Cosmic birefringence tomography with radio galaxies I: Testing birefringence solutions to the CMB-BAO tension
Abstract
We present an independent test of cosmic birefringence induced by axionlike particles (ALPs) at low redshift using radio galaxies. We focus on models that can alleviate the mild tension between recent baryon acoustic oscillation (BAO) measurements and observations of the cosmic microwave background (CMB). This tension can be explained by a large cosmic birefringence rotation angle generated during the reionization epoch. Such a large rotation can arise if the recent isotropic cosmic birefringence measurements are subject to an nπ phase ambiguity, with n∈ℤ, or if cold dark matter injects energy into ALPs. We constrain these two scenarios by fitting the cosmic birefringence angles estimated from the jet morphologies and polarization angles of radio galaxies obtained by Battye, Jackson & Browne (2026). For the nπ model, the radio-galaxy data exclude |n|≥ 1 at more than 2σ for log10(mϕ/eV)≲ −30.7. For the energy injection model, the data are consistent with no energy injection, but with a slight relative preference for a nonzero energy injection compared to the no-injection case. Since our samples are limited to ∼ 3000 and there could still be several astrophysical uncertainties and statistical fluctuations, further exploration of tomographic cosmic birefringence using a large number of low-redshift radio galaxies is important for independent tests of cosmic birefringence.
Related
- Alleviating CMB-BAO tension with a large cosmic birefringence angle during reionization induced by energy injection to axion-like particles
- Stars Would Remember a Recent Gravitational Transition: Testing G-step Resolutions of the Hubble Tension with Red Dwarfs
- Dark matter haloes from dwarf to massive galaxies: no systematic inner-density tension with ΛCDM hydrodynamical simulations
- GPAge: a Global Parameterization based on cosmic Age for some unified early-time and late-time solutions to the Hubble tension
- Guide for the Hubble Tension: Mid-Time Solutions and Generalized PAge Parameterizations
BibTeX
@misc{namikawa2026cosmic,
title = {{Cosmic birefringence tomography with radio galaxies I: Testing birefringence solutions to the CMB-BAO tension}},
author = {Toshiya Namikawa and Fumihiro Naokawa and Richard Battye and Salvatore Samuele Sirletti},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.39449},
eprint = {2610.39449},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.39449},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Cosmic birefringence tomography with radio galaxies I: Testing birefringence solutions to the CMB-BAO tension
AU - Toshiya Namikawa
AU - Fumihiro Naokawa
AU - Richard Battye
AU - Salvatore Samuele Sirletti
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.39449
UR - https://arxiv.org/abs/2610.39449
AB - We present an independent test of cosmic birefringence induced by axionlike particles (ALPs) at low redshift using radio galaxies. We focus on models that can alleviate the mild tension between recent baryon acoustic oscillation (BAO) measurements and observations of the cosmic microwave background (CMB). This tension can be explained by a large cosmic birefringence rotation angle generated during the reionization epoch. Such a large rotation can arise if the recent isotropic cosmic birefringence measurements are subject to an nπ phase ambiguity, with n∈ℤ, or if cold dark matter injects energy into ALPs. We constrain these two scenarios by fitting the cosmic birefringence angles estimated from the jet morphologies and polarization angles of radio galaxies obtained by Battye, Jackson & Browne (2026). For the nπ model, the radio-galaxy data exclude |n|≥ 1 at more than 2σ for log_10(m_ϕ/eV)≲ −30.7. For the energy injection model, the data are consistent with no energy injection, but with a slight relative preference for a nonzero energy injection compared to the no-injection case. Since our samples are limited to ∼ 3000 and there could still be several astrophysical uncertainties and statistical fluctuations, further exploration of tomographic cosmic birefringence using a large number of low-redshift radio galaxies is important for independent tests of cosmic birefringence.
ER -