We know of the existence of so-called stellar-mass black holes that form when stars die, and much heavier, supermassive black holes located the centers of galaxies. It has been an open question whether there is anything between these two populations, in the mass range of 10^2-10^5 solar masses. These, so-called intermediate mass black holes could be a missing link that connects the supermassive and stellar-mass black hole populations. The LIGO and Virgo gravitational wave observatories are sensitive to collisions of black holes with up to about 10^3 solar masses. They have already started seeing black holes that are more massive than what we expected from stars. I will outline possible ways intermediate mass black holes can form in the universe and discuss what we learned about the possible origin of such events from LIGO-Virgo's observations so far.
Gayathri V received her Ph.D from the Indian Institute of Technology Bombay, and currently works as postdoctoral fellow at the University of Florida. She is a member of the LIGO Scientific Collaboration. She has been a HOPE fellow in 2018. She chair's LIGO/Virgo/KAGRA's intermediate-mass black hole working group and led the collaborations' searches for such black holes. As part of LIGO she has been the recipient of a Special Breakthrough Prize in Fundamental Physics, the Gruber Cosmology Prize, the Princess of Asturias Award for Technical and Scientific Research, the Einstein Medal and the Bruno Rossi Prize.