Cosmic anisotropies from quasars

par Dr Vincent PELGRIMS (LPSC)

lundi 25 sept. 2017, 14:00 → 15:00 Europe/Paris

Large-scale correlations of the position angles of the polarization vectors of the light form quasars were discovered almost twenty years ago. These correlations take place over giga parsec scale distances. Due to their extreme-scale nature these observations have been recognized as potentially competing the isotropy of the well-accepted concordance cosmological model. Later these observations have been confirmed and the correlation signal enhanced by means of additional data. After a review of the main features of those large-scale polarization alignments, I shall present the related results that I obtained. Therefore, I shall address two types of unexpected, but observed, correlations that involve the orientation of the linear polarization vectors of the light of quasars, at optical and radio wavelengths. First, the quasar polarization vectors appear to be coherently oriented to one another over very large scales and, second, their orientations are found to be correlated with specific directions defined by the quasar spatial distribution. I will discuss a tentative interpretation of the data following which the polarization correlations reflect the coevolution of the black hole spin axes with —and within— the cosmic web.

VP_presentation.pdf