Hunting Gamma-Ray Bursts at Palomar Observatory
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. HPWREN’s microwave link has increased the Observatory’s
bandwidth by 28 times. This allows remote astronomers to rapidly point the newly
automated telescopes and their high performance digital cameras in real time to
catch these and other elusive events.
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 161 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.
Related Links
High Performance Wireless Research and Education Network