Dynamics of Astrophysical Bubbles and Bubble-Driven Shocks: Basic Theory, Analytical Solutions and Observational Signatures

TL;DR

This paper develops a theoretical framework for understanding the dynamics of bubbles and shocks in the interstellar medium driven by astrophysical sources, providing analytical solutions for different energy output histories and predicting observable signatures.

Contribution

It introduces analytical solutions for bubble-driven shocks based on source luminosity laws, expanding beyond traditional blast wave models and applicable to various astrophysical phenomena.

Findings

Derived conditions for shock existence under different luminosity laws

Analytical solutions for shocks with self-similar and finite-time energy input

Predicted observational signatures for astrophysical bubble-driven shocks

Abstract

Bubbles in the interstellar medium are produced by astrophysical sources, which continuously or explosively deposit large amount of energy into the ambient medium. These expanding bubbles can drive shocks in front of them, which dynamics is markedly different from the widely used Sedov-von Neumann-Taylor blast wave solution. Here we present the theory of a bubble-driven shock and show how its properties and evolution are determined by the temporal history of the source energy output, generally referred to as the source luminosity law, $L(t)$. In particular, we find the analytical solutions for a driven shock in two cases: the self-similar scaling $L\propto (t/t_s)^p$ law (with $p$ and $t_s$ being constants) and the finite activity time case, $L\propto (1-t/t_s)^{-p}$. The latter with $p>0$ describes a finite-time-singular behavior, which is relevant to a wide variety of systems with explosive-type energy release. For both luminosity laws, we derived the conditions needed for the driven shock to exist and predict the shock observational signatures. Our results can be relevant to stellar systems with strong winds, merging neutron star/magnetar/black hole systems, and massive stars evolving to supernovae explosions.