Measurement of extragalactic magnetic fields by TeV gamma ray telescopes

by A. Neronov (University of Oxford)

Wednesday 13 Jun 2007, 11:00 → 12:00 Europe/Zurich

1/1-025 (CERN)

1. Measurement of extragalactic magnetic fields by TeV gamma ray telescopes ( 40 min + discussion) After a short discussion of different ways of measurement of magnetic fields in the Universe, I will explain a method of measurement of extragalactic magnetic fields in observations of TeV gamma-rays from distant blazars. Multi-TeV gamma-rays interact with the infrared photon background producing secondary electrons and positrons, which can be just slightly deflected by extragalactic magnetic fields before they emit secondary gamma-rays via inverse Compton scattering of cosmic microwave background photons. Secondary gamma-rays emitted toward an observer on the Earth can be detected as extended emission around initially point source. Energy dependent angular size of extended emission is related to the value of extragalactic magnetic field along the line of sight. Small magnetic fields B < 1e-12 G in the voids of the large scale structure can be measured (or ruled out) in this way. Ref: astro-ph/0604607. 2. Neutrino masses and dark energy with future cosmological surveys (20 min +discussion)