Discovery of the nearby long, soft GRB 100316D with an associated supernova

• Published in: arXiv.org 2010-10
• Main Authors: Starling, R L C, Wiersema, K, Levan, A J, Sakamoto, T, Bersier, D, Goldoni, P, Oates, S R, Rowlinson, A, Campana, S, Sollerman, J, Tanvir, N R, Malesani, D, Fynbo, J P U, Covino, S, D'Avanzo, P, O'Brien, P T, Page, K L, Osborne, J P, Vergani, S D, Barthelmy, S, Burrows, D N, Cano, Z, Curran, P A, De Pasquale, M, D'Elia, V, Evans, P A, Flores, H, Fruchter, A S, Garnavich, P, Gehrels, N, Gorosabel, J, Hjorth, J, Holland, S T, A J van der Horst, Hurkett, C P, Jakobsson, P, Kamble, A P, Kouveliotou, C, Kuin, N P M, Kaper, L, Mazzali, P A, Nugent, P E, Pian, E, Stamatikos, M, Thoene, C C, Woosley, S E
• Format: Article
• Language: English
• Subjects: Astrometry; Emission analysis; Galaxies; Gamma ray bursts; Gamma rays; High energy astronomy; Light curve; Morphology; Red shift
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1004.2919

We report the Swift discovery of nearby long, soft gamma-ray burst GRB 100316D, and the subsequent unveiling of its low redshift host galaxy and associated supernova. We derive the redshift of the event to be z = 0.0591 +/- 0.0001 and provide accurate astrometry for the GRB-SN. We study the extremely unusual prompt emission with time-resolved gamma-ray to X-ray spectroscopy, and find that the spectrum is best modelled with a thermal component in addition to a synchrotron emission component with a low peak energy. The X-ray light curve has a remarkably shallow decay out to at least 800 s. The host is a bright, blue galaxy with a highly disturbed morphology and we use Gemini South, VLT and HST observations to measure some of the basic host galaxy properties. We compare and contrast the X-ray emission and host galaxy of GRB 100316D to a subsample of GRB-SNe. GRB 100316D is unlike the majority of GRB-SNe in its X-ray evolution, but resembles rather GRB 060218, and we find that these two events have remarkably similar high energy prompt emission properties. Comparison of the host galaxies of GRB-SNe demonstrates, however, that there is a great diversity in the environments in which GRB-SNe can be found. GRB 100316D is an important addition to the currently sparse sample of spectroscopically confirmed GRB-SNe, from which a better understanding of long GRB progenitors and the GRB--SN connection can be gleaned.