Main Question or Discussion Point
Signature of an Intermediate-Mass Black Hole in the Central Molecular Zone of Our Galaxy - arXiv 1512.04661 (free reprint)Signs of second largest black hole in the Milky Way
Astronomers assume that this possible “intermediate mass” black hole is a key to understanding the birth of supermassive black holes located in the centers of galaxies.
Astronomers using the Nobeyama 45-meter radio telescope have detected signs of an invisible black hole with a mass of 100,000 times the mass of the Sun around the center of the Milky Way. The team assumes that this possible “intermediate mass” black hole is a key to understanding the birth of the supermassive black holes located in the centers of galaxies.
Apparently there was another thread with a similar title ("Second black hole may lurk at Milky Way's heart") from June 2003, but it really had nothing to do with a second intermediate-mass or super-massive black hole.
It is also presumptuous for the above article to state that this possible intermediate-mass black hole is the "second largest black hole in the Milky Way," because it presumes to know the mass of all the other (if any) intermediate-mass black holes in the Milky Way galaxy.