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




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Resumen

We present X-ray, UV-optical, and radio observations of the stripped-envelope, core-collapse supernova SN2011ei, one of the least luminous SNe IIb or Ib observed to date. Our observations begin with a discovery within∼1 day of explosion and span several months afterward. Early optical spectra exhibit broad, Type II-like hydrogenBalmer 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 12,000 km s−1H-rich shell, which is likely present in many Type Ib events. Radio observations imply a shock velocity ofv ≈ 0.13 c and a progenitor star average mass-loss rate of M˙ ≈ 1.4 × 10−5 M yr−1 assuming wind velocityvw = 103 km s−1. This is consistent with independent constraints from deep X-ray observations with Swift-XRTand Chandra. Overall, the multi-wavelength properties of SN 2011ei are consistent with the explosion of a lowermass3–4 M , compact R∗ 1 × 1011 cm, He-core star. The star retained a thin hydrogen envelope at thetime of explosion, and was embedded in an inhomogeneous circumstellar wind suggestive of modest episodic massloss. We conclude that SN 2011ei’s rapid spectral metamorphosis is indicative of time-dependent classificationsthat bias estimates of the relative explosion rates for Type IIb and Ib objects, and that important information abouta progenitor star’s evolutionary state and mass loss immediately prior to SN explosion can be inferred from timelymulti-wavelength observations.Nota general

Artículo de publicación ISI



Autor: vljevic, Dan Milisa; - Margutti, Raffaella; - Soderberg, Alicia M.; - Pignata Libralato, Giuliano; - Chomiuk, Laura; - Fesen, Rob

Fuente: http://repositorio.uchile.cl/



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