0 Assigned ID: 328 ----- Attempting Submission 1 (Fri Apr 05 03:41:34 GMT 2019) ----- Above the thin disk of cold gas and stars lies a warm ionized disk with scale height of a few kpc, along with a circumgalactic medium that may extend to the virial radius (~250 kpc). These components produce absorption lines toward hot stars and background AGNs. From the existing data of many sightlines, we show it is possible to determine the warm gas density distributions in the Milky Way disk and CGM (and the gas mass), as well as their kinematics: the rotation of the CGM (and separately of the disk component); and the accretion rate (or outflow) of the gas. In particular, the data provide the power to determine the steepness of the CGM radial distribution, leading to a major improvement in the MW CGM mass, which is currently uncertain by an order of magnitude. We will measure the rotation of the CGM to an accuracy of about 10 km/s, which is significantly better than the X-ray determination of the rotating hot halo, and is an important angular momentum constraint on the formation of the CGM. The infall rate can also be extracted, which we already detect (5 sigma) with just 8% of the sample. These goals will be achieved by using the Si IV and C IV absorption systems with S/N > 10, for which there are 240 separate sightlnes in the COS archive: 170 external sightlines (mostly AGN); and 70 sightlines toward Galactic stars. This project will provide an accurate velocity field and the best large-scale distribution of the warm gas in the MW, which is crucial for understanding Galactic feedback and accretion. Dr. Joel Bregman has spent most of his career in the area of the gaseous medium of galaxies, clusters, and the IGM. He has published a number of papers in the areas of cooling flows and feedback both in X-ray, UV astronomy, and theory. He has worked with and published both HST imaging data and spectral data. He will contribute in the model development and the interpretation of the results. Dr. Edmund Hodges-Kluck is an expert in diffuse hot and cool gas around galaxies, including absorption-line spectroscopy of the hot gas around the Milky Way, where he measured a rotation signature. He will assist in constructing a self-consistent kinematic model for the warm and hot gas based on the HST results. Dr. Jiangtao Li is an expert on the multi-wavelength observations of the CGM, with expertise on X-ray observations of the hot gas in the halo. He is now leading a few approved X-ray, radio, and optical observations of the sample galaxies. He will participate in the data interpretation and preparation of the paper for publication. Mr. Zhijie Qu works in the observations and theories of the diffuse gaseous components, specifically the warm-hot gas in the galaxy halo. He has several observational studies using HST/COS spectra, including the detection of the hot ions (e.g., MgX and NeVIII) and the warm gas in nearby galaxies (e.g., NGC 891). He will lead the data reduction and the model development. Galaxies and the IGM 0 Regular false false true false false SUPPORTED