SN 2004A: Another Type II-P Supernova with a Red Supergiant Progenitor
/ Authors
M. Hendry, S. Smartt, R. M. Crockett, J. Maund, A. Gal-yam, D. moon, S. Cenko, D. Fox, R. Kudritzki, C. Benn
and 26 more authors
R. F. D. O. Astronomy, U. Cambridge, Cambridge, UK., D. Physics, Astronomy, Queen's University of Belfast, Belfast, A. Department, U. Texas, Austin, Tx, Usa, D. O. Astronomy, C. I. O. Technology., Pasadena, Ca, Hubble Fellow, Space Radiation Laboratory, Institute for Astronomy, U. Hawaii, Honolulu, Hawaii, Isaac Newton Group, Santa Cruz de la Palma, Espana
/ Abstract
We present a monitoring study of SN 2004A and probable discovery of a progenitor star in pre-explosion Hubble Space Telescope (HST) images. The photometric and spectroscopic monitoring of SN 2004A show that it was a normal Type II-P which was discovered in NGC 6207 about two weeks after explosion. We compare SN 2004A to the similar Type II-P SN 1999em and estimate an explosion epoch of 2004 January 6. We also calculate three new distances to NGC 6207 of 21.0 ± 4.3, 21.4 ± 3.5 and 25.1 ± 1.7 Mpc. The former was calculated using the Standard Candle Method (SCM) for SNe II-P, and the latter two from the brightest supergiants method (BSM). We combine these three distances with existing kinematic distances, to derive a mean value of 20.3 ± 3.4 Mpc. Using this distance, we estimate that the ejected nickel mass in the explosion is 0.046+0.031-0.017 Mo. The progenitor of SN 2004A is identified in pre-explosion WFPC2 F814W images with a magnitude of mF814W = 24.3 ± 0.3, but is below the detection limit of the F606W images. We show that this was likely a red supergiant (RSG) with a mass of 9+3-2 Mo. The object is detected at 4.7σ above the background noise. Even if this detection is spurious, the 5σ upper limit would give a robust upper mass limit of 12 Mo for a RSG progenitor. These initial masses are very similar to those of two previously identified RSG progenitors of the Type II-P SNe 2004gd (8+4-2 Mo) and 2005cs (9+3-2 Mo).
Journal: Monthly Notices of the Royal Astronomical Society