Can axionlike particles explain the alignments of the polarizations of light from quasars?

Abstract

The standard axion-like particle explanation of the observed large-scale coherent orientations of quasar polarisation vectors is ruled out by the recent measurements of vanishing of circular polarisation. We introduce a more general wave-packet formalism and show that, although decoherence effects between waves of different frequencies can reduce significantly the amount of circular polarisation, the axion-like particle hypothesis is disfavoured given the bandwidth with which part of the observations were performed. Finally, we show that a more sophisticated model of extragalactic fields does not lead to an alignment of polarisations.

Optical circular polarization in quasars

“…Photon-pseudoscalar mixing generates dichroism and birefringence, the latter transforming linear polarization into circular polarization and vice-versa along the line of sight. If photonpseudoscalar mixing produces the linear polarization needed to explain the observed alignments, a comparable amount of circular polarization would be expected (Raffelt & Stodolsky 1988;Jain et al 2002;Das et al 2005;Gnedin et al 2007;Hutsemékers et al 2008;Payez et al 2008). Hence, we present accurate circular polarization measurements for a sample of quasars whose polarization vectors are coherently oriented.…”

Photon and axion oscillation in a magnetized medium: A general treatment

“…This phenomenon has been used for laboratory and astrophysical searches for such particles, leading to stringent limits [24][25][26][27][28][29][30][31][32][33][34]. Furthermore, the astrophysical and cosmological consequences of this mixing have been studied extensively in the literature [33][34][35][36][37][38][39][40][41][42][43][44]. The mixing increases the transparency of the intergalactic and galactic medium to propagation of high energy photons due to the very weak coupling of pseudoscalars to visible matter [45][46][47].…”

Quasar polarization with ultralight (pseudo-)scalars

“…Therefore it is argued that the ALPs cannot explain the alignments and only constrain ALPs [17]. Furthermore recently it was reported that the radio waves (8.4 GHz) show the similar coherent orientations of polarization from quasars [18] by extending the first investigation with no alignment in Ref [19].…”

“…We , in section IV delineate our results to compare the observations with our model. We summarize in section V & comment on the viability of ALPs vis-a-vis 'Large scale coherent orientation' [9] observation on quasars. We demonstrate that previous objections raised disfavouring ALPs as a viable model for the (HUTSEMEKERS) effect may be nullified in this novel route.…”

“…This is of particular interest in astrophysics, where this mixing of photons with axion makes the universe transparent to the former [10] and also changes their polarization properties [9]. It is also believed to be potentially responsible for effects like 'Supernovae dimming' [10] or 'Large scale coherent orientation' [9] of the universe, through quasar polarization.…”