically similar to some type Ia supernovae at the time of maximum light emission, except with lower ejecta velocities. They are also distinguished by lower luminosities. At late times, their spectroscopic properties diverge from those of other supernovae, but their composition (dominated by iron-group and intermediate-mass elements) suggests a physical connection to normal type Ia supernovae. Supernovae of type Iax are not rare; they occur at a rate between 5 and 30 per cent of the normal type Ia rate. The leading models for type Iax supernovae are thermonuclear explosions of accreting carbon-oxygen white dwarfs that do not completely unbind the star, implying that they are `less successful' versions of normal type Ia supernovae, where complete stellar disruption is observed. Here we report the detection of the luminous, blue progenitor system of the type Iax SN 2012Z in deep pre-explosion imaging. The progenitor system's luminosity, colours, environment and similarity to the progenitor of the Galactic helium nova V445 Puppis suggest that SN 2012Z was the explosion of a white dwarf accreting material from a helium-star companion. Observations over the next few years, after SN 2012Z has faded, will either confirm this hypothesis or perhaps show that this supernova was actually the explosive death of a massive star.

A luminous, blue progenitor system for the type Iax supernova 2012Z.

PubMed

McCully, Curtis; Jha, Saurabh W; Foley, Ryan J; Bildsten, Lars; Fong, Wen-fai; Kirshner, Robert P; Marion, G H; Riess, Adam G; Stritzinger, Maximilian D

2014-08-07

Type Iax supernovae are stellar explosions that are spectroscopically similar to some type Ia supernovae at the time of maximum light emission, except with lower ejecta velocities. They are also distinguished by lower luminosities. At late times, their spectroscopic properties diverge from those of other supernovae, but their composition (dominated by iron-group and intermediate-mass elements) suggests a physical connection to normal type Ia supernovae. Supernovae of type Iax are not rare; they occur at a rate between 5 and 30 per cent of the normal type Ia rate. The leading models for type Iax supernovae are thermonuclear explosions of accreting carbon-oxygen white dwarfs that do not completely unbind the star, implying that they are 'less successful' versions of normal type Ia supernovae, where complete stellar disruption is observed. Here we report the detection of the luminous, blue progenitor system of the type Iax SN 2012Z in deep pre-explosion imaging. The progenitor system's luminosity, colours, environment and similarity to the progenitor of the Galactic helium nova V445 Puppis suggest that SN 2012Z was the explosion of a white dwarf accreting material from a helium-star companion. Observations over the next few years, after SN 2012Z has faded, will either confirm this hypothesis or perhaps show that this supernova was actually the explosive death of a massive star.

Detection of the gravitational lens magnifying a type Ia supernova.

PubMed

Quimby, Robert M; Oguri, Masamune; More, Anupreeta; More, Surhud; Moriya, Takashi J; Werner, Marcus C; Tanaka, Masayuki; Folatelli, Gaston; Bersten, Melina C; Maeda, Keiichi; Nomoto, Ken'ichi

2014-04-25

Objects of known brightness, like type Ia supernovae (SNIa), can be used to measure distances. If a massive object warps spacetime to form multiple images of a background SNIa, a direct test of cosmic expansion is also possible. However, these lensing events must first be distinguished from other rare phenomena. Recently, a supernova was found to shine much brighter than normal for its distance, which resulted in a debate: Was it a new type of superluminous supernova or a normal SNIa magnified by a hidden gravitational lens? Here, we report that a spectrum obtained after the supernova faded away shows the presence of a foreground galaxy-the first found to strongly magnify a SNIa. We discuss how more lensed SNIa can be found than previously predicted.

Hubble Finds Supernova Companion Star after Two Decades of Searching

NASA Image and Video Library

2017-12-08

This is an artist's impression of supernova 1993J, an exploding star in the galaxy M81 whose light reached us 21 years ago. The supernova originated in a double-star system where one member was a massive star that exploded after siphoning most of its hydrogen envelope to its companion star. After two decades, astronomers have at last identified the blue helium-burning companion star, seen at the center of the expanding nebula of debris from the supernova. The Hubble Space Telescope identified the ultraviolet glow of the surviving companion embedded in the fading glow of the supernova. More info: Using NASA’s Hubble Space Telescope, astronomers have discovered a companion star to a rare type of supernova. The discovery confirms a long-held theory that the supernova, dubbed SN 1993J, occurred inside what is called a binary system, where two interacting stars caused a cosmic explosion. "This is like a crime scene, and we finally identified the robber," said Alex Filippenko, professor of astronomy at University of California (UC) at Berkeley. "The companion star stole a bunch of hydrogen before the primary star exploded." SN 1993J is an example of a Type IIb supernova, unusual stellar explosions that contains much less hydrogen than found in a typical supernova. Astronomers believe the companion star took most of the hydrogen surrounding the exploding main star and continued to burn as a super-hot helium star. “A binary system is likely required to lose the majority of the primary star’s hydrogen envelope prior to the explosion. The problem is that, to date, direct observations of the predicted binary companion star have been difficult to obtain since it is so faint relative to the supernova itself,” said lead researcher Ori Fox of UC Berkeley. Read more: 1.usa.gov/1Az5Qb9 Credit: NASA, ESA, G. Bacon (STScI) NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar

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.

Flamsteed's Supernova of 1680

NASA Astrophysics Data System (ADS)

Fesen, R. A.

2001-12-01

A recent proper motion study of 40 knots in the Cas A supernova remnant indicated a knot convergent date of A.D. 1671.3 +/-0.9 assuming no deceleration (Thorstensen, Fesen, & van den Bergh 2001, AJ, 122, 297). However, because these optical knots are made visible by their shock passage through the local ISM/CSM, some deceleration is expected. A deceleration of just ~ 1.6 km s-1 yr-1 over a 300 yr time span would yield an explosion date around A.D. 1680, consistent with a suspected sighting of the Cas A supernova by J. Flamsteed in August 1680 (Ashworth, 1980, J. Hist. Astron., 11, 1). We discuss Flamsteed's likely observations of SN 1680 in terms of their constrains on the light curve and peak brightness and possible implications regarding the Cas A SN subtype.

Lensed Type Ia supernovae as probes of cluster mass models

Science.gov Websites

SAO/NASA ADS Astronomy Abstract Service Title: Lensed Type Ia supernovae as probes of cluster mass Origin: OUP Astronomy Keywords: gravitational lensing: strong, supernovae: general, galaxies: clusters

What Can We Learn By Observing Supernova Neutrinos?

NASA Astrophysics Data System (ADS)

Beacom, John

1999-10-01

A core-collapse supernova emits of the order of 10^58 neutrinos of all flavors over about 10 seconds, with an average energy of about 11 MeV for ν_e, 16 MeV for barν_e, and 25 MeV for ν_μ, ν_τ, barν_μ, and barν_τ. The present and near-term solar neutrino detectors can readily observe a supernova anywhere in our Galaxy. The expected supernova rate in our Galaxy is about 3 per century. What can we learn by observing the neutrinos from the next Galactic supernova? Besides the nuclear and astrophysical aspects of the collapse mechanism, there will be an unprecedented opportunity to measure neutrino properties, in particular their masses. The ν_μ and ν_τ masses can be measured by time-of-flight relative to the νe and barνe neutrinos, with a nearly model-independent sensitivity down to about 30 eV. If the time development of the supernova neutrino luminosities were better known from theory, this could be reduced to 10 eV or less. In either case, it will be essential to map out the neutrino energy spectra by measuring the signals on several different nuclear targets. Direct information on the absolute scale of the neutrino masses is especially crucial now since the apparently positive signals from neutrino oscillation experiments indicate nonzero differences in neutrino masses, with no information on the overall scale.

Search for core-collapse supernovae using the MiniBooNE neutrino detector

NASA Astrophysics Data System (ADS)

Aguilar-Arevalo, A. A.; Anderson, C. E.; Bazarko, A. O.; Brice, S. J.; Brown, B. C.; Bugel, L.; Cao, J.; Coney, L.; Conrad, J. M.; Cox, D. C.; Curioni, A.; Djurcic, Z.; Finley, D. A.; Fisher, M.; Fleming, B. T.; Ford, R.; Garcia, F. G.; Garvey, G. T.; Grange, J.; Green, C.; Green, J. A.; Hart, T. L.; Hawker, E.; Imlay, R.; Johnson, R. A.; Karagiorgi, G.; Kasper, P.; Katori, T.; Kobilarcik, T.; Kourbanis, I.; Koutsoliotas, S.; Laird, E. M.; Linden, S. K.; Link, J. M.; Liu, Y.; Liu, Y.; Louis, W. C.; Mahn, K. B. M.; Marsh, W.; Mauger, C.; McGary, V. T.; McGregor, G.; Metcalf, W.; Meyers, P. D.; Mills, F.; Mills, G. B.; Monroe, J.; Moore, C. D.; Mousseau, J.; Nelson, R. H.; Nienaber, P.; Nowak, J. A.; Osmanov, B.; Ouedraogo, S.; Patterson, R. B.; Pavlovic, Z.; Perevalov, D.; Polly, C. C.; Prebys, E.; Raaf, J. L.; Ray, H.; Roe, B. P.; Russell, A. D.; Sandberg, V.; Schirato, R.; Schmitz, D.; Shaevitz, M. H.; Shoemaker, F. C.; Smith, D.; Soderberg, M.; Sorel, M.; Spentzouris, P.; Spitz, J.; Stancu, I.; Stefanski, R. J.; Sung, M.; Tanaka, H. A.; Tayloe, R.; Tzanov, M.; van de Water, R. G.; Wascko, M. O.; White, D. H.; Wilking, M. J.; Yang, H. J.; Zeller, G. P.; Zimmerman, E. D.; MiniBooNE Collaboration

2010-02-01

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

Supernova remnant S 147 and its associated neutron star(s)

NASA Astrophysics Data System (ADS)

Gvaramadze, V. V.

2006-07-01

The supernova remnant S 147 harbors the pulsar PSR J 0538+2817 whose characteristic age is more than an order of magnitude greater than the kinematic age of the system (inferred from the angular offset of the pulsar from the geometric center of the supernova remnant and the pulsar proper motion). To reconcile this discrepancy we propose that PSR J 0538+2817 could be the stellar remnant of the first supernova explosion in a massive binary system and therefore could be as old as its characteristic age. Our proposal implies that S 147 is the diffuse remnant of the second supernova explosion (that disrupted the binary system) and that a much younger second neutron star (not necessarily manifesting itself as a radio pulsar) should be associated with S 147. We use the existing observational data on the system to suggest that the progenitor of the supernova that formed S 147 was a Wolf-Rayet star (so that the supernova explosion occurred within a wind bubble surrounded by a massive shell) and to constrain the parameters of the binary system. We also restrict the magnitude and direction of the kick velocity received by the young neutron star at birth and find that the kick vector should not strongly deviate from the orbital plane of the binary system.

Left Behind: A Bound Remnant from a White Dwarf Supernova?

NASA Astrophysics Data System (ADS)

Jha, Saurabh

2017-08-01

Type Ia supernovae (SN Ia) have enormous importance to cosmology and astrophysics, but their progenitors and explosion mechanisms are not understood in detail. Recently, observations and theoretical models have suggested that not all thermonuclear white-dwarf supernova explosions are normal SN Ia. In particular, type Iax supernovae (peculiar cousins to SN Ia), are thought to be exploding white dwarfs that are not completely disrupted, leaving behind a bound remnant. In deep and serendipitous HST pre-explosion data, we have discovered a luminous, blue progenitor system for the type Iax SN 2012Z in NGC 1309, which we interpret as a helium-star donor to the exploding white dwarf. HST observations of SN 2012Z in 2016, when the supernova light was expected to have faded away, still show a source at the location, as expected in our model where the pre-explosion flux was coming from the companion. However, the 2016 data also show a surprise: an excess flux compared to the progenitor system. Our proposed observations here will help unravel the mystery of that excess flux: is it from the bound ex-white dwarf remnant? Or is it from the shocked companion star that has been bombarded by supernova ejecta? Either of these possibilities would provide key new evidence as to the nature of these white dwarf supernovae.

Detection of a Red Supergiant Progenitor Star of a Type II-Plateau Supernova

NASA Astrophysics Data System (ADS)

Smartt, Stephen J.; Maund, Justyn R.; Hendry, Margaret A.; Tout, Christopher A.; Gilmore, Gerard F.; Mattila, Seppo; Benn, Chris R.

2004-01-01

We present the discovery of a red supergiant star that exploded as supernova 2003gd in the nearby spiral galaxy M74. The Hubble Space Telescope (HST) and the Gemini Telescope imaged this galaxy 6 to 9 months before the supernova explosion, and subsequent HST images confirm the positional coincidence of the supernova with a single resolved star that is a red supergiant of 8+4-2 solar masses. This confirms both stellar evolution models and supernova theories predicting that cool red supergiants are the immediate progenitor stars of type II-plateau supernovae.

Probing r-Process Production of Nuclei Beyond 209Bi with Gamma Rays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qian, Y.-Z.; Vogel, P.; Wasserburg, G. J.

We estimate gamma-ray fluxes due to the decay of nuclei beyond 209Bi from a supernova or a supernova remnant assuming that the r-process occurs in supernovae. We find that a detector with a sensitivity of {approx}10-7 {gamma} cm-2 s-1 at energies from {approx}40 keV to {approx}3 MeV may detect fluxes due to the decay of 226Ra, 229Th, 241Am, 243Am, 249Cf, and 251Cf in the newly discovered supernova remnant near Vela. In addition, such a detector may detect fluxes due to the decay of 227Ac and 228Ra produced in a future supernova at a distance of {approx}1 kpc. Because nuclei withmore » mass numbers A>209 are produced solely by the r-process, such detections are the best proof for a supernova r-process site. Further, they provide the most direct information on yields of progenitor nuclei with A>209 at r-process freeze-out. Finally, detection of fluxes due to the decay of r-process nuclei over a range of masses from a supernova or a supernova remnant provides the opportunity to compare yields in a single supernova event with the solar r-process abundance pattern. (c) (c) 1999. The American Astronomical Society.« less

Kepler Supernova Remnant: A View from Hubble Space Telescope

NASA Image and Video Library

2004-10-06

This image represents a view of NASA Kepler supernova remnant taken in X-rays, visible light, and infrared radiation, indicating that the bubble of gas that makes up the supernova remnant appears different in various types of light. http://photojournal.jpl.nasa.gov/catalog/PIA06909

VLA radio upper limit on Type IIn Supernova 2007rt

NASA Astrophysics Data System (ADS)

Chandra, Poonam; Soderberg, Alicia

2008-01-01

Poonam Chandra and Alicia Soderberg report on behalf of a larger collaboration: We observed a Type IIn supernova SN 2007rt (CBET 1148) with the Very Large Array (VLA) in the 8.46 GHz band on 2008, January 12.55 UT. The observations were taken for total duration of one hour in the VLA B-configuration. We do not detect any radio emission at the supernova position (CBET 1148). The flux density at the supernova position is 9 ± 27 uJy.

Observing the Next Galactic Supernova

NASA Astrophysics Data System (ADS)

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

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 (sime 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 (sime 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^{+7.3}_{-2.6} per century and a Galactic SN Ia rate of 1.4^{+1.4}_{-0.8} per century for a

Kepler Beyond Planets: Finding Exploding Stars (Type Felt Supernova)

NASA Image and Video Library

2018-03-26

This frame from an animation shows a kind of stellar explosion called a Fast-Evolving Luminous Transient. In this case, a giant star "burps" out a shell of gas and dust about a year before exploding. Most of the energy from the supernova turns into light when it hits this previously ejected material, resulting in a short, but brilliant burst of radiation. Stellar explosions forge and distribute materials that make up the world in which we live, and also hold clues to how fast the universe is expanding. By understanding supernovae, scientists can unlock mysteries that are key to what we are made of and the fate of our universe. But to get the full picture, scientists must observe supernovae from a variety of perspectives, especially in the first moments of the explosion. That's really difficult -- there's no telling when or where a supernova might happen next. An animation is available at https://photojournal.jpl.nasa.gov/catalog/PIA22351

Supernova 2010ev: A reddened high velocity gradient type Ia supernova

NASA Astrophysics Data System (ADS)

Gutiérrez, Claudia P.; González-Gaitán, Santiago; Folatelli, Gastón; Pignata, Giuliano; Anderson, Joseph P.; Hamuy, Mario; Morrell, Nidia; Stritzinger, Maximilian; Taubenberger, Stefan; Bufano, Filomena; Olivares E., Felipe; Haislip, Joshua B.; Reichart, Daniel E.

2016-05-01

Aims: We present and study the spectroscopic and photometric evolution of the type Ia supernova (SN Ia) 2010ev. Methods: We obtain and analyze multiband optical light curves and optical/near-infrared spectroscopy at low and medium resolution spanning -7 days to +300 days from the B-band maximum. Results: A photometric analysis shows that SN 2010ev is a SN Ia of normal brightness with a light-curve shape of Δm15(B) = 1.12 ± 0.02 and a stretch s = 0.94 ± 0.01 suffering significant reddening. From photometric and spectroscopic analysis, we deduce a color excess of E(B - V) = 0.25 ± 0.05 and a reddening law of Rv = 1.54 ± 0.65. Spectroscopically, SN 2010ev belongs to the broad-line SN Ia group, showing stronger than average Si IIλ6355 absorption features. We also find that SN 2010ev is a high velocity gradient SN with v˙Si = 164 ± 7 km s-1 d-1. The photometric and spectral comparison with other supernovae shows that SN 2010ev has similar colors and velocities to SN 2002bo and SN 2002dj. The analysis of the nebular spectra indicates that the [Fe II]λ7155 and [Ni II]λ7378 lines are redshifted, as expected for a high velocity gradient supernova. All these common intrinsic and extrinsic properties of the high velocity gradient (HVG) group are different from the low velocity gradient (LVG) normal SN Ia population and suggest significant variety in SN Ia explosions. This paper includes data gathered with the Du Pont Telescope at Las Campanas Observatory, Chile; and the Gemini Observatory, Cerro Pachon, Chile (Gemini Program GS-2010A-Q-14). Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile (ESO Programme 085.D-0577).

Supernova Cosmology Project

Science.gov Websites

<= Back to SCP Home Page Discovery of Unusual Optical Transient with the Hubble Space Telescope observations of SCP 06F6, an unusual optical transient discovered during the Hubble Space Telescope Cluster Supernova Survey. The transient brightened over a period of ~100 days, reached a peak magnitude of ~21.0 in

Supernova dynamics in the laboratory: Radiative shocks produced by ultra-high pressure implosion experiments on the National Ignition Facility

NASA Astrophysics Data System (ADS)

Pak, Arthur

2012-10-01

Thermonuclear fuel experiments on the National Ignition Facility implode 2-mm diameter capsules with a cryogenic deuterium-tritium ice layer to 1000x liquid density and pressures exceeding 100 Gbar (10^11 atm). About 200 ps after peak compression, a spherical supernova-like radiative shock wave is observed that expands with shock velocities of uS = 300 km/s, temperatures of order 1 keV at densities of 1 g/cc resulting in a radiation strength parameter of Q ˜uS^5 = 10^4. Radiation-hydrodynamic simulations indicate that the shock launched at stagnation first goes down a strong density gradient while propagating outward from the highly compressed DT fuel (˜ 1000g/cc) to the ablation front (˜ 1 g/cc). Similar to what happens inside a star, the shock pressure drops as it accelerates and heats. The radiative shock emission is first observed when it breaks out of the dense compressed fuel shell into the low-density inflowing plasma at the ablation front mimicking the supernova situation where the shock breaks out through the star surface into surrounding in-falling matter [1,2]; the shock is subsequently approaching the supercritical state with a strong pre-cursor followed by rapid cooling. These observations are consistent with the rapid vanishing of the radiation ring 400 ps after peak compression due to strong radiation losses and spherical expansion. The evolution and brightness of the radiative shock provides insight into the performance of these implosions that have the goal to produce burning fusion plasmas in the laboratory. By modifying the capsule ablator composition and thickness, the stagnation pressure, density gradients, shock velocity and radiative properties could be tailored to study various regimes related to supernovae radiative remnants.[4pt] [1] W. David Arnett, Supernovae as phenomena of high-energy astrophysics, Ann NY Aca. Science 302, 90 (1977).[0pt] [2] L. Ensman and A. Burrows, Shock breakout in SN1987A, ApJ 393, 742.

Electron-capture supernovae of super-asymptotic giant branch stars and the Crab supernova 1054

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nomoto, Ken'ichi; Tominaga, Nozomu; Blinnikov, Sergei I.

2014-05-02

An electron-capture supernova (ECSN) is a core-collapse supernova explosion of a super-asymptotic giant branch (SAGB) star with a main-sequence mass M{sub Ms} ∼ 7 - 9.5M{sub ⊙}. The explosion takes place in accordance with core bounce and subsequent neutrino heating and is a unique example successfully produced by first-principle simulations. This allows us to derive a first self-consistent multicolor light curves of a core-collapse supernova. Adopting the explosion properties derived by the first-principle simulation, i.e., the low explosion energy of 1.5 × 10{sup 50} erg and the small {sup 56}Ni mass of 2.5 × 10{sup −3} M{sub ⊙}, we performmore » a multigroup radiation hydrodynamics calculation of ECSNe and present multicolor light curves of ECSNe of SAGB stars with various envelope mass and hydrogen abundance. We demonstrate that a shock breakout has peak luminosity of L ∼ 2 × 10{sup 44} erg s{sup −1} and can evaporate circumstellar dust up to R ∼ 10{sup 17} cm for a case of carbon dust, that plateau luminosity and plateau duration of ECSNe are L ∼ 10{sup 42} erg s{sup −1} and {sup t} ∼ 60 - 100 days, respectively, and that a plateau is followed by a tail with a luminosity drop by ∼ 4 mag. The ECSN shows a bright and short plateau that is as bright as typical Type II plateau supernovae, and a faint tail that might be influenced by spin-down luminosity of a newborn pulsar. Furthermore, the theoretical models are compared with ECSN candidates: SN 1054 and SN 2008S. We find that SN 1054 shares the characteristics of the ECSNe. For SN 2008S, we find that its faint plateau requires a ECSN model with a significantly low explosion energy of E ∼ 10{sup 48} erg.« less

Dynamic Facial Expressions Prime the Processing of Emotional Prosody.

PubMed

Garrido-Vásquez, Patricia; Pell, Marc D; Paulmann, Silke; Kotz, Sonja A

2018-01-01

Evidence suggests that emotion is represented supramodally in the human brain. Emotional facial expressions, which often precede vocally expressed emotion in real life, can modulate event-related potentials (N100 and P200) during emotional prosody processing. To investigate these cross-modal emotional interactions, two lines of research have been put forward: cross-modal integration and cross-modal priming. In cross-modal integration studies, visual and auditory channels are temporally aligned, while in priming studies they are presented consecutively. Here we used cross-modal emotional priming to study the interaction of dynamic visual and auditory emotional information. Specifically, we presented dynamic facial expressions (angry, happy, neutral) as primes and emotionally-intoned pseudo-speech sentences (angry, happy) as targets. We were interested in how prime-target congruency would affect early auditory event-related potentials, i.e., N100 and P200, in order to shed more light on how dynamic facial information is used in cross-modal emotional prediction. Results showed enhanced N100 amplitudes for incongruently primed compared to congruently and neutrally primed emotional prosody, while the latter two conditions did not significantly differ. However, N100 peak latency was significantly delayed in the neutral condition compared to the other two conditions. Source reconstruction revealed that the right parahippocampal gyrus was activated in incongruent compared to congruent trials in the N100 time window. No significant ERP effects were observed in the P200 range. Our results indicate that dynamic facial expressions influence vocal emotion processing at an early point in time, and that an emotional mismatch between a facial expression and its ensuing vocal emotional signal induces additional processing costs in the brain, potentially because the cross-modal emotional prediction mechanism is violated in case of emotional prime-target incongruency.

An updated Type II supernova Hubble diagram

NASA Astrophysics Data System (ADS)

Gall, E. E. E.; Kotak, R.; Leibundgut, B.; Taubenberger, S.; Hillebrandt, W.; Kromer, M.; Burgett, W. S.; Chambers, K.; Flewelling, H.; Huber, M. E.; Kaiser, N.; Kudritzki, R. P.; Magnier, E. A.; Metcalfe, N.; Smith, K.; Tonry, J. L.; Wainscoat, R. J.; Waters, C.

2018-03-01

We present photometry and spectroscopy of nine Type II-P/L supernovae (SNe) with redshifts in the 0.045 ≲ z ≲ 0.335 range, with a view to re-examining their utility as distance indicators. Specifically, we apply the expanding photosphere method (EPM) and the standardized candle method (SCM) to each target, and find that both methods yield distances that are in reasonable agreement with each other. The current record-holder for the highest-redshift spectroscopically confirmed supernova (SN) II-P is PS1-13bni (z = 0.335-0.012+0.009), and illustrates the promise of Type II SNe as cosmological tools. We updated existing EPM and SCM Hubble diagrams by adding our sample to those previously published. Within the context of Type II SN distance measuring techniques, we investigated two related questions. First, we explored the possibility of utilising spectral lines other than the traditionally used Fe IIλ5169 to infer the photospheric velocity of SN ejecta. Using local well-observed objects, we derive an epoch-dependent relation between the strong Balmer line and Fe IIλ5169 velocities that is applicable 30 to 40 days post-explosion. Motivated in part by the continuum of key observables such as rise time and decline rates exhibited from II-P to II-L SNe, we assessed the possibility of using Hubble-flow Type II-L SNe as distance indicators. These yield similar distances as the Type II-P SNe. Although these initial results are encouraging, a significantly larger sample of SNe II-L would be required to draw definitive conclusions. Tables A.1, A.3, A.5, A.7, A.9, A.11, A.13, A.15 and A.17 are also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/611/A25

Study of the influence of Type Ia supernovae environment on the Hubble diagram

NASA Astrophysics Data System (ADS)

Henne, Vincent

2016-06-01

The observational cosmology with distant Type Ia supernovae as standard candles claims that the Universe is in accelerated expansion, caused by a large fraction of dark energy. In this report we investigated SNe Ia environment, studying the impact of the nature of their host galaxies and their distance to the host galactic center on the Hubble diagram fitting. The supernovae used in the analysis were extracted from Joint-Light-curves-Analysis compilation of high-redshift and nearby supernovae. The analysis are based on the empirical fact that SN Ia luminosities depend on their light curve shapes and colors. No conclusive correlation between SN Ia light curve parameters and galocentric distance were identified. Concerning the host morphology, we showed that the stretch parameter of Type Ia supernovae is correlated with the host galaxy type. The supernovae with lower stretch mainly exploded in elliptical and lenticular galaxies. The studies show that into old star population and low dust environment, supernovae are fainter. We did not find any significant correlation between Type Ia supernovae color and host morphology. We confirm that supernova properties depend on their environment and propose to incorporate a host galaxy term into the Hubble diagram fit in the future cosmological analysis.

Towards Limits on Neutrino Mixing Parameters from Nucleosynthesis in the Big Bang and Supernovae

NASA Astrophysics Data System (ADS)

Cardall, Christian Young

1997-11-01

Astrophysical environments can often provide stricter limits on neutrino mass and mixing parameters than terrestrial experiments. However, before firm limits can be found, there must be confidence in the understanding of the astrophysical environment being used to make these limits. In this dissertation, progress towards limits on neutrino mixing parameters from big bang nucleosynthesis and supernova r-process nucleosynthesis is sought. By way of assessment of current knowledge of neutrino oscillation parameters, we examine the potential for a 'natural' three-neutrino mixing scheme (one without sterile neutrinos) to satisfy available data and astrophysical arguments. A small parameter space currently exists for a natural three-neutrino oscillation solution meeting known constraints. If such a solution is ruled out, and current hints about neutrino oscillations are confirmed, mixing between active and sterile neutrinos will probably be required. Because mixing between active and sterile neutrinos with parameters appropriate for the atmospheric or solar neutrino problems increases the primordial 4He abundance, big bang nucleosynthesis considerations can place limits on such mixing. In the present work the overall consistency of standard big bang nucleosynthesis is discussed in light of recent discordant determinations of the primordial deuterium abundance. Cosmological considerations favor a larger baryon density, which supports the lower reported value of D/H. Studies of limits on active-sterile neutrino mixing derived from big bang nucleosynthesis considerations are here extended to consider the dependance of these constraints on the primordial deuterium abundance. If the neutrino-heated ejecta in the post-core-bounce supernova environment is the site of r-process nucleosynthesis, limits can be placed on mixing between νe, and νsbμ, or νsbτ. Refined limits will require a better understanding of this r-process environment, since current supernova models do not

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

NASA Astrophysics Data System (ADS)

Menon, Athira

2015-08-01

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

Possible linkage between supernovae, increased terrestrial lightning, and wildfire activity in the Late Miocene and Early Pleistocene

NASA Astrophysics Data System (ADS)

Thomas, B. C.; Feulner, G.; Melott, A. L.; Kirsten, T.; von Bloh, W.

2017-12-01

Radioisotopes from deep-sea deposits show that Earth was affected by nearby supernovae about 2.5 and 8 million years ago. Recent modelling work shows that high-energy particles from these events resulted in greatly enhanced ionization of the troposphere. This could have led to an increase in wildfires via more frequent lightning. Here we show that published data on global fire activity from charcoal records reveal a marked increase in wildfires around the times of the supernova explosions. We use a dynamic global vegetation model to assess the impact of increased lightning frequency on vegetation patterns, finding a patchy global decrease in tree cover. Regionally, vegetation changes are particularly pronounced in western North America, the Mediterranean, Central Asia, Northern Indochina, subtropical South America, Africa and Australia, and notably East Africa, in agreement with empirical evidence for a global shift towards savannas during the Pleistocene. Our results demonstrate that moderately nearby supernovae have the potential to affect life on Earth even if they are too distant to initiate a mass extinction. Finally, we note that the shift from forest to savannah biomes in the East African Rift Valley region has been tentatively linked to hominin evolution in this region.

Real-time supernova neutrino burst monitor at Super-Kamiokande

NASA Astrophysics Data System (ADS)

Abe, K.; Haga, Y.; Hayato, Y.; Ikeda, M.; Iyogi, K.; Kameda, J.; Kishimoto, Y.; Miura, M.; Moriyama, S.; Nakahata, M.; Nakano, Y.; Nakayama, S.; Sekiya, H.; Shiozawa, M.; Suzuki, Y.; Takeda, A.; Tanaka, H.; Tomura, T.; Ueno, K.; Wendell, R. A.; Yokozawa, T.; Irvine, T.; Kajita, T.; Kametani, I.; Kaneyuki, K.; Lee, K. P.; McLachlan, T.; Nishimura, Y.; Richard, E.; Okumura, K.; Labarga, L.; Fernandez, P.; Berkman, S.; Tanaka, H. A.; Tobayama, S.; Gustafson, J.; Kearns, E.; Raaf, J. L.; Stone, J. L.; Sulak, L. R.; Goldhaber, M.; Carminati, G.; Kropp, W. R.; Mine, S.; Weatherly, P.; Renshaw, A.; Smy, M. B.; Sobel, H. W.; Takhistov, V.; Ganezer, K. S.; Hartfiel, B. L.; Hill, J.; Keig, W. E.; Hong, N.; Kim, J. Y.; Lim, I. T.; Akiri, T.; Himmel, A.; Scholberg, K.; Walter, C. W.; Wongjirad, T.; Ishizuka, T.; Tasaka, S.; Jang, J. S.; Learned, J. G.; Matsuno, S.; Smith, S. N.; Hasegawa, T.; Ishida, T.; Ishii, T.; Kobayashi, T.; Nakadaira, T.; Nakamura, K.; Oyama, Y.; Sakashita, K.; Sekiguchi, T.; Tsukamoto, T.; Suzuki, A. T.; Takeuchi, Y.; Bronner, C.; Hirota, S.; Huang, K.; Ieki, K.; Kikawa, T.; Minamino, A.; Murakami, A.; Nakaya, T.; Suzuki, K.; Takahashi, S.; Tateishi, K.; Fukuda, Y.; Choi, K.; Itow, Y.; Mitsuka, G.; Mijakowski, P.; Hignight, J.; Imber, J.; Jung, C. K.; Yanagisawa, C.; Wilking, M. J.; Ishino, H.; Kibayashi, A.; Koshio, Y.; Mori, T.; Sakuda, M.; Yamaguchi, R.; Yano, T.; Kuno, Y.; Tacik, R.; Kim, S. B.; Okazawa, H.; Choi, Y.; Nishijima, K.; Koshiba, M.; Suda, Y.; Totsuka, Y.; Yokoyama, M.; Martens, K.; Marti, Ll.; Vagins, M. R.; Martin, J. F.; de Perio, P.; Konaka, A.; Chen, S.; Zhang, Y.; Connolly, K.; Wilkes, R. J.

2016-08-01

We present a real-time supernova neutrino burst monitor at Super-Kamiokande (SK). Detecting supernova explosions by neutrinos in real time is crucial for giving a clear picture of the explosion mechanism. Since the neutrinos are expected to come earlier than light, a fast broadcasting of the detection may give astronomers a chance to make electromagnetic radiation observations of the explosions right at the onset. The role of the monitor includes a fast announcement of the neutrino burst detection to the world and a determination of the supernova direction. We present the online neutrino burst detection system and studies of the direction determination accuracy based on simulations at SK.

Walter Baade, Fritz Zwicky, and Rudolph Minkowski's Early Supernova Research, 1927 - 1973

NASA Astrophysics Data System (ADS)

Osterbrock, D. E.

1999-12-01

Long before he ``discovered" the two stellar populations, Walter Baade was a pioneer in research on supernovae and their remnants. In 1927, while still in Germany, Baade emphasized what he called ``Hauptnovae" (chief novae) as highly luminous, potential distance indicators. He joined the Mount Wilson staff in 1931, bringing the ``secret" of the Schmidt camera with him, and encouraged Fritz Zwicky to carry out a supernova search with one at Palomar. Baade and Zwicky used the term ``supernova" in their 1933 joint paper. Zwicky began a systematic search in 1936, and Baade followed up with the 100-in reflector to derive light curves. He confirmed that Tycho's ``nova" of 1572 and the Crab nebula had been supernovae in our Galaxy. Baade advised N. U. Mayall, at Lick, on his spectroscopic study of the Crab nebula. In 1933, after Hitler came to power, Rudolph Minkowski had to leave Germany. Baade managed to get him a Mount Wilson staff position. Minkowski then did the spectroscopic observations of supernovae, beginning in 1937. Within a few years he and Baade were able to distinguish type I and II supernovae. Baade's further work on supernovae included historical research in Latin, Italian, and German, as well as filter photography. He searched hard for a remnant of SN 1885 in M 31, but never succeeded in finding it. After World War II the Crab nebula was found to be a strong radio source, and Baade and Minkowski used the 200-in to identify other supernova remnants, beginning with Cas A. Baade collaborated closely with Jan Oort and his student, Lo Woltjer, in their studies of the Crab nebula. After Baade retired in 1958, Minkowski continued supernova research for more than a decade; one of his favorite objects was the expanding Cygnus Loop.

Quark Phase Transition in Compact Objects and Multimessenger Astronomy: Neutrino Signals, Supernovae and Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Sokolov, V. V.; Vlasyuk, V. V.; Petkov, V. B.

2016-06-01

The International Workshop on Quark Phase Transition in Compact Objects and Multimessenger Astronomy: Neutrino Signals, Supernovae and Gamma-Ray Bursts (October, 7-14, 2015) was dedicated to Quantum ChromoDynamics (QCD) Phase Transitions and observational signals of these transitions related to formation of compact astrophysical objects. The aim of this workshop was to bring together researchers working on the problems of behavior of matter under critical conditions achievable in such astrophysical objects as "strange" or "hybrid" stars and in laboratories at heavy-ion collisions to discuss fundamental issues and recent developments. Topics included both observations (radio, optical and X-ray astronomy, gamma ray bursts, gravitational waves, neutrino detection, heavy-ion collisions, etc.) and theory (supernova simulations, proto-neutron and neutron stars, equation of state of dense matter, neutron star cooling, unstable modes, nucleosynthesis, explosive transitions, quark-gluon plasma).

Revealing the supernova-gamma-ray burst connection with TeV neutrinos.

PubMed

Ando, Shin'ichiro; Beacom, John F

2005-08-05

Gamma-ray bursts (GRBs) are rare, powerful explosions displaying highly relativistic jets. It has been suggested that a significant fraction of the much more frequent core-collapse supernovae are accompanied by comparably energetic but mildly relativistic jets, which would indicate an underlying supernova-GRB connection. We calculate the neutrino spectra from the decays of pions and kaons produced in jets in supernovae, and show that the kaon contribution is dominant and provides a sharp break near 20 TeV, which is a sensitive probe of the conditions inside the jet. For a supernova at 10 Mpc, 30 events above 100 GeV are expected in a 10 s burst in the IceCube detector.

Neutrinos from type Ia supernovae: The deflagration-to-detonation transition scenario

DOE PAGES

Wright, Warren P.; Nagaraj, Gautam; Kneller, James P.; ...

2016-07-19

It has long been recognized that the neutrinos detected from the next core-collapse supernova in the Galaxy have the potential to reveal important information about the dynamics of the explosion and the nucleosynthesis conditions as well as allowing us to probe the properties of the neutrino itself. The neutrinos emitted from thermonuclear—type Ia—supernovae also possess the same potential, although these supernovae are dimmer neutrino sources. For the first time, we calculate the time, energy, line of sight, and neutrino-flavor-dependent features of the neutrino signal expected from a three-dimensional delayed-detonation explosion simulation, where a deflagration-to-detonation transition triggers the complete disruption ofmore » a near-Chandrasekhar mass carbon-oxygen white dwarf. We also calculate the neutrino flavor evolution along eight lines of sight through the simulation as a function of time and energy using an exact three-flavor transformation code. We identify a characteristic spectral peak at ˜10 MeV as a signature of electron captures on copper. This peak is a potentially distinguishing feature of explosion models since it reflects the nucleosynthesis conditions early in the explosion. We simulate the event rates in the Super-K, Hyper-K, JUNO, and DUNE neutrino detectors with the SNOwGLoBES event rate calculation software and also compute the IceCube signal. Hyper-K will be able to detect neutrinos from our model out to a distance of ˜10 kpc. Here, at 1 kpc, JUNO, Super-K, and DUNE would register a few events while IceCube and Hyper-K would register several tens of events.« less

Slow-speed Supernovae from the Palomar Transient Factory: Two Channels

NASA Astrophysics Data System (ADS)

White, Christopher J.; Kasliwal, Mansi M.; Nugent, Peter E.; Gal-Yam, Avishay; Howell, D. Andrew; Sullivan, Mark; Goobar, Ariel; Piro, Anthony L.; Bloom, Joshua S.; Kulkarni, Shrinivas R.; Laher, Russ R.; Masci, Frank; Ofek, Eran O.; Surace, Jason; Ben-Ami, Sagi; Cao, Yi; Cenko, S. Bradley; Hook, Isobel M.; Jönsson, Jakob; Matheson, Thomas; Sternberg, Assaf; Quimby, Robert M.; Yaron, Ofer

2015-01-01

Since the discovery of the unusual prototype SN 2002cx, the eponymous class of Type I (hydrogen-poor) supernovae with low ejecta speeds has grown to include approximately two dozen members identified from several heterogeneous surveys, in some cases ambiguously. Here we present the results of a systematic study of 1077 Type I supernovae discovered by the Palomar Transient Factory, leading to nine new members of this peculiar class. Moreover, we find there are two distinct subclasses based on their spectroscopic, photometric, and host galaxy properties: "SN 2002cx-like" supernovae tend to be in later-type or more irregular hosts, have more varied and generally dimmer luminosities, have longer rise times, and lack a Ti II trough when compared to "SN 2002es-like" supernovae. None of our objects show helium, and we counter a previous claim of two such events. We also find that the occurrence rate of these transients relative to Type Ia supernovae is 5.6-3.8+22% (90% confidence), lower compared to earlier estimates. Combining our objects with the literature sample, we propose that these subclasses have two distinct physical origins.

On the Interpretation of Supernova Light Echo Profiles and Spectra

NASA Astrophysics Data System (ADS)

Rest, A.; Sinnott, B.; Welch, D. L.; Foley, R. J.; Narayan, G.; Mandel, K.; Huber, M. E.; Blondin, S.

2011-05-01

The light echo (LE) systems of historical supernovae in the Milky Way and local group galaxies provide an unprecedented opportunity to reveal the effects of asymmetry on observables, particularly optical spectra. Scattering dust at different locations on the LE ellipsoid witnesses the supernova from different perspectives, and the light consequently scattered toward Earth preserves the shape of line profile variations introduced by asymmetries in the supernova photosphere. However, the interpretation of supernova LE spectra to date has not involved a detailed consideration of the effects of outburst duration and geometrical scattering modifications due to finite scattering dust filament dimension, inclination, and image point-spread function and spectrograph slit width. In this paper, we explore the implications of these factors and present a framework for future-resolved supernova LE spectra interpretation, and test it against Cas A and SN 1987A LE spectra. We conclude that the full modeling of the dimensions and orientation of the scattering dust using the observed LEs at two or more epochs is critical for the correct interpretation of LE spectra. Indeed, without doing so one might falsely conclude that differences exist when none are actually present.

Density profiles of supernova matter and determination of neutrino parameters

NASA Astrophysics Data System (ADS)

Chiu, Shao-Hsuan

2007-08-01

The flavor conversion of supernova neutrinos can lead to observable signatures related to the unknown neutrino parameters. As one of the determinants in dictating the efficiency of resonant flavor conversion, the local density profile near the Mikheyev-Smirnov-Wolfenstein (MSW) resonance in a supernova environment is, however, not so well understood. In this analysis, variable power-law functions are adopted to represent the independent local density profiles near the locations of resonance. It is shown that the uncertain matter density profile in a supernova, the possible neutrino mass hierarchies, and the undetermined 1-3 mixing angle would result in six distinct scenarios in terms of the survival probabilities of νe and ν¯e. The feasibility of probing the undetermined neutrino mass hierarchy and the 1-3 mixing angle with the supernova neutrinos is then examined using several proposed experimental observables. Given the incomplete knowledge of the supernova matter profile, the analysis is further expanded to incorporate the Earth matter effect. The possible impact due to the choice of models, which differ in the average energy and in the luminosity of neutrinos, is also addressed in the analysis.

Supernova neutrino physics with xenon dark matter detectors: A timely perspective

NASA Astrophysics Data System (ADS)

Lang, Rafael F.; McCabe, Christopher; Reichard, Shayne; Selvi, Marco; Tamborra, Irene

2016-11-01

Dark matter detectors that utilize liquid xenon have now achieved tonne-scale targets, giving them sensitivity to all flavors of supernova neutrinos via coherent elastic neutrino-nucleus scattering. Considering for the first time a realistic detector model, we simulate the expected supernova neutrino signal for different progenitor masses and nuclear equations of state in existing and upcoming dual-phase liquid xenon experiments. We show that the proportional scintillation signal (S2) of a dual-phase detector allows for a clear observation of the neutrino signal and guarantees a particularly low energy threshold, while the backgrounds are rendered negligible during the supernova burst. XENON1T (XENONnT and LZ; DARWIN) experiments will be sensitive to a supernova burst up to 25 (35; 65) kpc from Earth at a significance of more than 5 σ , observing approximately 35 (123; 704) events from a 27 M⊙ supernova progenitor at 10 kpc. Moreover, it will be possible to measure the average neutrino energy of all flavors, to constrain the total explosion energy, and to reconstruct the supernova neutrino light curve. Our results suggest that a large xenon detector such as DARWIN will be competitive with dedicated neutrino telescopes, while providing complementary information that is not otherwise accessible.

Implications of supernova remnant origin model of galactic cosmic rays on gamma rays from young supernova remnants

NASA Astrophysics Data System (ADS)

Banik, Prabir; Bhadra, Arunava

2017-06-01

It is widely believed that Galactic cosmic rays are originated in supernova remnants (SNRs), where they are accelerated by a diffusive shock acceleration (DSA) process in supernova blast waves driven by expanding SNRs. In recent theoretical developments of the DSA theory in SNRs, protons are expected to accelerate in SNRs at least up to the knee energy. If SNRs are the true generators of cosmic rays, they should accelerate not only protons but also heavier nuclei with the right proportions, and the maximum energy of the heavier nuclei should be the atomic number (Z ) times the mass of the proton. In this work, we investigate the implications of the acceleration of heavier nuclei in SNRs on energetic gamma rays produced in the hadronic interaction of cosmic rays with ambient matter. Our findings suggest that the energy conversion efficiency has to be nearly double for the mixed cosmic ray composition compared to that of pure protons to explain observations. In addition, the gamma-ray flux above a few tens of TeV would be significantly higher if cosmic ray particles could attain energies Z times the knee energy in lieu of 200 TeV, as suggested earlier for nonamplified magnetic fields. The two stated maximum energy paradigms will be discriminated in the future by upcoming gamma-ray experiments like the Cherenkov telescope array (CTA).

Imaging pH and oxygen at the soil-root interface by planar optodes: a challenging technology to study dynamic rhizosphere processes.

NASA Astrophysics Data System (ADS)

Daudin, Gabrielle; Oburger, Eva; Schmidt, Hannes; Borisov, Sergey; Pradier, Céline; Jourdan, Christophe; Marsden, Claire; Obermaier, Daniela; Woebken, Dagmar; Richter, Andreas; Wenzel, Walter; Hinsinger, Philippe

2017-04-01

Roots do not only take up water and nutrients from surrounding soil but they also release a wide range of exudates, such as low molecular weight organic compounds, CO2 or protons. Root-soil interactions trigger heterogeneous rhizosphere processes based on differences in root activity along the root axis and with distance from the root surface. Elucidating their temporal and spatial dynamics is of crucial importance for a better understanding of these interrelated biogeochemical processes in the rhizosphere. Therefore, monitoring key parameters at a fine scale and in a non-invasive way at the root-soil interface is essential. Planar optodes are an emerging technology that allows in situ and non-destructive imaging of mainly pH, CO2 and O2. Originated in limnology, planar optodes have recently been applied to soil-root systems in laboratory conditions. This presentation will highlight advantages and challenges of using planar optodes to image pH and O2 dynamics in the rhizosphere, focusing on two RGB (red-green-blue) approaches: a commercially available system (PreSens) and a custom-made one. Important insights into robustness, accuracy, potentials and limitations of the two systems applied to different laboratory/greenhouse-based experimental conditions (flooded and aerobic rhizobox systems, plant species) will be addressed. Furthermore, challenges of optode measurements in the field, including a first case study with Eucalyptus grandis in Brazil, will be discussed.

Abundances of presolar graphite and SiC from supernovae and AGB stars in the Murchison meteorite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amari, Sachiko; Zinner, Ernst; Gallino, Roberto

2014-05-02

Pesolar graphite grains exhibit a range of densities (1.65 – 2.20 g/cm{sup 3}). We investigated abundances of presolar graphite grains formed in supernovae and in asymptotic giant branch (AGB) stars in the four density fractions KE3, KFA1, KFB1 and KFC1 extracted from the Murchison meteorite to probe dust productions in these stellar sources. Seventy-six and 50% of the grains in the low-density fractions KE3 and KFA1, respectively, are supernova grains, while only 7.2% and 0.9% of the grains in the high-density fractions KFB1 and KFC1 have a supernova origin. Grains of AGB star origin are concentrated in the high-density fractionsmore » KFB1 and KFC1. From the C isotopic distributions of these fractions and the presence of s-process Kr with {sup 86}Kr/{sup 82}Kr = 4.43±0.46 in KFC1, we estimate that 76% and 80% of the grains in KFB1 and KFC1, respectively, formed in AGB stars. From the abundance of graphite grains in the Murchison meteorite, 0.88 ppm, the abundances of graphite from supernovae and AGB stars are 0.24 ppm and 0.44 ppm, respectively: the abundances of graphite in supernovae and AGB stars are comparable. In contrast, it has been known that 1% of SiC grains formed in supernovae and 95% formed in AGB stars in meteorites. Since the abundance of SiC grains is 5.85 ppm in the Murchison meteorite, the abundances of SiC from supernovae and AGB stars are 0.063 ppm and 5.6 ppm, respectively: the dominant source of SiC grains is AGB stars. Since SiC grains are harder and likely to survive better in space than graphite grains, the abundance of supernova graphite grains, which is higher than that of supernova SiC grains, indicates that supernovae proficiently produce graphite grains. Graphite grains from AGB stars are, in contrast, less abundant that SiC grains from AGB stars (0.44 ppm vs. 5.6 ppm). It is difficult to derive firm conclusions for graphite and SiC formation in AGB stars due to the difference in susceptibility to grain destruction

A Unique Supernova Graphite: Contemporaneous Condensation of All Things Carbonaceous

NASA Astrophysics Data System (ADS)

Croat, T. K.; Jadhav, M.; Lebsack, E.; Bernatowicz, T. J.

2011-03-01

We report a supernova graphite that contains internal subgrains of TiC, SiC, Fe and Ni silicides, and iron metal. These phases comprise a complete list of the phases predicted by equilibrium calculations to condense from C-rich supernova zones.

Quantum state-to-state dynamics for the quenching process of Br(2P1/2) + H2(v(i) = 0, 1, j(i) = 0).

PubMed

Xie, Changjian; Jiang, Bin; Xie, Daiqian; Sun, Zhigang

2012-03-21

Quantum state-to-state dynamics for the quenching process Br((2)P(1/2)) + H(2)(v(i) = 0, 1, j(i) = 0) → Br((2)P(3/2)) + H(2)(v(f), j(f)) has been studied based on two-state model on the recent coupled potential energy surfaces. It was found that the quenching probabilities have some oscillatory structures due to the interference of reflected flux in the Br((2)P(1/2)) + H(2) and Br((2)P(3/2)) + H(2) channels by repulsive potential in the near-resonant electronic-to-vibrational energy transfer process. The final vibrational state resolved integral cross sections were found to be dominated by the quenching process Br((2)P(1/2)) + H(2)(v) → Br((2)P(3/2)) + H(2)(v+1) and the nonadiabatic reaction probabilities for Br((2)P(1/2)) + H(2)(v = 0, 1, j(i) = 0) are quite small, which are consistent with previous theoretical and experimental results. Our calculated total quenching rate constant for Br((2)P(1/2)) + H(2)(v(i) = 0, j(i) = 0) at room temperature is in good agreement with the available experimental data. © 2012 American Institute of Physics

Light-curve and spectral properties of ultrastripped core-collapse supernovae leading to binary neutron stars

NASA Astrophysics Data System (ADS)

Moriya, Takashi J.; Mazzali, Paolo A.; Tominaga, Nozomu; Hachinger, Stephan; Blinnikov, Sergei I.; Tauris, Thomas M.; Takahashi, Koh; Tanaka, Masaomi; Langer, Norbert; Podsiadlowski, Philipp

2017-04-01

We investigate light-curve and spectral properties of ultrastripped core-collapse supernovae. Ultrastripped supernovae are the explosions of heavily stripped massive stars that lost their envelopes via binary interactions with a compact companion star. They eject only ˜0.1 M⊙ and may be the main way to form double neutron-star systems that eventually merge emitting strong gravitational waves. We follow the evolution of an ultrastripped supernova progenitor until iron core collapse and perform explosive nucleosynthesis calculations. We then synthesize light curves and spectra of ultrastripped supernovae using the nucleosynthesis results and present their expected properties. Ultrastripped supernovae synthesize ˜0.01 M⊙ of radioactive 56Ni, and their typical peak luminosity is around 1042 erg s-1 or -16 mag. Their typical rise time is 5-10 d. Comparing synthesized and observed spectra, we find that SN 2005ek, some of the so-called calcium-rich gap transients, and SN 2010X may be related to ultrastripped supernovae. If these supernovae are actually ultrastripped supernovae, their event rate is expected to be about 1 per cent of core-collapse supernovae. Comparing the double neutron-star merger rate obtained by future gravitational-wave observations and the ultrastripped supernova rate obtained by optical transient surveys identified with our synthesized light-curve and spectral models, we will be able to judge whether ultrastripped supernovae are actually a major contributor to the binary neutron-star population and provide constraints on binary stellar evolution.

Merging white dwarfs and thermonuclear supernovae.

PubMed

van Kerkwijk, M H

2013-06-13

Thermonuclear supernovae result when interaction with a companion reignites nuclear fusion in a carbon-oxygen white dwarf, causing a thermonuclear runaway, a catastrophic gain in pressure and the disintegration of the whole white dwarf. It is usually thought that fusion is reignited in near-pycnonuclear conditions when the white dwarf approaches the Chandrasekhar mass. I briefly describe two long-standing problems faced by this scenario, and the suggestion that these supernovae instead result from mergers of carbon-oxygen white dwarfs, including those that produce sub-Chandrasekhar-mass remnants. I then turn to possible observational tests, in particular, those that test the absence or presence of electron captures during the burning.

Neutrino Observation of Core Collapse Supernovae

NASA Astrophysics Data System (ADS)

Nakazato, Ken'ichiro

The event rate of the supernova neutrinos are predicted for the future SK-Gd experiment. With an eye on the neutron tagging by Gd, the energy and angular distributions are calculated both for tagged events from inverse β decay reaction and untagged events from other reactions. As a result, it is indicated that the shock revival in the supernova is detectable through the decrease of the event rate and decline of the average energy of events. It is also implied that a careful treatment for the neutrino spectra is needed to investigate the untagged events owing to the high neutrino threshold energy of 16O reactions.

Hot interstellar tunnels. 1: Simulation of interacting supernova remnants

NASA Technical Reports Server (NTRS)

Smith, B. W.

1976-01-01

The theory required to build a numerical simulation of interacting supernova remnants is developed. The hot cavities within a population of remnants will become connected, with varying ease and speed, for a variety of assumed conditions in the outer shells of old remnants. Apparently neither radiative cooling nor thermal conduction in a large-scale galactic magnetic field can destroy hot cavity regions, if they grow, faster than they are reheated by supernova shock waves, but interstellar mass motions disrupt the contiguity of extensive cavities necessary for the dispersal of these shocks over a wide volume. Monte Carlo simulations show that a quasi-equilibrium is reached in the test space within 10 million yrs of the first supernova and is characterized by an average cavity filling fraction of the interstellar volume. Aspects of this equilibrium are discussed for a range of supernova rates. Two predictions are not confirmed within this range: critical growth of hot regions to encompass the entire medium, and the efficient quenching of a remnant's expansion by interaction with other cavities.

Infrared Emission from Supernova Remnants: Formation and Destruction of Dust

NASA Astrophysics Data System (ADS)

Williams, Brian J.; Temim, Tea

2016-09-01

We review the observations of dust emission in supernova remnants (SNRs) and supernovae (SNe). Theoretical calculations suggest that SNe, particularly core-collapse, should make significant quantities of dust, perhaps as much as a solar mass. Observations of extragalactic SNe have yet to find anywhere near this amount, but this may be the result of observational limitations. SN 1987A, in the process of transitioning from a SN to an SNR, does show signs of a significant amount of dust forming in its ejecta, but whether this dust will survive the passage of the reverse shock to be injected into the ISM is unknown. IR observations of SNRs have not turned up significant quantities of dust, and the dust that is observed is generally swept up by the forward shock, rather than created in the ejecta. Because the shock waves also destroy dust in the ISM, we explore the question of whether SNe might be net destroyers, rather than net creators of dust in the universe.

Infrared Emission from Supernova Remnants: Formation and Destruction of Dust

NASA Astrophysics Data System (ADS)

Williams, Brian J.; Temim, Tea

We review the observations of dust emission in supernova remnants (SNRs) and supernovae (SNe). Theoretical calculations suggest that SNe, particularly core-collapse, should make significant quantities of dust, perhaps as much as a solar mass. Observations of extragalactic SNe have yet to find anywhere near this amount, but this may be the result of observational limitations. SN 1987A, in the process of transitioning from a SN to an SNR, does show signs of a significant amount of dust forming in its ejecta, but whether this dust will survive the passage of the reverse shock to be injected into the ISM is unknown. IR observations of SNRs have not turned up significant quantities of dust, and the dust that is observed is generally swept up by the forward shock, rather than created in the ejecta. Because the shock waves also destroy dust in the ISM, we explore the question of whether SNe might be net destroyers, rather than net creators of dust in the universe.

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.

Cassiopeia A supernova

NASA Image and Video Library

2017-12-08

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

A Deep Search with HST for Late Time Supernova Signatures in the Hosts of XRF 011030 and XRF 020427

NASA Technical Reports Server (NTRS)

Patel, Sandeep; Kouveliotou, Chryssa; Levan, Andrew; Fruchter, Andrew; Rol, Evert; Rhoads, James; Gorosabel, Javier; Ramirez-Ruiz, Enrico; Hjorth, Jens; Wijers, Ralph

2004-01-01

X-ray Flashes (XRFs), are, like Gamma-Ray Bursts (GRBs) thought to signal the collapse of massive stars in distant galaxies. Many models posit that the isotropic equivalent energies of XRFs are lower than those for GRBs, such that they are visible hom a reduced range of distances when compared with GRBs. Here we present the results of two epoch Hubble Space Telescope imaging of two XRFs. These images taken approximately 45 and 200 days post bust reveal no evidence for an associated supernova in either case. Supernovae such as SN 1998bw would have been visible out to z approximately 1.5 in each case, while faint supernovae such as SN 2002ap would be visible to z approximately 1. At these distances the bursts would not fit the observed correlations between E(sub p) and E(sub iso) and would have required extremely luminous X-ray afterglows. We conclude that should these XRFs reside at low redshift, it is necessary either that their line of sight is heavily extinguished, or that XRFs, unlike GRBs do not have temporally coincident supernovae.

Predicting the next local supernova

NASA Astrophysics Data System (ADS)

Middleditch, John

2018-06-01

It has been over 31 years since Supernova 1987A, and we have learned many things from the neutrinos, light curve, evolving spectrum including the “Bochum Event” at day 19.2, the associated “Bright Spot” or “Mystery Spot,” and its motion away from the position of the progenitor, Sk -69o202, the mixing, rings, X- and gamma-rays, polarization, and the 467.5 Hz pulsation and its associated ~1,000 s precession (or the lack of any strongly magnetized remnant). Finally, our understanding of this event has progressed to the point where we have a time interval of a few months during which we can predict which supergiant star in our local neighborhood out to 5 Megaparsecs will be the next to die in a supernova explosion.

Evolution of Supernova Remnants Near the Galactic Center

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yalinewich, A.; Piran, T.; Sari, R.

Supernovae near the Galactic center (GC) evolve differently from regular Galactic supernovae. This is mainly due to the environment into which the supernova remnants (SNRs) propagate. SNRs near the GC propagate into a wind swept environment with a velocity directed away from the GC, and a graded density profile. This causes these SNRs to be non-spherical, and to evolve faster than their Galactic counterparts. We develop an analytic theory for the evolution of explosions within a stellar wind, and verify it using a hydrodynamic code. We show that such explosions can evolve in one of three possible morphologies. Using thesemore » results we discuss the association between the two SNRs (SGR East and SGR A’s bipolar radio/X-ray lobes) and the two neutron stars (the Cannonball and SGR J1745-2900) near the GC. We show that, given the morphologies of the SNR and positions of the neutron stars, the only possible association is between SGR A’s bipolar radio/X-ray lobes and SGR J1745-2900. If a compact object was created in the explosion of SGR East, it remains undetected, and the SNR of the supernova that created the Cannonball has already disappeared.« less

IceCube Sensitivity for Low-Energy Neutrinos from Nearby Supernovae

NASA Technical Reports Server (NTRS)

Stamatikos, M.; Abbasi, R.; Berghaus, P.; Chirkin, D.; Desiati, P.; Diaz-Velez, J.; Dumm, J. P.; Eisch, J.; Feintzeig, J.; Hanson, K.;

Hubble Supernova Bubble Resembles Holiday Ornament

NASA Image and Video Library

2017-12-08

NASA image release December 14, 2010 A delicate sphere of gas, photographed by NASA's Hubble Space Telescope, floats serenely in the depths of space. The pristine shell, or bubble, is the result of gas that is being shocked by the expanding blast wave from a supernova. Called SNR 0509-67.5 (or SNR 0509 for short), the bubble is the visible remnant of a powerful stellar explosion in the Large Magellanic Cloud (LMC), a small galaxy about 160,000 light-years from Earth. Ripples in the shell's surface may be caused by either subtle variations in the density of the ambient interstellar gas, or possibly driven from the interior by pieces of the ejecta. The bubble-shaped shroud of gas is 23 light-years across and is expanding at more than 11 million miles per hour (5,000 kilometers per second). Astronomers have concluded that the explosion was one of an especially energetic and bright variety of supernovae. Known as Type Ia, such supernova events are thought to result from a white dwarf star in a binary system that robs its partner of material, takes on much more mass than it is able to handle, and eventually explodes. Hubble's Advanced Camera for Surveys observed the supernova remnant on Oct. 28, 2006 with a filter that isolates light from glowing hydrogen seen in the expanding shell. These observations were then combined with visible-light images of the surrounding star field that were imaged with Hubble's Wide Field Camera 3 on Nov. 4, 2010. With an age of about 400 years as seen from Earth, the supernova might have been visible to southern hemisphere observers around the year 1600, however, there are no known records of a "new star" in the direction of the LMC near that time. A more recent supernova in the LMC, SN 1987A, did catch the eye of Earth viewers and continues to be studied with ground- and space-based telescopes, including Hubble. For images and more information about SNR 0509, visit: hubblesite.org/news/2010/27 heritage.stsci.edu/2010/27 www

The computation of dynamic fractional difference parameter for S&P500 index

NASA Astrophysics Data System (ADS)

Pei, Tan Pei; Cheong, Chin Wen; Galagedera, Don U. A.

2015-10-01

This study evaluates the time-varying long memory behaviors of the S&P500 volatility index using dynamic fractional difference parameters. Time-varying fractional difference parameter shows the dynamic of long memory in volatility series for the pre and post subprime mortgage crisis triggered by U.S. The results find an increasing trend in the S&P500 long memory volatility for the pre-crisis period. However, the onset of Lehman Brothers event reduces the predictability of volatility series following by a slight fluctuation of the factional differencing parameters. After that, the U.S. financial market becomes more informationally efficient and follows a non-stationary random process.

Supernova SN 2014C Optical and X-Ray

NASA Image and Video Library

2017-01-24

This visible-light image from the Sloan Digital Sky Survey shows spiral galaxy NGC 7331, center, where astronomers observed the unusual supernova SN 2014C . The inset images are from NASA's Chandra X-ray Observatory, showing a small region of the galaxy before the supernova explosion (left) and after it (right). Red, green and blue colors are used for low, medium and high-energy X-rays, respectively. http://photojournal.jpl.nasa.gov/catalog/PIA21088

Supernova Remnant Science with AXIS

NASA Astrophysics Data System (ADS)

Williams, Brian J.; Yamaguchi, Hiroya; AXIS Science Team

2018-01-01

We present an overview of the supernova remnant (SNR) science that will be achieved with the Advanced X-ray Imaging Satellite (AXIS). AXIS follows in the footsteps of the spectacularly successful Chandra X-ray Observatory with similar or higher angular resolution and an order of magnitude more collecting area in the 0.3-10 keV band. These capabilities enable major advances in several areas of SNR science. These include, but are not limited to: 1) a more thorough spatial mapping of the ejecta products of both intermediate-mass and iron-group elements in core-collapse and Type Ia SNRs, particularly in remnants with a small diameter. The iron-group elements, specifically Cr, Mn, and Ni, are extremely important for constraining the explosion mechanism for SNe, but are generally weak and difficult to detect with Chandra, XMM-Newton, and Suzaku. 2) Studying the interface of a shock wave with the ambient ISM/CSM to constrain the degree of particle heating and acceleration at shock fronts. Chandra has only provided upper limits on shock precursor emission, and a detailed study of the thermal and nonthermal emission at the shock with greatly increased photon count rates will constrain the properties of the immediate post-shock plasma. 3) A high spatial resolution X-ray observatory will continue to build on the legacy begun by Chandra of studying the proper motion of young remnants. Directly measuring the dynamics of an SNR's evolution is crucial for understanding the explosion mechanism, and with the order of magnitude increase collecting area, we can measure the expansion of individual elemental species in the ejecta. 4) We will greatly increase the statistics of SNRs in nearby galaxies, going much faster and deeper than Chandra's observations. The increased depth of coverage would allow us to do spectroscopy in places where it was previously possible only to do rudimentary statistics. We can compare the local SNR population with the local star-formation rates for galaxies

The Progenitor of the New COMPTEL/ROSAT Supernova Remnant in Vela

NASA Technical Reports Server (NTRS)

Chen, Wan; Gehrels, Neil

1999-01-01

We show that (1) the newly discovered supernova remnant (SNR) GROJ0852-4642/RXJ0852.0-4622 was created by a core-collapse supernova of a massive star and (2) the same supernova event that produced the Ti-44 detected by COMPTEL from this source is probably also responsible for a large fraction of the observed Al-26 emission in the Vela region detected by the same instrument. The first conclusion is based on the fact that the remnant is currently expanding too slowly given its young age for it to be caused by a Type la supernova. If the current SNR shell expansion speed is greater than 3000 km/s, a 15 solar mass. Type II supernova with a moderate kinetic energy exploding at about 150 pc away is favored. If the SNR expansion speed is lower than 2000 km/s, as derived naively from X-ray data, a much more energetic supernova is required to have occurred at approximately 250 pc away in a dense environment at the edge of the Gum Nebula. This progenitor has a preferred ejecta mass of less than or equal to 10(Solar Mass), and therefore it is probably a Type Ib or Type Ic supernova. However, the required high ambient density of n(sub H) greater than or equal to 100 cu cm in this scenario is difficult to reconcile with the regional CO data. A combination of our estimates of the age/energetics of the new SNR and the almost perfect positional coincidence of the new SNR with the centroid of the COMPTEL Al-26 emission feature of the Vela region strongly favors a causal connection. If confirmed, this will be the first case in which both Ti-44 and Al-26 are detected from the same young SNR, and together they can be used to select preferred theoretical core-collapse supernova models.

Models of Interacting Supernovae: Understanding the Physics and Probing the Circumstellar Environment

NASA Astrophysics Data System (ADS)

Baron, Edward

"Interacting supernovae" are poorly understood astronomical events with great potential for expanding our understanding of how stars evolve and die, and could provide important clues about the early formation of large-scale structures such as galaxies in the universe. Interacting supernovae occur when a star explodes within a dense cloud of material shed from the star in the course of its evolution. The resulting violent interaction between the expanding supernova explosion and the cloud of circumstellar material can lead to an enormously bright visual display --- indeed, many of the brightest supernovae ever recorded are thought to arise from circumstellar interaction. In order to understand the properties of the progenitor star and the details of the circumstellar interaction, there is a need for theoretical models of interacting supernovae. These simulated computer spectra can be directly compared to the spectra observed by telescopes. These models allow us to probe the physical circumstances that underlie the observations. The spectra of interacting supernovae are dominated by strong, narrow emission lines of light elements such as hydrogen and helium. These narrow lines give Type IIn supernovae their designation. Similarly, objects of Type Ian, Ibn, Icn, and IIn are somewhat distinct, but are all defined by the narrow emission lines that result from the interaction of their expanding envelopes with their surroundings. The photosphere in these supernovae is formed in the material accreted during the coasting phase, and most of the luminosity has its origin from the conversion of kinetic explosion energy into luminosity. Both thermonuclear (Type Ia) and core-collapse (Types Ib/Ic and II) supernovae may be the inner engine. In fact, several Type IIn supernovae at early times have later been classified as Type Ia, Type Ib/c, or Type II as their spectra reveal more details about the nature of the central explosion. As a result of the dominance of the interaction

A very luminous magnetar-powered supernova associated with an ultra-long γ-ray burst.

PubMed

Greiner, Jochen; Mazzali, Paolo A; Kann, D Alexander; Krühler, Thomas; Pian, Elena; Prentice, Simon; Olivares E, Felipe; Rossi, Andrea; Klose, Sylvio; Taubenberger, Stefan; Knust, Fabian; Afonso, Paulo M J; Ashall, Chris; Bolmer, Jan; Delvaux, Corentin; Diehl, Roland; Elliott, Jonathan; Filgas, Robert; Fynbo, Johan P U; Graham, John F; Guelbenzu, Ana Nicuesa; Kobayashi, Shiho; Leloudas, Giorgos; Savaglio, Sandra; Schady, Patricia; Schmidl, Sebastian; Schweyer, Tassilo; Sudilovsky, Vladimir; Tanga, Mohit; Updike, Adria C; van Eerten, Hendrik; Varela, Karla

2015-07-09

A new class of ultra-long-duration (more than 10,000 seconds) γ-ray bursts has recently been suggested. They may originate in the explosion of stars with much larger radii than those producing normal long-duration γ-ray bursts or in the tidal disruption of a star. No clear supernova has yet been associated with an ultra-long-duration γ-ray burst. Here we report that a supernova (SN 2011kl) was associated with the ultra-long-duration γ-ray burst GRB 111209A, at a redshift z of 0.677. This supernova is more than three times more luminous than type Ic supernovae associated with long-duration γ-ray bursts, and its spectrum is distinctly different. The slope of the continuum resembles those of super-luminous supernovae, but extends further down into the rest-frame ultraviolet implying a low metal content. The light curve evolves much more rapidly than those of super-luminous supernovae. This combination of high luminosity and low metal-line opacity cannot be reconciled with typical type Ic supernovae, but can be reproduced by a model where extra energy is injected by a strongly magnetized neutron star (a magnetar), which has also been proposed as the explanation for super-luminous supernovae.

An asymptotic-giant-branch star in the progenitor system of a type Ia supernova.

PubMed

Hamuy, Mario; Phillips, M M; Suntzeff, Nicholas B; Maza, José; González, L E; Roth, Miguel; Krisciunas, Kevin; Morrell, Nidia; Green, E M; Persson, S E; McCarthy, P J

2003-08-07

Stars that explode as supernovae come in two main classes. A type Ia supernova is recognized by the absence of hydrogen and the presence of elements such as silicon and sulphur in its spectrum; this class of supernova is thought to produce the majority of iron-peak elements in the Universe. They are also used as precise 'standard candles' to measure the distances to galaxies. While there is general agreement that a type Ia supernova is produced by an exploding white dwarf star, no progenitor system has ever been directly observed. Significant effort has gone into searching for circumstellar material to help discriminate between the possible kinds of progenitor systems, but no such material has hitherto been found associated with a type Ia supernova. Here we report the presence of strong hydrogen emission associated with the type Ia supernova SN2002ic, indicating the presence of large amounts of circumstellar material. We infer from this that the progenitor system contained a massive asymptotic-giant-branch star that lost several solar masses of hydrogen-rich gas before the supernova explosion.

From point process observations to collective neural dynamics: Nonlinear Hawkes process GLMs, low-dimensional dynamics and coarse graining

PubMed Central

Truccolo, Wilson

2017-01-01

This review presents a perspective on capturing collective dynamics in recorded neuronal ensembles based on multivariate point process models, inference of low-dimensional dynamics and coarse graining of spatiotemporal measurements. A general probabilistic framework for continuous time point processes reviewed, with an emphasis on multivariate nonlinear Hawkes processes with exogenous inputs. A point process generalized linear model (PP-GLM) framework for the estimation of discrete time multivariate nonlinear Hawkes processes is described. The approach is illustrated with the modeling of collective dynamics in neocortical neuronal ensembles recorded in human and non-human primates, and prediction of single-neuron spiking. A complementary approach to capture collective dynamics based on low-dimensional dynamics (“order parameters”) inferred via latent state-space models with point process observations is presented. The approach is illustrated by inferring and decoding low-dimensional dynamics in primate motor cortex during naturalistic reach and grasp movements. Finally, we briefly review hypothesis tests based on conditional inference and spatiotemporal coarse graining for assessing collective dynamics in recorded neuronal ensembles. PMID:28336305

From point process observations to collective neural dynamics: Nonlinear Hawkes process GLMs, low-dimensional dynamics and coarse graining.

PubMed

Truccolo, Wilson

2016-11-01

This review presents a perspective on capturing collective dynamics in recorded neuronal ensembles based on multivariate point process models, inference of low-dimensional dynamics and coarse graining of spatiotemporal measurements. A general probabilistic framework for continuous time point processes reviewed, with an emphasis on multivariate nonlinear Hawkes processes with exogenous inputs. A point process generalized linear model (PP-GLM) framework for the estimation of discrete time multivariate nonlinear Hawkes processes is described. The approach is illustrated with the modeling of collective dynamics in neocortical neuronal ensembles recorded in human and non-human primates, and prediction of single-neuron spiking. A complementary approach to capture collective dynamics based on low-dimensional dynamics ("order parameters") inferred via latent state-space models with point process observations is presented. The approach is illustrated by inferring and decoding low-dimensional dynamics in primate motor cortex during naturalistic reach and grasp movements. Finally, we briefly review hypothesis tests based on conditional inference and spatiotemporal coarse graining for assessing collective dynamics in recorded neuronal ensembles. Published by Elsevier Ltd.

EVOLUTION OF THE CRAB NEBULA IN A LOW ENERGY SUPERNOVA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Haifeng; Chevalier, Roger A., E-mail: hy4px@virginia.edu, E-mail: rac5x@virginia.edu

The nature of the supernova leading to the Crab Nebula has long been controversial because of the low energy that is present in the observed nebula. One possibility is that there is significant energy in extended fast material around the Crab but searches for such material have not led to detections. An electron capture supernova model can plausibly account for the low energy and the observed abundances in the Crab. Here, we examine the evolution of the Crab pulsar wind nebula inside a freely expanding supernova and find that the observed properties are most consistent with a low energy event.more » Both the velocity and radius of the shell material, and the amount of gas swept up by the pulsar wind point to a low explosion energy (∼10{sup 50} erg). We do not favor a model in which circumstellar interaction powers the supernova luminosity near maximum light because the required mass would limit the freely expanding ejecta.« less

A mixed helium-oxygen shell in some core-collapse supernova progenitors

NASA Astrophysics Data System (ADS)

Gofman, Roni Anna; Gilkis, Avishai; Soker, Noam

2018-04-01

We evolve models of rotating massive stars up to the stage of iron core collapse using the MESA code and find a shell with a mixed composition of primarily helium and oxygen in some cases. In the parameter space of initial masses of 13-40M⊙ and initial rotation velocities of 0-450 kms-1 that we investigate, we find a mixed helium-oxygen (He-O) shell with a significant total He-O mass and with a helium to oxygen mass ratio in the range of 0.5-2 only for a small fraction of the models. While the shell formation due to mixing is instigated by rotation, the pre-collapse rotation rate is not very high. The fraction of models with a shell of He-O composition required for an energetic collapse-induced thermonuclear explosion is small, as is the fraction of models with high specific angular momentum, which can aid the thermonuclear explosion by retarding the collapse. Our results suggest that the collapse-induced thermonuclear explosion mechanism that was revisited recently can account for at most a small fraction of core-collapse supernovae. The presence of such a mixed He-O shell still might have some implications for core-collapse supernovae, such as some nucleosynthesis processes when jets are present, or might result in peculiar sub-luminous core-collapse supernovae.

A mixed helium-oxygen shell in some core-collapse supernova progenitors

NASA Astrophysics Data System (ADS)

Gofman, Roni Anna; Gilkis, Avishai; Soker, Noam

2018-07-01

We evolve models of rotating massive stars up to the stage of iron core collapse using the MESA code and find a shell with a mixed composition of primarily helium and oxygen in some cases. In the parameter space of initial masses of 13-40 M⊙ and initial rotation velocities of 0-450 km s-1 that we investigate, we find a mixed helium-oxygen (He-O) shell with a significant total He-O mass and with a helium to oxygen mass ratio in the range of 0.5-2 only for a small fraction of the models. While the shell formation due to mixing is instigated by rotation, the pre-collapse rotation rate is not very high. The fraction of models with a shell of He-O composition required for an energetic collapse-induced thermonuclear explosion is small, as is the fraction of models with high specific angular momentum, which can aid the thermonuclear explosion by retarding the collapse. Our results suggest that the collapse-induced thermonuclear explosion mechanism that was revisited recently can account for at most a small fraction of core-collapse supernovae. The presence of such a mixed He-O shell still might have some implications for core-collapse supernovae, such as some nucleosynthesis processes when jets are present, or might result in peculiar sub-luminous core-collapse supernovae.

Dynamic analysis of process reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shadle, L.J.; Lawson, L.O.; Noel, S.D.

1995-06-01

The approach and methodology of conducting a dynamic analysis is presented in this poster session in order to describe how this type of analysis can be used to evaluate the operation and control of process reactors. Dynamic analysis of the PyGas{trademark} gasification process is used to illustrate the utility of this approach. PyGas{trademark} is the gasifier being developed for the Gasification Product Improvement Facility (GPIF) by Jacobs-Siffine Engineering and Riley Stoker. In the first step of the analysis, process models are used to calculate the steady-state conditions and associated sensitivities for the process. For the PyGas{trademark} gasifier, the process modelsmore » are non-linear mechanistic models of the jetting fluidized-bed pyrolyzer and the fixed-bed gasifier. These process sensitivities are key input, in the form of gain parameters or transfer functions, to the dynamic engineering models.« less

Explosion of a supernova with a red giant companion

NASA Technical Reports Server (NTRS)

Livne, E.; Tuchman, Y.; Wheeler, J. C.

1992-01-01

Two-dimensional numerical simulations of the collision between spherical ejecta from a supernova and a red giant companion are presented. In contrast to previous numerical studies, in which the companion was a main-sequence star or a compact object, the collision consequences are found to have a dramatic impact upon the red giant. In most cases the red giant companion loses most of its envelope in a time scale of 10 exp 7 s with typical velocities about an order of magnitude less than those of the expanding velocity of the supernova shell. We confirm the conclusion of Chugai (1986) that the stripped hydrogen tends to come off as a low-velocity component interior to the supernova ejecta. Possible observational consequences of the results are discussed.

Pair-instability supernovae of fast rotating stars

NASA Astrophysics Data System (ADS)

Chen, Ke-Jung

2015-01-01

We present 2D simulations of pair-instability supernovae considering rapid rotation during their explosion phases. Recent studies of the Population III (Pop III) star formation suggested that these stars could be born with a mass scale about 100 M⊙ and with a strong rotation. Based on stellar evolution models, these massive Pop III stars might have died as highly energetic pair-instability supernovae. We perform 2D calculations to investigate the impact of rotation on pair-instability supernovae. Our results suggest that rotation leads to an aspherical explosion due to an anisotropic collapse. If the first stars have a 50% of keplerian rotational rate of the oxygen core before their pair-instability explosions, the overall 56Ni production can be significantly reduced by about two orders of magnitude. An extreme case of 100% keplerian rotational rate shows an interesting feature of fluid instabilities along the equatorial plane caused by non-synchronized and non-isotropic ignitions of explosions, so that the shocks run into the in-falling gas and generate the Richtmyer-Meshkov instability.

Supernova Remnant Kes 17: An Efficient Cosmic Ray Accelerator inside a Molecular Cloud

NASA Astrophysics Data System (ADS)

Gelfand, Joseph; Slane, Patrick; Hughes, John; Temim, Tea; Castro, Daniel; Rakowski, Cara

Supernova remnant are believed to be the dominant source of cosmic rays protons below the "knee" in the energy spectrum. However, relatively few supernova remnants have been identified as efficient producers of cosmic ray protons. In this talk, I will present evidence that the production of cosmic ray protons is required to explain the broadband non-thermal spectrum of supernova remnant Kes 17 (SNR G304.6+0.1). Evidence for efficient cosmic ray acceleration in Kes 17 supports recent theoretical work concluding that the strong magnetic field, turbulence, and clumpy nature of molecular clouds enhance cosmic ray production in supernova remnants. While additional observations are needed to confirm this interpretation, further study of Kes 17 and similar sources are important for understanding how cosmic rays are accelerated in supernova remnants.

THE ENGINES BEHIND SUPERNOVAE AND GAMMA-RAY BURSTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

FRYER, CHRISTOPHER LEE

2007-01-23

The authors review the different engines behind supernova (SNe) and gamma-ray bursts (GRBs), focusing on those engines driving explosions in massive stars: core-collapse SNe and long-duration GRBs. Convection and rotation play important roles in the engines of both these explosions. They outline the basic physics and discuss the wide variety of ways scientists have proposed that this physics can affect the supernova explosion mechanism, concluding with a review of the current status in these fields.

ASASSN-15lh: A highly super-luminous supernova

NASA Astrophysics Data System (ADS)

Dong, Subo; Shappee, B. J.; Prieto, J. L.; Jha, S. W.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Thompson, T. A.; Morrell, N.; Thompson, I. B.; Basu, U.; Beacom, J. F.; Bersier, D.; Brimacombe, J.; Brown, J. S.; Bufano, F.; Chen, Ping; Conseil, E.; Danilet, A. B.; Falco, E.; Grupe, D.; Kiyota, S.; Masi, G.; Nicholls, B.; Olivares E., F.; Pignata, G.; Pojmanski, G.; Simonian, G. V.; Szczygiel, D. M.; Woźniak, P. R.

2016-01-01

We report the discovery of ASASSN-15lh (SN 2015L), which we interpret as the most luminous supernova yet found. At redshift z = 0.2326, ASASSN-15lh reached an absolute magnitude of Mu,AB = -23.5 ± 0.1 and bolometric luminosity Lbol = (2.2 ± 0.2) × 1045 ergs s-1, which is more than twice as luminous as any previously known supernova. It has several major features characteristic of the hydrogen-poor super-luminous supernovae (SLSNe-I), whose energy sources and progenitors are currently poorly understood. In contrast to most previously known SLSNe-I that reside in star-forming dwarf galaxies, ASASSN-15lh appears to be hosted by a luminous galaxy (MK ≈ -25.5) with little star formation. In the 4 months since first detection, ASASSN-15lh radiated (1.1 ± 0.2) × 1052 ergs, challenging the magnetar model for its engine.

Light Echoes from Recent Supernovae

NASA Astrophysics Data System (ADS)

Sugerman, Ben; SEEDS Collaboration

2009-01-01

Since the launch of the Spitzer Space Telescope, we have been carrying out a sensitive mid-IR Survey for Evolution of Emission from Dust in SNe (SEEDS, P.I. Mike Barlow), to address the extent to which SNe produce dust, and whether they are a primary source of dust in the Universe. During the course of our survey, we have followed the lightcurves of many nearby supernovae past a few hundred days (which is when most people lose interest in them). As a result, we have found (or others have hypothesized) optical light echoes at late times. Here, we present an update on echoes from SNe 2002hh, 2003gd and 2004et, and discuss the extent to which these echoes affect the optical and mid-IR light curves, and hence the formation of dust within the ejecta.

A massive hypergiant star as the progenitor of the supernova SN 2005gl.

PubMed

Gal-Yam, A; Leonard, D C

2009-04-16

Our understanding of the evolution of massive stars before their final explosions as supernovae is incomplete, from both an observational and a theoretical standpoint. A key missing piece in the supernova puzzle is the difficulty of identifying and studying progenitor stars. In only a single case-that of supernova SN 1987A in the Large Magellanic Cloud-has a star been detected at the supernova location before the explosion, and been subsequently shown to have vanished after the supernova event. The progenitor of SN 1987A was a blue supergiant, which required a rethink of stellar evolution models. The progenitor of supernova SN 2005gl was proposed to be an extremely luminous object, but the association was not robustly established (it was not even clear that the putative progenitor was a single luminous star). Here we report that the previously proposed object was indeed the progenitor star of SN 2005gl. This very massive star was likely a luminous blue variable that standard stellar evolution predicts should not have exploded in that state.

IceCube sensitivity for low-energy neutrinos from nearby supernovae

NASA Astrophysics Data System (ADS)

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

2011-11-01

This paper describes the response of the IceCube neutrino telescope located at the geographic south pole to outbursts of MeV neutrinos from the core collapse of nearby massive stars. IceCube was completed in December 2010 forming a lattice of 5160 photomultiplier tubes that monitor a volume of ~1 km3 in the deep Antarctic ice for particle induced photons. The telescope was designed to detect neutrinos with energies greater than 100 GeV. Owing to subfreezing ice temperatures, the photomultiplier dark noise rates are particularly low. Hence IceCube can also detect large numbers of MeV neutrinos by observing a collective rise in all photomultiplier rates on top of the dark noise. With 2 ms timing resolution, IceCube can detect subtle features in the temporal development of the supernova neutrino burst. For a supernova at the galactic center, its sensitivity matches that of a background-free megaton-scale supernova search experiment. The sensitivity decreases to 20 standard deviations at the galactic edge (30 kpc) and 6 standard deviations at the Large Magellanic Cloud (50 kpc). IceCube is sending triggers from potential supernovae to the Supernova Early Warning System. The sensitivity to neutrino properties such as the neutrino hierarchy is discussed, as well as the possibility to detect the neutronization burst, a short outbreak of \\barνe's released by electron capture on protons soon after collapse. Tantalizing signatures, such as the formation of a quark star or a black hole as well as the characteristics of shock waves, are investigated to illustrate IceCube's capability for supernova detection.

New Suspect Identified in Supernova Explosion

NASA Image and Video Library

2014-06-04

Supernovas are often thought of as the tremendous explosions that mark the ends of massive stars' lives. While this is true, not all supernovas occur in this fashion. A common supernova class, called Type Ia, involves the detonation of white dwarfs -- small, dense stars that are already dead. New results from NASA's Spitzer Space Telescope have revealed a rare example of Type Ia explosion, in which a dead star "fed" off an aging star like a cosmic zombie, triggering a blast. The results help researchers piece together how these powerful and diverse events occur. "It's kind of like being a detective," said Brian Williams of NASA's Goddard Space Flight Center in Greenbelt, Maryland, lead author of a study submitted to the Astrophysical Journal. "We look for clues in the remains to try to figure out what happened, even though we weren't there to see it." Read more: 1.usa.gov/1i0PAaa NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Gravitational waves and core-collapse supernovae

NASA Astrophysics Data System (ADS)

Bisnovatyi-Kogan, G. S.; Moiseenko, S. G.

2017-11-01

A mechanism of formation of gravitational waves in the Universe is considered for a nonspherical collapse of matter. Nonspherical collapse results are presented for a uniform spheroid of dust and a finite-entropy spheroid. Numerical simulation results on core-collapse supernova explosions are presented for the neutrino and magneto-rotational models. These results are used to estimate the dimensionless amplitude of the gravitational wave with a frequency ν ~ 1300 Hz, radiated during the collapse of the rotating core of a pre-supernova with a mass of 1.2 M⊙ (calculated by the authors in 2D). This estimate agrees well with many other calculations (presented in this paper) that have been done in 2D and 3D settings and which rely on more exact and sophisticated calculations of the gravitational wave amplitude. The formation of the large-scale structure of the Universe in the Zel’dovich pancake model involves the emission of very long-wavelength gravitational waves. The average amplitude of these waves is calculated from the simulation, in the uniform spheroid approximation, of the nonspherical collapse of noncollisional dust matter, which imitates dark matter. It is noted that a gravitational wave radiated during a core-collapse supernova explosion in our Galaxy has a sufficient amplitude to be detected by existing gravitational wave telescopes.

Probing neutrino mass hierarchy by comparing the charged-current and neutral-current interaction rates of supernova neutrinos

NASA Astrophysics Data System (ADS)

Lai, Kwang-Chang; Lee, Fei-Fan; Lee, Feng-Shiuh; Lin, Guey-Lin; Liu, Tsung-Che; Yang, Yi

2016-07-01

The neutrino mass hierarchy is one of the neutrino fundamental properties yet to be determined. We introduce a method to determine neutrino mass hierarchy by comparing the interaction rate of neutral current (NC) interactions, ν(bar nu) + p → ν(bar nu) + p, and inverse beta decays (IBD), bar nue + p → n + e+, of supernova neutrinos in scintillation detectors. Neutrino flavor conversions inside the supernova are sensitive to neutrino mass hierarchy. Due to Mikheyev-Smirnov-Wolfenstein effects, the full swapping of bar nue flux with the bar nux (x = μ, τ) one occurs in the inverted hierarchy, while such a swapping does not occur in the normal hierarchy. As a result, more high energy IBD events occur in the detector for the inverted hierarchy than the high energy IBD events in the normal hierarchy. By comparing IBD interaction rate with the mass hierarchy independent NC interaction rate, one can determine the neutrino mass hierarchy.

Simulating Supernovae Driven Outflows in Dwarf Galaxies

NASA Astrophysics Data System (ADS)

Rodriguez, Jaimee-Ian

2018-01-01

Galactic outflows, or winds, prove to be a necessary input for galactic simulations to produce results comparable to observation, for it solves issues caused by what previous literature dubbed the “angular momentum catastrophe.” While it is known that the nature of outflows depends on the nature of the Interstellar Medium (ISM), the mechanisms behind outflows are still not completely understood. We investigate the driving force behind galactic outflows and the factors that influence their behavior, hypothesizing that supernovae within the galaxy drive these winds. We study isolated, high-resolution, smooth particle hydrodynamic simulations, focusing specifically on dwarf galaxies due to their shallow potential wells, which allow for more significant outflows. We find that outflows follow star formation (and associated supernovae) suggesting the causal relationship between the two. Furthermore, simulations with higher diffusivity differ little in star formation rate, but show significantly lower outflow rates, suggesting that environmental factors that have little effect on regulating star formation can greatly influence outflows, and so efficient outflows can be driven by a constant rate of supernovae, depending on ISM behavior. We are currently analyzing disk morphology and ambient density in order to comprehend the effect of supernovae on the immediate interstellar gas. By attaining greater understanding of the origin of galactic outflows, we will be able to not only improve the accuracy of simulations, we will also be able to gain greater insight into galactic formation and evolution, as outflows and resultant inflows may be vital to the regulation of galaxies throughout their lifetimes.

Neutrino oscillations in magnetically driven supernova explosions

NASA Astrophysics Data System (ADS)

Kawagoe, Shio; Takiwaki, Tomoya; Kotake, Kei

2009-09-01

We investigate neutrino oscillations from core-collapse supernovae that produce magnetohydrodynamic (MHD) explosions. By calculating numerically the flavor conversion of neutrinos in the highly non-spherical envelope, we study how the explosion anisotropy has impacts on the emergent neutrino spectra through the Mikheyev-Smirnov-Wolfenstein effect. In the case of the inverted mass hierarchy with a relatively large θ13 (sin2 2θ13 gtrsim 10-3), we show that survival probabilities of bar nue and νe seen from the rotational axis of the MHD supernovae (i.e., polar direction), can be significantly different from those along the equatorial direction. The event numbers of bar nue observed from the polar direction are predicted to show steepest decrease, reflecting the passage of the magneto-driven shock to the so-called high-resonance regions. Furthermore we point out that such a shock effect, depending on the original neutrino spectra, appears also for the low-resonance regions, which could lead to a noticeable decrease in the νe signals. This reflects a unique nature of the magnetic explosion featuring a very early shock-arrival to the resonance regions, which is in sharp contrast to the neutrino-driven delayed supernova models. Our results suggest that the two features in the bar nue and νe signals, if visible to the Super-Kamiokande for a Galactic supernova, could mark an observational signature of the magnetically driven explosions, presumably linked to the formation of magnetars and/or long-duration gamma-ray bursts.