Gamma-Ray Cosmology and Tests of Fundamental Physics

Gamma Ray Astronomy: Implications for Fundamental Physics

Gamma Ray Astronomy studies cosmic accelerators through their electromagnetic radiation in the energy range between ∼100 MeV and ∼100 TeV. The present most sensitive observations in this energy band are performed, from space, by the Large Area Telescope onboard the Fermi satellite and, from Earth, by the Imaging Air Cherenkov Telescopes MAGIC, H.E.S.S. and VERITAS. These instruments have revolu...

Early Cosmology and Fundamental Physics

Gamma-ray bursts and cosmology.

I review the current status of the use of gamma-ray bursts (GRBs) as probes of the early Universe and cosmology. I describe the promise of long GRBs as probes of the high redshift (z>4) and very high redshift (z>5) Universe, and several key scientific results that have come from observations made possible by accurate, rapid localizations of these bursts by Swift. I then estimate the fraction of...

Cosmology with Gamma Ray Bursts

— Apparently, Gamma–Ray Bursts (GRBs) are all but standard candles. Their emission is collimated into a cone and the received flux depends on the cone aperture angle. Fortunately we can derive the aperture angle through an achro-matic steepening of the lightcurve of the afterglow, and thus we can measure the " true " energetics of the prompt emission. Ghirlanda et al. (2004) found that this col...

Cosmology with Gamma–ray Bursts

Gamma–Ray Bursts (GRBs) are the brightest sources in the universe, emit mostly in the hard X–ray energy band and have been detected at redshifts up to ∼8.1. Thus, they are in principle very powerful probes for cosmology. I shortly review the researches aimed to use GRBs for the measurement of cosmological parameters, which are mainly based on the correlation between spectral peak photon energy ...