Gelszinnis, Jakob
[VerfasserIn]
;
Hatzes, Artie
[AkademischeR BetreuerIn];
Gasperin, Francesco de
[AkademischeR BetreuerIn];
Pfrommer, Christoph
[AkademischeR BetreuerIn]Friedrich-Schiller-Universität Jena
Anmerkungen:
Tag der Verteidigung: 12.5.2020
Zusammenfassungen in deutscher und englischer Sprache
Beschreibung:
We present the compilation of a homogeneous sample and analysis of radio relics found in actual and mock sky surveys at 1.4 GHz. We aim at setting constraints on the physics of CR electrons and the magnetic fields in the ICM. As the observational data, we compile an updated catalog of radio relics found in the NRAO VLA Sky Survey. For the synthetic sky survey, we improve the scheme that we developed in (Nuza et al., 2017, MNRAS) by considering the amplification of magnetic fields through shock compression and a more careful consideration of the survey incompleteness towards compact radio relics. We investigate the synchrotron emission model of (Hoeft & Brueggen, 2007, MNRAS) - corresponding to DSA of electrons of ICM electrons from the thermal pool. We are the first to present the results of a likelihood-free parameter inference on ICM properties with approximate Bayesian computation. This approach is based on ranking samples of synthetic sky surveys against the observational data, each trial with an individual set of model parameters. While considerable agreement in detection counts and power-size distribution can be reached, observed relics tend to be farther away and have on average steeper integrated spectral index than their simulated counterparts for all reasonable parameter sets. The estimated fraction of thermalized shock energy put into electrons by the DSA mechanism is log10(xi_e) = 5.0 +- 0.2 at an \ICM magnetic field strength of log10(B_0/μG) = (1.4 +- 0.7) + 0.53^{+0.40}_{-0.49} log10(n_e/10^-4cm-3). The model also suggests that half the relics above a flux density of 3.6 mJy are yet undiscovered. Lastly, we show that an expansion of the modeling including a population of pre-existing CR-electrons in the ICM does not significantly improve the match between model and data. Our work demonstrates how sky surveys and cosmological simulations can be used to infer model parameters; radio relic surveys to study particle acceleration in the ICM.