Several of these entities were discovered by the Nuker collaboration, and these entities' mass is related to the 4th or 5th power of the velocity dispersion according to the (*) M-sigma relation.
One team that discovered several of these entities is the namesake of a two-power-law to estimate surface brightness of galaxies. A rapidly growing one of these entities is found in the Phoenix Cluster. One method of measuring the mass of these entities sets mass equal to form factor times the radius of the broad-line region times the square of the root-mean-square velocity of gas near these objects all over G; that method is called reverberation mapping. Several of these entities were discovered by the Nuker collaboration, and these entities' mass is related to the 4th or 5th power of the velocity dispersion according to the (*) M-sigma relation. Bruce Balick and Robert Brown found a candidate for this kind of body in the Milky Way using the NRAO Green Bank interferometer; that object is Sagittarius A-star. These objects may accrete gas to become an active galactic nucleus. For 10 points, name these objects that are hundreds of thousands to billions of solar masses large and are found in the center of galaxies.
One team that discovered several of these entities is the namesake of a two-power-law to estimate surface brightness of galaxies.
supermassive black holes [prompt on “black holes”, “black holes at the center of galaxies” etc; accept active galactic nuclei or galactic nuclei until they’re mentioned]