Thesis Defense: Enrico Garaldi

/Thesis Defense: Enrico Garaldi

Thesis Defense: Enrico Garaldi

Event Details

From galaxies to the cosmic web


Astrophysical phenomena occur on a large variety of spatial scales. Although ubiquitous, the interaction between them is often neglected because of the difficulties in their simultaneous modeling. In this talk I will very briefly describe three cases where this interplay is of primary importance, namely: the assembly bias, the radial acceleration relation and the epoch of cosmic reionization. Then, I will focus on assembly bias and present a detailed numerical investigation of its effect on dark matter halo and galaxies.
Assembly bias denotes the fact that dark matter haloes of the same mass have clustering properties that depend on their formation time. This effect is due to the cosmic environment of such haloes, that halts the accretion of new material in regions where the tidal field exerted by nearby structures is strong. Therefore, the assembly of objects strongly clustered is more efficiently suppressed. In this Thesis, we study the properties of satellite galaxies that reside within haloes with different assembly histories, and therefore cosmic environments. We show that their content is insensitive to the large-scale geometry of the matter distribution. However, the latter has a strong impact on the satellite dynamics, producing a preferentially-radial motion in objects embedded in a knot of the cosmic web, and isotropically-distributed velocities in region within filaments. We apply this knowledge to the satellites of the Milky Way and infer that our Galaxy resides in a prominent filamentary structure.