Where Did You Come From? A Supermassive Black Hole Detected by JWST in a Diminutive UCD

Ultra-compact dwarf galaxies (UCDs) bridge the gap between globular clusters and dwarf galaxies, often appearing as the most massive star clusters within a galaxy. However, their origins are far more complex. Most UCDs have a dynamical mass-to-light ratio that is higher than can be explained by their stellar population, suggesting they are more than just massive star clusters. Previous detections of central supermassive black holes in some of the most massive UCDs indicate that some of these objects were once larger nucleated dwarf galaxies that lost their diffuse stellar envelopes to tidal interactions within a galaxy cluster environment. Technological and observational constraints have restricted searches for black holes to only the biggest and brightest UCDs; to truly understand the evolutionary connections between UCDs and dwarf galaxies, smaller and dimmer UCDs must be probed for central black holes. The presence, or lack thereof, of a central black hole will indicate the origins of those systems. In this talk I will discuss the results of a 2.2 million solar mass black hole in a UCD observed by the James Webb Space Telescope. A central black hole of this mass implies that the progenitor was probably a small spiral galaxy roughly one tenth of our own.