Valenti 2009 对超新星 SN2008ha的观测

主要内容:
一个很弱的超新星. 没有氢包层. 很可能是和伽玛暴成协的.
提出一种可能性, 那些像GRB 060614这样没有超新星成协的暴, 可能是因为超新星本身太暗了看不到.

如果后续观测得到射电辐射, 证明SN 2008da确实和一个伽玛暴成协, 就更好了. 不只射电, 我们还可以对光学有一些限制, 偏轴的光学余辉要在怎样的情况下我们才看不到, 这个也许可以否定他们说可能成协的结论.

但是反驳文章本身不太可能, 人家只是提出存在这样暗的超新星, 没说所有暗的超新星都产生伽玛暴.

不过射电观测基本排出了有伽玛暴喷流的可能. 见后面的引用(form Xu Dong).

精彩摘抄:

From pictures

注意右图包括了GRB 060614的光变和SN2008ha的光变, 假设和GRB 060614成协的超新星和SN2008ha一样弱的话, 辐射就会被淹没在宿主星系而看不到了.

文章信息:

---

· Find Similar Abstracts (with default settings below)

· Electronic Refereed Journal Article (HTML)

· arXiv e-print (arXiv:0901.2074)

· References in the article

· Citations to the Article (5) (Citation History)

· Refereed Citations to the Article

· Also-Read Articles (Reads History)

·

· Translate This Page

Title:		A low-energy core-collapse supernova without a hydrogen envelope
Authors:		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.
Publication:		Nature, Volume 459, Issue 7247, pp. 674-677 (2009). (Nature Homepage)
Publication Date:		06/2009
Origin:		NATURE
Abstract Copyright:		(c) 2009: Nature
DOI:		10.1038/nature08023
Bibliographic Code:		2009Natur.459..674V

Abstract

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 SN2008ha 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 SN2002cx-like events). This discovery could link these faint supernovae to some long-duration γ-ray bursts, because extremely faint, hydrogen-stripped core-collapse supernovae have been proposed to produce such long γ-ray bursts, the afterglows of which do not show evidence of associated supernovae.

---

Bibtex entry for this abstract Preferred format for this abstract (see Preferences)



ATEL #1948 ATEL #1948

Title: Radio Observations of SN 2008ha
Author: Alicia Soderberg (Harvard/CfA)
Queries: asoderberg@cfa.harvard.edu
Posted: 3 Mar 2009; 19:17 UT
Subjects: Radio, Novae, Supernovae

I observed the peculiar SN 2008ha (CBET #1567) with the Very Large Array
on 2008 Nov 21.99 UT at a frequency of 8.46 GHz. No radio source is detected
at the optical SN position to a limit of 93 microJy (3 sigma). At a distance
of 21 Mpc, this corresponds to a radio luminosity limit similar to those
of nearby Type Ia supernovae (Panagia et al. 2006). It is also consistent
with the observed radio luminosities for the nearest Type Ibc supernovae
(e.g., SN 2002ap; Berger, Kulkarni & Chevalier 2002), but a factor of 10^3
and 10^5 below the radio luminosities of sub-energetic GRBs (Soderberg
et al. 2006) and classical long-duration GRB afterglows (Frail et al. 2003),
respectively. Moreover, the radio upper limit rules out the presence
of an off-axis GRB jet, initially directed within 30 degrees of our line-of-sight
(Soderberg et al. 2006). While the non-detection of radio emission
from SN 2008ha does not distinguish it to be either a thermonuclear or
core-collapse supernova, the observations clearly rule out an on-axis GRB
jet or sub-energetic GRB. Additional radio observations are underway to
constrain the late-time radio evolution from this explosion, including
any emission from a misdirected GRB jet.

------------------------------

------------------------------------------------
Password Certification: Alicia M. Soderberg (ams@astro.caltech.edu)
http://www.astronomerstelegram.org/?read=1948