Astrophys. J., 629, 636-653 (2005/August-3)
The connection between galaxies and intergalactic absorption lines at redshift 2≲z≲3.
ADELBERGER K.L., SHAPLEY A.E., STEIDEL C.C., PETTINI M., ERB D.K. and REDDY N.A.
Abstract (from CDS):
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 (Δv>260 km/s) and produces very strong absorption lines (N_CIV_≫1014/cm2) 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 N_CIV_≃1014/cm2 extends out to ∼80 kpc, a radius large enough to imply that most strong intergalactic C IV absorption is associated with star-forming galaxies like those in our sample. Our measurement of the galaxy-C IV spatial correlation function shows that even the weakest detectable C IV systems are found in the same regions as galaxies; we find that the cross-correlation length increases with C IV column density and is similar to the galaxy autocorrelation length (r0∼4 h–1 Mpc) for N_CIV_≳1012.5/cm2. Distortions in the redshift-space galaxy-C IV correlation function on small scales may imply that some of the C IV systems have large peculiar velocities. Four of the five detected O VI absorption systems in our sample lie within 400 proper kpc of a known galaxy. Strong Lyα absorption is produced by the intergalactic gas within 1 h–1 comoving Mpc of most galaxies, but for a significant minority (~(1)/(3)) the absorption is weak or absent. This is not observed in smooth-particle hydrodynamic 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 H I absorption and the rest, although galaxies with weak absorption may have higher star formation rates. Galaxies near intergalactic C IV systems appear to reside in relatively dense environments and to have distinctive spectral energy distributions that are characterized by blue colors and young ages.
Galaxies: Formation - Galaxies: High-Redshift - Galaxies: Intergalactic Medium - Galaxies: Quasars: Absorption Lines
Table 2: [ESS2003] Q1623-BXNNN N=2 added, [ESS2003] Q2343-BXNNN N=1 added. Table 3: [ESS2003] Q2346-BXNNN N=2 added.
Table 2: Q2342+125 is not identified, Q2343+125 = [HB93] 2343+125, Q2344+125 = [HB93] 2344+125.
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