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T: Fachverband Teilchenphysik
T 90: Gammaastronomie 2
T 90.9: Talk
Tuesday, February 28, 2012, 18:55–19:10, ZHG 008
Models for γ ray emission in W51 — Sara Rebecca Gozzini1, •Fabian Jankowski1, and Wlodek Bednarek2 — 1DESY, 15738 Zeuthen, Germany — 2Division of Astrophysics, University of Łódź, 90236, Poland
We investigated the possible physical origin of the observed γ ray emission from the W51 complex, hosting the supernova remnant W51C.
High energy photons are produced in processes from either a leptonic or a hadronic initial state. Leptonic initial states radiate γ rays through inverse Compton scattering or non-thermal Bremsstrahlung; synchrotron emission, in the environment of SNRs, yields photons in the radio or X-ray range. High energy γ rays of hadronic origin are the product of neutral pion decay, which is produced in flight off a proton-proton or proton-nucleon scattering. Both Bremsstrahlung and π0 decay have as a target the molecular cloud with which the shell front of the supernova remnant interacts; inverse Compton scattering occurs onto photons of the cosmic microwave background, and on infra-red and optical photons of starlight.
Models for each emission process are obtained folding initial spectra of accelerated electrons or protons with the cross sections; the outcome is a distribution of energy carried by gamma rays at Earth level.
We collected spectral data for W51 in several wavelengths and modeled its spectral energy distribution, assuming different scenarios for the input spectra of accelerated particles. Physical parameters deduced from fits on data are used to interpret the possible mechanisms for emission of high energy photons.