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<ri:Resource created="1998-09-24T10:19:18Z" status="active" updated="2025-05-19T09:50:00Z" version="1.2" xmlns:cs="http://www.ivoa.net/xml/ConeSearch/v1.0" xmlns:ri="http://www.ivoa.net/xml/RegistryInterface/v1.0" xmlns:vr="http://www.ivoa.net/xml/VOResource/v1.0" xmlns:vs="http://www.ivoa.net/xml/VODataService/v1.1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.ivoa.net/xml/ConeSearch/v1.0 http://vo.ari.uni-heidelberg.de/docs/schemata/ConeSearch.xsd http://www.ivoa.net/xml/VOResource/v1.0 http://vo.ari.uni-heidelberg.de/docs/schemata/VOResource.xsd http://www.ivoa.net/xml/VODataService/v1.1 http://vo.ari.uni-heidelberg.de/docs/schemata/VODataService.xsd" xsi:type="vs:CatalogService"><title>Einstein EMSS Survey</title><shortName>IX/15</shortName><identifier>ivo://CDS.VizieR/IX/15</identifier><curation><publisher ivo-id="ivo://CDS">CDS</publisher><creator><name>Gioia I.M.</name></creator><creator><name>Maccacaro T.</name></creator><creator><name>Schild R.E.</name></creator><creator><name>Wolter A.</name></creator><date role="Updated">1998-09-24T10:19:25Z</date><date role="Created">1998-09-24T10:19:18Z</date><contact><name>CDS support team</name><address>CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France</address><email>cds-question@unistra.fr</email></contact></curation><content><subject>x-ray-sources</subject><subject>active-galactic-nuclei</subject><subject>bl-lacertae-objects</subject><subject>galaxy-clusters</subject><subject>galaxy-planes</subject><subject>milky-way-galaxy</subject><description>The Einstein Extended Medium Sensitivity Survey (EMSS) consists of 835 serendipitous X-ray sources detected at or above 4 times the rms level in 1435 IPC fields with their centers located away from the galactic plane. Their limiting sensitivities range from ~5*10-14 to to ~ 3*10-12 erg.cm-2.s-1 in the 0.3-3.5keV band. A total area of 778 square degrees of the high galactic latitude sky (|b|&gt;20) has been covered. The analysis has been performed using data from the Rev 1 processing system at the CfA. The resulting EMSS catalog is a flux-limited and homogeneous sample of astronomical objects that can be used for statistical studies. Here we present the table listing all the sources taken from the publication referenced below and the optical identifications. At present over 96% of the 835 X-ray sources have been successfully identified in the following proportions: active galactic nuclei (QSO's, quasars and Seyfert), 51.1%; BL Lacertae objects, 4.3%; clusters of galaxies, 12.2%; normal galaxies, 2.1%; cooling flow galaxies, 0.6%; Galactic stars 25.8%; and unidentified, 3.9%. Most of the individual optical counterparts are previously unknown objects and so constitute large statistical samples independent of previously selection methods. The contents of the table is described below. The sky coverage computed for a specific assumed source spectrum is also given under "Additional Information" below. For further details please see the published articles: Gioia et al. 1990, Stocke et al. 1991. Additional Information: The EMSS sky coverage. ---------------------- This sky coverage has been produced using the counts in the standard detection algorithm and assuming a power law spectrum with energy index = 1 and the measured Galactic hydrogen column density in the direction of each IPC pointing. We caution the user that this sky coverage is not appropriate for computation of functions like logN(&gt;S)-logS, or Luminosity Functions of resolved sources, like clusters of galaxies or "normal" galaxies, nor of stars. The fluxes for these objects have been calculated either using extended counts, when appropriate, and/or different assumptions for the incident spectrum (see below). Limiting Sensitivity Area Covered (erg/cm**2/s) (sq. deg) 5.08E-14 0.09 6.09E-14 0.72 7.31E-14 2.54 8.78E-14 6.37 1.05E-13 15.1 1.26E-13 29.4 1.52E-13 55.2 1.82E-13 94.2 2.18E-13 139.4 2.62E-13 191.6 3.14E-13 249.5 3.77E-13 319.1 4.53E-13 402.0 5.43E-13 497.0 6.52E-13 582.9 7.83E-13 657.7 9.39E-13 711.8 1.13E-12 743.7 1.35E-12 762.7 1.62E-12 771.9 1.95E-12 775.7 2.34E-12 777.4 2.80E-12 777.9 3.36E-12 778.1 --------------------------------------------------------------------------------</description><source format="bibcode">1990ApJS...72..567G</source><referenceURL>https://cdsarc.cds.unistra.fr/viz-bin/cat/IX/15</referenceURL><type>Catalog</type><contentLevel>Research</contentLevel><relationship><relationshipType>IsServedBy</relationshipType><relatedResource ivo-id="ivo://CDS.VizieR/TAP">TAP VizieR generic service</relatedResource></relationship><relationship><relationshipType>IsServedBy</relationshipType><relatedResource>Conesearch service</relatedResource></relationship><relationship><relationshipType>related-to</relationshipType><relatedResource ivo-id="ivo://CDS.VizieR/IX/18">IX/18 : EINSTEIN extended source survey (EXSS) (Oppenheimer+ 1997)</relatedResource><relatedResource ivo-id="ivo://CDS.VizieR/J/ApJ/461/127">J/ApJ/461/127 : The Einstein Two-Sigma Catalog (Moran+ 1996)</relatedResource></relationship></content><rights>https://cds.unistra.fr/vizier-org/licences_vizier.html</rights><capability><interface xsi:type="vr:WebBrowser"><accessURL use="full">https://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=IX/15</accessURL><mirrorURL title="VizieR at IUCAA: Pune, India">https://vizier.iucaa.in/viz-bin/VizieR-2?-source=IX/15</mirrorURL><mirrorURL title="VizieR at SAAO: SAAO, South Africa">http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=IX/15</mirrorURL></interface></capability><capability><interface xsi:type="vs:ParamHTTP"><accessURL use="base">https://vizier.cds.unistra.fr/viz-bin/votable?-source=IX/15</accessURL><mirrorURL title="VizieR at IUCAA: Pune, India">https://vizier.iucaa.in/viz-bin/votable?-source=IX/15</mirrorURL><mirrorURL title="VizieR at SAAO: SAAO, South Africa">http://vizieridia.saao.ac.za/viz-bin/votable?-source=IX/15</mirrorURL><queryType>GET</queryType><resultType>text/xml+votable</resultType></interface></capability><capability standardID="ivo://ivoa.net/std/TAP#aux"><interface xsi:type="vs:ParamHTTP" role="std"><accessURL use="base">https://tapvizier.cds.unistra.fr/TAPVizieR/tap</accessURL></interface></capability><capability xsi:type="cs:ConeSearch" standardID="ivo://ivoa.net/std/ConeSearch"><description>Cone search capability for table IX/15/catalog (EMSS Catalogue)</description><interface xsi:type="vs:ParamHTTP" role="std"><accessURL use="base">https://vizier.cds.unistra.fr/viz-bin/conesearch/IX/15/catalog?</accessURL><mirrorURL title="VizieR at IUCAA: Pune, India">https://vizier.iucaa.in/viz-bin/conesearch/IX/15/catalog?</mirrorURL><mirrorURL title="VizieR at SAAO: SAAO, South Africa">http://vizieridia.saao.ac.za/viz-bin/conesearch/IX/15/catalog?</mirrorURL><queryType>GET</queryType><resultType>text/xml+votable</resultType></interface><maxSR>180.0</maxSR><maxRecords>50000</maxRecords><verbosity>true</verbosity><testQuery><ra>1.256172</ra><dec>16.346961</dec><sr>0.005555555555555556</sr></testQuery></capability><facility>Einstein</facility><coverage><footprint ivo-id="ivo://ivoa.net/std/moc">https://cdsarc.cds.unistra.fr/viz-bin/moc/IX/15?format=ascii</footprint><waveband>X-ray</waveband></coverage><tableset><schema><name>default</name><table><name>IX/15/catalog</name><description>EMSS Catalogue</description><column><name>e_pos</name><description>*Positional Uncertainty</description><unit>arcsec</unit><ucd>stat.error</ucd><dataType xsi:type="vs:VOTableType">int</dataType></column><column><name>z</name><description>*? Redshift</description><ucd>src.redshift</ucd><dataType xsi:type="vs:VOTableType">float</dataType><flag>nullable</flag></column><column><name>recno</name><description>Record number assigned by the VizieR team. Should Not be used for identification.</description><ucd>meta.record</ucd><dataType xsi:type="vs:VOTableType">int</dataType></column><column><name>name</name><description>*Name of EMSS source</description><ucd>meta.id;meta.main</ucd><dataType xsi:type="vs:VOTableType" arraysize="13*">char</dataType></column><column><name>RAB1950</name><description>*Right Ascension (B1950.0) hours</description><ucd>pos.eq.ra;meta.main</ucd></column><column><name>DEB1950</name><description>*Declination sign (B1950.0)</description><ucd>pos.eq.dec;meta.main</ucd></column><column><name>x</name><description>*? Position offset between optical and X-ray</description><unit>arcsec</unit><ucd>pos;arith.diff</ucd><dataType xsi:type="vs:VOTableType">int</dataType><flag>nullable</flag></column><column><name>y</name><description>*? Position offset between optical and X-ray</description><unit>arcsec</unit><ucd>pos;arith.diff</ucd><dataType xsi:type="vs:VOTableType">int</dataType><flag>nullable</flag></column><column><name>fX</name><description>*X-ray flux (*1.E-13 ergs/cm**2/s or *1.E-16 W/m**2) in the 0.3-3.5 keV band</description><unit>1e-16W.m**-2</unit><ucd>phot.flux;em.X-ray</ucd><dataType xsi:type="vs:VOTableType">float</dataType></column><column><name>ext_flag</name><description>*Flagged '*' if source is extended</description><ucd>meta.note</ucd><dataType xsi:type="vs:VOTableType" arraysize="1*">char</dataType></column><column><name>e_fX</name><description>*1 sigma error on X-ray flux</description><unit>1e-16W.m**-2</unit><ucd>stat.error</ucd><dataType xsi:type="vs:VOTableType">float</dataType></column><column><name>ctrate</name><description>*Corrected IPC count rate</description><unit>ct/ks</unit><ucd>phot.count;em.X-ray</ucd><dataType xsi:type="vs:VOTableType">float</dataType></column><column><name>sn</name><description>*Signal to Noise Ratio</description><ucd>stat.snr</ucd><dataType xsi:type="vs:VOTableType">float</dataType></column><column><name>cts</name><description>*Uncorrected net counts in 0.2-3.5 keV</description><ucd>phot.count;em.X-ray</ucd><dataType xsi:type="vs:VOTableType">float</dataType></column><column><name>e_cts</name><description>*Error on net counts</description><ucd>stat.error</ucd><dataType xsi:type="vs:VOTableType">float</dataType></column><column><name>live</name><description>*Corrected exposure time</description><unit>s</unit><ucd>time.duration;obs.exposure</ucd><dataType xsi:type="vs:VOTableType">int</dataType></column><column><name>bkgcts</name><description>*Total background counts</description><ucd>instr.background</ucd><dataType xsi:type="vs:VOTableType">float</dataType></column><column><name>seqno</name><description>*IPC sequence number of the image used</description><ucd>meta.id</ucd><dataType xsi:type="vs:VOTableType">int</dataType></column><column><name>cts_ext</name><description>*? Net extended counts</description><ucd>phot.count;em.X-ray</ucd><dataType xsi:type="vs:VOTableType">int</dataType><flag>nullable</flag></column><column><name>nH</name><description>*Hydrogen column density (*E+25 m^-2 or *E+21 cm^-2)</description><unit>1e+25m**-2</unit><ucd>phys.columnDensity</ucd><dataType xsi:type="vs:VOTableType">float</dataType></column><column><name>Vmag</name><description>*? Visual magnitude</description><unit>mag</unit><ucd>phot.mag;em.opt.V</ucd><dataType xsi:type="vs:VOTableType">float</dataType><flag>nullable</flag></column><column><name>n_fR</name><description>'&lt;' for upper limit in fR</description><ucd>meta.note</ucd><dataType xsi:type="vs:VOTableType" arraysize="1*">char</dataType></column><column><name>fR</name><description>*? Radio flux at 5 GHZ</description><unit>mJy</unit><ucd>phot.flux.density;em.radio.3-6GHz</ucd><dataType xsi:type="vs:VOTableType">float</dataType><flag>nullable</flag></column><column><name>fX/fv</name><description>*? 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