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Intersting too much new data : New Challenge open

The astrophysics community enthusiastically awaits the upcoming launch of the Gamma-ray Large Area Space Telescope (GLAST), the latest and most powerful gamma-ray telescope. But interpreting the huge amount of new data that GLAST will collect may prove difficult.

Until now, existing instruments have allowed astrophysicists to detect about 300 possible sources of gamma-rays in the universe, and scientists have had to analyze and classify these sources one by one. GLAST's increased sensitivity, 30 to 100 times greater than that of its predecessors, will allow the telescope to potentially detect thousands of new sources of gamma rays.

"We'll have a hard time identifying them," says Stanford Physicist Olaf Reimer. "We can't apply the individual approach for thousands of sources anymore. Researchers took 20 years to identify Geminga, the radio-quiet gamma ray pulsar, but we cannot spend 20 years on a single source again."

To address the scientific challenges GLAST will raise, Reimer and several colleagues organized a conference called "The Multi-messenger Approach to High-energy Gamma Ray Sources," which was held last July in Barcelona. This conference was the third in a series exclusively devoted to the problem of gamma-ray source identification. In a book to be published this June, based on the conference, Reimer suggests combining the established identification technique with a population-based statistical approach.

"The idea is to establish the characteristics of the populations hiding in the wells of new data," Reimer says. Then, researchers could proceed to single out the most appropriate candidates for new gamma-ray sources among those populations.

The problem with identifying new populations of gamma-ray sources is that astrophysicists do not know how the sources behave. "We know that active galactic nuclei occasionally flare, pulsars pulse, binaries have characteristic orbits… these are clear signatures," Reimer says. "But for new galactic phenomena, we don't have that knowledge."

Reimer admits this new scientific problem is tough. "But we have to address it, because you can only make science if you know what you're dealing with in the sky," he says.

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About GLAST Mission-
GLAST Mission is part of NASA's Office of Space and Science Strategic Plan, with launch anticipated in 2006. GLAST is a next generation high-energy gamma-ray observatory designed for making observations of celestial gamma-ray sources in the energy band extending from 10 MeV to more than 100 GeV. It follows in the footsteps of the CGRO-EGRET experiment, which was operational between 1991 and 1999.
The key scientific objectives of the GLAST mission are:
To understand the mechanisms of particle acceleration in AGNs, pulsars, and SNRs. This understanding is a key to solving the mysteries of the formation of jets, the extraction of rotational energy from spinning neutron stars, and the dynamics of shocks in SNRs.
Resolve the gamma-ray sky: unidentified sources and diffuse emission.Interstellar emission from the Milky Way and a large number of unidentified sources are prominent features of the gamma-ray sky.
Determine the high-energy behavior of gamma-ray bursts and transients. Variability has long been a powerful method to decipher the workings of objects in the Universe on all scales. Variability is a central feature of the gamma-ray sky.
Probe dark matter and early Universe. Observations of gamma-ray AGN serve to probe supermassive black holes through jet formation and evolution studies, and provide constraints on the star-formation rate at early epochs through photon-photon absorption over extragalactic distances. There are also the possibilities of observing monoenergetic gamma-ray "lines" above 30 GeV from supersymmetric dark matter interaction; detecting decays of relics from the very early Universe, such as cosmic strings or evaporating primordial black holes; or even using gamma-ray bursts to detect quantum gravity effects.
The GLAST LAT has a field of view about twice as wide (more than 2.5 steradians), and sensitivity about 50 times that of EGRET at 100 MeV and even more at higher energies. Its two year limit for source detection in an all-sky survey is 1.6 x 10-9 photons cm-2 s-1 (at energies> 100 MeV). It will be able to locate sources to positional accuracies of 30 arc seconds to 5 arc minutes. Yet, it is a relatively small and inexpensive mission, which will be able to be launched on a Delta II rocket.

The Advisory Team-
GLAST Senior Scientist Advisory Committee has members from the chief institutions in the collaboration.

William Atwood, Santa Cruz Institute for Particle Physics
Guido Barbiellini, INFN and University of Trieste
Ronaldo Bellazzini, INFN and University of Pisa
Elliott Bloom, Stanford Linear Accelerator Center
Toby Burnett, University of Washington
Per Carlson, Royal Institute of Technology (KTH), Stockholm
Richard Dubois, Stanford Linear Accelerator Center
Neil Gehrels, NASA Goddard Space Flight Center
Isabelle Grenier, Commissariat à l'Énergie Atomique, Saclay
Neil Johnson, U. S. Naval Research Laboratory, E. O. Hulbert Center for Space Research
Robert Johnson, Santa Cruz Institute for Particle Physics
Tune Kamae, Stanford Linear Accelerator Center
Peter Michelson, Stanford University, W. W. Hansen Experimental Physics Laboratory
Jonathan F. Ormes, NASA Goddard Space Flight Center
Steve Ritz, NASA Goddard Space Flight Center
Hartmut Sadrozinski, Santa Cruz Institute for Particle Physics
David Smith, Centre d'Études Nucléaires de Bordeaux Gradignan
David Thompson, NASA Goddard Space Flight Center
Kent Wood, U. S. Naval Research Laboratory, E. O. Hulbert Center for Space Research

Some Other Important links-
Further Information About education-
http://www-glast.sonoma.edu/
Nasa's Glast website-
http://glast.gsfc.nasa.gov/
Link To Other Glast websites-
http://www-glast.stanford.edu/links.html
Nasa"s launch Schedule-
http://www.nasa.gov/missions/highlights/schedule.html
The GLUST Burst Monitor-
http://f64.nsstc.nasa.gov/gbm/

Release link: http://today.slac.stanford.edu/feature/2007/data-glast.asp