Dark galaxies: Probing the ΛCDM cosmological model on unprecedented scales

The currently favoured Lambda-Cold-Dark-Matter (ΛCDM) cosmological model makes specific predictions about theabundance, structure and clustering of dark matter halos (DMHs), the sites where galaxies form. These predictions areaccurate at describing large scale observations.

On smaller scales, the agreement between ΛCDM and observations ofdwarf galaxies is unclear because (i) the structure of DMHs depends on particularities of different galaxy formation models,and (ii) observations of dwarfs suffer from sizable uncertainties. Is ΛCDM successful on small scales?

A definite answer tothis major open question may either reveal the nature of DM or change dramatically our understanding of structure formationin the Universe.

My research will deliver the foundations to probe ΛCDM on unprecedented small scales by exploiting afundamental prediction of the model: the existence of nearby DM-dominated “dark” galaxies (so-called RELHICs).

RELHICsare pristine collapsed DMHs that contain sufficient gas leftover from the epoch of reionization to recombine and emitradiation that can be observed in 21 cm (or recombination lines) but without becoming self-shielding and forming stars.Firstly, I will develop and analyse high-resolution hydrodynamical simulations performed with state-of-the-art numericalcodes that include cutting-edge galaxy formation and radiative-transfer (RT) models to predict the abundance and clusteringof RELHICs.

Secondly, I will design robust survey strategies targeted at detecting RELHICs with current and upcomingobserving facilities (e.g., ALMA, FAST, MEERKAT, WALLABY).

The detection and characterization of REHICs will offer anunprecedented and clean probe to ΛCDM on scales that have not yet been probed.My extensive expertise in numerical simulations, cosmology and galaxy formation, combined with that of Prof.

MicheleFumagalli in RT and physics of the interstellar medium will enable me to materialize my predictions into observational probes.