Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userGALEX Detection of Shock Breakout in Type II-P Supernova PS1-13arp: Implications for the Progenitor Star Wind
121
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
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 detected in these systems. We interpret the ~ 1 d duration of the UV signal with a shock breakout in the wind of a red supergiant with a pre-explosion mass-loss rate of ~ 10^-3 Msun yr^-1. This mass-loss rate is enough to prolong the duration of the shock breakout signal, but not enough to produce an excess in the optical plateau light curve or narrow emission lines powered by circumstellar interaction. This detection of non-standard, potentially episodic high mass-loss in a RSG SN progenitor has favorable consequences for the prospects of future wide-field UV surveys to detect shock breakout directly in these systems, and provide a sensitive probe of the pre-explosion conditions of SN progenitors.
rate research
Read More
The mode of explosive burning in Type Ia SNe remains an outstanding problem. It is generally thought to begin as a subsonic deflagration, but this may transition into a supersonic detonation (the DDT). We argue that this transition leads to a breakout shock, which would provide the first unambiguous evidence that DDTs occur. Its main features are a hard X-ray flash (~20 keV) lasting ~0.01 s with a total radiated energy of ~10^{40} ergs, followed by a cooling tail. This creates a distinct feature in the visual light curve, which is separate from the nickel decay. This cooling tail has a maximum absolute visual magnitude of M_V = -9 to -10 at approximately 1 day, which depends most sensitively on the white dwarf radius at the time of the DDT. As the thermal diffusion wave moves in, the composition of these surface layers may be imprinted as spectral features, which would help to discern between SN Ia progenitor models. Since this feature should accompany every SNe Ia, future deep surveys (e.g., m=24) will see it out to a distance of approximately 80 Mpc, giving a maximum rate of ~60/yr. Archival data sets can also be used to study the early rise dictated by the shock heating (at about 20 days before maximum B-band light). A similar and slightly brighter event may also accompany core bounce during the accretion induced collapse to a neutron star, but with a lower occurrence rate.
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 most frequent core-collapse SNe, and predict apparent multicolor light curves of shock breakout at various redshifts $z$. We derive the observable SN rate and reachable redshift as functions of filter $x$ and limiting magnitude $m_{x,{rm lim}}$ by taking into account an initial mass function, cosmic star formation history, intergalactic absorption, and host galaxy extinction. We propose a realistic survey strategy optimized for shock breakout. For example, the $g$-band observable SN rate for $m_{g,{rm lim}}=27.5$ mag is 3.3 SNe degree$^{-2}$ day$^{-1}$ and a half of them locates at $zgeq1.2$. It is clear that the shock breakout is a beneficial clue to probe high-$z$ core-collapse SNe. We also establish ways to identify shock breakout and constrain SN properties from the observations of shock breakout, brightness, time scale, and color. We emphasize that the multicolor observations in blue optical bands with $sim$ hour intervals, preferably over $geq2$ continuous nights, are essential to efficiently detect, identify, and interpret shock breakout.
We report the serendipitous detection by GALEX of fast (<1 day) rising (>1 mag) UV emission from two Type II plateau (II-P) supernovae (SNe) at z=0.185 and 0.324 discovered by the Supernova Legacy Survey. Optical photometry and VLT spectroscopy 2 weeks after the GALEX detections link the onset of UV emission to the time of shock breakout. Using radiation hydrodynamics and non-LTE radiative transfer simulations, and starting from a standard red supergiant (RSG; Type II-P SN progenitor) star evolved self-consistently from the main sequence to iron core collapse, we model the shock breakout phase and the 55 hr that follow. The small scale height of our RSG atmosphere model suggests that the breakout signature is a thermal soft X-ray burst (lambda_peak ~ 90AA) with a duration of <~ 2000 s. Longer durations are possible but require either an extended and tenuous non-standard envelope, or an unusually dense RSG wind with dot{M} ~ 10^(-3) Msun yr^(-1). The GALEX observations miss the peak of the luminous (M_FUV ~ -20) UV burst but unambiguously capture the rise of the emission and a subsequent 2 day long plateau. The postbreakout, UV-bright plateau is a prediction of our model in which the shift of the peak of the spectral energy distribution (SED) from ~100 to ~1000AA and the ejecta expansion both counteract the decrease in bolometric luminosity from ~10^11 to ~10^9 L_sun over that period. Based on the observed detection efficiency of our study we make predictions for the breakout detection rate of the GALEX Time Domain Survey.
The radius and surface composition of an exploding massive star, as well as the explosion energy per unit mass, can be measured using early ultraviolet (UV) observations of core-collapse supernovae (CC SNe). We present the results from a simultaneous GALEX and Palomar Transient Factory (PTF) search for early UV emission from SNe. We analyze five CC SNe for which we obtained $NUV$ measurements before the first ground-based $R$-band detection. We introduce SOPRANOS, a new maximum likelihood fitting tool for models with variable temporal validity windows, and use it to fit the citet{SapirWaxman2017} shock cooling model to the data. We report four Type II SNe with progenitor radii in the range of $R_*approx600-1100R_odot$ and a shock velocity parameter in the range of $v_{s*}approx 2700-6000 ,rm km,s^{-1}$ ($E/Mapprox2-8times10^{50},rm erg/M_odot$) and one type IIb SN with $R_*approx210R_odot$ and $v_{s*}approx11000 rm, km,s^{-1}$ ($E/Mapprox1.8times10^{51},rm erg/M_odot$). Our pilot GALEX/PTF project thus suggests that a dedicated, systematic SN survey in the $NUV$ band, such as the wide-field UV explorer textit{ULTRASAT} mission, is a compelling method to study the properties of SN progenitors and SN energetics.
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). Moreover, we found that this supernova has an unusually long rise time of about 12.6 $pm$ 0.5 days in the $R$ band (versus $sim$ 7.0 days for typical SNe IIP). The optical light curves and spectral evolution are quite similar to the fast-declining type IIP object SN 2013ej, except that SN 2016X has a relatively brighter tail. Based on the evolution of photospheric temperature as inferred from the $Swift$ data in the early phase, we derive that the progenitor of SN 2016X has a radius of about 930 $pm$ 70 R$_{odot}$. This large-size star is expected to be a red supergiant star with an initial mass of $gtrsim$ 19 -- 20 M$_{odot}$ based on the mass $--$ radius relation of the Galactic red supergiants, and it represents one of the most largest and massive progenitors found for SNe IIP.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
