|
||
|
||
|
||
Pasadena, CA
|
|
|
|
 EMAIL ARTICLE LINK TO ARTICLE
 PRINT ARTICLE |
| Article Published: Friday, September 12, 2003 - 7:16:44 PM PST |
 |
X-ray flashes emerge from existing galaxies Scientists find source of blasts PASADENA -- The mysterious energy blasts from space known as X-ray flashes, first identified in 2001, now have galaxies to call home, Caltech and Harvard astronomers announced this week. The discovery quells a major controversy by proving X-ray flashes emerge from existing galaxies and are not the death throes of stars exploding in the early universe. X-ray flashes come from random areas of the sky and last for tens to hundreds of seconds. Scientists had speculated the flashes were ancient gamma ray bursts, the bright eruptions generated when a massive star explodes into a supernova. Gamma ray bursts from the earliest supernovas in the universe could lose so much energy on their long journey to Earth that they would shift down the spectrum to X-rays. That was the going theory, until a cell phone owned by Caltech graduate student Alicia Soderberg rang last September. Astronomers around the world receive e-mail messages when the High Energy Transient Explorer satellite detects new bursts or flashes. Soderberg got notice of an X-ray flash via cell phone on Sept. 3, 2002. Within seven hours, Soderberg and her adviser, Caltech astronomy professor Shri Kulkarni, had the 200-inch telescope at Palomar Observatory pointed toward the arc of sky where the flash appeared. They made the first detection of a fading visible "afterglow' from the source of an X-ray flash, likely a massive exploding star, and measured the distance to the source 2.6 billion light years. "I was very excited. I could not sleep for three days,' Soderberg said. Follow-up observations with the Very Large Array, radio telescopes in New Mexico, showed the source galaxy is actually four interacting galaxies with a history of lots of star formation, Soderberg said Thursday from the international conference in New Mexico where she presented her results. Understanding how X-ray flashes fit into the field of cosmic explosions will advance understanding of the physics of the universe and the birth of black holes, Kulkarni said. In a separate study, a team of astronomers relied on the Hubble Space Telescope and Chandra X-ray Observatory to show two X-ray flashes came from "faint blue galaxies' about 6 billion to 11 billion light years from Earth. "Now that the very distant origin has been ruled out, X-ray flashes could be due to exploding massive stars, just like gamma ray bursts,' said Josh Bloom of the Harvard-Smithsonian Center for Astrophysics, lead author of the study. "But the explosion from an X-ray flash would need to contain less matter or less energy than a typical gamma-ray burst,' Bloom added. The unanswered question is whether X-ray flashes are somehow poorer cousins of gamma ray bursts, or simply gamma ray bursts seen from a different perspective, Kulkarni said. "We learned so much from the one localized as a result of the Caltech work I think there's an excellent chance we will have enormously more information in next year to test this,' said MIT research scientist George Ricker, principal investigator for the HETE satellite. Becky Oskin can be reached at (626) 578-6300, Ext. 4451, or by e-mail at becky.oskin@sgvn.com. |
 RETURN TO TOP |
 |
||
Los Angeles Newspaper Group |
||
|
||
