Supernova PTF12glz: a possible shock breakout driven through an aspherical wind
Maayane T. Soumagnac, Eran O. Ofek, Avishay Gal-Yam, Eli Waxmann, Sivan Ginzburg, Nora Linn Strotjohann, Tom A. Barlow, Ehud Behar, Doron Chelouche, Christoffer… 展开作者
Maayane T. Soumagnac, Eran O. Ofek, Avishay Gal-Yam, Eli Waxmann, Sivan Ginzburg, Nora Linn Strotjohann, Tom A. Barlow, Ehud Behar, Doron Chelouche, Christoffer Fremling, Noam Ganot, Suvi Gerazi, Mansi M. Kasliwal, Shai Kaspi, Shrinivas R. Kulkarni, Russ R. Laher, Dan Maoz, Christopher D. Martin, Ehud Nakar, James D. Neill, Peter E. Nugent, Dovi Poznanski, Steve Schulze, Ofer Yaron
We present visible-light and ultraviolet (UV) observations of the supernova PTF12glz. The SN was discovered and monitored in near-UV and R bands as part of a joint GALEX and Palomar Transient Factory campaign. It is among the most energetic Type IIn supernovae observed to date (~10^{51} erg). If the radiated energy mainly came from the thermalization of the shock kinetic energy, we show that PTF12glz was surrounded by ~1 solar mass of circumstellar material (CSM) prior to its explosive death. PTF12glz shows a puzzling peculiarity: at early times, while the freely expanding ejecta are presumably masked by the optically thick CSM, the radius of the blackbody that best fits the observations grows at ~7000 km/s. Such a velocity is characteristic of fast moving ejecta rather than optically thick CSM. This phase of radial expansion takes place before any spectroscopic signature of expanding ejecta appears in the spectrum and while both the spectroscopic data and the bolometric luminosity seem to indicate that the CSM is optically thick. We propose a geometrical solution to this puzzle, involving an aspherical structure of the CSM around PTF12glz. By modelling radiative diffusion through a slab of CSM, we show that an aspherical geometry of the CSM can result in a growing effective radius. This simple model also allows us to recover the decreasing blackbody temperature of PTF12glz. SLAB-Diffusion, the code we wrote to model the radiative diffusion of photons through a slab of CSM and evaluate the observed radius and temperature, is made available on-line.
The shock breakout emission is the first light that emerges from a supernova. In the spherical case it is characterized by a brief UV flash. In an axisymmetric, non-spherical prolate explosion, the shock first breaches the surface along the symmetry axis, then peels around to larger angles, producing a breakout light curve which may differ substantially from the spherically symmetric case. We study the emergence of a non-relativistic, bipolar shock from a spherical star, and estimate the basic properties of the associated bolometric shock breakout signal. We identify four possible classes of b…
Shock breakout is the earliest, readily-observable emission from a core-collapse supernova explosion. Observing supernova shock breakout may yield information about the nature of the supernova shock prior to exiting the progenitor and, in turn, about the core-collapse supernova mechanism itself. X-ray Outburst 080109, later associated with SN 2008D, is a very well-observed example of shock breakout from a core-collapse supernova. Despite excellent observational coverage and detailed modeling, fundamental information about the shock breakout, such as the radius of breakout and driver of the lig…
We investigate effects of aspherical energy deposition in core-collapse supernovae on the light curve of the supernova shock breakout. We performed two-dimensional hydrodynamical calculations of an aspherical supernova explosion to obtain the time when a shock wave generated in the stellar interior reaches the stellar surface in each radial direction. Using results of the calculations, light curves during the shock breakout are derived in an approximate way. We show that the light curve during the shock breakout can be a strong indicator of aspherical properties of core-collapse supernovae.
The breakout of a supernova blast wave from its progenitor star provides strong constraints on the star and its immediate surroundings. These surroundings are shaped by mass loss from the star and can include a wide variety of inhomogeneities. Here we present results of multi-dimensional radiation-hydrodynamics calculations of the interactions of the supernova blast wave with inhomogeneities in the immediate surroundings of a massive Wolf-Rayet star, calculating the effect these interactions have on the shock breakout signal from supernovae.
Stars close to the Eddington luminosity can have large low-density inflated envelopes. We show that the rise times of shock breakout signals from supernovae can be extended significantly if supernova progenitors have an inflated stellar envelope. If the shock breakout occurs in such inflated envelopes, the shock breakout signals diffuse in them, and their rise time can be significantly extended. Then, the rise times of the shock breakout signals are dominated by the diffusion time in the inflated envelope rather than the light-crossing time of the progenitors. We show that our inflated Wolf-Ra…
We investigate the properties of X-ray emission from shock breakout of a supernova in a stellar wind. We consider a simple model describing aspherical explosions, in which the shock front with an ellipsoidal shape propagates into the dense circumstellar matter. For this model, both X-ray light curves and spectra are simultaneously calculated using a Monte Carlo method. We show that the shock breakout occurs simultaneously in all directions in a steady and spherically symmetric wind. As a result, even for the aspherical explosion, the rise and decay timescales of the light curve do not signific…
Early light from core-collapse supernovae, now detectable in high-cadence surveys, holds clues to a star and its environment just before it explodes. However, effects that alter the early light have not been fully explored. We highlight the possibility of non-radial flows at the time of shock breakout. These develop in sufficiently non-spherical explosions if the progenitor is not too diffuse. When they do develop, non-radial flows limit ejecta speeds and cause ejecta-ejecta collisions. We explore these phenomena and their observational implications, using global, axisymmetric, non-relativisti…
Some features of the physics of radiation-dominated shock waves are discussed with emphasis on the peculiarities which are important for correct numerical modeling of shock breakouts in supernova. With account of those peculiarities, a number of models for different supernova types is constructed based on multigroup radiation transfer coupled to hydrodynamics. We describe the implementation of a new algorithm RADA, designed for modeling photon transfer at extremely-relativistic motions of matter, into our older code STELLA. The results of numerical simulations of light curves, and continuum sp…
Mass loss remains one of the primary uncertainties in stellar evolution. In the most massive stars, mass loss dictates the circumstellar medium and can significantly alter the fate of the star. Mass loss is caused by a variety of wind mechanisms and also through binary interactions. Supernovae are excellent probes of this mass loss, both the circumstellar material and the reduced mass of the hydrogen-rich envelope. In this paper, we focus on the effects of reducing the hydrogen-envelope mass on the supernova light curve, studying both the shock breakout and peak light curve emission for a wide…
We study properties of early radio emission from stripped-envelope supernovae (those of type IIb/Ib/Ic). We suggest there is a sub-class of stripped-envelope supernovae in their radio properties, including optically well-studied type Ic supernovae (SNe Ic) 2002ap and 2007gr, showing a rapid rise to a radio peak within ~ 10 days reaching to a low luminosity (at least an order of magnitude fainter than a majority of SNe IIb/Ib/Ic). They show a decline after the peak shallower than others while the spectral index is similar. We show that all these properties are naturally explained if the circums…
We show that a collisionless shock necessarily forms during the shock breakout of a supernova (SN) surrounded by an optically thick wind. An intense non-thermal flash of <~ MeV gamma rays, hard X-rays and multi-TeV neutrinos is produced simultaneously with and following the soft X-ray breakout emission, carrying similar or larger energy than the soft emission. The non-thermal flash is detectable by current X-ray telescopes and may be detectable out to 10's of Mpc by km-scale neutrino telescopes.
There are currently many large-field surveys operational and planned including the powerful Vera C. Rubin Observatory Legacy Survey of Space and Time. These surveys will increase the number and diversity of transients dramatically. However, for some transients, like supernovae (SNe), we can gain more understanding by directed observations (e.g. shock breakout, $γ$-ray detections) than by simply increasing the sample size. For example, the initial emission from these transients can be a powerful probe of these explosions. Upcoming ground-based detectors are not ideally suited to observe the ini…
Multi-wavelength Signatures of Supernova Shock Breakout from Red Supergiants in Two Dimensions
National Taiwan University（台湾大学）；Academia Sinica, Institute of Astronomy and Astrophysics（中央研究院天文及天文物理研究所）；Heidelberger Institut für Theoretische Studien（海德堡理论研究所）；RIKEN Pioneering Research Institute (PRI)（理化学研究所前沿研究 institutes）；Zentrum für Astronomie der Universität Heidelberg, Astronomisches Rechenzentrum（海德堡大学天文学中心天文计算中心）
Shock breakout is the brightest radiative phenomenon in a supernova (SN) but is difficult to be observed owing to the short duration and X-ray/ultraviolet (UV)-peaked spectra. After the first observation from the rising phase reported in 2008, its observability at high redshift is attracting enormous attention. We perform multigroup radiation hydrodynamics calculations of explosions for evolutionary presupernova models with various main-sequence masses $M_{\rm MS}$, metallicities $Z$, and explosion energies $E$. We present multicolor light curves of shock breakout in Type II plateau SNe, being…
The properties of the first generation of stars and their supernova (SN) explosions remains unknown due to the lack of their actual observations. Recently many transient surveys are conducted and the feasibility of the detection of supernovae (SNe) of Pop III stars is growing. In this paper we study the multicolor light curves for a number of metal-free core-collapse SN models (25-100 M$_{\odot}$) to provide the indicators for finding and identification of first generation SNe. We use mixing-fallback supernova explosion models which explain the observed abundance patterns of metal poor stars. …
The recent discoveries of many double neutron star systems and their detection as LIGO-Virgo merger events call for a detailed understanding of their origin. Explosions of ultra-stripped stars in binary systems have been shown to play a key role in this context and have also generated interest as a potential explanation for rapidly evolving hydrogen-free transients. Here we present the first attempt to model such explosions based on binary evolution calculations that follow the mass transfer to the companion to obtain a consistent core-envelope structure as needed for reliable predictions of t…
The breakout of a supernova shock wave through the progenitor star's outer envelope is expected to appear as an X-ray flash. However, if the supernova explodes inside an optically-thick wind, the breakout flash is delayed. We present a simple model for estimating the conditions at shock breakout in a wind based on the general observable quantities in the X-ray flash lightcurve: the total energy E_X, and the diffusion time after the peak, t_diff. We base the derivation on the self-similar solution for the forward-reverse shock structure expected for an ejecta plowing through a pre-existing wind…
A two-dimensional special relativistic radiation-hydrodynamics code is developed and applied to numerical simulations of supernova shock breakout in bipolar explosions of a blue supergiant. Our calculations successfully simulate the dynamical evolution of a blast wave in the star and its emergence from the surface. Results of the model with spherical energy deposition show a good agreement with previous simulations. Furthermore, we calculate several models with bipolar energy deposition and compare their results with the spherically symmetric model. The bolometric light curves of the shock bre…
High cadence ultraviolet, optical and near-infrared photometric and low-resolution spectroscopic observations of the peculiar Type II supernova (SN) 2018hna are presented. The early phase multiband light curves exhibit the adiabatic cooling envelope emission following the shock breakout up to ~14 days from the explosion. SN~2018hna has a rise time of $\sim$\,88 days in the V-band, similar to SN 1987A. A $\rm^{56}Ni$ mass of ~0.087$\pm$0.004 $\rm M_{\odot}$ is inferred for SN 2018hna from its bolometric light curve. Hydrodynamical modelling of the cooling phase suggests a progenitor with a radi…
We investigate roles of the bulk comptonization process in the propagation of thermal photons emitted at the shock breakout of a supernova explosion. We use a hydrodynamical model based on a self-similar solution for the shock breakout. The propagation of photons is treated by a Monte-Carlo technique. Results of the simulations successfully reproduce the power-law spectrum observed by X-ray observations for XRF 080109/SN 2008D, if a mildly relativistic shock velocity is assumed. Effects of some radiative processes, photoionization, radiative recombination, and free-free absorption on the propa…
The light curves of some luminous supernovae are suspected to be powered by the spindown energy of a rapidly rotating magnetar. Here we describe a possible signature of the central engine: a burst of shock breakout emission occurring several days after the supernova explosion. The energy input from the magnetar inflates a high-pressure bubble that drives a shock through the pre-exploded supernova ejecta. If the magnetar is powerful enough, that shock will near the ejecta surface and become radiative. At the time of shock breakout, the ejecta will have expanded to a large radius (~10^{14} cm) s…
Recent supernovae (SNe) observations have motivated renewed interest in SN shock breakouts from stars surrounded by thick winds. In such events the interaction with the wind powers the observed luminosity, and predictions include observable hard X-rays. Wind breakouts on timescales of a day or longer are currently the most probable for detection. Here we study the signal that follows such events. We start from the breakout of the radiation mediated shock, finding that the breakout temperature can vary significantly from one event to another ($10^4 - 5 \times 10^6$ K) due to possible deviation …
Recent observations suggest that some supernovae may be the result of an explosion into an optically thick circumstellar material, the product of pre-explosion mass-loss (wind) by the progenitor star. This scenario has been studied previously both analytically and numerically. However, many previous studies base their analysis on the diffusion approximation for radiation transfer, which is inappropriate in the optically thin outer layers of the wind. Here we study the deviations from diffusion, and calculate light curves more accurately using a Monte Carlo approach to photon transfer. We disti…
We calculate the distance-dependent performance of a few representative terrestrial neutrino detectors in detecting and measuring the properties of the $ν_e$ breakout burst light curve in a Galactic core-collapse supernova. The breakout burst is a signature phenomenon of core collapse and offers a probe into the stellar core through collapse and bounce. We examine cases of no neutrino oscillations and oscillations due to normal and inverted neutrino-mass hierarchies. For the normal hierarchy, other neutrino flavors emitted by the supernova overwhelm the $ν_e$ signal, making a detection of the …
Massive stars are characterized by a significant loss of mass either via spherically symmetric stellar winds or pre-explosion pulses, or by aspherical forms of circumstellar matter (CSM) such as bipolar lobes or outflowing circumstellar equatorial disks. A significant fraction of most massive stars end their lives by a core collapse; supernovae (SNe) are always located inside circumstellar envelopes created by their progenitors. We study the dynamics and thermal effects of collision between expanding ejecta of SNe and CSM that may be formed during, for example, a sgB[e] star phase, a luminous …
A large variety of explosions result in mildly or ultra relativistic shock breakouts. Here we calculate the luminosity and spectrum that these breakouts produce. In order to do so we improve an analytic description of relativistic radiation mediated shocks and follow the system from the breakout itself, through the planar phase and into the spherical phase. We limit our calculation to cases where the post breakout acceleration of the gas ends during the planar phase. (i.e., the final gas Lorentz factor <~30). We find that spherical relativistic breakouts produce a flash of gamma-rays with ener…
In a non-spherical stellar explosion, non-radial motions become important near the stellar surface. For realistic deviations from spherical symmetry, non-radial flow dramatically alters the dynamics and emission of shock emergence on a significant fraction of the surface. The breakout flash is stifled, ejecta speeds are limited, and matter is cast sideways. Non-radial ejection allows for collisions outside the star, which may engender a new type of transient. Strongly oblique breakouts are most easily produced in compact stellar progenitors, such as white dwarfs and stripped-envelope core coll…
We present extensive ultraviolet (UV) and optical photometry, as well as dense optical spectroscopy for type II Plateau (IIP) supernova SN 2016X that exploded in the nearby ($\sim$ 15 Mpc) spiral galaxy UGC 08041. The observations span the period from 2 to 180 days after the explosion; in particular, the Swift UV data probably captured the signature of shock breakout associated with the explosion of SN 2016X. It shows very strong UV emission during the first week after explosion, with contribution of $\sim$ 20 -- 30% to the bolometric luminosity (versus $\lesssim$ 15% for normal SNe IIP). More…
Non-spherical explosions develop non-radial flows as the pattern of shock emergence progresses across the stellar surface. In supernovae these flows can limit ejecta speeds, stifle shock breakout emission, and cause collisions outside the star. Similar phenomena occur in stellar and planetary collisions, tidal disruption events, accretion-induced collapses, and propagating detonations. We present two-dimensional, nested-grid Athena simulations of non-radial shock emergence in a frame comoving with the breakout pattern, focusing on the adiabatic, non-relativistic limit in a plane stratified env…
The origin of super-luminous supernovae (SLSNe), especially the source of their huge luminosities, has not been clarified yet. While a strong interaction between SN ejecta and dense circumstellar media (CSM) is a leading scenario, alternative models have been proposed. In this Letter, we suggest new diagnostics to discriminate the strong SN-CSM interaction scenario from the others: a decline in the luminosity ('dip') before the main peak of the light curve. This dip is an unavoidable consequence of having a dense CSM within which the shock breakout occurs. If a dense CSM shell is located far a…
Some supernova (SN) explosions show evidence for interaction with pre-existing non-spherically symmetric circumstellar medium (CSM) in their light curves, spectral line profiles, and polarization signatures. To better understand the connection with binary stars and to aid in the interpretation of observations, we perform two-dimensional axisymmetric hydrodynamic simulations where an expanding spherical SN ejecta initialized with realistic density and velocity profiles collide with various aspherical CSM distributions. We consider CSM in the form of a circumstellar disk, colliding wind shells i…
The brief transient emitted as a shock wave erupts through the surface of a presupernova star carries information about the stellar radius and explosion energy. Here the CASTRO code, which treats radiation transport using multigroup flux-limited diffusion, is used to simulate the light curves and spectra of shock breakout in very low-energy supernovae (VLE SNe), explosions in giant stars with final kinetic energy much less than 10$^{51}$ erg. VLE SNe light curves, computed here with the KEPLER code, are distinctively faint, red, and long-lived, making them challenging to find with transient su…
We present here an efficient numerical scheme for solving the non-relativistic 1D radiation-hydrodynamics equations including inelastic Compton scattering, which is not included in most codes and is crucial for solving problems such as shock breakout. The devised code is applied to the problems of a steady-state planar radiation mediated shock (RMS) and RMS breakout from a stellar envelope. The results are in agreement with those of a previous work on shock breakout \citep{Sapir13}, in which Compton equilibrium between matter and radiation was assumed and the "effective photon" approximation w…
Early-time observations of the Type II supernovae (SNe) 2013cu and 2013fs have revealed an interaction of ejecta with material near the star surface. Unlike the Type IIn SN2010jl, which interacts with a dense wind for ~1yr, the interaction ebbs after 2-3d, suggesting a dense and compact circumstellar envelope. Here, we use multi-group radiation-hydrodynamics and non-local-thermodynamic-equilibrium radiative transfer to explore the properties of red supergiant (RSG) star explosions embedded in a variety of dense envelopes. We consider the cases of an extended static atmosphere or a steady-state…
Shock breakout is the brightest radiative phenomenon in a Type II supernova (SN). Although it was predicted to be bright, the direct observation is difficult due to the short duration and X-ray/ultraviolet-peaked spectra. First entire observations of the shock breakouts of Type II Plateau SNe (SNe IIP) were reported in 2008 by ultraviolet and optical observations by the {\it GALEX} satellite and supernova legacy survey (SNLS), named SNLS-04D2dc and SNLS-06D1jd. We present multicolor light curves of a SN IIP, including the shock breakout and plateau, calculated with a multigroup radiation hydro…
Optical spectropolarimetry of the normal thermonuclear supernova SN2019np from -14.5 to +14.5 days relative to B-band maximum detected an intrinsic continuum polarization, p(cont), of 0.21+-0.09% at the first epoch. Between days -11.5 to +05, p(cont) remained about 0 and by day +14.5 was again significant at 0.19+-0.10%. Not considering the first epoch, the dominant axis of SiII(6355A) was roughly constant, staying close to the continuum until both rotated in opposite directions on day +14.5. Detailed radiation-hydrodynamical simulations produce a very steep density slope in the outermost ejec…
For the initial mass range (140 < M < 260 Msun) stars die in a thermonuclear runaway triggered by the pair-production instability. The supernovae they make can be remarkably energetic (up to ~10^53 ergs) and synthesize considerable amounts of radioactive isotopes. Here we model the evolution, explosion, and observational signatures of representative pair-instability supernovae (PI SNe) spanning a range of initial masses and envelope structures. The predicted light curves last for hundreds of days and range in luminosity, from very dim to extremely bright, L ~ 10^44 ergs/s. The most massive eve…
We present the GALEX detection of a UV burst at the time of explosion of an optically normal Type II-P supernova (PS1-13arp) from the Pan-STARRS1 survey at z=0.1665. The temperature and luminosity of the UV burst match the theoretical predictions for shock breakout in a red supergiant, but with a duration a factor of ~50 longer than expected. We compare the $NUV$ light curve of PS1-13arp to previous GALEX detections of Type IIP SNe, and find clear distinctions that indicate that the UV emission is powered by shock breakout, and not by the subsequent cooling envelope emission previously detecte…
We present theoretical expectations for non-thermal emission due to the bulk Comptonization at the ultra-relativistic shock breakout. We calculate the transfer of photons emitted from the shocked matter with a Monte Carlo code fully taking into account special relativity. As a hydrodynamical model, we use a self-similar solution of Nakayama & Shigeyama (2005). Our calculations reveal that the spectral shape exhibits a double peak or a single peak depending on the shock temperature at the shock breakout. If it is significantly smaller than the rest energy of an electron, the spectrum has a doub…
We present 3D simulations of core-collapse supernovae from blast-wave initiation by the neutrino-driven mechanism to shock breakout from the stellar surface, considering two 15 Msun red supergiants (RSG) and two blue supergiants (BSG) of 15 Msun and 20 Msun. We demonstrate that the metal-rich ejecta in homologous expansion still carry fingerprints of asymmetries at the beginning of the explosion, but the final metal distribution is massively affected by the detailed progenitor structure. The most extended and fastest metal fingers and clumps are correlated with the biggest and fastest-rising p…
Interaction of supernova (SN) ejecta with the optically thick circumstellar medium (CSM) of a progenitor star can result in a bright, long-lived shock breakout event. Candidates for such SNe include Type IIn and superluminous SNe. If some of these SNe are powered by interaction, then there should be a relation between their peak luminosity, bolometric light-curve rise time, and shock-breakout velocity. Given that the shock velocity during shock breakout is not measured, we expect a correlation, with a significant spread, between the rise time and the peak luminosity of these SNe. Here, we pres…
Relativistic shocks that accompany supernovae (SNe) produce X-ray burst emissions as they break out in the dense circumstellar medium around the progenitors. This phenomenon is sometimes associated with peculiar low-luminosity gamma-ray bursts (LL GRBs). Here, we investigate the high energy neutrino and gamma-ray counterparts of such a class of SNe. Just beyond the shock breakout radius, particle acceleration in the collisionless shock starts to operate in the presence of breakout photons. We show that protons may be accelerated to sufficiently high energies and produce high energy neutrinos a…
During a supernova explosion, a radiation-dominated shock (RDS) travels through its progenitor. A collisionless shock (CS) is usually assumed to replace it during shock breakout (SB). We demonstrate here that for some realistic progenitors enshrouded in optically thick winds, such as possibly SN 2008D, a CS forms deep inside the wind, soon after the RDS leaves the core, and therefore significantly before SB. The RDS does not survive the transition from the core to the thick wind when the wind close to the core is not sufficiently dense to compensate for the $r^{-2}$ dilution of photons due to …
Observable Signatures of Supernova Shock Breakout in Confined Circumstellar Medium
National Taiwan University（台湾大学）；Academia Sinica, Institute of Astronomy and Astrophysics（中央研究院天文及天文物理研究所）；Heidelberger Institut für Theoretische Studien（海德堡理论研究所）；Kyoto University（京都大学）；Zentrum für Astronomie der Universität Heidelberg（海德堡大学天文学计算中心）
We present three-dimensional simulations of core-collapse supernovae using the FLASH code that follow the progression of the explosion to the stellar surface, starting from neutrino-radiation hydrodynamic simulations of the neutrino-driven phase performed with the CHIMERA code. We consider a 9.6-$M_{\odot}$ zero-metallicity progenitor starting from both 2D and 3D CHIMERA models, and a 10-$M_{\odot}$ solar-metallicity progenitor starting from a 2D CHIMERA model, all simulated until shock breakout in 3D while tracking 160 nuclear species. The relative velocity difference between the supernova sh…
The discovery of early bumps in some type-I superluminous supernovae (SLSNe-I) before the main peaks offers an important clue to their energy source mechanisms. In this paper, we updated an analytic magnetar-powered model for fitting the multi-band light curves of double-peaked SLSNe-I: the early bump is powered by magnetar-driven shock breakout thermal emission, and the main peak is powered by a radiative diffusion through the SN ejecta as in the standard magnetar-powered model. Generally, the diffusive luminosity is greater than the shock breakout luminosity at the early time, which makes th…
Type II supernovae (SNe) originate from the explosion of hydrogen-rich supergiant massive stars. Their first electromagnetic signature is the shock breakout, a short-lived phenomenon which can last from hours to days depending on the density at shock emergence. We present 26 rising optical light curves of SN II candidates discovered shortly after explosion by the High cadence Transient Survey (HiTS) and derive physical parameters based on hydrodynamical models using a Bayesian approach. We observe a steep rise of a few days in 24 out of 26 SN II candidates, indicating the systematic detection …
Recently, the rapid multiwavelength photometry and flash spectra of supernova (SN) 2013fs imply that the progenitor stars of regular type II SNe (SNe II) might be commonly surrounded with a confined dense stellar wind ejected by themselves with large mass loss rate few years before the SNe. Based on the assumption that the pre-SN progenitor stars of SNe II have a SN 2013fs-like wind, with mass loss rate $\dot{M}\sim3\times10^{-3}(v_w/100\rm km\,s^{-1})M_\odot\rm yr^{-1}$, we investigate the neutrino emission during the wind breakouts of SN shocks. We find that the regular SNe II can convert a …
Several explosions of thermonuclear supernovae (SNe Ia) have been found to exhibit deviations from spherical symmetry upon closer inspection. Examples are the gamma-ray lines from SN 2014J as measured by INTEGRAL/SPI, and morphology information from radioactive isotopes in older remnants such as Tycho. A systematic study on the effects of parameters such as ignition geometry and burning morphology in SNe Ia is still missing. We use a 2D hydrodynamics code with post-processing nucleosynthesis and simulate the double detonations in a sub-Chandrasekhar mass carbon-oxygen white dwarf starting from…
Strong explosion of a compact star surrounded by a thick stellar wind drives a fast ($>0.1c$) radiation mediated shock (RMS) that propagates in the wind, and ultimately breaks out gradually once photons start escaping from the shock transition layer. In exceptionally strong or aspherical explosions the shock velocity may even be relativistic. The properties of the breakout signal depend on the dynamics and structure of the shock during the breakout phase. Here we present, for the first time, spectra and lightcurves of the breakout emission of fast Newtonian and mildly relativistic shocks, that…
