%0 Generic %1 Robertson2011 %A Robertson, Brant E. %A Ellis, Richard S. %D 2011 %K evolution grb redshift sfr %T Connecting the Gamma Ray Burst Rate and the Cosmic Star Formation History: Implications for Reionization and Galaxy Evolution %U http://arxiv.org/abs/1109.0990 %X (Abridged) The contemporary discoveries of galaxies and gamma ray bursts (GRBs) at high redshift have supplied the first direct information on star formation when the universe was only a few hundred million years old. The probable origin of long duration GRBs in the deaths of massive stars would link the universal GRB rate to the redshift-dependent star formation rate density, although exactly how is currently unknown. Using an extensive sample of 112 GRBs above a fixed luminosity limit drawn from the Second Swift Burst Alert Telescope catalog and accounting for uncertainty in their redshift distribution by considering the contribution of "dark" GRBs, we compare the cumulative redshift distribution N(<z) of GRBs with the star formation density rho_*(z) measured from UV-selected galaxies over 0<z<4. We find only marginal evidence for evolution in the GRB rate to star formation rate ratio Psi(z), consistent with Psi(z) (1+z)^0.5. We show that such a modest change can be readily explained if GRBs occur primarily in low-metallicity galaxies which are proportionally more numerous at earlier times. While some previous studies of the GRB-star formation rate connection have concluded that GRB-inferred star formation at high redshift would be sufficient to maintain cosmic reionization over 6<z<9 and reproduce the observed optical depth of Thomson scattering to the cosmic microwave background, we show that such a star formation history would over-predict the observed stellar mass density at z>4 measured from rest-frame optical surveys. The resolution of this important disagreement is currently unclear. Regardless of the explanation, the continued study of z>6 GRBs will offer a valuable independent probe of the assumptions made in the interpretation of star-forming galaxies and their contribution to cosmic reionization.

@misc{Robertson2011, abstract = { (Abridged) The contemporary discoveries of galaxies and gamma ray bursts (GRBs) at high redshift have supplied the first direct information on star formation when the universe was only a few hundred million years old. The probable origin of long duration GRBs in the deaths of massive stars would link the universal GRB rate to the redshift-dependent star formation rate density, although exactly how is currently unknown. Using an extensive sample of 112 GRBs above a fixed luminosity limit drawn from the Second Swift Burst Alert Telescope catalog and accounting for uncertainty in their redshift distribution by considering the contribution of "dark" GRBs, we compare the cumulative redshift distribution N(<z) of GRBs with the star formation density rho_*(z) measured from UV-selected galaxies over 0<z<4. We find only marginal evidence for evolution in the GRB rate to star formation rate ratio Psi(z), consistent with Psi(z) (1+z)^0.5. We show that such a modest change can be readily explained if GRBs occur primarily in low-metallicity galaxies which are proportionally more numerous at earlier times. While some previous studies of the GRB-star formation rate connection have concluded that GRB-inferred star formation at high redshift would be sufficient to maintain cosmic reionization over 6<z<9 and reproduce the observed optical depth of Thomson scattering to the cosmic microwave background, we show that such a star formation history would over-predict the observed stellar mass density at z>4 measured from rest-frame optical surveys. The resolution of this important disagreement is currently unclear. Regardless of the explanation, the continued study of z>6 GRBs will offer a valuable independent probe of the assumptions made in the interpretation of star-forming galaxies and their contribution to cosmic reionization. }, added-at = {2011-09-07T21:33:18.000+0200}, author = {Robertson, Brant E. and Ellis, Richard S.}, biburl = {https://www.bibsonomy.org/bibtex/26c3fdaaf0be63e04f36821dec935eb10/miki}, description = {[1109.0990] Connecting the Gamma Ray Burst Rate and the Cosmic Star Formation History: Implications for Reionization and Galaxy Evolution}, interhash = {6ff31bcc33fc883cc12a3e6dd0feb521}, intrahash = {6c3fdaaf0be63e04f36821dec935eb10}, keywords = {evolution grb redshift sfr}, note = {cite arxiv:1109.0990 Comment: Submitted to ApJ}, timestamp = {2011-09-07T21:33:18.000+0200}, title = {Connecting the Gamma Ray Burst Rate and the Cosmic Star Formation History: Implications for Reionization and Galaxy Evolution}, url = {http://arxiv.org/abs/1109.0990}, year = 2011 }