Late-Time Observations of Type Ia Supernova SN 2014J with the Hubble Space Telescope Wide Field Camera 3

TL;DR

This study presents late-time HST observations of SN 2014J, confirming previous findings, analyzing light echoes, and strengthening the correlation between supernova luminosity and decline rates by direct filter comparison.

Contribution

It provides new photometry of SN 2014J at late times, compares it with previous data, and confirms the luminosity-decline rate correlation with reduced systematic uncertainties.

Findings

SN 2014J's photometry is consistent with previous measurements in some filters.

Light echoes are spatially resolved but do not contaminate photometry.

More luminous SNe Ia have slower decline rates, supporting existing correlations.

Abstract

Recent works have studied the late-time light curves of Type Ia supernovae (SNe Ia) when these were older than 500 days past B-band maximum light. Of these, SN 2014J, which exploded in the nearby galaxy M82, was studied with the Advanced Camera for Surveys onboard the Hubble Space Telescope (HST) by Yang et al. Here, I report complementary photometry of SN 2014J taken with the HST Wide Field Camera 3 when it was ~360-1300 days old. My F555W measurements are consistent with the F606W measurements of Yang et al., but the F438W measurements are ~1 mag fainter than their F475W measurements. I corroborate their finding that even though SN 2014J has spatially resolved light echoes, its photometry is not contaminated by an unresolved echo. Finally, I compare the F438W and F555W light curves of SN 2014J to those of the other late-time SNe Ia observed to date and show that more intrinsically luminous SNe have slower light-curve decline rates. This is consistent with the correlation claimed by Graur et al., which was based on a comparison of pseudo-bolometric light curves. By conducting a direct comparison of the late-time light curves in the same filters, I remove any systematic uncertainties introduced by the assumptions that go into constructing the pseudo-bolometric light curves, thus strengthening the Graur et al. claim.