Speaker
Fabrizio Nicastro
Description
Baryons are missing at all scales in the Universe, from the largest scale structures down to galaxies.
Hydrodynamical simulations in a Lambda-CDM framework predict that the vast majority of such baryons are roaming in-and-out of galaxies, hiding in a metal-enriched warm-hot phase, at temperatures of 1e5-1e7 K (and perhaps even lower).
The chemical and physical state of these baryons is regulated by the continuous interaction between virtualized structures and the surrounding circum-galactic (CGM) and intergalactic (IGM) medium.
Here, we first briefly review the current observational evidence for the roaming baryons, established from a privileged laboratory, our own Milky Way, and then present our new results from two sizable, S/N-limited samples of Galactic and extragalactic targets, that powerfully constrain and characterize the luke-warm phase of such baryons in the surroundings of the Milky Way.
I will conclude by highlighting the most promising strategies for future deeper studies of the missing baryons, with current and future instrumentation.
