Max Tegmark's cosmology library: bursts

Please click here to download a 500K compressed version of the paper, including all the figures (unpack it with "gunzip"). If speed isn't an issue, you can get the 2.9MB uncompressed postscript file by clicking here. If you are interested in printing out the color figures in color, we recommend that you use the high-resolution versions. Click here for a compressed high-resolution version of Figure 7 (the smoothed burst map shown above), and here for a plate containing figures 7, 8, 9 and 10 tiled on a single page. Click here if you are interested in other research of mine.



Max Tegmark, Dieter H. Hartmann, Michael S. Briggs & Charles A. Meegan


We compute the angular power spectrum C_l from the BATSE 3B catalog of 1122 gamma-ray bursts, and find no evidence for clustering on any scale. These constraints bridge the entire range from small scales (which probe source clustering and burst repetition) to the largest scales (which constrain possible anisotropies from the Galactic halo or from nearby cosmological large scale structures). We develop an analysis technique that takes the angular position errors into account, which enables us to place tight upper limits on the clustering down to scales l\approx 60, corresponding to a few degrees on the sky.
The minimum-variance burst weighting that we employ is graphically visualized as an all-sky map where each burst is smeared out by an amount corresponding to its position uncertainty. We also present separate band-pass filtered sky maps for the quadrupole term and for the multipole-ranges l=3-10 and l=11-30, so that the fluctuations on different angular scales can be separately inspected for visual features such as localized ``hot spots" or structures aligned with the Galactic plane. These filtered maps reveal no apparent deviations from isotropy.

Online references:

This site also contains the latest versions of a paper that is referenced in the text; Tegmark 1995. You can find many of the referenced papers from the BATSE team here.

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This page was last modified July 1, 1998.