Recorded Delivery
glipizide xl The discovery also delivers a blow to astronomers hoping to find conclusive evidence for an "intermediate-mass" black hole in M101 ULX-1. Such black holes would have masses roughly between 100 and 1000 times the mass of the Sun, placing them between normal stellar-mass black holes and the monstrous supermassive black holes that reside in the centers of galaxies. So far these objects have been frustratingly elusive, with potential candidates but no broadly-accepted detection. Ultra-luminous X-ray sources (ULXs) have been one of the main proposed hiding places for intermediate-mass black holes, and M101 ULX-1 was one of the most promising-looking contenders.