The Intrinsic Luminosity of Gamma Ray Burst from BATSE-PVO

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Session 33 -- Gamma-Rays and Cosmic Rays
Display presentation, Tuesday, 9:30-6:30, Heller Lounge Room

[33.03] The Intrinsic Luminosity of Gamma Ray Burst from BATSE-PVO

E. E. Fenimore (LANL), R. I. Epstein (LANL), C. Ho (LANL), J. G. Laros (LANL), M. Meier (LANL), T. E. Strohmayer (LANL), G. Pendleton (MSFC), G. Fishman (MSFC), C. Kouveliotou (MSFC), C. Meegan (MSFC)

The Burst and Transient Experiment (BATSE) on the Compton Gamma-Ray Observatory (CGRO) has shown that Gamma-Ray Bursts (GRBs) are isotropic yet there is a dearth of weak events compared to that expected from a homogeneous distribution. It appears that the bursts are either in an extended galactic halo with distance ${\sim}$ 100 kpc or at cosmological distances, about 1 Gpc. We show that a cosmological distribution of GRBs with constant comoving density and standard candle luminosities can fit the observed intensity distribution from BATSE and Pioneer Venus Orbiter (PVO) over a dynamic range of ${10^3}$. The resulting gamma-ray luminosity is tightly constrained (${6^{+1.1}_{-0.8} \times 10^{50}}$ erg sec$^{-1}$). Using the brightest extragalactic objects in 8 GRB error boxes imply an absolute visual magnitude fainter than -18 for the host galaxy. Strong evolutionary effects might modify this to be -22.5. Bright Active Galactic Nuclei (AGN) models, (e.g., quasars) are ruled out with 90\% confidence and models involving faint AGNs (Seyfert galaxies) are allowed only if there is strong density evolution. The intensity distribution and the bright object limits are consistent with GRBs associated with objects whose density scales with normal stars. The resulting event rate is ${\sim 10^{-20}}$ GRBs yr$^{-1}$ M$_{\odot}^{-1}$.

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