J/ApJ/514/148ivo://CDS.VizieR/J/ApJ/514/148doi:10.26093/cds/vizier.15140148CDSDe Grandi S.Bohringer H.Guzzo L.Molendi S.Chincarini G.,Collins C.Cruddace R.Neumann D.Schindler S.Schuecker P.Voges W.2008-05-01T16:04:34Z2008-05-01T16:01:14ZCDS support team

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

cds-question@unistra.frgalaxy-clusterssurveysx-ray-sourcesWe describe the selection of an X-ray flux-limited sample of bright clusters of galaxies in the southern hemisphere, based on the first analysis of the ROSAT All-Sky Survey data (RASS1). The sample is constructed starting from an identification of candidate clusters in RASS1, after which their X-ray fluxes are remeasured using the steepness-ratio technique. This method is better suited than the RASS1 standard algorithm to measuring flux from extended sources. The final sample is count-rate-limited in the ROSAT hard band (0.5-2.0 keV), so that as a result of the distribution of N_H_, its effective flux limit varies between {~}3 and 4x10^-12^ ergs cm^-2^ s^-1^ over the selected area. This covers the {delta} < 2.5{deg} part of the south Galactic cap region (b < -20{deg}), excluding patches of low RASS1 exposure time and of the Magellanic Clouds area, for a total of 8235 deg^2^. One hundred and thirty candidate sources fulfill our selection criteria for bona fide clusters of galaxies in this area. Of these, 101 are Abell/ACO clusters, while 29 do not have a counterpart in these catalogs. Of these clusters, 126 (97%) have a redshift, and for these we compute an X-ray luminosity. 20% of the cluster redshifts come from new observations, as part of the ESO Key Program survey of RASS clusters that is currently under completion. Considering the intrinsic biases and incompletenesses introduced by the flux selection and source identification processes, we estimate the overall completeness to be better than 90%. The observed number count distribution, log Nlog S, is well fitted by a power law with slope {alpha} =1.34{+/-}0.15 and normalization A=11.87{+/-}1.04 sr^-1^ (10^-11^ ergs cm^-2^ s^-1^)^{alpha}^, in good agreement with other measurements.1999ApJ...514..148Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/514/148CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/502/558 : Catalog of ROSAT galaxy clusters (Vikhlinin+ 1998)IX/10A : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/514/148https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/514/148http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/514/148https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/514/148https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/514/148http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/514/148GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/514/148/table1 (ROSAT cluster catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/514/148/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/514/148/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/514/148/table1?GETtext/xml+votable180.050000true0.7892083-35.93944440.005555555555555556ROSAT6/6 16410 16411 16434 16454 16486 16492 16510 16543 16609 16642 16683 16713 16765 16806 17141 17237 17300 17387 17452 17457 17515 17784 18009 18016 18035 18184 18566 18584 18585 18598 18623 18668 18683 18742 19097 19204 20481 20494 20507 20624 20640 20707 21064 21069 21073 21387 22545 22577 22722 22792 23306 32798 32894 32907 33235 33614 33628 33649 34159 34161 34229 34260 34423 34442 34443 34910 35055 35147 35171 35455 35755 35950 35985 36144 37550 38973 39067 39068 39077 39079 39087 39466 39577 39613 45421 45433 45500 45506 45523 45542 45543 45562 45584 45893 45906 45984 45997 46020 46127 46237 46244 46255 46441 46474 46484 46643 46652 46687 46763 46855 46889 46892 46911 47016 47188 47358 47573 48258 48344 48346 48456 48479 48489 48594 48639 48688 48738 48966https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/514/148?format=asciiX-raydefaultJ/ApJ/514/148/table1ROSAT cluster catalogz? Redshiftsrc.redshiftfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeqSequence number in the catalogmeta.id;meta.mainintprimaryRAJ2000Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainNHHydrogen Column density (units of 10^20^ cm^-2^) from Dickey & Lockman (1990ARA&A..28..215D)1e+20cm**-2meta.unit;phys.columnDensityfloatTimeVignetting-corrected exposure timestime.duration;obs.exposurefloatCR5Count rate within a 5' radius from the 0.5-2.0 KeV energy bandct/sphot.count;em.X-rayfloate_CR5Uncertainty (1{sigma}) in CR5ct/sstat.errorfloatCRsrtSteepness-ratio technique (SRT) count rate in the 0.5-2.0 KeV bandct/sphot.count;em.X-rayfloate_CRsrtLower limit to CRsrtct/sstat.errorfloatE_CRsrtUpper limit to CRsrtct/sstat.error;stat.maxfloatProbProbability that the source is pointlike (Prob < 1% is extended)%statfloatFluxUnabsorbed X-ray flux in the 0.5-2.0 KeV band (units of 10^-11^ ergs/cm^2^/s)1e-14W.m**-2phot.flux;em.X-rayfloate_FluxUncertainty (1{sigma}) in Flux1e-14W.m**-2stat.error;phot.fluxfloatLum? X-ray luminosity in the 0.5-2.0 keV band (units 10^44^ ergs/s) (1)1e+37Wphys.luminosity;em.X-rayfloatnullablee_Lum? Uncertainty (1{sigma}) in Lum1e+37Wstat.errorfloatnullableIDOptical identification namemeta.id.crosscharq_ID[ABC] ID class (2)meta.code.qualcharr_z? Redshift reference (see refs.dat)meta.ref;pos.frameintnullablef_zIndicates an estimated redshiftmeta.codecharNote? Notes on single objects (see notes.dat)meta.noteintnullableJ/ApJ/514/148/notesNotes on single sources in table1.datrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeqSequence number of the source in the catalogmeta.numberintNoteNote number referenced in table1.datmeta.noteintTextComments on single sources in table1.datmeta.notecharJ/ApJ/514/148/refsRedshift references in table1.datrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefRedshift reference numbermeta.bibintBibCodeBibliographic reference codemeta.bib.bibcodecharCommentsReference or description of datameta.ref;pos.framechar