Miércoles 29 de Noviembre de 2006, Ip nº 181

Astronomers Spot Black Hole's Tantrum
An eruption of high-energy radiation recently signaled a tantrum unleashed by a black hole, astronomers announced today.

The event, which occurred near the crowded center of our galaxy, is a rare prize for astronomers.

The outburst was discovered Sept. 17 in data from the European Space Agency's orbiting gamma-ray observatory, Integral. Gamma rays are the highest form of radiation known.

The Integral astronomers notified other observatories, and a watch began for the gamma rays, X-rays and other wavelengths of light [image].

The outburst continued to rise in brightness for a few days before beginning a gradual decline that lasted for weeks. The pattern is called a light curve.

The light curve from this event suggests it was created by an eruption in a binary star system containing a Sun-like star and a black hole. In these systems, the gravity of the black hole is ripping the Sun-like star to pieces. As the doomed star orbits the black hole, it leaves its gas in what's called an accretion disk surrounding the black hole.

Occasionally, this accretion disk becomes unstable and collapses onto the black hole, causing the kind of outburst Integral witnessed.

Astronomers expect Integral to see such an outbursts only once every few years in our galaxy. The results of what is now called X-ray nova IGR J17497-2821 will be detailed in an upcoming issue of the Astronomy and Astrophysics.

  27/11/2006. Space.com.