High-Energy Shock Breakout from Supernovae and Gamma-ray Bursts

TL;DR

This paper develops a semi-analytic model for shock breakout emissions from supernovae and gamma-ray bursts, enhancing understanding of these explosive events and their detectability across different observational platforms.

Contribution

It introduces a more accurate semi-analytic approach focusing on thermal Bremsstrahlung radiation to model diverse SBO signals, improving upon previous analytical methods.

Findings

Stripped envelope SBOs can be detected serendipitously with survey telescopes.

Type Ia and II SBO detections require rapid X-ray follow-up triggered by gravitational wave or neutrino alerts.

Models help constrain explosion mechanisms and interpret historic and future SBO observations.

Abstract

Cosmic explosions play a critical role in a broad range of astrophysical fields. Although considerable progress has been made to understand the explosive engines and their progenitors, many of the details are not well understood. One of the most powerful electromagnetic probes of the explosive mechanism and the stellar progenitor is the first burst of photons emitted from this blastwave as it exits the stellar photosphere, known as shock breakout (SBO). Our understanding of SBO has evolved considerably in the past decade. Shock heating as the blastwave propagates through the star and circumstellar material can drastically alter this emission producing a much broader range of potential SBO signals than that predicted by standard analytical approaches. Here we present a semi-analytic approach to model this diverse SBO emission, focused on thermal Bremsstrahlung radiation, which more accurately captures the complexities in Nature over previous treatments. We calculate a range of signals for a range of supernova and gamma-ray burst types. Our models demonstrate how we can use these signals to place constraints on the nature of the explosive engines and better understand the role SBO can play in prompt gamma-ray bursts. We study the implications of these results to historic observations, Einstein Probe transients, and in the context of proposed missions. We find that stripped envelope events can be detected serendipitously with survey telescopes, but type Ia and II SBO detections require fast-pointing X-ray observations in response to early warning alerts from gravitational wave or neutrino detectors.