Hydrodynamic Evolution and Detectability of Nova Remnants in the Galactic Center

TL;DR

This study uses hydrodynamical simulations to assess the detectability of nova remnants in the Galactic Center across multiple wavelengths, providing insights into their observability with current and future telescopes.

Contribution

The paper presents the first comprehensive hydrodynamical modeling of nova remnants in the GC environment, estimating their multiwavelength detectability and detection probabilities.

Findings

Approximately 20% chance to detect remnants in X-ray with current telescopes.

Most detectable remnants peak in X-ray and Paschen-$\alpha$ bands.

Detection windows range from weeks to hundreds of years.

Abstract

Thousands of X-ray sources have been detected in the Galactic center (GC), most believed to be cataclysmic variables (CVs). As a potential probe of the old stellar population, in particular CVs, the existence and detectability of novae in the GC remain elusive, due to the prohibitive extinction toward the GC and their relatively low occurrence rate. Nova remnants evolving in the characteristic hot ($T\sim{10^{6}~\rm K}$) and dense ($n_e\sim{10~\rm cm^{-3}}$) interstellar medium in the GC may shed light on recent novae and provide useful insight on the GC ecosystem. In this work, we perform hydrodynamical simulations of putative nova remnants in the GC environment and calculate their time-dependent multiwavelength emission to estimate the detectability. Among 79 models sampling the nova parameter space (primarily ejecta mass and velocity), 6, 44, and 51 modelled nova remnants are detectable at their X-ray, radio, and Paschen-$\alpha$ maximum, respectively, for existing Chandra, VLA, and HST observations of the GC. The predicted peak luminosities are $\sim10^{32}~\rm erg~s^{-1}$, $\sim10^{31}~\rm erg~s^{-1}$, and $\sim10^{36}~\rm erg~s^{-1}$ in these three bands and the detectable window ranges from weeks to notably hundred years. By specifying a CV population of the nuclear star cluster, we estimate the probability of detecting at least one remnant to be 20%, 8%, and 18% in X-rays, radio, and Pa$\alpha$. The nova remnant would be best resolved in the X-ray band. Our study highlights the potential for detecting nova remnants through further observations, leveraging JWST and the potentially forthcoming AXIS and SKA.