The Metamorphosis of Supernova SN 2008D/XRF 080109: A Link Between Supernovae and GRBs/Hypernovae

Abstract

The only supernovae (SNe) to show gamma-ray bursts (GRBs) or early x-ray emission thus far are overenergetic, broad-lined type Ic SNe (hypernovae, HNe). Recently, SN 2008D has shown several unusual features: (i) weak x-ray flash (XRF), (ii) an early, narrow optical peak, (iii) disappearance of the broad lines typical of SN Ic HNe, and (iv) development of helium lines as in SNe Ib. Detailed analysis shows that SN 2008D was not a normal supernova: Its explosion energy ( E ≈ 6×10 51 erg) and ejected mass [∼7 times the mass of the Sun ( \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(M_{{\odot}}\) \end{document} )] are intermediate between normal SNe Ibc and HNe. We conclude that SN 2008D was originally a ∼30 \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(M_{{\odot}}\) \end{document} star. When it collapsed, a black hole formed and a weak, mildly relativistic jet was produced, which caused the XRF. SN 2008D is probably among the weakest explosions that produce relativistic jets. Inner engine activity appears to be present whenever massive stars collapse to black holes.

Determining gravitational wave radiation from close galaxy pairs using a binary population synthesis approach

“…Furthermore, based on our estimate of the merger rate of close galaxies and making several evolutionary hypotheses, we can compute the number of SMBH sources that can be detected by the PTA (or SKA) detector. Additionally, the strength of GW signal from the merger of SMBH binaries will be blurred by other fierce energy release processes (such as supernova explosion, Mazzali et al 2008). Finally, the evolutionary properties of SMBHs could indeed be more complex than we have described.…”

Stellar Forensics with the Supernova‐GRB Connection

“…Using our reliable and early-time measurements of the bolometric output of this SN in conjunction with models by Waxman et al (2007) and Chevalier & Fransson (2008), as well as published values of kinetic energy and ejecta mass, we derived a progenitor radius of 1.2 ± 0.7 R (in agreement with Soderberg et al 2008) and 12 ± 7 R , respectively, the latter being more in line with typical WN stars. We furthermore showed that the observed X-ray emission by which it was discovered (Soderberg et al 2008) is different from those of X-ray flashes, the weaker cousins of GRBs, which demonstrates that even normal SN Ib, surprisingly, can give rise to highenergy phenomena (but see Mazzali et al 2008). Lastly, our spectra obtained at three and four months after maximum light show double-peaked oxygen lines that we associate with departures from spherical symmetry, as has been suggested for the inner ejecta of a number of SN Ib cores.…”

“…Lastly, our spectra obtained at three and four months after maximum light show double-peaked oxygen lines that we associate with departures from spherical symmetry, as has been suggested for the inner ejecta of a number of SN Ib cores. Our detailed observations and their analysis, as well as those of others (Soderberg et al 2008;Mazzali et al 2008;Malesani et al 2009;Maund et al 2009b;Tanaka et al 2009c) have inspired a number of theorists to develop and refine sophisticated models of SN shock breakout including relativistic-mediated shocks (Katz et al 2010), aspherity (Couch et al 2011) and the impact of a wind (Balberg & Loeb 2011) to explain its X-ray shock breakout, as well as refine models of the subsequently cooling envelope (Nakar & Sari 2010;Rabinak & Waxman 2011) aimed at reproducing the observations and predicting their appearance at high-z (Tominaga et al 2011). Observed optical and NIR light curves of SN 2008D after the onset (the right panel) of XRT 080109, which we adopt as the time of shock breakout.…”

VLBI Constraints on Type I b/c Supernovae

“…Some authors suggested that it is of supernova-shock origin (Soderberg et al 2008;Chevalier & Fransson 2008), while others suggested that it was caused by a mildly relativistic jet, which penetrated the envelope of the progenitor (Mazzali et al 2008;Li 2008;Xu, Zou, & Fan 2008).…”