Probing axions through tomography of anisotropic cosmic birefringence

Cosmic birefringence is the in-vacuo rotation of linear polarization plane experienced by photons Microwave Background (CMB) radiation when theoretically well-motivated parity-violating extensions Maxwell electromagnetism are considered. If angle, parametrizing such a dependent on photon's direction, then this phenomenon called Anisotropic Birefringence (ACB). In paper, we perform for first time tomographic treatment ACB, considering emitted both at recombination and reionization epoch. This allows one to extract additional complementary information about physical source cosmic with respect isotropic case. We focus here case an axion-like field $\chi$, whose coupling electromagnetic sector induces phenomenon, using analytical numerical approach (which involves modification CLASS code). find that anisotropic component exhibits peculiar behavior: increase axion mass implies enhancement amplitude, allowing probe wider range masses purely Moreover, show large angular scales, interplay between contributions ACB sensitive mass, so sufficiently low multipoles, light masses, contribution overtakes one, making promising tool investigating properties field.