The Peculiar SN 2005hk: Do Some Type Ia Supernovae Explode as Deflagrations?
Abstract
We present extensive u'g'r'i'BVRIYJHKs photometry and optical spectroscopy of SN 2005hk. These data reveal that SN 2005hk was nearly identical in its observed properties to SN 2002cx, which has been called ``the most peculiar known type Ia supernova.'' Both supernovae exhibited high ionization SN 1991T-like pre-maximum spectra, yet low peak luminosities like SN 1991bg. The spectra reveal that SN 2005hk, like SN 2002cx, exhibited expansion velocities that were roughly half those of typical type Ia supernovae. The R and I light curves of both supernovae were also peculiar in not displaying the secondary maximum observed for normal type Ia supernovae. Our YJH photometry of SN 2005hk reveals the same peculiarity in the near-infrared. By combining our optical and near-infrared photometry of SN 2005hk with published ultraviolet light curves obtained with the Swift satellite, we are able to construct a bolometric light curve from ~10 days before to ~60 days after B maximum. The shape and unusually low peak luminosity of this light curve, plus the low expansion velocities and absence of a secondary maximum at red and near-infrared wavelengths, are all in reasonable agreement with model calculations of a 3D deflagration which produces ~0.25 M_sun of 56Ni.
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Cite
@article{arxiv.astro-ph/0611295,
title = {The Peculiar SN 2005hk: Do Some Type Ia Supernovae Explode as Deflagrations?},
author = {M. M. Phillips and W. Li and J. A. Frieman and S. I. Blinnikov and D. DePoy and J. L. Prieto and P. Milne and C. Contreras and G. Folatelli and N. Morrell and M. Hamuy and N. B. Suntzeff and M. Roth and S. Gonzalez and W. Krzeminski and A. V. Filippenko and W. L. Freedman and R. Chornock and S. Jha and B. F. Madore and S. E. Persson and C. R. Burns and P. Wyatt and D. Murphy and R. J. Foley and M. Ganeshalingam and F. J. D. Serduke and K. Krisciunas and B. Bassett and A. Becker and B. Dilday and J. Eastman and P. M. Garnavich and J. Holtzman and R. Kessler and H. Lampeitl and J. Marriner and S. Frank and J. L. Marshall and G. Miknaitis and M. Sako and D. P. Schneider and K. van der Heyden and Naoki Yasuda},
journal= {arXiv preprint arXiv:astro-ph/0611295},
year = {2008}
}
Comments
Accepted by PASP, to appear in April 2007 issue, 63 pages, 16 figures, 11 tables