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arXiv · 1705.08405

Relativistic inverse Compton scattering of photons from the early universe

Siddharth Malu·Abhirup Datta·Sergio Colafrancesco·Paolo Marchegiani·Ravi Subrahmanyan·D Narasimha·Mark H. Wieringa
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Abstract

Electrons at relativistic speeds, diffusing in magnetic fields, cause copious emission at radio frequencies in both clusters of galaxies and radio galaxies, through the non-thermal radiation emission called synchrotron. However, the total power radiated through this mechanism is ill constrained, as the lower limit of the electron energy distribution, or low-energy cutoffs, for radio emission in galaxy clusters and radio galaxies have not yet been determined. This lower limit, parametrized by the lower limit of the electron momentum - pmin - is critical for estimating the energetics of non-thermal electrons produced by cluster mergers or injected by radio galaxy jets, which impacts the formation of large-scale structure in the universe, as well as the evolution of local structures inside galaxy clusters. The total pressure due to the relativistic, non-thermal population of electrons is critically dependent on pmin, making the measurement of this non-thermal pressure a promising technique to estimate the electron low-energy cutoff. We present here the first unambiguous detection of this pressure for a non-thermal population of electrons in a radio galaxy jet/lobe, located at a significant distance away from the center of the Bullet cluster of galaxies.

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Siddharth Malu, Abhirup Datta, Sergio Colafrancesco, Paolo Marchegiani, Ravi Subrahmanyan, D Narasimha, Mark H. Wieringa. 2017-05-23. Relativistic inverse Compton scattering of photons from the early universe. https://doi.org/10.1038/s41598-017-17104-8

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