February 4, 2004
HPWREN and the Palomar Observatory - Lifting the Veil on the Universe
One of the universe's most mysterious and explosive events is the
phenomenon known to astronomers as a Gamma-Ray Burst (GRB). They
are briefly bright enough to be visible billions of light years
away. They are difficult to study as they are short lived and take
place at seemingly random locations and times. To achieve an
understanding of what exactly a GRB is and why they occur, astronomers
need to act quickly to pin down their exact location and observe
them while they are exploding.
The existence of UCSD's High Performance Wireless Research and Education Network (HPWREN) has been absolutely critical to GRB research at the Palomar Observatory.
A recent example illustrates how this works. Gamma rays do not penetrate our atmosphere, so must first be detected by an orbiting satellite. The satellite detects the explosion but can only pin down its location to a relatively large region of the sky, about twice the diameter of the full moon. Within seconds, it sends an email with this location to all interested observers. In October of 2002, GRB021004 was detected by the HETE satellite. Upon receiving the announcement, Caltech astronomer Derek Fox used the HPWREN microwave link to seize control of the wide-field 48-inch Samuel Oschin Telescope and take an image of the field with the JPL/NEAT CCD camera just 9 minutes after the explosion began. The microwave link allowed the data to be rapidly transferred to Derek at Caltech. Analyzing it, he was able to pin down the exact location of the GRB (see figure), which he announced to astronomers world-wide only three hours after the burst occurred. This enabled the details of the afterglow's fading behavior to be observed around the world with unprecedented precision.
The study of this and more recent gamma-ray busts are starting to
provide a picture of what may be their cause - the explosion of a
massive star during the creation of a black hole in galaxies far
away - a particularly energetic example of a supernova explosion.
Modern electronic cameras used on astronomical telescopes generate
large volumes of data. The new QUEST camera on the Samuel Oschin
Telescope at Palomar has 170 million pixels, making it one of the
largest and most capable digital cameras in the world. HPWREN gives
the Observatory the bandwidth to allow astronomers to control and
process data from these powerful facilities quickly. Early astronomy
concentrated on moving and transient sources visible to the naked
eye. The advent of large telescopes and long exposures enabled us
to observe faint but mainly unchanging objects. Modern rapid-response
facilities enable us to observe the exciting but difficult realm
of very faint moving and transient objects.
-- Scott Kardel, Public Affairs Coordinator, Palomar Observatory
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