Late-time Flattening of Type Ia Supernova Light Curves: Constraints from SN 2014J in M82

• Published in: The Astrophysical journal Vol. 852; no. 2; pp. 89 - 98
• Main Authors: Yang, Yi, Wang, Lifan, Baade, Dietrich, Brown, Peter. J., Cikota, Aleksandar, Cracraft, Misty, Höflich, Peter A., Maund, Justyn R., Patat, Ferdinando, Sparks, William B., Spyromilio, Jason, Stevance, Heloise F., Wang, Xiaofeng, Wheeler, J. Craig
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 10.01.2018; IOP Publishing
• Subjects: Astrophysics; Bolometers; Echoes; Flattening; Hubble Space Telescope; Light curve; Luminosity; nuclear reactions, nucleosynthesis, abundances; Radioactive decay; Reprocessing; Space telescopes; Stellar evolution; Supernova; Supernovae; supernovae: individual (SN 2014J); White dwarf stars
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/aa9e4c

The very nearby Type Ia supernova 2014J in M82 offers a rare opportunity to study the physics of thermonuclear supernovae at extremely late phases ( 800 days). Using the Hubble Space Telescope, we obtained 6 epochs of high-precision photometry for SN 2014J from 277 days to 1181 days past the B-band maximum light. The reprocessing of electrons and X-rays emitted by the radioactive decay chain is needed to explain the significant flattening of both the F606W-band and the pseudo-bolometric light curves. The flattening confirms previous predictions that the late-time evolution of type Ia supernova luminosities requires additional energy input from the decay of 57Co. By assuming the F606W-band luminosity scales with the bolometric luminosity at ∼500 days after the B-band maximum light, a mass ratio is required. This mass ratio is roughly ∼3 times the solar ratio and favors a progenitor white dwarf with a mass near the Chandrasekhar limit. A similar fit using the constructed pseudo-bolometric luminosity gives a mass ratio . Astrometric tests based on the multi-epoch HST ACS/WFC images reveal no significant circumstellar light echoes in between 0.3 and 100 pc from the supernova.