William Atkins
Wednesday, 27 August 2008 19:27
Science -
Space
Page 2 of 3
The space telescope was launched on June 11, 2008, at 16:05 GMT, aboard a Delta 2 7920-H rocket. From low-Earth orbit, the telescopes two primary instruments, the Large Area Telescope (LAT) and the GLAST Burst Monitor (GBM) were tested over the following two months.
The mission of
LAT will enable scientists to perform an all-sky survey of astrophysical and cosmological phenomena such as pulsars, active galactic nuclei, dark matter, and other high-energy sources.
The
GBM mission will allow astronomers to study gamma-ray bursts.
Now in August 2008, the observatory, through its LAT instrument, is showing the world a
“gamma-ray sky” full of
“glowing gas of the Milky Way, blinking pulsars, and a flaring galaxy billions of light-years away.”
The LAT’s “first-light” image is a compilation of 95 hours of observation of the telescope.
The NASA media release states,
“The image shows gas and dust in the plane of the Milky Way glowing in gamma rays due to collisions with accelerated nuclei called cosmic rays. The famous Crab Nebula and Vela pulsars also shine brightly at these wavelengths. These fast-spinning neutron stars, which form when massive stars die, were originally discovered by their radio emissions.”
Further,
“The image's third pulsar, named Geminga and located in Gemini, is not a radio source. It was discovered by an earlier gamma-ray satellite. Fermi is expected to discover many more radio-quiet pulsars, providing key information about how these exotic objects work. A fourth bright spot in the LAT image lies some 7.1 billion light-years away, far beyond our galaxy. This is 3C 454.3 in Pegasus, a type of active galaxy called a blazar. It's now undergoing a flaring episode that makes it especially bright.”
And,
“The LAT scans the entire sky every three hours when operating in survey mode, which will occupy most of the telescope's observing time during the first year of operations. These fast snapshots will let scientists monitor rapidly changing sources.”
Peter Michelson, Stanford University, said of the all-sky map,
“This is like the night sky at a Fourth of July celebration, but we're seeing it on a cosmic scale.” [New Scientist (subscription required): “
New 'Fermi' gamma-ray telescope makes first sky map”]
Continue to page three.
