MULTI-WAVELENGTH OBSERVATIONS OF SUPERNOVA 2011ei: TIME-DEPENDENT CLASSIFICATION OF TYPE IIb AND Ib SUPERNOVAE AND IMPLICATIONS FOR THEIR PROGENITORS

作者：Milisavljevic Dan^*; Margutti Raffaella; Soderberg Alicia M; Pignata Giuliano; Chomiuk Laura; Fesen Robert A; Bufano Filomena; Sanders Nathan E; Parrent Jerod T; Parker Stuart; Mazzali Paolo; Pian Elena; Pickering Timothy; Buckley David A H; Crawford Steven M; Gulbis Amanda A S; Hettlage Christian; Hooper Eric; Nordsieck Kenneth H; O' Donoghue Darragh; Husser Tim Oliver; Potter Stephen; Kniazev Alexei; Kotze Paul; Romero Colmenero Encarni; Vaisanen Petri

来源：Astrophysical Journal, 2013, 767(1): 71.

DOI：10.1088/0004-637X/767/1/71

• supernovae: general
• supernovae: individual (SN 2011ei)

We present X-ray, UV/optical, and radio observations of the stripped-envelope, core-collapse supernova (SN) 2011ei, one of the least luminous SNe IIb or Ib observed to date. Our observations begin with a discovery within similar to 1 day of explosion and span several months afterward. Early optical spectra exhibit broad, Type II-like hydrogen Balmer profiles that subside rapidly and are replaced by Type Ib-like He-rich features on a timescale of one week. High-cadence monitoring of this transition suggests absorption attributable to a high-velocity (greater than or similar to 12,000 km s(-1)) H-rich shell, which is likely present in many Type Ib events. Radio observations imply a shock velocity of v approximate to 0.13 c and a progenitor star average mass-loss rate of (M) over dot approximate to 1.4 x 10(-5) M-circle dot yr(-1) (assuming wind velocity v(w) = 10(3) km s(-1)). This is consistent with independent constraints from deep X-ray observations with Swift-XRT and Chandra. Overall, the multi-wavelength properties of SN 2011ei are consistent with the explosion of a lower-mass (3-4 M-circle dot), compact (R-* less than or similar to 1 x 10(11) cm), He-core star. The star retained a thin hydrogen envelope at the time of explosion, and was embedded in an inhomogeneous circumstellar wind suggestive of modest episodic mass loss. We conclude that SN 2011ei%26apos;s rapid spectral metamorphosis is indicative of time-dependent classifications that bias estimates of the relative explosion rates for Type IIb and Ib objects, and that important information about a progenitor star%26apos;s evolutionary state and mass loss immediately prior to SN explosion can be inferred from timely multi-wavelength observations.

• 出版日期2013-4-10
• 单位中国科学院理论物理研究所