Monday, July 8, 2013

1307.1470 (Yi Cao et al.)

Discovery, Progenitor & Early Evolution of a Stripped Envelope Supernova iPTF13bvn    [PDF]

Yi Cao, Mansi M. Kasliwal, Iair Arcavi, Assaf Horesh, Paul Hancock, Stefano Valenti, S. Bradley Cenko, S. R. Kulkarni, Avishay Gal-Yam, Evgeny Gorbikov, Eran O. Ofek, David Sand, Ofer Yaron, Melissa Graham, Jeffrey M. Silverman, J. Craig Wheeler, G. H. Marion, Emma Walker, Paolo Mazzali, D. Andrew Howell, Josh Bloom, Peter E. Nugent, Jason Surace, Frank Masci, John Carpenter, Nathalie Degenaar, Christopher Gelino
The intermediate Palomar Transient Factory reports our discovery of a young supernova, iPTF13bvn, in the nearby galaxy, NGC5806 (22.5Mpc). Our spectral sequence in the optical and infrared suggests a likely Type Ib classification. We identify a single, blue progenitor candidate in deep pre-explosion imaging within a 2sigma error circle of 80 mas (8.7 pc). The candidate has a MB luminosity of -5.2+/-0.4 mag and a B-I color of 0.1+/-0.3 mag. If confirmed by future observations, this would be the first direct detection for a progenitor of a Type Ib. Fitting a power law to the early light curve, we find an extrapolated explosion date around 1.1 days before our first detection. We see no evidence of shock cooling. The pre-explosion detection limits constrain the radius of the progenitor to be smaller than a few solar radii. iPTF13bvn is also detected in cm and mm-wavelengths. Fitting a synchrotron self-absorption model to our radio data, we ?nd a mass loading parameter of 1.3*10^12 g/cm. Assuming a wind velocity of 10^3km/s, we derive a progenitor mass loss rate of 3*10^5Msun/yr. Our observations, taken as a whole, are consistent with a Wolf Rayet progenitor of the supernova iPTF13bvn.
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