On the Polarisation of Radio Relics

Autor: Matthias Hoeft, Kamlesh Rajpurohit, Denis Wittor, Gabriella di Gennaro, Paola Domínguez-Fernández
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Galaxies, Vol 10, Iss 1, p 10 (2022)
Druh dokumentu: article
ISSN: 2075-4434
DOI: 10.3390/galaxies10010010
Popis: Radio relics are extended radio emission features which trace shock waves in the periphery of galaxy clusters originating from cluster mergers. Some radio relics show a highly polarised emission, which make relics an excellent probe for the magnetisation of the intra-cluster medium. The origin of the relic polarisation is still debated. It could be a result of tangentially stretching the magnetic field at the shock surface. This scenario would naturally explain the alignment of the polarisation (E-vectors) with the shock normal. We have implemented a toy model for the relic polarisation according to this scenario. We find that the magnetic field strength itself crucially affects the fractional polarisation. Moreover, we find that the shock strength has surprisingly little effect on the overall polarisation fraction. Finally, we find that the fractional polarisation may decrease downstream depending on the magnetic field strength. Our results demonstrates that the shock compression scenario provides a very plausible explanation for the radio relic polarisation which specific features permitting to test the origin of radio relic polarisation.
Databáze: Directory of Open Access Journals