0 Assigned ID: 475 ----- Attempting Submission 1 (Fri Aug 17 23:06:41 GMT 2018) ----- HST Phase I Proposal 475 (CCC2.apt) successfully submitted. Receipt: # 475-1 ----- Attempting Submission 2 (Fri Aug 17 23:49:22 GMT 2018) ----- ----- Attempting Submission 3 (Fri Aug 17 23:50:18 GMT 2018) ----- ----- Attempting Submission 4 (Fri Aug 17 23:53:56 GMT 2018) ----- Phase II ID is a required field. Couldn't identify "AR" as a legal selection. Observing Description is a required field. 0 Observations of the circumgalactic medium (CGM) about galaxies are providing independent constraints on cosmological simulations tuned to match galaxies' stellar properties. We propose to produce a large statistical sample of CGM measurements at z<1 using the entire HST/COS G130M/G160M and G185M/G225M archive of QSO observations. We will select galaxy halos using ~300 strong HI absorbers, which have been demonstrated to probe dense gas in the CGM, including tidal material, feedback-expelled material, and intergalactic accretion. We will derive new metallicity estimates for all absorbers, marginalizing over EUV background uncertainties; we will use the ensemble of measurements to quantitatively describe the best ionizing background for deriving future ionization corrections. We will characterize the multiphase ionized gas associated with strong HI-selected galaxy halos using the full set of UV+EUV lines to trace all gas-phases of the CGM at T<500,000 K. We will quantify the dichotomy in the multiphase gas properties between metal-poor (~2% solar) and metal-rich (~40% solar) absorbers to understand the relationship of high ionization gas to accretion and feedback structures. Our survey, of unprecedented size for CGM studies, will provide empirical constraints needed to understand the mismatch between simulations and CGM observations. We will release over 650 fully continuum fitted, science ready COS spectra as part of this program, which will undoubtedly leads to several major ancillary discoveries. Galaxies and the IGM 0 Legacy false false true false SUPPORTED