Back to Volume
Paper: Gamma-Ray Bursts as a Probe of the Epoch of Reionization
Volume: 312, Third Rome Workshop on Gamma-Ray Bursts in the Afterglow Era
Page: 287
Authors: Lamb, D.Q.; Haiman, Z.
Abstract: GRBs are expected to occur at redshifts far higher than the highest quasar redshifts so far detected. And unlike quasars, GRB afterglows may provide "clean" probes of the epoch of reionizations because no complications (such as the presence of a strong Lyα emission line) or "proximity effects" (such as the Strömgren sphere produced by ionizing photons from the quasar) are expected. Thus NIR and optical observations of GRB afterglows may provide unique information about the epoch of reionization. In particular the flux at wavelengths shortward of Lyα provides a direct measure of the density fluctuations of the IGM at the GRB redshift, while the flux at wavelengths longward of Lyα provides an integrated measure of the number of ionizing photons produced by stars in the host galaxy of the GRB up until the burst occurs. A comparison of the sized of the Strömgren spheres produced by stars in the host galaxies of GRBs and by quasars then provides an estimate of the relative contributions of star formation and quasars to reionization. We use detailed calculations of the expected shape of the GRB afterglow spectrum in the vicinity of Lyα for GRBs at a variety of redshifts to illustrate these points.
Back to Volume