QSO ABSORPTION SYSTEMS DETECTED IN Ne VIII: HIGH-METALLICITY CLOUDS WITH A LARGE EFFECTIVE CROSS SECTION

Journal Article · Wed Apr 10 04:00:00 EDT 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/767/1/49· OSTI ID:22167399

Meiring, J. D.; Tripp, T. M. ^[1]; Werk, J. K.; Prochaska, J. X. ^[2]; Howk, J. C. ^[3]; Jenkins, E. B. ^[4]; Lehner, N.; Sembach, K. R. ^[5]

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1. Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)
2. University of California Observatories-Lick Observatory, UC Santa Cruz, CA 95064 (United States)
3. Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States)
4. Princeton University Observatory, Peyton Hall, Ivy Lane, Princeton, NJ 08544 (United States)
5. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

Using high-resolution, high signal-to-noise ultraviolet spectra of the z{sub em} = 0.9754 quasar PG1148+549 obtained with the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope, we study the physical conditions and abundances of Ne VIII+O VI absorption line systems at z{sub abs} = 0.68381, 0.70152, 0.72478. In addition to Ne VIII and O VI, absorption lines from multiple ionization stages of oxygen (O II, O III, O IV) are detected and are well aligned with the more highly ionized species. We show that these absorbers are multiphase systems including hot gas (T Almost-Equal-To 10{sup 5.7} K) that produces Ne VIII and O VI, and the gas metallicity of the cool phase ranges from Z = 0.3 Z{sub Sun} to supersolar. The cool ( Almost-Equal-To 10{sup 4} K) phases have densities n{sub H} Almost-Equal-To 10{sup -4} cm{sup -3} and small sizes (<4 kpc); these cool clouds are likely to expand and dissipate, and the Ne VIII may be within a transition layer between the cool gas and a surrounding, much hotter medium. The Ne VIII redshift density, dN/dz{approx}7{sup +7}{sub -3}, requires a large number of these clouds for every L > 0.1 L* galaxy and a large effective absorption cross section ({approx}> 100 kpc), and indeed, we find a star-forming {approx}L {sup *} galaxy at the redshift of the z{sub abs} = 0.72478 system, at an impact parameter of 217 kpc. Multiphase absorbers like these Ne VIII systems are likely to be an important reservoir of baryons and metals in the circumgalactic media of galaxies.

• OSTI ID: 22167399
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 767; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION
ABUNDANCE
BARYONS
CLOUDS
CROSS SECTIONS
DENSITY
GALAXIES
IMPACT PARAMETER
IONIZATION
METALS
OXYGEN
QUASARS
RED SHIFT
RESOLUTION
SIGNAL-TO-NOISE RATIO
STARS
TELESCOPES
ULTRAVIOLET SPECTRA