New constraints on light axion-like particles using Chandra transmission grating spectroscopy of the powerful cluster-hosted quasar H1821+643

Sisk-Reynés, Júlia; Matthews, James H; Reynolds, Christopher S; Russell, Helen R; Smith, Robyn N; Marsh, M. C.David

Abstract

Axion-like particles (ALPs) are predicted by several Beyond the Standard Model theories, in particular, string theory. In the presence of an external magnetic field perpendicular to the direction of propagation, ALPs can couple to photons. Therefore, if an X-ray source is viewed through a magnetized plasma, such as a luminous quasar in a galaxy cluster, we may expect spectral distortions that are well described by photon–ALP oscillations. We present a 571 ks combined high- and low-energy transmission grating Chandra observation of the powerful radio-quiet quasar H1821+643, hosted by a cool-core cluster at redshift 0.3. The spectrum is well described by a double power-law continuum and broad+narrow iron line emission typical of type-1 active galactic nuclei (AGNs), with remaining spectral features <2.5 per cent⁠. Using a cell-based approach to describe the turbulent cluster magnetic field, we compare our spectrum with photon–ALP mixing curves for 500 field realizations, assuming that the thermal-to-magnetic pressure ratio β remains constant up to the virial radius. At 99.7 per cent credibility and taking β = 100, we exclude all couplings gaγ > 6.3 × 10−13 GeV−1 for most ALP masses <10−12 eV. Our results are moderately more sensitive to constraining ALPs than the best previous result from Chandra observations of the Perseus cluster, albeit with a less constrained field model. We reflect on the promising future of ALP studies with bright AGNs embedded in rich clusters, especially with the upcoming Athena mission.

Citation

Sisk-Reynés, J., Matthews, J. H., Reynolds, C. S., Russell, H. R., Smith, R. N., & Marsh, M. C. (2022). New constraints on light axion-like particles using Chandra transmission grating spectroscopy of the powerful cluster-hosted quasar H1821+643. Monthly Notices of the Royal Astronomical Society, 510(1), 1264-1277. https://doi.org/10.1093/mnras/stab3464

• Journal Article Type: Article
• Acceptance Date: Nov 24, 2021
• Online Publication Date: Dec 2, 2021
• Publication Date: Feb 1, 2022
• Deposit Date: Feb 18, 2022
• Publicly Available Date: Feb 18, 2022
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 510
• Issue: 1
• Pages: 1264-1277
• DOI: https://doi.org/10.1093/mnras/stab3464
• Keywords: Space and Planetary Science; Astronomy and Astrophysics
• Public URL: https://nottingham-repository.worktribe.com/output/7357548
• Publisher URL: https://academic.oup.com/mnras/article-abstract/510/1/1264/6448485?redirectedFrom=fulltext
• Additional Information: This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record Júlia Sisk-Reynés, James H Matthews, Christopher S Reynolds, Helen R Russell, Robyn N Smith, M C David Marsh, New constraints on light axion-like particles using Chandra transmission grating spectroscopy of the powerful cluster-hosted quasar H1821+643, Monthly Notices of the Royal Astronomical Society, Volume 510, Issue 1, February 2022, Pages 1264–1277 is available online at: https://academic.oup.com/mnras/article-abstract/510/1/1264/6448485.