COS-burst: Observations of the Impact of Starburst-driven Winds on the Properties of the Circum-galactic Medium

Journal Article · Sun Sep 10 04:00:00 EDT 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/AA80DC· OSTI ID:22679859

Heckman, Timothy; Borthakur, Sanchayeeta ^[1]; Wild, Vivienne ^[2]; Schiminovich, David ^[3]; Bordoloi, Rongmon ^[4]

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1. Center for Astrophysical Sciences, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States)
2. School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9AJ (United Kingdom)
3. Department of Astronomy, Columbia University, New York, NY 10027 (United States)
4. MIT-Kavli Center for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)

We report on observations made with the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope ( HST ) using background quasi-stellar objects to probe the circum-galactic medium (CGM) around 17 low-redshift galaxies that are undergoing or have recently undergone a strong starburst (the COS-Burst program). The sightlines extend out to roughly the virial radius of the galaxy halo. We construct control samples of normal star-forming low-redshift galaxies from the COS/ HST archive that match the starbursts in terms of galaxy stellar mass and impact parameter. We find clear evidence that the CGM around the starbursts differs systematically compared to the control galaxies. The Ly α , Si iii, C iv, and possibly O vi absorption lines are stronger as a function of impact parameter, and the ratios of the equivalent widths of C iv/Ly α and Si iii/Ly α are both higher than in normal star-forming galaxies. We also find that the widths and the velocity offsets (relative to v {sub sys}) of the Ly α absorption lines are significantly larger in the CGM of the starbursts, implying velocities of the absorbing material that are roughly twice the halo virial velocity. We show that these properties can be understood as a consequence of the interaction between a starburst-driven wind and the preexisting CGM. These results underscore the importance of winds driven from intensely star-forming galaxies in helping drive the evolution of galaxies and the intergalactic medium. They also offer a new probe of the properties of starburst-driven winds and of the CGM itself.

• OSTI ID: 22679859
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 846; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION
COMPARATIVE EVALUATIONS
CONTROL
GALAXIES
GALAXY NUCLEI
IMPACT PARAMETER
INTERACTIONS
LYMAN LINES
MASS
QUASARS
RED SHIFT
STAR EVOLUTION
STARS
STELLAR WINDS
TELESCOPES
VELOCITY