Constraining the number of compact remnants near Sgr A*

Abstract

Due to dynamical friction stellar mass black holes and neutron stars are expected to form high density cusps in the inner parsec of our Galaxy. These compact remnants, expected to number around 20000, may be accreting cold dense gas present there, and give rise to potentially observable X-ray emission. Here we build a simple but detailed time-dependent model of such emission. We find that at least several X-ray sources of this nature should be detectable with Chandra at any one time. Turning this issue around, we also ask a question of what current observational constraints might be telling us about the total number of compact remnants. A cusp with ~ 40 thousand black holes over-predicts the number of discrete sources and the total X-ray luminosity of the inner parsec, and is hence ruled out. Future observations of the distribution and orbits of the cold ionised gas in the inner parsec of Sgr A* will put tighter constraints on the cusp of compact remnants.

9 pages, 3 Postscript figures

References in corpus (2)

• Stellar remnants in galactic nuclei: mass segregation
• Galactic Centre stellar winds and Sgr A* accretion

Cited by in corpus (8)

• Gravitational waves from scattering of stellar-mass black holes in galactic nuclei
• Simulations of the formation of stellar discs in the Galactic centre via cloud-cloud collisions
• Millisecond pulsar interpretation of the Galactic center gamma-ray excess
• Red giant stellar collisions in the Galactic Centre
• Production of Hypervelocity Stars through Encounters with Stellar-Mass Black Holes in the Galactic Centre
• Star formation in accretion discs : from the Galactic Center to Active Galactic Nuclei
• X-rays from cusps of compact remnants near galactic centres
• Dynamics of galactic nuclei: Mass segregation and collisions