Periodic Reporting for period 4 - FEEDGALAXIES (A new vantage point on how gas flows regulate the build-up of galaxies in the early universe)
Berichtszeitraum: 2021-05-01 bis 2022-10-31
Thanks to the first significant statistical samples, we have been able to develop a novel methodology of analysis that adds new information on the mass of the galaxies that host the gas clouds we observe in absorption, a largely unknown but key quantity to compare observations with the results of numerical simulations. We have further been able to expand this analysis to the most distant epoch in the evolution of the Universe where it is possible to connect gas and galaxies directly. Our pilot observations at this very early times have hinted at a different distribution of galaxies around gas clouds compared to later times, with galaxies preferentially associated with clouds enriched of heavy elements that are illuminated by ionizing radiation. This finding suggests that sites rich of ionized heavy elements are more likely to be pintointing sites where galaxies forms at early times than regions of dense but less enriched and ionized gas.
Another significant advancement of our action has been in demonstrating the importance of the surrounding environment in shaping the gas distribution around galaxies. Thanks to the very complete surveys enabled by MUSE, we have been able to uncover several instances of multiple galaxies that are associated to gas clouds. Our analysis convincingly shows that the cases of multiple galaxies have a different gas distribution compared to isolated galaxies. This shows that in rich environments galaxies can interact more prominently with each other, and this shapes the gas distribution around the galaxies. In line with findings obtained when studying the stellar content of galaxies, our analysis of the CGM confirms that the evolution of galaxies in rich environments follows therefore a different path compared to galaxies that live in isolation. Finally, a very exciting result of this action, which has led to a high-profile publication in the Science magazine, is the first glimpse at the emission from gas in between galaxies (see attached figure). Using MUSE, we have in fact obtained a first view of the filaments connecting the CGM of rapidly star-forming galaxies in a rich cluster of galaxies that was assembling when the Universe was 10 billion years old. This study confirms the great promise of MUSE and of this action to re-shape the view of how gas is distributed in between galaxies.