ABSORPTION-LINE PROBES OF THE PREVALENCE AND PROPERTIES OF OUTFLOWS IN PRESENT-DAY STAR-FORMING GALAXIES

Journal Article · Sun Aug 15 04:00:00 EDT 2010 · Astronomical Journal (New York, N.Y. Online)

DOI:https://doi.org/10.1088/0004-6256/140/2/445· OSTI ID:21443273

Yanmei, Chen; Kauffmann, Guinevere; Jing, Wang ^[1]; Tremonti, Christy A ^[2]; Heckman, Timothy M ^[3]; Weiner, Benjamin J ^[4]; Brinchmann, Jarle ^[5]

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1. Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany)
2. Department of Astronomy, University of Wisconsin-Madison, 1150 University Avenue, Madison, WI 53706 (United States)
3. Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)
4. Steward Observatory, 933 North Cherry Street, University of Arizona, Tucson, AZ 85721 (United States)
5. 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), Journal Name: Astronomical Journal (New York, N.Y. Online) Journal Issue: 2 Vol. 140; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION
DUSTS
EVOLUTION
GALACTIC EVOLUTION
GALAXIES
GEOMETRY
MATHEMATICS
MOTION
PHYSICAL PROPERTIES
ROTATION
SORPTION
SPECTRA
STARS
VELOCITY