Star-formation in nuclear clusters and the origin of the Galactic Center apparent core distribution

TL;DR

This paper investigates how continuous in-situ star formation influences the structure and evolution of nuclear stellar clusters, particularly in the context of the Milky Way's center, revealing age-dependent spatial distributions.

Contribution

It demonstrates that in-situ star formation can produce NSCs with properties similar to the Milky Way's, including age-segregated structures and core-cusp variations.

Findings

In-situ star formation leads to Milky Way-like NSC properties.

Younger stars show core-like distributions inward and cuspy outskirts.

Older populations tend toward a steady-state Bahcall-Wolf cusp.

Abstract

Nuclear stellar cluster (NSCs) are known to exist around massive black holes (MBHs) in galactic nuclei. Two formation scenarios were suggested for their origin: Build-up of NSCs and Continuous in-situ star-formation. Here we study the effects of star formation on the build-up of NSCs and its implications for their long term evolution and their resulting structure. We show that continuous star-formation can lead to the build-up of an NSC with properties similar to those of the Milky-way NSC. We also find that the general structure of the old stellar population in the NSC with in-situ star-formation could be very similar to the steady-state Bahcall-Wolf cuspy structure. However, its younger stellar population do not yet achieve a steady state. In particular,formed/evolved NSCs with in-situ star-formation contain differential age-segregated stellar populations which are not yet fully mixed. Younger stellar populations formed in the outer regions of the NSC have a cuspy structure towards the NSC outskirts, while showing a core-like distribution inwards; with younger populations having larger core sizes.