HST/COS SPECTRA OF THREE QSOs THAT PROBE THE CIRCUMGALACTIC MEDIUM OF A SINGLE SPIRAL GALAXY: EVIDENCE FOR GAS RECYCLING AND OUTFLOW

Journal Article · Fri Mar 01 04:00:00 EST 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/765/1/27· OSTI ID:22167644

Keeney, Brian A.; Stocke, John T.; Danforth, Charles W.; Shull, J. Michael; Green, James C. ^[1]; Rosenberg, Jessica L. ^[2]; Ryan-Weber, Emma V. ^[3]

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1. Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309 (United States)
2. Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030 (United States)
3. Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Mail H30, P.O. Box 218, Hawthorn, 3122 VIC (Australia)

We have used the Cosmic Origins Spectrograph (COS) to obtain far-UV spectra of three closely spaced QSO sight lines that probe the circumgalactic medium (CGM) of an edge-on spiral galaxy, ESO 157-49, at impact parameters of 74 and 93 h {sup -1} {sub 70} kpc near its major axis and 172 h {sup -1} {sub 70} kpc along its minor axis. H I Ly{alpha} absorption is detected at the galaxy redshift in the spectra of all three QSOs, and metal lines of Si III, Si IV, and C IV are detected along the two major-axis sight lines. Photoionization models of these clouds suggest metallicities close to the galaxy metallicity, cloud sizes of {approx}1 kpc, and gas masses of {approx}10{sup 4} M {sub Sun }. Given the high covering factor of these clouds, ESO 157-49 could harbor {approx}2 Multiplication-Sign 10{sup 9} M {sub Sun} of warm CGM gas. We detect no metals in the sight line that probes the galaxy along its minor axis, but gas at the galaxy metallicity would not have detectable metal absorption with ionization conditions similar to the major-axis clouds. The kinematics of the major-axis clouds favor these being portions of a 'galactic fountain' of recycled gas, while two of the three minor-axis clouds are constrained geometrically to be outflowing gas. In addition, one of our QSO sight lines probes a second more distant spiral, ESO 157-50, along its major axis at an impact parameter of 88 h {sup -1} {sub 70} kpc. Strong H I Ly{alpha} and C IV absorption only are detected in the QSO spectrum at the redshift of ESO 157-50.

• OSTI ID: 22167644
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 765; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION SPECTRA
ABSORPTION SPECTROSCOPY
ASTRONOMY
ASTROPHYSICS
CARBON IONS
COSMIC GASES
GALAXIES
IMPACT PARAMETER
LYMAN LINES
METALS
PHOTOIONIZATION
QUASARS
RED SHIFT
SILICON IONS
ULTRAVIOLET SPECTRA