External Mass Accumulation onto Core Potentials: Implications for Star Clusters, Galaxies and Galaxy Clusters

TL;DR

This study investigates how non-point mass gravitational potentials, such as those of star clusters and galaxy halos, can collectively accrete gas from their surroundings, affecting star formation and black hole activity.

Contribution

It provides the first general analysis of gas accretion onto non-divergent core potentials using simulations and analytic methods, expanding understanding beyond point mass models.

Findings

Core potentials can efficiently accrete external gas under certain conditions.

Mass accumulation can trigger star formation in galaxy nuclei and star clusters.

Enhanced gas supply may increase central black hole accretion luminosity.

Abstract

Accretion studies have been focused on the flow around bodies with point mass gravitational potentials, but few general results are available for non-point mass distributions. Here, we study the accretion flow onto non-divergent, core potentials moving through a background medium. We use Plummer and Hernquist potentials as examples to study gas accretion onto star clusters, dwarf and large galaxy halos and galaxy clusters in a variety of astrophysical environments. The general conditions required for a core potential to collectively accrete large quantities of gas from the external medium are derived using both simulations and analytic results. The consequences of large mass accumulation in galaxy nuclei, dwarf galaxies and star clusters are twofold. First, if the gas cools effectively star formation can be triggered, generating new stellar members in the system. Second, if the collective potential of the system is able to alter the ambient gas properties before the gas is accreted onto the individual core members, the augmented mass supply rates could significantly alter the state of the various accreting stellar populations and result in an enhanced central black hole accretion luminosity.