The luminous Type IIN supernova SN 2017hcc: Infrared bright, X-ray and radio faint

TL;DR

This study presents multiwavelength observations of supernova SN 2017hcc, revealing late-time IR dominance, complex mass-loss history, and an asymmetric circumstellar environment, with faint X-ray and radio emissions.

Contribution

It provides new insights into the mass-loss behavior and circumstellar environment of a luminous Type IIN supernova through comprehensive multiwavelength data analysis.

Findings

IR emission dominates the spectral energy distribution at late times

Mass-loss rate declined from 0.1 to 0.02 solar masses per year over a decade

Progenitor experienced an enhanced mass-loss event before explosion

Abstract

We present multiwavelength observations of supernova (SN) 2017hcc with the Chandra X-ray telescope and the X-ray telescope onboard Swift (Swift-XRT) in X-ray bands, with the Spitzer and the TripleSpec spectrometer in near-infrared (IR) and mid-IR bands and with the Karl G. Jansky Very Large Array (VLA) for radio bands. The X-ray observations cover a period of 29 to 1310 days, with the first X-ray detection on day 727 with the Chandra. The SN was subsequently detected in the VLA radio bands from day 1000 onwards. While the radio data are sparse, synchrotron-self absorption is clearly ruled out as the radio absorption mechanism. The near- and the mid-IR observations showed that late time IR emission dominates the spectral energy distribution. The early properties of \snhcc\ are consistent with shock breakout into a dense mass-loss region, with $\dot M \sim 0.1 M_\odot \rm yr^{-1}$ for a decade. At few 100 days, the mass-loss rate declined to $\sim 0.02 M_\odot \rm yr^{-1}$, as determined from the dominant IR luminosity. In addition, radio data also allowed us to calculate a mass-loss rate at around day 1000, which is two orders of magnitude smaller than the mass-loss rate estimates around the bolometric peak. These values indicate that the SN progenitor underwent an enhanced mass-loss event a decade before the explosion. The high ratio of IR to X-ray luminosity is not expected in simple models and is possible evidence for an asymmetric circumstellar region.