Potential of EBL and cosmology studies with the Cherenkov Telescope Array

Abstract

Very high energy (VHE, E >100 GeV) gamma-rays are absorbed via interaction with low-energy photons from the extragalactic background light (EBL) if the involved photon energies are above the threshold for electron-positron pair creation. The VHE gamma-ray absorption, which is energy dependent and increases strongly with redshift, distorts the VHE spectra observed from distant objects. The observed energy spectra of the AGNs carry, therefore, an imprint of the EBL. The detection of VHE gamma-ray spectra of distant sources (z = 0.11 - 0.54) by current generation Imaging Atmospheric Cherenkov Telescopes (IACTs) enabled to set strong upper limits on the EBL density, using certain basic assumptions about blazar physics. In this paper it is studied how the improved sensitivity of the Cherenkov Telescope Array (CTA) and its enlarged energy coverage will enlarge our knowledge about the EBL and its sources. CTA will deliver a large sample of AGN at different redshifts with detailed measured spectra. In addition, it will provide the exciting opportunity to use gamma ray bursts (GRBs) as probes for the EBL density at high redshifts.

12 pages, 9 figures, to appear in Astroparticle Physics. arXiv admin note: text overlap with arXiv:1005.1196

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Cited by in corpus (9)

• On detecting oscillations of gamma rays into axion-like particles in turbulent and coherent magnetic fields
• Sensitivity of the Cherenkov Telescope Array to the Detection of Intergalactic Magnetic Fields
• Extragalactic background light models and GeV-TeV observation of blazars
• On the possiblity of using vertically pointing Central Laser Facilities to calibrate the Cherenkov Telescope Array
• Status of the Cherenkov Telescope Array Project
• CTA: the future of ground-based gamma-ray astrophysics
• Redshift measurement of Fermi Blazars for the Cherenkov Telescope Array
• The First VHE Activity of OJ 287 and the Extragalactic Background Light
• A New Eye on the VHE Transient Universe with the HAWC Online Flare Monitor