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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 709737.0, MPI für Astronomie / Publikationen_mpia
On the connection between the intergalactic medium and galaxies: the H I-galaxy cross-correlation at z < 1
Authors:Tejos, N.; Morris, S. L.; Finn, C. W.; Crighton, N. H. M.; Bechtold, J.; Jannuzi, B. T.; Schaye, J.; Theuns, T.; Altay, G.; Le Fèvre, O.; Ryan-Weber, E.; Davé, R.
Date of Publication (YYYY-MM-DD):2014
Title of Journal:Monthly Notices of the Royal Astronomical Society
Issue / Number:3
Start Page:2017
End Page:2075
Audience:Not Specified
Abstract / Description:We present a new optical spectroscopic survey of 1777 `star-forming' (`SF') and 366 `non-star-forming' (`non-SF') galaxies at redshifts z &tilde; 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&lsim; 1017 cm-2) and 496 `weak' (1013 &lsim; NHI < 1014 cm-2) intervening H I (Lyalpha) absorption-line systems at z &lsim; 1 (669 in total), observed in the spectra of eight QSOs at z &tilde; 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 H I absorption systems and 17 509 galaxies at transverse scales &lsim;50 Mpc, suitable for a two-point correlation function analysis. We present observational results on the H I-galaxy (xiag) and galaxy-galaxy (xigg) correlations at transverse scales r&perp; &lsim; 10 Mpc, and the H I-H I autocorrelation (xiaa) at transverse scales r&perp; &lsim; 2 Mpc. The two-point correlation functions are measured both along and transverse to the line of sight, xi(r&perp;, r||). We also infer the shape of their corresponding `real-space' correlation functions, xi(r), from the projected along the line-of-sight correlations, assuming power laws of the form xi(r) = (r/r0)-gamma. Comparing the results from xiag, xigg and xiaa, we constrain the H I-galaxy statistical connection, as a function of both H I column density and galaxy star formation activity. Our results are consistent with the following conclusions: (i) the bulk of H I systems on &tilde; Mpc scales have little velocity dispersion (&lsim;120 km s-1) with respect to the bulk of galaxies (i.e. no strong galaxy outflow/inflow signal is detected); (ii) the vast majority (&tilde;100 per cent) of `strong' H I systems and `SF' galaxies are distributed in the same locations, together with 75 ± 15 per cent of `non-SF' galaxies, all of which typically reside in dark matter haloes of similar masses; (iii) 25 ± 15 per cent of `non-SF' galaxies reside in galaxy clusters and are not correlated with `strong' H I systems at scales &lsim;2 Mpc; and (iv) >50 per cent of `weak' H I 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 H I systems within galaxy voids might still be evolving in the linear regime even at scales &lsim;2 Mpc.
Free Keywords:galaxies: formation; intergalactic medium; quasars: absorption lines; large-scale structure of Universe
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:ISSN:0035-8711 %R 10.1093/mnras/stt1844
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