Large-scale alignments of quasar polarisations: a detailed study of the spinless-particle scenario
by
Alexandre Payez(DESY, Hamburg)
→
Europe/Berlin
Building 67, SemRm 10 (DESY Hamburg)
Building 67, SemRm 10
DESY Hamburg
Description
The main motivation for our work has been a puzzling observation concerning quasars. No one expected the existence of correlations in the polarisation of visible light coming from objects separated by gigaparsecs, until they were first reported in the form of a redshift-dependent effect that has become more and more significant with the growth of the data sample.
We have studied in detail the most widely considered scenario, involving axion-photon mixing in extragalactic magnetic fields, and we give the results we obtain when we take into account constraints from good-quality linear and circular polarisation measurements, current estimates of magnetic field strengths and structures from the literature, and existing limits on pseudoscalar-photon couplings.
