G. Leloudas, E. Chatzopoulos, B. Dilday, J. Gorosabel, J. Vinko, A. Gallazzi, J. C. Wheeler, B. Bassett, J. Fischer, J. A. Frieman, J. P. U. Fynbo, A. Goobar, M. Jelinek, D. Malesani, R. C. Nichol, J. Nordin, L. Ostman, M. Sako, D. P. Schneider, M. Smith, J. Sollerman, M. D. Stritzinger, C. C. Thoene, A. de Ugarte Postigo
We study SN 2006oz, a newly-recognized member of the class of H-poor,
super-luminous supernovae. We present multi-color light curves from the SDSS-II
SN Survey, covering the rise time, as well as an optical spectrum showing that
the explosion occurred at z~0.376. We fit black body functions to estimate the
temperature and radius evolution of the photosphere and use the parametrized
code SYNOW to model the spectrum. We construct a bolometric light curve and
compare with explosion models. The very early light curves show a dip in the g
and r-bands and a possible initial cooling phase in the u-band before rising to
maximum light. The bolometric light curve shows a precursor plateau with a
duration between 6-10 days in the rest-frame. A lower limit of M_u < -21.5 can
be placed on the absolute peak luminosity of the SN, while the rise time is
constrained to be at least 29 days. During our observations, the emitting
sphere doubled its radius to 2x10^15 cm, while the temperature remained hot at
15000 K. As for other similar SNe, the spectrum is best modeled with elements
including O II and Mg II, while we tentatively suggest that Fe III might be
present. We suggest that the precursor plateau might be related to a
recombination wave in a circumstellar medium (CSM) and discuss whether it is a
common property of all similar explosions. The subsequent rise can be equally
well described by input from a magnetar or by ejecta-CSM interaction, but the
models are not well constrained due to the lack of post-maximum observations,
and CSM interaction has difficulties accounting for the precursor plateau
self-consistently. Radioactive decay is less likely as a mechanism powering the
luminosity. The host galaxy, detected in deep imaging with the 10 m GTC, is a
moderately young and star-forming, but not a starburst, galaxy. It has an
absolute magnitude of M_g = -16.9.
View original:
http://arxiv.org/abs/1201.5393
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