A Census of Virgo Ultra-Compact Dwarf Galaxies for Central Black Holes

Abstract

Supermassive black hole (BH) detections in ultra-compact dwarf galaxies (UCDs) indicate that these objects are the nuclei of formerly larger dwarf galaxies that underwent tidal stripping. Ground-based telescopes are limited in their capacity to observe dim, compact objects such as UCDs, however the James Webb Space Telescope has expanded the field. In this work, integral field unit spectroscopy data is radially binned, optimizing signal-to- noise to measure reliable stellar kinematics in the cores of six UCDs. Velocity dispersion measurements were then used in dynamical modelling to determine the presence of a central BH affecting the kinematics. The results of this work found four of the six UCDs had central BH measurements at a 1σ significance, although dynamical modelling did suggest all of them had a BH. Adding these results to the five previously probed, 11 UCDs have been analyzed and nine have signatures of central BHs.