SMuK 2023 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 88: Gamma Astronomy IV
T 88.3: Vortrag
Mittwoch, 22. März 2023, 18:00–18:15, POT/0151
Intergalactic magnetic fields and Mkn 421 gamma-ray observations — •Matias Sotomayor Webar and Dieter Horns — Institut für Experimentalphysik, Universität Hamburg, Luruper Chausseee 149, D-22761 Hamburg
The existence of intergalactic magnetic fields as a relic of a phase transition in the early universe has so far not been confirmed through observations. While Faraday rotation measure provide an upper bound ( 10−9 G), lower bounds have been proposed via the non-detection of gamma-ray emission produced in inverse Compton/pair production cascades. Sufficiently large magnetic fields ( 10−16 G are required to deflect the secondary electrons out of the line of sight and suppress the visible inverse Compton emission. The interpretation of these limits is however debatable, as oblique pair instabilities could be a dominating energy-loss mechanism, providing the long sought additional heating of the intergalactic medium to explain Ly−α forest data. In this contribution, we present the results for a search for a strongly suppressed cascade emission from the direction of the prominent nearby blazar Mkn 421 (z=0.031) using Fermi LAT data. Preliminary results will be presented at the conference.