Researchers at the NASA's Swift, Hubble Space Telescope and Chandra X-ray Observatory have teamed up to study one of the most puzzling cosmic blasts observed till date.
On March 28, 2011, Swift's Burst Alert Telescope discovered a source in the far northern sky constellation Draco, when it erupted with a series of powerful X-ray blasts.
Swift determined a position for the explosion which is now referred to as gamma-ray burst (GRB) 110328A. Astronomers across the world were then informed about this unusual phenomenon and dozens of telescopes focused at the spot as mentioned by the satellite.
They quickly noticed that very near to the Swift position, a small, distant galaxy appeared. A deep image taken by Hubble on April 4 pinpoints the source of the explosion at the center of this galaxy, which lies 3.8 billion light-years away.
NASA's Chandra X-ray Observatory then made a four-hour long exposure of the puzzling source on the same day. The image, which locates the object 10 times more precisely than Swift can, shows that it lies at the center of the galaxy Hubble imaged.
We know of objects in our own galaxy that can produce repeated bursts, but they are thousands to millions of times less powerful than the bursts we are seeing now. This is truly extraordinary, stated Andrew Fruchter at the Space Telescope Science Institute in Baltimore.
Astronomers across the world said that they have never seen anything this bright, long-lasting and variable before.
Usually, gamma-ray bursts mark the destruction of a massive star, but flaring emission from these events never lasts more than a few hours.
We have been eagerly awaiting the Hubble observation, said Neil Gehrels, the lead scientist for Swift at NASA's Goddard Space Flight Center in Greenbelt, Md. The fact that the explosion occurred in the center of a galaxy tells us it is most likely associated with a massive black hole. This solves a key question about the mysterious event.
Although research is ongoing, astronomers are still puzzled at the phenomenon.
Previously, there have been several instances when stars disrupted by supermassive black holes have been detected, but none have shown the X-ray brightness and variability seen in GRB 110328A. The current source has repeatedly flared and has, in fact, brightened more than five times since April 3, 2011.