Astrophysical Limits on Very Light Axion-like Particles from Chandra Grating Spectroscopy of NGC 1275

Reynolds, Christopher S.; Marsh, M. C. David; Russell, Helen R.; Fabian, Andrew C.; Smith, Robyn; Tombesi, Francesco; Veilleux, Sylvain

Abstract

Axions/axion-like particles (ALPs) are a well-motivated extension of the Standard Model and are generic within String Theory. The X-ray transparency of the intracluster medium (ICM) in galaxy clusters is a powerful probe of light ALPs (with mass < 10-11eV); as X-ray photons from an embedded or background source propagate through the magnetized ICM, they may undergo energy-dependent quantum mechanical conversion into ALPs (and vice versa), imprinting distortions on the X-ray spectrum. We present Chandra data for the active galactic nucleus NGC 1275 at the center of the Perseus cluster. Employing a 490 ks High Energy Transmission Gratings exposure, we obtain a high-quality 1-9 keV spectrum free from photon pileup and ICM contamination. Apart from iron-band features, the spectrum is described by a power-law continuum, with any spectral distortions at the <3% level. We compute photon survival probabilities as a function of ALP mass m a and ALP-photon coupling constant gaγ for an ensemble of ICM magnetic field models, and then use the NGC 1275 spectrum to constrain the (ma, gaγ)-plane. Marginalizing over magnetic field realizations, the 99.7% credible region limits the ALP-photon coupling to gaγ < 6-8 × 10-13 GeV-1 (depending upon magnetic field model) for masses ma < 1 × 10-12. These are the most stringent limit to date on gaγ for these light ALPs, and have already reached the sensitivity limits of next-generation helioscopes and light-shining-through-wall experiments. We highlight the potential of these studies with the next-generation X-ray observatories Athena and Lynx, but note the critical importance of advances in relative calibration of these future X-ray spectrometers.

Citation

Reynolds, C. S., Marsh, M. C. D., Russell, H. R., Fabian, A. C., Smith, R., Tombesi, F., & Veilleux, S. (2020). Astrophysical Limits on Very Light Axion-like Particles from Chandra Grating Spectroscopy of NGC 1275. Astrophysical Journal, 890(1), Article 59. https://doi.org/10.3847/1538-4357/ab6a0c

• Journal Article Type: Article
• Acceptance Date: Jan 8, 2020
• Online Publication Date: Feb 12, 2020
• Publication Date: Feb 10, 2020
• Deposit Date: Apr 16, 2020
• Publicly Available Date: Apr 21, 2020
• Journal: The Astrophysical Journal
• Print ISSN: 0004-637X
• Electronic ISSN: 1538-4357
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 890
• Issue: 1
• Article Number: 59
• DOI: https://doi.org/10.3847/1538-4357/ab6a0c
• Keywords: Space and Planetary Science; Astronomy and Astrophysics
• Public URL: https://nottingham-repository.worktribe.com/output/4297911
• Publisher URL: https://iopscience.iop.org/article/10.3847/1538-4357/ab6a0c
• Additional Information: Journal title: The Astrophysical Journal; Article type: paper; Article title: Astrophysical Limits on Very Light Axion-like Particles from Chandra Grating Spectroscopy of NGC 1275; Copyright information: © 2020. The American Astronomical Society. All rights reserved.; Date received: 2019-07-05; Date accepted: 2020-01-08; Online publication date: 2020-02-12