Dark matter microphysics and 21 cm observations

Constraining dark matter through 21 cm observations

Beyond reionization epoch cosmic hydrogen is neutral and can be directly observed through its 21 cm line signal. If dark matter (DM) decays or annihilates the corresponding energy input affects the hydrogen kinetic temperature and ionized fraction, and contributes to the Lyα background. The changes induced by these processes on the 21 cm signal can then be used to constrain the proposed DM cand...

White Noise from Dark Matter: 21 cm Observations of Early Baryon Collapse

In concordance cosmology, dark matter density perturbations generated by inflation lead to nonlinear, virialized minihalos, into which baryons collapse at redshift z ∼ 20. We survey here novel baryon evolution produced by a modification of the power spectrum from white noise density perturbations at scales below k ∼ 10h Mpc (the smallest scales currently measured with the Lyman-α forest). Exoti...

21-cm Synthesis Observations of Virgohi 21 - a Possible Dark Galaxy in the Virgo Cluster

Many observations indicate that dark matter dominates the extra-galactic Universe, yet no totally dark structure of galactic proportions has ever been convincingly identified. Previously we have suggested that VIRGOHI 21, a 21-cm source we found in the Virgo Cluster using Jodrell Bank, was a possible dark galaxy because of its broad line-width (∼ 200 km s−1) unaccompanied by any visible gravita...

Exploring dark matter microphysics with galaxy surveys

We use present cosmological observations and forecasts of future experiments to illustrate the power of large-scale structure (LSS) surveys in probing dark matter (DM) microphysics and unveiling potential deviations from the standard ΛCDM scenario. To quantify this statement, we focus on an extension of ΛCDM with DM–neutrino scattering, which leaves a distinctive imprint on the angular and matt...

CMB and 21-cm signals for dark matter with a long-lived excited state