Resolving the Physics of the Circumgalactic and Intergalactic Media with the help of Fluorescent Emission
Sebastiano Cantalupo (Università Milano Bicocca)
Tuesday 01/02/2022 @ 14:00, Remote talk
Our standard cosmological model predicts that galaxies form and evolve through the accretion of gas flowing through the “Cosmic Web” - the network of filaments which connect all galaxies in the universe. The diffuse nature of such gas and previous limitation in our instrumentation hampered until very recent the possibility to directly detect this gas in emission, especially at high redshift, leaving several fundamental gas properties such as morphology, density distribution and kinematics mostly unconstrained. In this talk, I will present the results of an ongoing series of projects which use bright quasars as “flashlight” to illuminate, with fluorescent emission, the gas around galaxies from kpc to Mpc scales. In particular, I will discuss recent multi-wavelength observations using the MUSE and KCWI optical Integral-Field-Spectrographs and MOSFIRE Near-Infrared-Spectroscopy which are revealing unexpected properties of the Circumgalactic Medium around quasars through the study of Ly-alpha, HeII H-alpha and Hydrogen H-alpha fluorescent emission. I will show how these observations, combined with the results of high-resolution radiation-hydrodynamical simulations, could suggest that the Circumgalactic and Intergalactic Media (CGM and IGM) are much more clumpy, multi-phase and turbulent than previously expected from some large-scale cosmological simulations, possibly challenging our understanding of how galaxies get their gas from the CGM. Finally, I will present an overview of ongoing and approved multi-wavelength projects with Chandra, ALMA and JWST on fields with extended IGM and CGM fluorescent emission which will provide a new and more complete view, at high-resolution, of both galaxies and gas around bright quasars.