A Multi-Wavelength View on the Rapidly-Evolving Supernova 2018ivc: An Analog of SN IIb 1993J but Powered Primarily by Circumstellar Interaction

TL;DR

SN 2018ivc is a peculiar supernova exhibiting characteristics of both SNe IIP and IIb, with multi-wavelength observations revealing that its emission is mainly powered by interaction with circumstellar material, indicating a transitional evolutionary stage.

Contribution

This study provides the first multi-wavelength analysis of SN 2018ivc showing it is primarily powered by SN-CSM interaction, bridging the gap between SNe IIP and IIb in binary evolution.

Findings

SN 2018ivc's synchrotron emission resembles SN IIb 1993J.

Its emission is mainly driven by ejecta-CSM interaction.

Progenitor's mass-loss history suggests a link between SNe IIP and IIb/Ib/Ic.

Abstract

SN 2018ivc is an unusual type II supernova (SN II). It is a variant of SNe IIL, which might represent a transitional case between SNe IIP with a massive H-rich envelope, and IIb with only a small amount of the H-rich envelope. However, SN 2018ivc shows an optical light curve evolution more complicated than canonical SNe IIL. In this paper, we present the results of prompt follow-up observations of SN 2018ivc with the Atacama Large Millimeter/submillimeter Array (ALMA). Its synchrotron emission is similar to that of SN IIb 1993J, suggesting that it is intrinsically an SN IIb-like explosion of a He star with a modest (~0.5 - 1 Msun) extended H-rich envelope. Its radio, optical, and X-ray light curves are explained primarily by the interaction between the SN ejecta and the circumstellar material (CSM); we thus suggest that it is a rare example (and the first involving the `canonical' SN IIb ejecta) for which the multi-wavelength emission is powered mainly by the SN-CSM interaction. The inner CSM density, reflecting the progenitor activity in the final decade, is comparable to that of SN IIb 2013cu that showed a flash spectral feature. The outer CSM density, and therefore the mass-loss rate in the final ~200 years, is larger than that of SN 1993J by a factor of ~5. We suggest that SN 2018ivc represents a missing link between SNe IIP and IIb/Ib/Ic in the binary evolution scenario.