AAS 197, January 2001
Session 73. Gamma Ray Bursts Observations and Analysis
Display, Wednesday, January 10, 2001, 9:30am-7:00pm, Exhibit Hall

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[73.04] Null GRB Millilensing Search Limits Universe Composition

R. J. Nemiroff (Michigan Tech), G. F. Marani (NASA/NRC), J. P. Norris (NASA/GSFC), J. T. Bonnell (NASA/USRA)

A new search for the gravitational lens effects of a significant cosmological density of supermassive compact objects (SCOs) on gamma-ray bursts has yielded a null result. We inspected the timing data of 774 BATSE-triggered GRBs for evidence of millilensing: repeated peaks similar in light-curve shape and spectra. Our null detection leads us to conclude that, in all candidate universes simulated, \OmegaSCO < 0.1 is favored for 105 < MSCO/M\odot < 109, while in some universes and mass ranges the density limits are as much as 10 times lower. Therefore, a cosmologically significant population of SCOs near globular cluster mass neither came out of the primordial universe, nor condensed at recombination.

The author(s) of this abstract have provided an email address for comments about the abstract: nemiroff@mtu.edu

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