TY - JOUR
T1 - Multi-wavelength observations of supernova 2011ei
T2 - Time-dependent classification of type IIb and Ib supernovae and implications for their progenitors
AU - Milisavljevic, Dan
AU - Margutti, Raffaella
AU - Soderberg, Alicia M.
AU - Pignata, Giuliano
AU - Chomiuk, Laura
AU - Fesen, Robert A.
AU - Bufano, Filomena
AU - Sanders, Nathan E.
AU - Parrent, Jerod T.
AU - Parker, Stuart
AU - Mazzali, Paolo
AU - Pian, Elena
AU - Pickering, Timothy
AU - Buckley, David A.H.
AU - Crawford, Steven M.
AU - Gulbis, Amanda A.S.
AU - Hettlage, Christian
AU - Hooper, Eric
AU - Nordsieck, Kenneth H.
AU - O'Donoghue, Darragh
AU - Husser, Tim Oliver
AU - Potter, Stephen
AU - Kniazev, Alexei
AU - Kotze, Paul
AU - Romero-Colmenero, Encarni
AU - Vaisanen, Petri
AU - Wolf, Marsha
AU - Bietenholz, Michael F.
AU - Bartel, Norbert
AU - Fransson, Claes
AU - Walker, Emma S.
AU - Brunthaler, Andreas
AU - Chakraborti, Sayan
AU - Levesque, Emily M.
AU - MacFadyen, Andrew
AU - Drescher, Colin
AU - Bock, Greg
AU - Marples, Peter
AU - Anderson, Joseph P.
AU - Benetti, Stefano
AU - Reichart, Daniel
AU - Ivarsen, Kevin
PY - 2013/4/10
Y1 - 2013/4/10
N2 - 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 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 (≳ 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 0.13 c and a progenitor star average mass-loss rate of (assuming wind velocity vw = 103 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), compact (R* ≲ 1 × 1011 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'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's evolutionary state and mass loss immediately prior to SN explosion can be inferred from timely multi-wavelength observations.
AB - 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 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 (≳ 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 0.13 c and a progenitor star average mass-loss rate of (assuming wind velocity vw = 103 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), compact (R* ≲ 1 × 1011 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'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's evolutionary state and mass loss immediately prior to SN explosion can be inferred from timely multi-wavelength observations.
KW - supernovae: general
KW - supernovae: individual (SN 2011ei)
UR - http://www.scopus.com/inward/record.url?scp=84875662177&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84875662177&partnerID=8YFLogxK
U2 - 10.1088/0004-637X/767/1/71
DO - 10.1088/0004-637X/767/1/71
M3 - Article
AN - SCOPUS:84875662177
SN - 0004-637X
VL - 767
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 71
ER -