But Hjellming said energy bursts from the other microquasars fade more slowly, often lasting for weeks. A black hole is an extremely dense object with a gravitation field so powerful that not even light can escape. As a black hole pulls matter into its center, gas and dust are heated to millions of degrees. Many black holes acquire an envelope of gas and dust called an accretion disk. Matter from the disk streams constantly into the black hole, triggering a steady X-ray signal.
Black holes are usually in the center of quasars and characteristically have accretion disks.
The brief bursts from the V4641 Sgr black hole suggests it is not being fed constantly by a reservoir of matter from an accretion disk. This puzzles astronomers. The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.