Evidence for Rapid Variability in the Optical Light Curve of the Type Ia SN 2014J

TL;DR

This study reports rapid optical brightness fluctuations in the nearby Type Ia supernova SN 2014J, observed with high time resolution, suggesting complex ejecta or environmental interactions influencing supernova light curves.

Contribution

First high-cadence optical monitoring of SN 2014J revealing rapid variability on timescales of minutes, indicating possible ejecta clumpiness or circumstellar interaction.

Findings

Detected 0.02-0.05 mag variability on 15-60 min timescales

Observed steeper decline in B-band than V-band

Noted decreasing decline rate over four nights

Abstract

We present results of high-cadence monitoring of the optical light curve of the nearby, Type Ia SN 2014J in M82 using the 2.3m Aristarchos telescope. $B$ and $V$-band photometry on days 15-18 after $t_{max}(B)$, obtained with a cadence of 2 min per band, reveals evidence for rapid variability at the 0.02-0.05 mag level on timescales of 15-60 min on all four nights, taking the red noise estimation at face value. The decline slope was measured to be steeper in the $B$-band than in $V$-band, and to steadily decrease in both bands from 0.15 mag/day (night 1) to 0.04 mag/day (night 4) in V and from 0.19 mag/day (night 1) to 0.06 mag/day (night 4) in B, corresponding to the onset of the secondary maximum. We propose that rapid variability could be due to one or a combination of the following scenarios: the clumpiness of the ejecta, their interaction with circumstellar material, the asymmetry of the explosion, or the mechanism causing the secondary maximum in the near-infrared light curve. We encourage the community to undertake high-cadence monitoring of future, nearby and bright supernovae to investigate the intraday behavior of their light curves.