The Cosmological Density and Ionization of Hot Gas: Oxygen VI Absorption in Quasar Spectra

Abstract

We have conducted the first survey for Oxygen VI $\lambda \lambda 1032,1038$ absorption lines in QSO spectra. We used medium resolution ($R\approx 1300$) high signal-to-noise ($\approx 20$) Faint Object Spectrograph spectra of 11 QSOs ($0.53\le$\zem$\le 2.08$) from the Hubble Space Telescope Archive. We use simulated spectra to determine the significance of the line identifications, which lie exclusively in the \Lya forest. We found 12 O~VI doublets of which 9 are expected to be real and 6 constitute a uniform sample with both lines exceeding a rest equivalent width of $W_r=0.21$ Å. The number of O~VI doublets per unit redshift at a mean absorption redshift of $z_{ave}=0.9$ is $⟨N(z)⟩=1.0\pm 0.6$, which is similar to the density of C~IV and Mg~II absorbers.

28 pages, 5 figures, style file: aaspp4.sty included. Latex file, style file, and five figures are tarred, compressed and uuencoded using uufiles

Cited by in corpus (59)

• The Deuterium Abundance Towards Q1937-1009
• Elemental Abundances in QSOs: Star Formation and Galactic Nuclear Evolution at High Redshifts
• The First Cosmic Structures and their Effects
• The Physics of the Intergalactic Medium
• Probing the IGM/Galaxy Connection V: On the Origin of Lya and OVI Absorption at z<0.2
• The Minimum Universal Metal Density Between Redshifts of 1.5 and 5.5
• Intervening O VI Quasar Absorption Systems at Low Redshift: A Significant Baryon Reservoir
• The Primordial Abundance of He4: An Update
• Probing Galactic Halos with Fast Radio Bursts
• The Distribution of Metallicity in the IGM at z~2.5: OVI and CIV Absorption in the Spectra of 7 QSOs
• The intergalactic medium over the last 10 billion years I: Lyman alpha absorption and physical conditions
• The intergalactic medium over the last 10 billion years II: Metal-line absorption and physical conditions
• Nuclear Astrophysics
• O VI and Multicomponent H I Absorption Associated with a Galaxy Group in the Direction of PG0953+415: Physical Conditions and Baryonic Content
• The detection of oxygen in the low-density intergalactic medium
• Characterizing the Warm-Hot IGM at High Redshift: A High Resolution Survey for O VI at z = 2.5
• The X-Ray Forest: A New Prediction of Hierarchical Structure Formation Models
• Hot Halos around High Redshift Protogalaxies: Observations of O VI and N V Absorption in Damped Lyman Alpha systems
• First Comparison of Ionization and Metallicity in Two Lines of Sight Toward HE 1104-1805 AB at z=1.66
• The Effects of an Early Galactic Wind on the Evolution of D, \he3 and Z
• The enrichment history of the intergalactic medium: O VI in Ly-alpha forest systems at redshift z ~ 2
• Probing the IGM/Galaxy Connection Toward PKS0405-123 I: UV Spectroscopy and Metal-Line Systems
• Is High Primordial Deuterium Consistent With Galactic Evolution?
• Constraining the Metallicity of the Low Density Lyman-alpha Forest Using OVI Absorption
• A STIS Survey for OVI Absorption Systems at 0.12 < z < 0.5 II.: Physical Conditions of the Ionised Gas
• Probing the Intergalactic Medium with the OVI Forest
• A STIS Survey for OVI Absorption Systems at 0.12 < z < 0.5 I.: The Statistical Properties of Ionized Gas
• Probing the IGM-galaxy connection at z<0.5 II. New insights into the galaxy environments of OVI absorbers in PKS 0405-123
• Geometrical Effects of Baryon Density Inhomogeneities on Primordial Nucleosynthesis
• Big Bang Nucleosynthesis and Lepton Number Asymmetry in the Universe
• The Multiple Phases of Interstellar and Halo Gas in a Possible Group of Galaxies at z~1
• Low Mass Stars and the He3 Problem
• Big Bang Nucleosynthesis: an accurate determination of light element yields
• Generalized Limits to the Number of Light Particle Degrees of Freedom from Big Bang Nucleosynthesis
• A Big Bang Nucleosynthesis Likelihood Analysis of the Baryon-to-Photon Ratio and the Number of Light Particle Degrees of Freedom
• Temperature Fluctuations and Abundances in HII Galaxies
• A Stochastic Approach to Chemical Evolution
• GHRS and ORFEUS-II Observations of the Highly Ionized Interstellar Medium Toward ESO141-055
• The Prompt Inventory from Very Massive Stars and Elemental Abundances in Ly Alpha Systems
• High-resolution O VI absorption line observations at 1.2 < z < 1.7 in the bright QSO HE 0515-4414
• The Surprisingly Constant Strength of O VI Absorbers over Cosmic Time
• Star Formation Histories versus Redshift : Consequences for Overall Metallicity and Deuterium Destruction
• A Study of Quasar Proximity in O VI Absorbers at z=2-3
• Anisotropic AGN Outflows and Enrichment of the Intergalactic Medium. II. Metallicity
• Non-Nucleosynthetic Constraints on the Baryon Density and Other Cosmological Parameters
• The Nature and Origin of z_a~z_e Absorption Lines in the Redshift 0.20 Quasar, PKS 2135-147
• Baryonic Mass Fraction in Rich Clusters and the Total Mass Density in the Cosmos
• Finite temperature effects on cosmological baryon diffusion and inhomogeneous Big-Bang nucleosynthesis
• A Differential X-Ray Gunn-Peterson Test Using a Giant Cluster Filament
• High-ion absorption in the proximate damped Lyman-alpha system toward Q0841+129
• A Survey of Metal Lines at High-redshift (II) : SDSS Absorption Line Studies - OVI line density, space density and gas metallicity at z_abs ~ 3.0
• Where are the absorbers towards Q2302+029?
• Big Bang Nucleosynthesis
• Big Bang Nucleosynthesis
• Big Bang Nucleosynthesis
• Big Bang Nucleosynthesis
• Non-BBN Constraints On The Key Cosmological Parameters
• New results in primordial nucleosynthesis
• The BBN Manifesto