Heidelberg 2007 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 402: γ-Astronomie III
T 402.3: Vortrag
Donnerstag, 8. März 2007, 17:15–17:30, INF 308 Kl. HS
New Limits on the Extragalactic Background Light from TeV-Blazar Observations — •Martin Raue1 and Daniel Mazin2 — 1Institut für Experimentalphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg — 2Max-Planck-Institut für Physik, Föhringer Ring 6, 80805 Munich, Germany
The star and galaxy formation history has left a visible imprint on the diffuse extragalactic radiation field. In the spectral energy distribution two distinct bumps are expected: A first bump in the optical coming from direct starlight redshifted over time and a second bump in the infrared from dust-reemission. Direct measurements of this extragalactic background light (EBL) have proven to be difficult, especially in the infrared where foregrounds dominate (zodiacal light). The observation of distant sources of TeV-photons via Imaging Cherenkov Telescopes can provide an indirect measurement of the EBL: The TeV-photons are attenuated via pair production and the observed spectra therefore carry an imprint of the EBL. With assumptions about the source spectrum limits on the EBL can be derived. In our paper we describe a generic way to derive limits on the EBL utilizing a scan on a grid in EBL wavelength vs EBL density and using only minimal assumptions about the source spectrum. This technique allows us to explore a wide range of EBL-shapes and to treat all TeV blazar spectra a consistent way. Preliminary limits on the EBL are reported.