Searching for axion-like particle decay in the near-infrared background:
  an updated analysis
  The extragalactic background light is comprised of the cumulative radiation
from all galaxies across the history of the universe. The angular power
spectrum of the anisotropies of such a background at near-infrared (IR)
frequencies lacks of a complete understanding and shows a robust excess which
cannot be easily explained with known sources. Dark matter in the form of
axion-like particles (ALPs) with a mass around the electronvolt will decay into
two photons with wavelengths in the near-IR band, possibly contributing to the
background intensity. We compute the near-IR background angular power spectrum
including emissions from galaxies, as well as the contributions from the
intra-halo light and ALP decay, and compare it to measurements from the Hubble
Space Telescope and Spitzer. We find that the preferred values for the ALP mass
and ALP-photon coupling to explain the excess are in tension with star cooling
data and observations of dwarf spheroidal galaxies.
