English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Axions/axion-like particles (ALPs) are a well motivated extension of theStandard Model and are generic within String Theory. The X-ray transparency ofthe intracluster medium (ICM) in galaxy clusters is a powerful probe of lightALPs (with mass $<10^{-11}\,{\rm eV}$); as X-ray photons from an embedded orbackground source propagate through the magnetized ICM, they may undergoenergy-dependent quantum mechanical conversion into ALPs (and vice versa),imprinting distortions on the X-ray spectrum. We present Chandra data for theactive galactic nucleus NGC1275 at the center of the Perseus cluster. Employinga 490ks High-Energy Transmission Gratings (HETG) exposure, we obtain ahigh-quality 1-9keV spectrum free from photon pileup and ICM contamination.Apart from iron-band features, the spectrum is described by a power-lawcontinuum, with any spectral distortions at the $<3\%$ level. We compute photonsurvival probabilities as a function of ALP mass $m_a$ and ALP-photon couplingconstant $g_{a\gamma}$ for an ensemble of ICM magnetic field models, and thenuse the NGC1275 spectrum to constraint the $(m_a, g_{a\gamma})$-plane.Marginalizing over magnetic field realizations, the 99.7% credible regionlimits the ALP-photon coupling to $g_{a\gamma}<6-8\times 10^{-13}\, {\rmGeV}^{-1}$ (depending upon magnetic field model) for masses $m_a<1\times10^{-12}\,{\rm eV}$. These are the most stringent limit to date on$g_{a\gamma}$ for these light ALPs, and have already reached the sensitivitylimits of next-generation helioscopes and light-shining-through-wallexperiments. We highlight the potential of these studies with thenext-generation X-ray observatories Athena and Lynx, but note the criticalimportance of advances in relative calibration of these future X-rayspectrometers.

Astrophysical limits on very light axion-like particles from Chandra grating spectroscopy of NGC 1275