Constraining the Stellar Mass Function in the Galactic Center via Mass Loss from Stellar Collisions

TL;DR

This study models stellar collision-induced mass loss in the Galactic center, constraining the present-day and initial mass functions based on observed X-ray luminosity and collision rates.

Contribution

It provides new constraints on the stellar mass function in the Galactic center by linking collision mass loss rates to observed X-ray emissions.

Findings

Mass loss rate sensitive to the present-day mass function.

Constraints on the minimum stellar mass and slope of the mass function.

Implications for initial mass function based on star formation scenarios.

Abstract

The dense concentration of stars and high velocity dispersions in the Galactic centre imply that stellar collisions frequently occur. Stellar collisions could therefore result in significant mass loss rates. We calculate the amount of stellar mass lost due to indirect and direct stellar collisions and find its dependence on the present-day mass function of stars. We find that the total mass loss rate in the Galactic centre due to stellar collisions is sensitive to the present-day mass function adopted. We use the observed x-ray luminosity in the Galactic centre to preclude any present-day mass functions that result in mass loss rates $> 10^{-5} \mathrm{M_{\odot} yr^{-1}}$ in the vicinity of $\sim 1"$. For present-day mass functions of the form, $dN/dM \propto M^{-\alpha}$, we constrain the present-day mass function to have a minimum stellar mass $\lesssim 7\mathrm{M_{\odot}}$ and a power law slope $\gtrsim 1.25$. We also use this result to constrain the initial mass function in the Galactic centre by considering different star formation scenarios.