The Connection between Galaxies and Intergalactic Absorption Lines at Redshift 2 <

Content Provider	Semantic Scholar
Author	Adelberger, Kurt L. Shapley, Alice E. Erb, Dawn K. Reddy, N. Amarnath
Copyright Year	2008
Abstract	Absorption-line spectroscopy of 23 background QSOs and numerous background galaxies has let us measure the spatial distribution of metals and neutral hydrogen around 1044 UV-selected galaxies at redshifts 1.8 < ∼ z < ∼ 3.3. The typical galaxy is surrounded to radii r ∼ 40 proper kpc by gas that has a large velocity spread (∆v > 260 km s) and produces very strong absorption lines (NCIV ≫ 10 14 cm) in the spectra of background objects. These absorption lines are almost as strong as those produced by a typical galaxy’s own interstellar gas. Absorption with an average column density of NCIV ≃ 10 14 cm extends to ∼ 80 kpc, a radius large enough to imply that most strong intergalactic CIV absorption is associated with star-forming galaxies like those in our sample. Our measurement of the galaxy/CIV spatial correlation function shows that even the weakest detectable CIV systems are found in the same regions as galaxies; we find that the cross-correlation length increases with CIV column density and is similar to the galaxy auto-correlation length (r0 ∼ 4h −1 Mpc) for NCIV > ∼ 10 12.5 cm. Distortions in the redshift-space galaxy-CIV correlation function on small scales may imply that some of the CIV systems have large peculiar velocities. Four of the five detected OVI absorption systems in our sample lie within 400 proper kpc of a known galaxy. Strong Lyman-α absorption is produced by the intergalactic gas within 1h comoving Mpc of most galaxies, but for a significant minority (∼ 1/3) the absorption is weak or absent. This is not observed in SPH simulations that omit the effects of “feedback” from galaxy formation. We were unable to identify any statistically significant differences in age, dust reddening, environment, or kinematics between galaxies with weak nearby HI absorption and the rest, although galaxies with weak absorption may have higher star-formation rates. Galaxies near intergalactic CIV systems appear to reside in relatively dense environments and to have distinctive spectral energy distributions that are characterized by blue colors and young ages. Subject headings: galaxies: formation — galaxies: high-redshift — intergalactic medium — quasars:
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Alternate Webpage(s)	http://arxiv.org/pdf/astro-ph/0505122v1.pdf
Language	English
Access Restriction	Open
Subject Keyword	Autocorrelation CIV (rail travel) Color Computer simulation Cross-correlation Distortion Eighty Feedback GUCY2C protein, human Galaxy Hydrogen Medical Subject Headings Metals Ovi (Nokia) Physical object Redshift Reside Smoothed-particle hydrodynamics Velocity (software development)
Content Type	Text
Resource Type	Article