Optical photometry of SN 2010jl

By modeling the visible-light data, we robustly show that the mass of the circumstellar material within ~10^16^cm of the progenitor of SN 2010jl was in excess of 10M_{sun}_. This mass was likely ejected tens of years prior to the SN explosion. Our modeling suggests that the shock velocity during shock breakout was ~6000km/s, decelerating to ~2600km/s about 2yr after maximum light.

Furthermore, our late-time NuSTAR and XMM spectra of the SN presumably provide the first direct measurement of SN shock velocity 2yr after the SN maximum light--measured to be in the range of 2000-4500km/s if the ions and electrons are in equilibrium, and >~2000km/s if they are not in equilibrium. This measurement is in agreement with the shock velocity predicted by our modeling of the visible-light data. Our observations also show that the average radial density distribution of the CSM roughly follows an r^-2^ law.

A possible explanation for the >~10M_{sun}_ of CSM and the wind-like profile is that they are the result of multiple pulsational pair instability events prior to the SN explosion, separated from each other by years.