Transients by Black Hole Formation from Red Supergiants: Impact of Dense Circumstellar Matter

TL;DR

This study uses radiation hydrodynamical simulations to analyze failed supernovae from red supergiants with dense circumstellar matter, revealing prolonged early emission that aids detection.

Contribution

It introduces a detailed simulation framework for failed supernovae with dense CSM, highlighting the impact on early emission and detection prospects.

Findings

Early emission peaks at 10^7-10^8 L_sun in optical/UV

Dense CSM prolongs shock breakout/cooling emission

Detection prospects improve with upcoming wide-field surveys

Abstract

Failed supernovae (SNe), which are likely the main channel for forming stellar-mass black holes, are predicted to accompany mass ejections much weaker than typical core-collapse SNe. We conduct a grid of one-dimensional radiation hydrodynamical simulations to explore the emission of failed SNe from red supergiant progenitors, leveraging recent understanding of the weak explosion and the dense circumstellar matter (CSM) surrounding these stars. We find from these simulations and semi-analytical modeling that diffusion in the CSM prolongs the early emission powered by shock breakout/cooling. The early emission has peak luminosities of $\sim 10^7$-$10^8~L_\odot$ in optical and UV, and durations of days to weeks. The presence of dense CSM aids detection of the early bright peak from these events via near-future wide-field surveys such as Rubin Observatory, ULTRASAT and UVEX.