Constraints on axions from cosmic distance measurements

Abstract

Axion couplings to photons could induce photon-axion conversion in the presence of magnetic fields in the Universe. This conversion could impact various cosmic distance measurements, such as luminosity distances to type Ia supernovae and angular distances to galaxy clusters, in different ways. In this paper we consider different combinations of the most up-to-date distance measurements to constrain the axion-photon coupling. Employing the conservative cell magnetic field model for the magnetic fields in the intergalactic medium (IGM) and ignoring the conversion in the intracluster medium (ICM), we find the upper bounds on axion-photon couplings to be around 5×10−12 (nG/B) $$ \sqrt{\mathrm{Mpc}/s} $$ Mpc / s GeV–1 for axion masses ma below 10−13 eV, where B is the strength of the IGM magnetic field, and s is the comoving size of the magnetic domains. When including the conversion in the ICM, the upper bound is lowered and could reach 5 × 10−13 GeV−1 for ma< 5 × 10−12 eV. While this stronger bound depends on the ICM modeling, it is independent of the strength of the IGM magnetic field, for which there is no direct evidence yet. These constraints could be placed on firmer footing with an enhanced understanding and control of the astrophysical uncertainties associated with the IGM and ICM. All the bounds are determined by the shape of the Hubble rate as a function of redshift reconstructable from various distance measurements, and insensitive to today’s Hubble rate, of which there is a tension between early and late cosmological measurements. As an appendix, we discuss the model building challenges of the use of photon-axion conversion to make type Ia supernovae brighter to alleviate the Hubble problem/crisis.

Dark Matter In Extreme Astrophysical Environments

“…For axions with mass m 10 −13 eV, the conversion of photons to axions during the photon propagation through the magnetic field background leads to a dimming of the magnitude of sources such as Type IA SNe and galaxy clusters. This in turn alters the inferred cosmic distance and can be constrained by cosmic distance data sets [170]. This puts constraints on the axion-photon coupling to be below G aγγ 10 −11 − 10 −12 GeV −1 .…”

Feebly-interacting particles: FIPs 2020 workshop report

“…In this note, we point out a few novel effects in photon propagation that arise from the axion-photon coupling, which can be utilized to probe the axion-photon coupling strength. This includes the photon disappearance due to conversion into axions [598] and photon en route production by the axions due to their stimulated decay [599].…”

New Horizons: Scalar and Vector Ultralight Dark Matter

“…Although originally modeled for the photon-axion system [285], they can be easily adapted to constrain the scalar-photon coupling in the mass range of m φ 10 −12 eV. The discovery of lowmetallicity and cold gas medium in dwarf galaxies can as well set strong constraints on the kinetic mixing parameter of dark photons and the photon coupling of axions [286,287].…”