0 Assigned ID: 1820 ----- Attempting Submission 1 (Fri Apr 09 04:30:47 GMT 2021) ----- HST Phase I Proposal 1820 successfully submitted. Receipt: # 1820-1 ----- Attempting Submission 2 (Fri Apr 09 04:35:32 GMT 2021) ----- HST Phase I Proposal 1820 successfully submitted. Receipt: # 1820-2 ----- Attempting Submission 3 (Fri Apr 09 19:08:06 GMT 2021) ----- The circumgalactic medium (CGM) of a galaxy is shaped through inflows of pristine and recycled material and by outflows from starburst and AGN activity. Theoretical expectations are for metallicities in galaxy halos to be higher along the minor axis than along the major axis. However, previous studies have failed to identify a significant trend of this type, despite some indirect suggestions that it should be there. We hypothesize that the trend is "washed out" by methods of metallicity determination that associate all of the HI with the low ionization gas. More sophisticated models have demonstrated that a typical CGM sightline passes through a complex multi-phase, multi-cloud medium, with metallicities sometimes differing by up to 1-2 orders of magnitude between different phases/clouds. We propose an archival analysis of 47 absorption line systems produced by lines of sight through the CGM of galaxies at z<0.7 with known impact parameters and orientations. The analysis will use the photoionization code, CLOUDY, and a cloud-by-cloud, multiphase Bayesian method to separate out the phases along the line of sight, and place formal constraints on metallicity, density, and temperature for all the different gaseous structures. This method has been demonstrated to agree with simulation data, and several of the systems have been analyzed as a proof of concept. We expect either to confirm expectations of higher metallicities along the minor axis in some of the components, or to reveal a higher level of mixing and complexity than expected. Either way it will inform the needed sub-grid physics for next generation cosmological hydrodynamic simulatons of the CGM. Prof. Jane Charlton is an expert in quasar absorption line (QAL) spectroscopy and ionization modeling of quasar absorbers. She has been PI (Co-I) on 9 (over 20) HST programs. She will supervise the work in building detailed multiphase ionization models of the absorbers. Mr. Sameer will be the main graduate student to conduct the modeling work at Penn State, supervised by PI, Charlton. He has developed efficient Bayesian inference based ionization modeling codes. Dr. Jackson Norris has developed the methodology of cloud-by-cloud, multiphase modeling for his dissertation while formerly at Penn State. Dr. Christopher Culliton recently finished work at Penn State. He assisted in preparing this proposal and will contribute his expertise on absorption line modeling to this project. Prof. Chris Churchill is an expert in QAL spectroscopy, ionization modeling, and cosmological simulation. He has been PI of an HST/COS large program (PID:13398). He will contribute in interpreting the analysis and will supervise a student working on the project at NMSU. Prof. Glenn Kacprzak is an expert in galaxy redshift surveys and QAL spectroscopy. He will contribute the data for the "Multiphase Galaxy Halos" survey and aid in paper preparation and interpretation. Prof. Anand Narayanan is an expert in UV spectroscopy. He has worked closely with the COS GTO team. He and his students will contribute in ionization modeling. Dr. Sowgat Muzahid is an expert in QAL spectroscopy and MUSE IFU spectroscopy. He has been the PI of a successful COS program (PID:14655) on probing cluster outskirts using background quasar. He will contribute in COS data reduction, analysis, ionization modelling, and interpretation. Dr. Nikki Nielsen is an expert in QAL spectroscopy and galaxy surveys. She will contribute in analyzing the COS data for the "Multiphase Galaxy Halos" survey and aid in interpretation of connections to galaxy properties. Dr Bart Wakker has an extensive background in studies of the interstellar and intergalactic medium, having published over 100 papers on these subjects, using data from ground-based radio and optical telescopes, as well as many of the UV space instruments (IUE, FUSE, FOS, GHRS, STIS, COS), being PI on 11 HST observing and 5 HST archival projects, as well as Co-PI or Admin-PI on 8 others. Mr Benjamin Rosenwasser is a graduate student at UW Madison who is working on a number of projects analyzing absorption line data, focusing especially on photoionization models and finding galaxies near the QSOs. Intergalactic Medium and the Circumgalactic Medium Galaxies 0 Regular false false true false false SUPPORTED