spacetoday.net: Swift sees first gamma-ray bursts

Posted: Thu, Jan 6, 2005, 8:37 AM ET (1337 GMT)
Swift spacecraft illustration (NASA)

NASA's Swift gamma-ray observatory, launched last November, has seen its first gamma-ray bursts (GRBs), astronomers announced Wednesday. The spacecraft's Burst Alert Telescope detected its first GRB on December 17, while the instrument was still being calibrated, followed by three more on December 19 and one the following day. Astronomers were surprised by the number of bursts detected — they expected to see about two GRBs a week — and said they don't know yet if they were just lucky or if GRBs are more frequent than expected. Swift, launched November 20, is designed to quickly detect GRBs using the BAT and then orient itself towards the burst to study it with two other instruments. Swift will also relay the positions of GRBs it detects to the ground to allow other telescopes to quickly study it.