Black Hole Formation in the Lower Mass Gap through Mergers and Accretion in AGN Disks

Understand

The heaviest neutron stars and lightest black holes expected to be produced by stellar evolution leave the mass-range $2.2$ M$_{\odot}\lesssim m \lesssim 5$ M$_\odot$ largely unpopulated.

• Objects found in this so-called lower mass gap likely originate from a distinct astrophysical process.
• Such an object, with mass $2.6$ M$_\odot$ was recently detected in the binary merger GW190814 through gravitational waves by LIGO/Virgo.
• Here we show that black holes in the mass gap are naturally assembled through mergers and accretion in AGN disks, and can subsequently participate in additional mergers.