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IPAC Astronomy Lunch Seminar

Wednesday, January 18, 2012
12:00pm to 1:00pm
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IPAC 102 (Large Conference Room)
The Modeling of the Extragalactic Background Light and Gamma-ray Attenuation
Alberto Dominguez, UC Riverside,
The extragalactic background light (EBL) is of fundamental importance both for understanding the entire process of galaxy evolution and for gamma-ray astronomy, but the overall spectrum of the EBL between 0.1 and 1000 microns has never been determined directly from galaxy spectral energy distribution (SED) observations over a wide redshift range. Galaxy SED-type fractions from z=0.2-1 are estimated from a multi-wavelength sample from the AEGIS collaboration that allows a new determination of the evolving EBL. Then, the transparency of the Universe to very high energy (VHE) gamma-ray photons is derived. We find the maximum transparency of the Universe allowed by the standard framework. This result challenges current VHE observations of high redshift blazars. A solution to this problem is discussed utilizing VHE spectra of the highest redshift blazars assuming the existence of a plausible dark matter candidate known as axion-like particle.
For more information, please contact Luisa Rebull by phone at x4565 or by email at [email protected] or visit http://www.ipac.caltech.edu/events.