Star Formation in the Extreme Galactic Center Environment

TL;DR

This paper reviews star formation in the Galactic Center's dense environment, highlighting the complex interplay of turbulence, magnetic fields, and tidal forces that inhibit but also trigger star formation in specific regions.

Contribution

It synthesizes recent observations and hypotheses about the mechanisms and conditions influencing star formation in the Central Molecular Zone and the central parsec.

Findings

Star formation is suppressed by turbulence, magnetic fields, and tidal forces.

Trigger mechanisms like cloud compression are crucial for star formation.

Recent orbital data constrains where and how star formation occurs in the CMZ.

Abstract

Copious star formation occurs in the dense Central Molecular Zone (CMZ) of our Galaxy, but at a much smaller rate than occurs in a comparable mass of molecular gas in the Galactic disk. The combination of large turbulent velocity dispersions, a relatively strong magnetic field, and a strong tidal field all contribute to inhibiting star formation (SF) in different ways in different CMZ locations. Nonetheless, there are spectacular displays of recent and ongoing SF in the CMZ, including massive young stellar clusters, sites of abundant SF in progress, and numerous spots of protostellar or YSO activity. The presence of giant molecular clouds in the CMZ that are almost entirely devoid of SF indicates that SF requires a trigger that is not present everywhere. The dominant provocation of SF is likely to be cloud compression, either by large-scale shocks or by orbital motion of clouds into a region of enhanced tidal compression and/or enhanced external pressure. Recent hypotheses for where and how SF takes place in the CMZ are constrained by the recent orbital determinations of the massive Arches and Quintuplet clusters. Star formation in the central parsec is subject to a very different set of physical conditions, and is less well understood, but is important for the co-evolution of the central black hole and the nuclear star cluster.