Publication Date:
2013-12-23
Description:
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’ (10 14 ≤ N H I 10 17 cm –2 ) and 496 ‘weak’ (10 13 N H I 〈 10 14 cm –2 ) intervening H i (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 H i absorption systems and 17 509 galaxies at transverse scales 50 Mpc, suitable for a two-point correlation function analysis. We present observational results on the H i –galaxy ( ag ) and galaxy–galaxy ( gg ) correlations at transverse scales r 10 Mpc, and the H i –H i autocorrelation ( aa ) at transverse scales r 2 Mpc. The two-point correlation functions are measured both along and transverse to the line of sight, ( r , r || ). We also infer the shape of their corresponding ‘real-space’ correlation functions, ( r ), from the projected along the line-of-sight correlations, assuming power laws of the form ( r ) = ( r / r 0 ) – . Comparing the results from ag , gg and aa , 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 ~ Mpc scales have little velocity dispersion (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 (~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 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 2 Mpc.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
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