Eleven years of radio monitoring of the Type IIn supernova SN 1995N

TL;DR

This paper reports 11 years of radio monitoring of supernova SN 1995N, analyzing its emission mechanisms and physical conditions using multi-wavelength data, with a focus on free-free absorption dominance.

Contribution

It provides a comprehensive long-term radio dataset and models the supernova's emission, clarifying the absorption processes and physical parameters of the shocked regions.

Findings

FFA is the dominant absorption mechanism.

Model fits yield reasonable physical parameters.

Multi-wavelength data constrain the shocked ejecta and CSM conditions.

Abstract

We present radio observations of the optically bright Type IIn supernova SN 1995N. We observed the SN at radio wavelengths with the Very Large Array (VLA) for 11 years. We also observed it at low radio frequencies with the Giant Metrewave Radio Telescope (GMRT) at various epochs within $6.5-10$ years since explosion. Although there are indications of an early optically thick phase, most of the data are in the optically thin regime so it is difficult to distinguish between synchrotron self absorption (SSA) and free-free absorption (FFA) mechanisms. However, the information from other wavelengths indicates that the FFA is the dominant absorption process. Model fits of radio emission with the FFA give reasonable physical parameters. Making use of X-ray and optical observations, we derive the physical conditions of the shocked ejecta and the shocked CSM.