The type Iax supernova, SN 2015H

A white dwarf deflagration candidate

¹ Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Belfast, BT7 1NN, UK
e-mail: mmagee37@qub.ac.uk
² The Oskar Klein Centre & Department of Astronomy, Stockholm University, AlbaNova, 106 91 Stockholm Sweden
³ Department of Physics, Yale University, New Haven, CT 06250-8121, USA
⁴ Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
⁵ Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstraße 1, 85748 Garching, Germany
⁶ Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Emil- Fischer Straße 31, 97074 Würzburg, Germany
⁷ Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 76100 Rehovot, Israel
⁸ Milenium Institute of Astrophysics, 7820436 Macul Santiago, Chile
⁹ Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile
¹⁰ Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching bei München, Germany
¹¹ Sorbonne Universites, UPMC Univ. Paris 06, UMR 7585, LPNHE, 75005 Paris, France
¹² CNRS, UMR 7585, Laboratoire de Physique Nucléaire et des Hautes Énergies, 4 place Jussieu, 75005 Paris, France
¹³ Department of Physics, University of Warwick, Coventry CV4 7AL, UK
¹⁴ Heidelberger Institut für Theoretische Studien, Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany
¹⁵ Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611, Australia
¹⁶ ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO), Australia
¹⁷ Department of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ, UK
¹⁸ Department of Physics, University of California, Davis, CA 95616, USA

Received: 23 December 2015
Accepted: 14 March 2016

Abstract

We present results based on observations of SN 2015H which belongs to the small group of objects similar to SN 2002cx, otherwise known as type Iax supernovae. The availability of deep pre-explosion imaging allowed us to place tight constraints on the explosion epoch. Our observational campaign began approximately one day post-explosion, and extended over a period of about 150 days post maximum light, making it one of the best observed objects of this class to date. We find a peak magnitude of M_r = −17.27± 0.07, and a (Δm₁₅)_r = 0.69 ± 0.04. Comparing our observations to synthetic spectra generated from simulations of deflagrations of Chandrasekhar mass carbon-oxygen white dwarfs, we find reasonable agreement with models of weak deflagrations that result in the ejection of ~0.2 M_⊙ of material containing ~0.07 M_⊙ of ⁵⁶Ni. The model light curve however, evolves more rapidly than observations, suggesting that a higher ejecta mass is to be favoured. Nevertheless, empirical modelling of the pseudo-bolometric light curve suggests that ≲0.6 M_⊙ of material was ejected, implying that the white dwarf is not completely disrupted, and that a bound remnant is a likely outcome.