The phrase "hole mass" refers to the total amount of matter or substance that is missing or absent from a specific area or object. It implies that there is a void or empty space where there should be material present. Full definition
It appears that the relationship between nuclear black hole mass and other properties of late - type galaxies remains to be understood. (greenbankobservatory.org)
The quasar, with its central black hole mass of 12 billion solar masses and the luminosity of 420 trillion suns, is at a distance of 12.8 billion light - years from Earth. (sciencedaily.com)
RX J1140.1 +0307 is such a galaxy — in fact, it is centered on one of the lowest black hole masses known in any luminous galactic core. (sciencedaily.com)