The Highly Energetic Expansion of SN2010bh Associated with GRB 100316D
Creators: name: Bufano, Filomena
name: Pian, Elena
name: Sollerman, Jesper
name: Benetti, Stefano
name: Pignata, Giuliano
name: Valenti, Stefano
name: Covino, Stefano
name: D'Avanzo, Paolo
name: Malesani, Daniele
name: Cappellaro, Enrico
name: Della Valle, Massimo
name: Fynbo, Johan
name: Hjorth, Jens
name: Mazzali, Paolo A.
name: Reichart, Daniel E.
name: Starling, Rhaana L. C.
name: Turatto, Massimo
name: Vergani, Susanna D.
name: Wiersema, Klass
name: Amati, Lorenzo
name: Bersier, David
name: Campana, Sergio
name: Cano, Zach
name: Castro-Tirado, Alberto J.
name: Chincarini, Guido
name: D'Elia, Valerio
name: Postigo, Antonio de Ugarte
name: Deng, Jinsong
name: Ferrero, Patrizia
name: Filippenko, Alexei V.
name: Goldoni, Paolo
name: Gorosabel, Javier
name: Greiner, Jochen
name: Hammer, Francois
name: Jakobsson, Pall
name: Kaper, Lex
name: Kawabata, Koji S.
name: Klose, Sylvio
name: Levan, Andrew J.
name: Maeda, Keiichi
name: Masetti, Nicola
name: Milvang-Jensen, Bo
name: Mirabel, Felix I.
name: Moller, Palle
name: Nomoto, Kenichi
name: Palazzi, Eliana
name: Piranomonte, Silvia
name: Salvaterra, Ruben
name: Stratta, Giulia
name: Tagliaferri, Gianpiero
name: Tanaka, Masaomi
name: Tanvir, Nial R.
name: Wijers, Ralph A. M. J.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We present the spectroscopic and photometric evolution of the nearby (z = 0.059) spectroscopically confirmed type Ic supernova, SN 2010bh, associated with the soft, long-duration gamma-ray burst (X-ray flash) GRB 100316D. Intensive follow-up observations of SN 2010bh were performed at the ESO Very Large Telescope (VLT) using the X-shooter and FORS2 instruments. Owing to the detailed temporal coverage and the extended wavelength range (3000--24800 A), we obtained an unprecedentedly rich spectral sequence among the hypernovae, making SN 2010bh one of the best studied representatives of this SN class. We find that SN 2010bh has a more rapid rise to maximum brightness (8.0 +/- 1.0 rest-frame days) and a fainter absolute peak luminosity (L_bol~3e42 erg/s) than previously observed SN events associated with GRBs. Our estimate of the ejected (56)Ni mass is 0.12 +/- 0.02 Msun. From the broad spectral features we measure expansion velocities up to 47,000 km/s, higher than those of SNe 1998bw (GRB 980425) and 2006aj (GRB 060218). Helium absorption lines He I lambda5876 and He I 1.083 microm, blueshifted by ~20,000--30,000 km/s and ~28,000--38,000 km/s, respectively, may be present in the optical spectra. However, the lack of coverage of the He I 2.058 microm line prevents us from confirming such identifications. The nebular spectrum, taken at ~186 days after the explosion, shows a broad but faint [O I] emission at 6340 A. The light-curve shape and photospheric expansion velocities of SN 2010bh suggest that we witnessed a highly energetic explosion with a small ejected mass (E_k ~ 1e52 erg and M_ej ~ 3 Msun). The observed properties of SN 2010bh further extend the heterogeneity of the class of GRB supernovae.
description: 37 pages and 12 figures (one-column pre-print format), accepted for publication in ApJ