Folatelli 2006 SN 2005bf的观测，与伽玛暴成协

主要内容:
给出了对SN2005bf的光学观测，为解释光变的两个峰，认为这个爆发分为两部分：快的喷流＋慢的整体爆发，前者先被看到，显示为有高速度的吸收线，然后整体爆发被看到，出现第二个峰。而第一个峰有喷流，可能与伽玛暴成协。表现上还有从Ic型朝Ib型转化。

精彩摘抄:
超新星的位置。
光变曲线。

文章信息:
The Astrophysical Journal, 641:1039–1050, 2006 April 20
SN 2005bf: A POSSIBLE TRANSITION EVENT BETWEEN TYPE Ib/c SUPERNOVAE AND GAMMA-RAY BURSTS
Gasto´n Folatelli, et al
ABSTRACT
We present u0g0r 0i 0BV photometry and optical spectroscopy of the Type Ib/Ic SN 2005bf covering the first100 days following discovery. The u0g0BV light curves displayed an unprecedented morphology among Type Ib/Ic supernovae, with an initial maximum some 2 weeks after discovery and a second, main maximum about 25 days after that. The bolometric light curve indicates that SN 2005bf was a remarkably luminous event, radiating at least 6:3 ; 1042 ergs s ^-1 at maximum light and a total of 2:1 ; 1049 ergs during the first 75 days after the explosion. Spectroscopically, SN 2005bf underwent a unique transformation from a Type Ic-like event at early times to a typical Type Ib supernova at later phases. The initial maximum in u0g0BV was accompanied by the presence in the spectrum of high-velocity (>14,000 km s 1) absorption lines of Fe ii, Ca ii, andH i. The photospheric velocity derived fromspectra at early epochs was below 10,000 km s ^-1, which is unusually low compared with ordinary Type Ib supernovae. We describe one-dimensional computer simulations that attempt to account for these remarkable properties. The most favored model is that of a very energetic (2 ; 1051 ergs), asymmetric explosion of a massive (8.3M)Wolf-Rayet WN star that had lost most of its hydrogen envelope. We speculate that an unobserved relativistic jet was launched producing a two-component explosion consisting of (1) a polar explosion containing a small fraction of the total mass and moving at high velocity and (2) the explosion of the rest of the star. At first, only the polar explosion is observed, producing the initial maximum and the high-velocity absorption-line spectrum resembling a Type Ic event. At late times, this fast-moving component becomes optically thin, revealing the more slowly moving explosion of the rest of the star and transforming the observed spectrum to that of a typical Type Ib supernova. If this scenario is correct, then SN 2005bf is the best example to date of a transition object between normal Type Ib/Ic supernovae and gamma-ray bursts.