Abstract
We analyze the association of galaxies with Lyα and O VI absorption, the most commonly detected transitions of the low-z intergalactic medium (IGM), in the fields of 14 quasars with z em = 0.06-0.57. Confirming previous studies, we observe a high covering fraction for Lyα absorption to impact parameter ρ = 300h -1 72kpc: 33/37 of our L > 0.01 L* galaxies show Lyα equivalent width W Lyα ≥ 50m. Galaxies of all luminosity L > 0.01 L* and spectral type are surrounded by a diffuse and ionized circumgalactic medium (CGM), whose baryonic mass is estimated at ∼1010.5±0.3 M ⊙ for a constant N H = 1019 cm -2. The virialized halos and extended CGM of present-day galaxies are responsible for most strong Lyα absorbers (W Lyα > 300m) but cannot reproduce the majority of observed lines in the Lyα forest. We conclude that the majority of Lyα absorption with W Lyα = 30-300m occurs in the cosmic web predicted by cosmological simulations and estimate a characteristic width for these filaments of 400h -1 72kpc. Regarding O VI, we observe a near unity covering fraction to ρ = 200h -1 72kpc for L > 0.1 L* galaxies and to ρ = 300h -1 72kpc for sub-L* (0.1 L* < L < L*) galaxies. Similar to our Lyα results, stronger O VI systems (W 1031 > 70m) arise in the virialized halos of L > 0.1 L* galaxies. Unlike Lyα, the weaker O VI systems (W 1031 30m) arise in the extended CGM of sub-L* galaxies. The majority of O VI gas observed in the low-z IGM is associated with a diffuse medium surrounding individual galaxies with L 0.3 L* and rarely originates in the so-called warm-hot IGM (predicted by cosmological simulations.
Original language | English (US) |
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Article number | 91 |
Journal | Astrophysical Journal |
Volume | 740 |
Issue number | 2 |
DOIs | |
State | Published - Oct 20 2011 |
Keywords
- galaxies: structure
- intergalactic medium
- large-scale structure of universe
- quasars: absorption lines
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
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Ly{alpha} and OVI in galaxies around quasars
Prochaska, J. X. (Creator), Weiner, B. (Creator), Chen, H.-W. (Creator), Mulchaey, J. (Creator) & Cooksey, K. (Creator), Centre de Donnees Strasbourg (CDS), 2013
DOI: 10.26093/cds/vizier.17400091, https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/740/91
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