Another Paper!

Posted by barb on May 13, 2004 in Science Musings |

As part of my work, I’ve helped out on several conference proceedings and science papers. The latest one now appears in the astro-ph archive. The paper will appear in The Astrophysical Journal in August.

The paper describes an upcoming NASA mission (along with collaborators from other organizations and countries) designed to study gamma-ray bursts (GRBs).

GRBs were discovered in the 1960s when the Vela satellites observed bright flashes of gamma-rays. The Vela satellites were designed to watch for violations of the Nuclear Test Ban Treaty, and were watching the Earth for gamma-rays, since nuclear explosions emit strongly in gamma-rays. Instead, they observed cosmic flashes of gamma-rays (known to come from outside the Earth by triangulation of signals recieved from the different satellites).

Since then, GRBs have been largely a mystery. In 1997, BeppoSAX, an Italian X-ray astronomy mission, discovered X-ray afterglow from a GRB. From the afterglow observations, we now know that at least one class of GRBs is cosmological in distance (i.e. they do not come from our solar system or even our galaxy — they originate at distances halfway across the known Universe).

Afterglow has now been observed in X-ray, optical, and radio wavelengths (and everything in between). The key to understanding what causes GRBs is in using multiwavelength observations to map the evolution of radiation from a GRB.

That’s where the Swift mission comes into the picture. It is a satellite that will carry a gamma-ray all-sky telescope that will watch for a GRB to take place. As soon as it detects a GRB, the satellite will autonomously slew to bring the burst into the fields-of-view of its X-ray and optical telescopes. Within about a minute, the burst will be observed by three different wavebands simulateously.

In the past year, GRBs have been tied to supernovae in distant galaxies, but there are still several mysteries to solve about GRBs. For example, there is another class of GRBs whose origin has not been explained, though may be related to two orbitting neutron stars that collide. Also, since GRBs lie at cosmological distances, they might be useful for studying the Universe at high redshift, when it was much, much younger than it is now.

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