Black hole triggered star formation in the dwarf galaxy Henize 2-10

TL;DR

This study provides observational evidence that a black hole outflow in the dwarf galaxy Henize 2-10 has triggered recent star formation, highlighting a positive feedback mechanism in such galaxies.

Contribution

First direct evidence showing black hole outflows can trigger star formation in a dwarf galaxy, using high-resolution optical observations of Henize 2-10.

Findings

Detected a 150 pc ionized filament connecting black hole and star-forming region

Spectroscopy shows sinusoid-like velocity structure indicating a precessing bipolar outflow

Black hole outflow likely initiated recent star formation in Henize 2-10

Abstract

Black hole driven outflows have been observed in some dwarf galaxies with active galactic nuclei (1), and likely play a role in heating and expelling gas (thereby suppressing star formation), as they do in larger galaxies (2). The extent to which black hole outflows can trigger star formation in dwarf galaxies is unclear, because work in this area has hitherto focused on massive galaxies and the observational evidence is scarce (3,4,5). Henize 2-10 is a dwarf starburst galaxy previously reported to have a central massive black hole (6,7,8,9), though that interpretation has been disputed since some aspects of the observational evidence are also consistent with a supernova remnant (10,11). At a distance of ~9 Mpc, it presents an opportunity to resolve the central region and determine if there is evidence for a black hole outflow impacting star formation. Here we report optical observations of Henize 2-10 with a linear resolution of a few parsecs. We find a ~150 pc long ionized filament connecting the region of the black hole with a site of recent star formation. Spectroscopy reveals a sinusoid-like position-velocity structure that is well described by a simple precessing bipolar outflow. We conclude that this black hole outflow triggered the star formation.