Mon. Not. R. Astron. Soc., 437, 2017-2075 (2014/January-3)
On the connection between the intergalactic medium and galaxies: the HI-galaxy cross-correlation at z ≲ 1.
TEJOS N., MORRIS S.L., FINN C.W., CRIGHTON N.H.M., BECHTOLD J., JANNUZI B.T., SCHAYE J., THEUNS T., ALTAY G., LE FEVRE O., RYAN-WEBER E. and DAVE R.
Abstract (from CDS):
We present a new optical spectroscopic survey of 1777 `star-forming' (`SF') and 366 `non-star-forming' (`non-SF') galaxies at redshifts z ∼ 0-1 (2143 in total), 22 AGN and 423 stars, observed by instruments such as the Deep Imaging Multi-Object Spectrograph, the Visible Multi-Object Spectrograph and the Gemini Multi-Object Spectrograph, in three fields containing five quasi-stellar objects (QSOs) with Hubble Space Telescope (HST) ultraviolet spectroscopy. We also present a new spectroscopic survey of 173 `strong' (1014 ≤ NHI≲ 1017/cm2) and 496 `weak' (1013 ≲ NHI < 10^14./cm2) intervening Hi (Lyα) absorption-line systems at z ≲ 1 (669 in total), observed in the spectra of eight QSOs at z ∼ 1 by the Cosmic Origins Spectrograph and the Faint Object Spectrograph on the HST. Combining these new data with previously published galaxy catalogues such as the Very Large Telescope Visible Multi-Object Spectrograph Deep Survey and the Gemini Deep Deep Survey, we have gathered a sample of 654 Hi absorption systems and 17509 galaxies at transverse scales ≲ 50Mpc, suitable for a two-point correlation function analysis. We present observational results on the Hi-galaxy (ξag) and galaxy-galaxy (ξgg) correlations at transverse scales r⊥ ≲ 10Mpc, and the Hi-Hi autocorrelation (ξaa) at transverse scales r⊥ ≲ 2Mpc. The two-point correlation functions are measured both along and transverse to the line of sight, ξ(r⊥, r<P>). We also infer the shape of their corresponding `real-space' correlation functions, ξ(r), from the projected along the line-of-sight correlations, assuming power laws of the form ξ(r) = (r/r0)-γ. Comparing the results from ξag, ξgg and ξaa, we constrain the Hi-galaxy statistical connection, as a function of both Hi column density and galaxy star formation activity. Our results are consistent with the following conclusions: (i) the bulk of Hi systems on ∼ Mpc scales have little velocity dispersion ( ≲ 120km/s) with respect to the bulk of galaxies (i.e. no strong galaxy outflow/inflow signal is detected); (ii) the vast majority ( ∼ 100 percent) of `strong' Hi systems and `SF' galaxies are distributed in the same locations, together with 75±15 percent of `non-SF' galaxies, all of which typically reside in dark matter haloes of similar masses; (iii) 25±15 percent of `non-SF' galaxies reside in galaxy clusters and are not correlated with `strong' Hi systems at scales ≲ 2Mpc; and (iv) >50 percent of `weak' Hi systems reside within galaxy voids (hence not correlated with galaxies), and are confined in dark matter haloes of masses smaller than those hosting `strong' systems and/or galaxies. We speculate that Hi systems within galaxy voids might still be evolving in the linear regime even at scales ≲ 2Mpc.
© 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society (2013)
galaxies: formation - intergalactic medium - quasars: absorption lines - large-scale structure of Universe
VizieR on-line data:
<Available at CDS (J/MNRAS/437/2017): tablea1.dat-tablea12.dat >
Tables A9-A12: [TMF2014] DDD.ddddd+DD.ddddd N=1557+947+315+300.
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