ABSORPTION-LINE PROBES OF THE PREVALENCE AND PROPERTIES OF OUTFLOWS IN PRESENT-DAY STAR-FORMING GALAXIES
- Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany)
- Department of Astronomy, University of Wisconsin-Madison, 1150 University Avenue, Madison, WI 53706 (United States)
- Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)
- Steward Observatory, 933 North Cherry Street, University of Arizona, Tucson, AZ 85721 (United States)
- Leiden Observatory, Leiden University, 2300 RA, Leiden (Netherlands)
We analyze star-forming galaxies drawn from SDSS DR7 to show how the interstellar medium (ISM) Na I {lambda}{lambda}5890, 5896 (Na D) absorption lines depend on galaxy physical properties, and to look for evidence of galactic winds. We combine the spectra of galaxies with similar geometry/physical parameters to create composite spectra with signal-to-noise {approx}300. The stellar continuum is modeled using stellar population synthesis models, and the continuum-normalized spectrum is fit with two Na I absorption components. We find that (1) ISM Na D absorption lines with equivalent widths EW > 0.8 A are only prevalent in disk galaxies with specific properties-large extinction (A{sub V} ), high star formation rates (SFR), high SFR per unit area ({Sigma}{sub SFR}), or high stellar mass (M{sub *}); (2) the ISM Na D absorption lines can be separated into two components: a quiescent disk-like component at the galaxy systemic velocity and an outflow component; (3) the disk-like component is much stronger in the edge-on systems, and the outflow component covers a wide angle but is stronger within 60{sup 0} of the disk rotation axis; (4) the EW and covering factor of the disk component correlate strongly with dust attenuation, highlighting the importance that dust shielding may play in the survival of Na I; (5) the EW of the outflow component depends primarily on {Sigma}{sub SFR} and secondarily on A{sub V} ; and (6) the outflow velocity varies from {approx}120 to 160 km s{sup -1} but shows little hint of a correlation with galaxy physical properties over the modest dynamic range that our sample probes (1.2 dex in log {Sigma}{sub SFR} and 1 dex in log M{sub *}).
- OSTI ID:
- 21443273
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 140, Issue 2; Other Information: DOI: 10.1088/0004-6256/140/2/445; ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
Similar Records
THE COMPLEX STRUCTURE OF THE MULTI-PHASE GALACTIC WIND IN A STARBURST MERGER
THE PERSISTENCE OF COOL GALACTIC WINDS IN HIGH STELLAR MASS GALAXIES BETWEEN z {approx} 1.4 AND {approx}1