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Dark galaxies: Probing the ΛCDM cosmological model on unprecedented scales


The currently favoured Lambda-Cold-Dark-Matter (ΛCDM) cosmological model makes specific predictions about the
abundance, structure and clustering of dark matter halos (DMHs), the sites where galaxies form. These predictions are
accurate at describing large scale observations. On smaller scales, the agreement between ΛCDM and observations of
dwarf 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 to
this major open question may either reveal the nature of DM or change dramatically our understanding of structure formation
in the Universe. My research will deliver the foundations to probe ΛCDM on unprecedented small scales by exploiting a
fundamental prediction of the model: the existence of nearby DM-dominated “dark” galaxies (so-called RELHICs). RELHICs
are pristine collapsed DMHs that contain sufficient gas leftover from the epoch of reionization to recombine and emit
radiation 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 numerical
codes that include cutting-edge galaxy formation and radiative-transfer (RT) models to predict the abundance and clustering
of RELHICs. Secondly, I will design robust survey strategies targeted at detecting RELHICs with current and upcoming
observing facilities (e.g. ALMA, FAST, MEERKAT, WALLABY). The detection and characterization of REHICs will offer an
unprecedented 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. Michele
Fumagalli in RT and physics of the interstellar medium will enable me to materialize my predictions into observational probes.

Call for proposal

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Piazza Dell'ateneo Nuovo 1
20126 Milano
Activity type
Higher or Secondary Education Establishments
EU contribution
€ 183 473,28