Speaker
Description
Dark matter in cosmic structures is expected to produce signals
originated from its particle physics nature, among which the electromagnetic
emission represents a relevant opportunity, whose intensity is directly linked
to the amount of dark matter in galaxies and clusters. On the other hand, this
emission is very faint, thus contributing only at the unresolved level. These
unresolved radiation backgrounds are isotropic at first order, but must
exhibit a degree of anisotropy since they originate from clustered dark matter
haloes. This fact implies also that the anisotropies in the radiation fields
should be correlated to the same matter distribution in the Universe.
In this talk we propose to exploit this correlation by using the intensity
mapping of the 21cm emission line of neutral hydrogen as the tracer of matter
distribution, and gamma-rays as the tracer of particle dark matter
annihilation. Intensity mapping has the advantage of not being flux limited in
the measurement of the matter distribution (as instead galaxy catalogs are)
since it does not need to identify individual galaxies, and offers excellent
redshift information being a line emission. We show the expected level for
this cross-correlation signal and we derive forecasts for the study of this
novel signature through the combination of Fermi-LAT gamma-rays data and SKA
intensity mapping capabilities.
