On the kinematics of cold, metal-enriched galactic fountain flows in nearby star-forming falaxies

Galaxie

Stars on Double Duty: Probing Cool Gas in Galaxies at

The luminous components of galaxies can act as powerful probes of halo gas in foreground galaxies along the sightline. We use Keck/LRIS absorption-line spectroscopy of a luminous, blue background galaxy at z = 0.69 to study Mg II halo gas in the outskirts (ρ = 11.1h−1kpc) of a massive, poststarburst galaxy in the foreground at z = 0.47. The foreground absorber shows signs of recent merger activity and is host to a low-luminosity AGN. The halo absorption we observe is extremely strong (Wr(2796) = 4.0 ± 0.1Å) and is indicative of a large Mg II gas velocity width (> 400kms−1). We briefly discuss the possible origins of this absorption, including multiphase cooling of hot halo gas and galactic winds/outflows

The Nature of Ionized Gas in the Milky Way Galactic Fountain

We address the spatial scale, ionization structure, mass, and metal content of gas at the Milky Way disk–halo interface detected as absorption in the foreground of seven closely spaced, high-latitude halo blue horizontal branch stars with heights z = 3–14 kpc. We detect transitions that trace multiple ionization states (e.g., Ca II, Fe II, Si IV, C IV) with column densities that remain constant with height from the disk, indicating that the gas most likely lies within z < 3.4 kpc. The intermediate ionization state gas traced by C IV and Si IV is strongly correlated over the full range of transverse separations probed by our sight lines, indicating large, coherent structures greater than 1 kpc in size. The low ionization state material traced by Ca II and Fe II does not exhibit a correlation with either NH I or transverse separation, implying cloudlets or clumpiness on scales less than 10 pc. We find that the observed ratio log(NSi IV/NC IV), with a median value of −0.69 ± 0.04, is sensitive to the total carbon content of the ionized gas under the assumption of either photoionization or collisional ionization. The only self-consistent solution for photoionized gas requires that Si be depleted onto dust by 0.35 dex relative to the solar Si/C ratio, similar to the level of Si depletion in DLAs and in the Milky Way interstellar medium. The allowed range of values for the areal mass infall rate of warm, ionized gas at the disk−halo interface is 0.0003 < dMgas/dtdA [Me kpc−2 yr−1 ] <0.006. Our data support a physical scenario in which the Milky Way is fed by complex, multiphase processes at its disk−halo interface that involve kiloparsec-scale ionized envelopes or streams containing parsec-scale, cool clumps

On the kinematics of cold, metal-enriched galactic fountain flows in nearby star-forming falaxies

Galaxie

The Seventeenth Data Release of the Sloan Digital Sky Surveys: Complete Release of MaNGA, MaStar, and APOGEE-2 Data

This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 survey that publicly releases infrared spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the subsurvey Time Domain Spectroscopic Survey data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey subsurvey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated value-added catalogs. This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper, Local Volume Mapper, and Black Hole Mapper surveys