1110.4109 (Felipe Olivares E. et al.)

The Fast Evolution of SN 2010bh associated with XRF 100316D    [PDF]

Felipe Olivares E., Jochen Greiner, Patricia Schady, Arne Rau, Sylvio Klose, Thomas Krühler, Paulo M. J. Afonso, Adria C. Updike, Marco Nardini, Robert Filgas, Ana Nicuesa Guelbenzu, Christian Clemens, Jonny Elliott, D. Alexander Kann, Andrea Rossi, Vladimir Sudilovsky

About a decade ago the first observational evidence of the connection between supernovae and gamma-ray bursts was found. Since then, only half a dozen spectroscopically confirmed associations have been discovered and XRF 100316D/SN 2010bh lies among the latest. Starting observations at 12 hr and continuing until 80 days after the burst, GROND provided excellent photometric data of XRF 100316D/SN 2010bh in six filter bands from the optical to the near-infrared, significantly expanding the existing data set for this event. Combining GROND and Swift/UVOT+XRT data, the early SED is modelled with a blackbody and afterglow component attenuated by dust and gas absorption. The best-fit models imply a moderate host-galaxy extinction (A_V=1.2\pm0.1 mag). Furthermore, temperature and radius evolution of the thermal component are combined with earlier measurements available from the literature. The analysis reveals a cooling envelope at an apparent initial radius of 7\times10^11 cm, compatible with a dense wind surrounding a Wolf-Rayet star. Templates of SN 1998bw are fitted to the light curve in the SN phase. The multicolour comparison shows that SN 2010bh is ~65% as bright as SN 1998bw. It proves to be the most rapidly evolving GRB-SNe to date, reaching maximum brightness at ~8 days after the burst in the blue bands. Finally, a two-component model is fitted to the quasi-bolometric light curve, which delivers M_Ni=0.21\pm0.03M\bigodot and M_ej=2.6\pm0.2M\bigodot, typical values within the GRB-SN population. The kinetic energy is (2.4\pm0.7)\times10^52 erg, making this SN the second most energetic GRB-SN after SN1998bw. SN 2010bh shows one of the earliest peaks ever recorded and thereafter fades more rapidly than other comparable SNe. This hints at a possibly thin envelope that is expanding at very high velocities and, therefore, unable to retain the {\gamma}-rays that would prolong the duration of the SN event.

View original: http://arxiv.org/abs/1110.4109