J/A+A/706/A273ivo://CDS.VizieR/J/A+A/706/A273CDSSpina B.Bosman S.E.I.Maity B.Davies F.B.2026-03-02T06:25:50Z2026-02-16T09:46:01ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frquasarsspectroscopyvisible-astronomyinfrared-astronomyultraviolet-astronomyThe Lyman-{alpha} forest of high redshift quasars is a powerful probe of the late stages of the Epoch of Reionization (EoR), in particular thanks to the presence of Gunn-Peterson troughs. These troughs exhibit a broad range of lengths, with some extending up to ~100cMpc, suggesting large-scale coherent structures in the intergalactic medium (IGM). We aim to gain more insight into the presence, extent, and magnitude of correlations in the Lyman-{alpha} forest during the end of reionization, at 5<z<6.1. In particular, we want to quantify the scales over which correlations are significant in order to help inform the required size of cosmological simulations aiming to capture the evolution of the EoR. We utilize the extended XQR-30 dataset over the redshift range 5<z<6.1 ({Delta}z=0.05) to explore large-scale correlations. After accounting for the relevant systematics, the flux correlation matrix proves to be a powerful tool for probing large-scale correlations across redshifts. We perform an MCMC analysis to quantify the extent and strength of the correlation, making use of several functional forms. We moreover employ new large-volume (1.5^3^Gpc^3^) light-cones of Lyman-{alpha} transmission implementing different reionization scenarios to interpret the observed signal, including a fiducial box employing SCRIPT. We detect strong correlations at redshifts z>5.3, extending at least tens of Mpc and strongly increasing with redshift. Our results suggest a redshift-dependent correlation length, from L<=26.53(68.47)Mpc at 1-{sigma} (2-{sigma}) limit at redshift z=5.0 to L=252.72^+272.61^_-41.61_Mpc at redshift z=6.1. On the contrary, our simulations all demonstrate characteristic correlation scales <60Mpc with a very slow redshift evolution, in strong tension with our observations. The presence and redshift-dependence of correlations in the Lyman-{alpha} forest on >200Mpc scales at z=6 indicates that cosmological simulations should be larger than this scale to adequately sample the Lyman-{alpha} forest. Despite implementing a fluctuating UVB and numerous neutral islands at z<6, and matching well the sightline scatter in the Lyman-{alpha} forest, our fiducial SCRIPT- based simulation fails to reproduce the large-scale correlations. It may be that those ingredients are necessary, but not sufficient, to understanding the unfolding of the EoR.2026A&A...706A.273Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/706/A273CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJ/863/92 : LAE cand. at z~5.7 in the field of QSO J0148+0600J/MNRAS/506/4389 : Thermal parameters of the IGM at 2 <= z <= 4 (Gaikwad+,2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/706/A273https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/706/A273http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/706/A273https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/706/A273https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/706/A273http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/706/A273GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapUVOpticalInfrareddefaultJ/A+A/706/A273/table*Correlation matrix and error associated for each pair of redshift binsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintzbin1First redshift bin (z1)src.redshift;spect.binSizedoublezbin2Second redshift bin (z2)src.redshift;spect.binSizedoubleCorCorrelation coefficient (F)stat.correlation;arithdoublee_CorError associated to Cor ({sigma}F)stat.errordouble