J/ApJ/765/137ivo://CDS.VizieR/J/ApJ/765/137doi:10.26093/cds/vizier.17650137CDSO'Meara J.M.Prochaska J.X.Worseck G.Chen H.-W.Madau P.2017-06-27T06:37:49Z2014-12-01T09:58:49ZCDS support team

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

cds-question@unistra.frquasarsvisible-astronomysloan-photometryredshiftedspectroscopyultraviolet-astronomysurveysWe present the first science results from our Hubble Space Telescope survey for Lyman limit absorption systems (LLS) using the low dispersion spectroscopic modes of the Advanced Camera for Surveys and the Wide Field Camera 3. Through an analysis of 71 quasars, we determine the incidence frequency of LLS per unit redshift and per unit path length, l(z) and l(X), respectively, over the redshift range 1<z<2.6, and find a weighted mean of l(X)=0.29+/-0.05 for 2.0<z<2.5 through a joint analysis of our sample and that of Ribaudo et al. (2011, J/ApJ/736/42). Through stacked spectrum analysis, we determine a median (mean) value of the mean free path to ionizing radiation at z=2.4 of {lambda}^912^_mfp_=243(252)h^-1^_72_Mpc, with an error on the mean value of +/-43h^-1^_72_Mpc. We also re-evaluate the estimates of {lambda}^912^_mfp_ from Prochaska et al. (2010, J/ApJ/718/392) and place constraints on the evolution of {lambda}^912^_mfp_ with redshift, including an estimate of the "breakthrough" redshift of z=1.6. Consistent with results at higher z, we find that a significant fraction of the opacity for absorption of ionizing photons comes from systems with N_HI_<=10^17.5^cm^-2^ with a value for the total Lyman opacity of {tau}^Lyman^_eff_=0.40+/-0.15. Finally, we determine that at minimum, a 5-parameter (4 power law) model is needed to describe the column density distribution function f(N_HI_,X) at z~2.4, find that f(N_HI_,X) undergoes no significant change in shape between z~2.4 and z~3.7, and provide our best fit model for f(N_HI_,X).2013ApJ...765..137Ohttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/765/137CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/hst : HST Archived Exposures Catalog (STScI, 2007)II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)J/MNRAS/435/482 : DLA system from SDSS DR5 (Jorgenson+, 2013)J/ApJS/195/16 : Paper I: HST survey for Lyman limit systems (O'Meara+, 2011)J/ApJ/740/91 : Ly{alpha} in galaxies around quasars (Prochaska+, 2011)J/ApJ/736/42 : HST QSO Catalog (Ribaudo+, 2011)J/ApJ/728/23 : GALEX UV-bright high-redshift quasars (Worseck+, 2011)J/ApJ/718/392 : SDSS Lyman limit systems at z~3.5 (Prochaska+, 2010)J/A+A/505/1087 : DLAs in SDSS-DR7 (Noterdaeme+, 2009)J/AJ/131/2766 : Quasar luminosity function from SDSS-DR3 (Richards+, 2006)J/A+A/458/427 : Lyman alpha absorbers in 0.5<z<1.9 QSOs (Janknecht+, 2006)J/ApJ/635/123 : The SDSS-DR3 damped Ly{alpha} survey (Prochaska+, 2005)J/MNRAS/354/L31 : SDSS DR2 QSO and DLA properties (Murphy+, 2004)J/MNRAS/335/555 : Lyman-alpha forest of 5 QSOs (Kim+, 2002)J/A+A/373/757 : Lyman-Alpha Forest of 3 QSOs (Kim+, 2001)J/ApJ/475/469 : Composite HST Spectrum of Quasars (Zheng+ 1997)http://www.sdss.org/ : SDSS home pagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/765/137https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/765/137http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/765/137https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/765/137https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/765/137http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/765/137GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/765/137/table1 (Quasar sample and continuum)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/765/137/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/765/137/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/765/137/table1?GETtext/xml+votable180.050000true118.949291722.08058330.0055555555555555566/4115 4229 4238 4790 4844 5071 5102 5517 5586 6142 6576 6643 7178 7235 7316 7368 7427 7476 7496 7500 8203 9272 9364 9452 9604 9614 9797 9843 9861 9877 9961 10063 10545 10838 10919 10975 10976 11024 11025 11040 11093 11107 11212 11253 11326 11813 11872 11925 11932 12381 17584 17778 18514 19116 20032 22715 23076 26010 26091 26235 26329 26333 26372 26392 27104 27261 27355 27673 27691 281733.588997330618193e-19 4.653515163505597e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/765/137?format=asciiUVOpticaldefaultJ/ApJ/765/137/table1Quasar sample and continuumSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintInstInstrument (1)meta.id;instrcharNameQuasar name (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharMNumber of absorption redshifts from models (table 2)meta.numberintnullablePlateSDSS-DR7 platemeta.noteintFiberSDSS-DR7 fibermeta.noteintzem[2.2/2.6] SDSS quasar emission redshiftsrc.redshiftfloatg'mag[16.9/18.3] SDSS quasar AB g'-band magnitudemagphot.mag;em.opt.BfloatC[1/235] fitting parameter C (2)stat.paramfloatalpha[0/3] fitting parameter {alpha} (2)stat.paramfloatDR7Display the SDSS-DR7 (II/294) within 1"meta.ref.urlcharSloanDisplay the SDSS data for the nearest objectmeta.ref.urlcharNEDSimbad column added by the CDSmeta.ref.urlchar_RAPositions from quasars names (right ascension part)degpos.eq.ra;meta.main_DEPositions from quasars names (declination part)degpos.eq.dec;meta.mainJ/ApJ/765/137/table2Lyman limit absorption systems (LLS) modelsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintOCodeDescription of HST observationmeta.id;obscharNameQuasar name (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharz[1/2.7] Reshift from absorptionsrc.redshift;pos.heliocentricfloatlogNHI[16/18.6] Log of the H I column densitylog(cm**-2)phys.columnDensityfloatJ/ApJ/765/137/table6WFC3/UVIS-G280 stacked spectrumrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambda[601.9/1555.2] Wavelength; Angstroms0.1nmem.wlfloatFlux[0.4/3.4] Normalized flux (1)phot.flux;arith.ratiofloate_Flux[0/0.2] RMS in Flux (2)stat.error;phot.fluxfloat