In the era of precision cosmology, astronomers seek to understand how intergalactic gas flows the potential wells of galaxy halos, and how supernovae eject gas, metals, and energy back into the intergalactic medium. Regarding inflows, a variety of observations indirectly indicated that continuous replenishment of the gas reservoir of galaxies must occur, but direct evidence for accretion remains elusive. In contrast, evidence of outflows or galactic-winds is ubiquitous, but our knowledge of their physical origin and properties is still in its infancy after decades of research in this area.
Our limited knowledge on gas-flow properties prevents our ability to produce accurate numerical simulations. Gas in- and out-flows play a critical role in regulating the growth of galaxies. This ANR project « 3DGasFlows » (ANR-17-CE31-0017) aims at putting direct constraints on both in- and out-flow processes through innovation around 4 fronts:
- through observations using the non-conventional technique of background quasars whose line of sight passes near star-forming galaxies;
- through an observational campaign using novel techniques to spatially map outflows in emission using two state-of-the-art IFU surveys which will, by their instrumental or survey design, yield thousands of high signal-to-noise galaxies across cosmic times, enabling us a new view on galactic winds;
- a study of molecular gas content with millimeter interferometers;
- through a theoretical approach using state-of-the-art hydrodynamical simulations and radiative transfer models. The proposed program will allow us to study the circum-galactic medium to an unprecedented level of details with new techniques, to confront the theoretical expectations of cooling and accretion, and to enable major advances in our understanding of the properties of galactic flows.