The Galactic Environment of the NeVIII Absorber toward HE0226-4110

Abstract

We report the discovery of a small galaxy system in the vicinity of the NeVIII absorber at z=0.20701 toward HE0226-4110. The galaxy system consists of two 0.25 L* disk galaxies and a 0.05 L* galaxy all within Δv < 300 km/s and rho< 200 h^{-1} physical kpc of the absorber. We consider various scenarios for the origin of the NeVIII absorption, including photo-ionized gas from a AGN, a starburst driven wind, a hot intragroup medium, hot gas in a galaxy halo, and a conductive front produced by cool clouds moving at high speed through a hot medium. We argue that the conductive front scenario is most likely responsible for producing the NeVIII feature, because it is consistent with the observed galactic environment around the absorber and because it naturally explains the multi-phase nature of the gas and the kinematic signatures of the absorption profiles. Although our preferred scenario suggests that NeVIII may not be directly probing the warm-hot intergalactic medium, it does imply the existence of an extended hot confining medium around a disk galaxy that may contain a significant reservoir of baryons in the form of hot gas.

Accepted for Publication in ApJ Letters; 5 journal-style pages and 1 figure; full-resolution version is available at http://lambda.uchicago.edu/public/tmp/ne8_mc09.pdf

References in corpus (9)

• Time-Dependent Ionization in Radiatively Cooling Gas
• The Search for the Missing Baryons at Low Redshift
• A High-Resolution Survey of Low-Redshift QSO Absorption Lines: Statistics and Physical Conditions of O VI Absorbers
• X-Ray Absorption from the Milky Way Halo and the Local Group
• The Relationship Between Intergalactic HI/OVI and Nearby (z<0.017) Galaxies
• The Void Phenomenon Explained
• A STIS Survey for OVI Absorption Systems at 0.12 < z < 0.5 II.: Physical Conditions of the Ionised Gas
• A STIS Survey for OVI Absorption Systems at 0.12 < z < 0.5 I.: The Statistical Properties of Ionized Gas
• Low Redshift Intergalactic Absorption Lines in the Spectrum of HE0226-4110

Cited by in corpus (17)

• The COS-Halos Survey: An Empirical Description of the Metal-Line Absorption in the Low-Redshift Circumgalactic Medium
• The intergalactic medium over the last 10 billion years II: Metal-line absorption and physical conditions
• The Properties of Low Redshift Intergalactic O VI Absorbers Determined from High S/N Observations of 14 QSOs with the Cosmic Origins Spectrograph
• Probing the IGM-Galaxy Connection at z < 0.5 I: A Galaxy Survey in QSO Fields and a Galaxy-Absorber Cross-Correlation Study
• Hydrogen and Metal Line Absorption Around Low-Redshift Galaxies in Cosmological Hydrodynamic Simulations
• QSO Absorption Systems Detected in Ne VIII: High-Metallicity Clouds with a Large Effective Cross Section
• Probing the IGM-galaxy connection at z<0.5 II. New insights into the galaxy environments of OVI absorbers in PKS 0405-123
• Cosmic Origins Spectrograph Detection of Ne VIII Tracing Warm - Hot Gas Towards PKS 0405-123
• Cos observations of metal line and broad lyman alpha absorption in the multi-phase o vi and ne viii system toward he 02226-4110
• Detection of Ne VIII in an Intervening Multi-Phase Absorption System Towards 3C 263
• COS-Weak: Probing the CGM using analogs of weak Mg II absorbers at z < 0.3
• Understanding the strong intervening OVI absorber at z${}_{abs}$ ~0.93 towards PG1206+459
• Implications of an updated ultraviolet background for the ionization mechanisms of intervening Ne VIII absorbers
• Absorption signatures of warm-hot gas at low redshift: NeVIII
• Detection of Two Intervening Ne VIII Absorbers Probing Warm Gas at z~0.6
• Warm-hot gas in groups and galaxies toward H2356-309
• The Circumgalactic Medium in Massive Halos