J/MNRAS/467/3172ivo://CDS.VizieR/J/MNRAS/467/3172doi:10.26093/cds/vizier.74673172CDSGaikwad P.Srianand R.Choudhury T.R.Khaire V.2024-08-17T20:18:18Z2019-12-16T10:17:14ZCDS support team

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

cds-question@unistra.frquasarsh-i-line-emissionWe have developed a parallel code called the VoIgt profile Parameter Estimation Routine (VIPER) for automatically fitting the HI Ly{alpha} forest seen in the spectra of quasi-stellar objects (QSOs). We obtained the HI column density distribution function (CDDF) and linewidth (b) parameter distribution for z<0.45 using spectra of 82 QSOs obtained using the Cosmic Origins Spectrograph and VIPER. The consistency of these with existing measurements in the literature validates our code. By comparing this CDDF with those obtained from hydrodynamical simulations, we constrain the H I photoionization rate ({Gamma}_HI_) at z<0.45 in four redshift bins. VIPER, together with the Code for Ionization and Temperature Evolution (CITE), which we developed for GADGET-2, allows us to explore parameter space and perform {chi}^2^ minimization to obtain {Gamma}_HI_. We notice that the b parameters from the simulations are smaller than those derived from observations. We show that the observed b parameter distribution and b versus logNHI scatter can be reproduced in simulations by introducing subgrid-scale turbulence. However, it has very little influence on the derived {Gamma}_HI_. The {Gamma}_HI_(z) obtained here, (3.9+/-0.1)x10^-14^(1+z)^4.98+/-0.11^s^-1^, is in good agreement with the values derived by us using flux-based statistics in a previous article. These values are consistent with the hydrogen ionizing ultraviolet (UV) background being dominated mainly by QSOs, without needing any contribution from non-standard sources of UV photons.2017MNRAS.467.3172Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/467/3172CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/562/A23 : VIMOS Public Extragalactic Survey (VIPERS) DR1 (Garilli+, 2014)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/467/3172https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/467/3172http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/467/3172https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/467/3172https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/467/3172http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/467/3172GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/467/3172/list (List of studied QSOs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/467/3172/list?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/467/3172/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/467/3172/list?GETtext/xml+votable180.050000true157.827208350.89327780.0055555555555555566/2414 4821 5244 5262 5274 5409 5481 5687 5731 5820-5821 6021 6081 6104 6606 7508 7896 8915 9031 10472 11217 15351 16447 17186 17203 17488 17819 18601 18769 19700 22659 25132 25742 27023 27720 28083 28356 28589 31663 33796 33950 35180 35205 35542 35743 36443 37385 46299 46647https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/467/3172?format=asciiRadiodefaultJ/MNRAS/467/3172/listList of studied QSOsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintQSOQSO namemeta.id;meta.maincharzRedshiftsrc.redshiftfloatRAJ2000Simbad right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Simbad declination (J2000)pos.eq.dec;meta.mainSNameSimbad namemeta.idcharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/MNRAS/467/3172/tablea1Fitted parameters from the VIPER line cataloguerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintQSOQSO namemeta.id;meta.maincharlambdaWavelength0.1nmem.wldoublee_lambdarms uncertainty on lambda0.1nmstat.errorfloatlog(NHI)log of HI Column Densitylog(cm**-2)phys.columnDensityfloate_log(NHI)rms uncertainty on log(NHI)log(cm**-2)stat.errorfloatbb parameter (in km/s)km/sstat.paramfloate_brms uncertainty on bkm/sstat.errorfloat