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Session 101 - X-rays and X-ray Bursts.
Display session, Thursday, January 16
Metropolitan Ballroom,

[101.10] Gamma-ray Background in the GRATIS Balloon-borne Payload

J. W. Keck, W. W. Craig, C. J. Hailey, J. Hong, S. M. Kahn, R. McLean, M. J. Pivovaroff (Columbia Univ.), G. Sprehn, R. E. Wurtz, K. P. Ziock (LLNL), G. J. Jernigan (UC Berkeley), F. A. Harrison (UC Caltech), P. M. Lubin, M. Seiffert (UCSB)

The Gamma Ray Arcminute Telescope Imaging System (GRATIS) was flown from Alice Springs, Australia on October 17-18, 1995. The experiment consists of 36 individual one-dimensional coded-aperture telescopes with a field of view of 40 arcminutes in the imaging direction. Our highly collimated experiment is a sensitive probe of background fluctuations as a function of the attitude of the payload, as well as small-scale structure in the diffuse gamma-ray background. The long time at float allowed sampling of a wide range of altitudes and conditions. We discuss the current status of our background analysis, including the effect of payload attitude on the count rate. We delineate a model which describes the change in spectrum and countrate in good agreement with the observations.

The author(s) of this abstract have provided an email address for comments about the abstract: jwk@astro.nevis.columbia.edu

Program listing for Thursday