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arXiv · 1704.01431

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

Yi Yang·Lifan Wang·Dietrich Baade·Peter J. Brown·Aleksandar Cikota·Misty Cracraft·Peter A. Hoflich·Justyn Maund·Ferdinando Patat·William B. Sparks·Jason Spyromilio·Heloise F. Stevance·Xiaofeng Wang·J. Craig Wheeler
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Abstract

The very nearby Type Ia supernova 2014J in M82 offers a rare opportunity to study the physics of thermonuclear supernovae at extremely late phases ($\gtrsim$800 days). Using the Hubble Space Telescope (HST), we obtained six 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 $^{57}$Co$\rightarrow ^{57}$Fe are 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 $^{57}$Co (Seitenzahl et al. 2009). By assuming the $F606W$-band luminosity scales with the bolometric luminosity at $\sim$500 days after the $B-$band maximum light, a mass ratio $^{57}$Ni/$^{56}$Ni$\sim$0.065$_{-0.004}^{+0.005}$ is required. This mass ratio is roughly $\sim$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 $^{57}$Ni/$^{56}$Ni$\sim$0.066$_{-0.008}^{+0.009}$. Astrometric tests based on the multi-epoch HST ACS/WFC images reveal no significant circumstellar light echoes in between 0.3 pc and 100 pc (Yang et al. 2017) from the supernova.

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Yi Yang, Lifan Wang, Dietrich Baade, Peter J. Brown, Aleksandar Cikota, Misty Cracraft, Peter A. Hoflich, Justyn Maund, Ferdinando Patat, William B. Sparks, Jason Spyromilio, Heloise F. Stevance, Xiaofeng Wang, J. Craig Wheeler. 2017-04-05. Late-time Flattening of Type Ia Supernova Light Curves: Constraints From SN 2014J in M82. https://doi.org/10.3847/1538-4357/aa9e4c

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