Transverse and longitudinal correlation functions in the Intergalactic Medium from 32 close pairs of high-redshift quasars

Abstract

We present the transverse flux correlation function of the Lyman-alpha forest in quasar absorption spectra at z~2.1 from VLT-FORS and VLT-UVES observations of a total of 32 pairs of quasars; 26 pairs with separations in the range 0.6<theta<4 arcmin and 6 pairs with 4<theta<10 arcmin. Correlation is detected at the 3sigma level up to separations of the order of ~4 arcmin (or ~4.4 h^{-1} Mpc comoving at z=2.1 for Omega_{m}=0.3 and Omega_{Lambda}=0.7). We have, furthermore, measured the longitudinal correlation function at a somewhat higher mean redshift (z=2.39) from 20 lines of sight observed with high spectral resolution and high signal-to-noise ratio with VLT-UVES. We compare the observed transverse and longitudinal correlation functions to that obtained from numerical simulations and illustrate the effect of spectral resolution, thermal broadening and peculiar motions. The shape and correlation length of the correlation functions are in good agreement with those expected from absorption by the filamentary and sheet-like structures in the photoionized warm intergalactic medium predicted in CDM-like models for structures formation. Using a sample of 139 C_{iv} systems detected along the lines of sight toward the pairs of quasars we also investigate the transverse correlation of metals on the same scales. The observed transverse correlation function of intervening C_{iv} absorption systems is consistent with that of a randomly distributed population of absorbers. This is likely due to the small number of pairs with separation less than 2 arcmin. We detect, however, a significant overdensity of systems in the sightlines towards the quartet Q0103-294A&B, Q0102-2931 and Q0102-293 which extends over the redshift range 1.5<z<2.2 and an angular scale larger than 10 arcmin.

accepted for publication in MNRAS, Appendix B and C will be published online only

References in corpus (3)

• The Sources of Intergalactic Metals
• The density structure around quasars from optical depth statistics
• Expansion and Collapse in the Cosmic Web

Cited by in corpus (30)

• Cosmic dynamics in the era of Extremely Large Telescopes
• The ESO UVES Advanced Data Products Quasar Sample - II. Cosmological Evolution of the Neutral Gas Mass Density
• Transverse Sizes of CIV Absorption Systems Measured from Multiple QSO Sightlines
• Keck/Palomar Cosmic Web Imagers (KCWI/PCWI) Reveal an Enormous Ly$\alpha$ Nebula in an Extremely Overdense QSO Pair Field at $z=2.45$
• Tomography of the intergalactic medium with Ly-alpha forests in close QSO pairs
• Lyman continuum leaking AGN in the SSA22 field
• Pressure Support vs. Thermal Broadening in the Lyman-alpha Forest II: Effects of the Equation of State on Transverse Structure
• Simulations of BAO reconstruction with a quasar Lyman-alpha survey
• Metal Absorption Systems in Spectra of Pairs of QSOs
• Galaxy counterparts of intervening high-z sub-DLAs/DLAs and MgII absorbers towards gamma-ray bursts
• High resolution spectroscopy of the three dimensional cosmic web with close QSO groups
• Cross-correlation of the HI 21-cm Signal and Lyman-alpha Forest: A Probe Of Cosmology
• Constraining quasar host halo masses with the strength of nearby Lyman-alpha forest absorption
• Probing Reionization and Early Cosmic Enrichment with the MgII Forest
• Tracing the gas at redshift 1.7-3.5 with the Lyman-alpha forest: the FLO approach
• Three- and two-point spatial correlations of intergalactic medium at $z\sim 2$ using projected quasar triplets
• Constraining dark energy using the cross correlations of weak lensing with post-reionization probes of neutral hydrogen
• A ~6 Mpc overdensity at z = 2.7 detected along a pair of quasar sight lines: filament or protocluster?
• Cosmic density field reconstruction from Ly-alpha forest data
• Predictions for BAO distance estimates from the cross-correlation of the Lyman-alpha forest and redshifted 21-cm emission
• Transverse clues on the kpc-scale structure of the circumgalactic medium as traced by C IV absorption
• The Flux Auto- and Cross-Correlation of the Lyman-alpha Forest. I. Spectroscopy of QSO Pairs with Arcminute Separations and Similar Redshifts
• Three- and two-point spatial correlations of IGM at $z\sim 2$: Cloud based analysis using simulations
• Measurement of redshift-space two- and three-point correlation of Ly$\alpha$ absorbers at $1.7<z<3.5$: Implications on evolution of the physical properties of IGM
• The Flux Auto- and Cross-Correlation of the Lyman-alpha Forest. II. Modelling Anisotropies with Cosmological Hydrodynamic Simulations
• The Statistics of Cosmological Lyman-alpha Absorption
• The multiple coherence scales of C IV at cosmic noon
• Evidence for overdensity around z_em > 4 quasars from the proximity effect
• X-shooter observations of QSO pairs
• Probing dark energy using anisotropies in the clustering of post-EoR HI distribution