The Rise and Peak of the Luminous Type IIn SN 2017hcc/ATLAS17lsn from ASAS-SN and Swift UVOT Data

TL;DR

This paper reports detailed observations of the luminous Type IIn supernova SN 2017hcc/ATLAS17lsn, including its rise, peak brightness, spectral energy distribution, and energy output, providing insights into its physical properties.

Contribution

It presents the first comprehensive multi-wavelength observational analysis of SN 2017hcc/ATLAS17lsn, highlighting its extreme luminosity and detailed light curve characteristics.

Findings

Peak absolute magnitude of -20.7 mag

Bolometric luminosity of 1.3×10^{44} erg/s

Estimated rise time of 27 days

Abstract

We present observations of the rise and peak of the Type IIn supernova SN 2017hcc/ATLAS17lsn obtained by the All-Sky Automated Survey for Supernovae (ASAS-SN) and Swift UVOT. The light curve of SN 2017hcc/ATLAS17lsn peaks at $V\simeq 13.7$ mag, which from the estimated redshift of the host galaxy ($z=0.0168$, $D\simeq 73$ Mpc) implies an absolute peak magnitude $M_{V,peak} \simeq -20.7$ mag. The near-UV to optical spectral energy distribution of SN 2017hcc/ATLAS17lsn from Swift UVOT is consistent with a hot, but cooling blackbody with $\rm T_{bb}\simeq 16500$ K on Oct. 28.4 and $\rm T_{bb} \simeq 11700$ K on Nov. 19.6. The estimated peak bolometric luminosity $L_{bol, peak}\simeq 1.3\times 10^{44}$ erg s$^{-1}$ makes SN2017hcc/ATLAS17lsn one of the most luminous Type IIn supernovae studied to date. From the bolometric light curve we constrain the risetime to be $\sim 27$ days and the total radiated energy of the event to date is $4\times 10^{50}$ erg.