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SUMMARY:Through the Amber Spyglass: searching for Axion-like signals in X-
 ray spectra of cluster-hosted AGN - James Matthews (IoA)
DTSTART:20211013T124500Z
DTEND:20211013T131500Z
UID:TALK162721@talks.cam.ac.uk
CONTACT:Hannah Uebler
DESCRIPTION:Axions and axion-like particles (ALPs) are well-motivated exte
 nsions to the standard model of particle physics\, are predicted by certai
 n string theories and\, in certain mass regimes\, can be good dark matter 
 candidates. In the presence of external magnetic fields\, ALPs and photons
  interconvert\, meaning that bright astrophysical sources embedded in magn
 etic fields (such as cluster-hosted AGN) can be used to search for irregul
 arities in the spectra and place limits on the ALP coupling to electromagn
 etism. The signal appears as “wiggles” in the spectrum\, with their fo
 rm depending on the magnetic field strength and structure\, so having good
  models for the magnetic field is important. I will discuss the current be
 st limits on light ALPs (smaller 1e-11 eV) from Chandra grating spectrosco
 py of AGN such as NGC 1275 and H1821+643 and describe the modelling proces
 s and its limitations. I will then present a sensitivity study in which I 
 investigate the impact of different magnetic field models on ALP signals a
 nd the resulting limits\, using our publicly available code ALPRO. I will 
 finish by describing a new formalism that\, to first-order\, recasts the A
 LP conversion problem as simple Fourier-like transform of the line of sigh
 t magnetic field. This formalism provides a direct map between the real-sp
 ace magnetic field and the spectral features imprinted by ALPs\, offering 
 exciting prospects for the future.
LOCATION:Hybrid Sackler (sign-up needed) + Zoom - Details will be sent by 
 email.
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