Evidence for a Black Hole Remnant in the Type IIL Supernova 1979C

TL;DR

This paper analyzes long-term X-ray data of supernova SN 1979C, providing evidence for a black hole remnant based on its steady luminosity, which challenges previous models involving magnetars or dense winds.

Contribution

It presents the first long-term X-ray observational evidence suggesting a black hole remnant in a supernova, contrasting with existing magnetar or wind-driven models.

Findings

X-ray luminosity remains constant over 12 years.

Steady luminosity inconsistent with magnetar or wind models.

Possible black hole accretion source identified.

Abstract

We present an analysis of archival X-ray observations of the Type IIL supernova SN 1979C. We find that its X-ray luminosity is remarkably constant at (6.5+/-0.1) x 10^38 erg/s over a period of 12 years between 1995 and 2007. The high and steady luminosity is considered as possible evidence for a stellar-mass (~ 5-10Msun) black hole accreting material from either a supernova fallback disk or from a binary companion, or possibly from emission from a central pulsar wind nebula. We find that the bright and steady X-ray light curve is not consistent with either a model for a supernova powered by magnetic braking of a rapidly rotating magnetar, or a model where the blast wave is expanding into a dense circumstellar wind.