Milisavljevic, DanMargutti, RaffaellaSoderberg, Alicia M.Pignata, GiulianoChomiuk, LauraFesen, Robert A.Bufano, FilomenaSanders, Nathan E.Parrent, Jerod T.Parker, StuartPickering, TimothyBuckley, David A. H.Crawford, Steven M.Gulbis, Amanda A. S.Hettlage, ChristianHooper, EricNordsieck, Kenneth H.O'Donoghue, DarraghHusser, Tim-OliverPotter, StephenKniazev, AlexeiKotze, PaulRomero-Colmenero, EncarniVaisanen, PetriWolf, MarshaBartel, NorbertBietenholz, Michael F.Fransson, ClaesMazzali, PaoloBrunthaler, AndreasChakraborti, SayanLevesque, Emily M.MacFayden, AndrewDrescher, ColinBock, GregMarples, PeterAnderson, Joseph P.Benetti, StefanoReichart, DanielIvarsen, Kevin2013-10-222016-05-242013-10-222016-05-242012http://repositorio.unab.cl/xmlui/handle/ria/1930We 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 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 the timescale of one week. High-cadence monitoring of this transition identifies an absorption feature around 6250 °A to be chiefly due to hydrogen, as opposed to C II, Ne I, or Si II. Similarities between this observed feature and several SNe Ib suggest that hydrogen absorption attributable to a high velocity (& 12, 000 km s−1) H-rich shell is not rare in Type Ib events. Radio observations imply a shock velocity of v 0.13c and a progenitor star mass-loss rate of ˙M 1.4 × 10−5 M⊙ yr−1 (assuming wind velocity vw = 103 km s−1). This is consistent with independent constraints estimated from deep X-ray observations with Swift -XRT and Chandra. We find the multi-wavelength properties of SN2011ei to be consistent with the explosion of a lower-mass (3−4 M⊙), compact (R∗ 1×1011 cm), He core star. The star retained a thin hydrogen envelope at the time of outburst, and was embedded in an inhomogeneous circumstellar wind suggestive of modest episodic mass-loss. We conclude that SN2011ei’s rapid spectral metamorphosis calls attention to time-dependent classifications that bias estimates of explosion rates for a subset of Type IIb and Ib objects. Further, that important information about a progenitor star’s evolutionary state and associated mass-loss in the days to years prior to SN outburst can be inferred from timely multi-wavelength observations.Supernovae: general — supernova: individual (SN2011ei)Artículo