PI: Michele Fumagalli, Carnegie Observatories, firstname.lastname@example.org
Address: Carnegie Observatories, 813 Santa Barbara St., Pasadena, CA 91101, USA
CoI: John O'Meara, Saint Michael's College
CoI: Avishai Dekel, The Hebrew University, Jerusalem, Israel
Title: Imaging pristine gas systems at z>2.5
Abstract: Gas inflow on collapsing structures is the most fundamental aspect of galaxy formation. Despite a well-developed theoretical framework, our empirical knowledge of this process remains limited. This proposal aims to move a step forward in detecting gas accretion onto galaxies. We propose to obtain multiband imaging of the surroundings of four gas clouds at z>2.5. These clouds have been discovered in the foreground of quasars using absorption spectroscopy and are known to be nearly pristine in their composition, being at very low metallicity (below 1/100 to 1/10000 the solar value). Three clouds also exhibit a primordial abundance of deuterium. Further, because of the high column density of neutral hydrogen that is observed in these systems, this gas likely resides in overdense regions that are common to the halo of galaxies. All these characteristics are consistently predicted by models to be signatures of infalling material. By associating pristine gas to galaxies with reliable photometric redshifts, this program would offer the best candidates for gas accretion in the high redshift universe.
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