J/ApJ/481/95ivo://CDS.VizieR/J/ApJ/481/95doi:10.26093/cds/vizier.14810095CDSMattox J.R.Schachter J.Molnar L.Hartman R.C.Patnaik A.R.2013-03-05T06:35:18Z1998-09-19T16:25:08ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleiradio-sourcesgamma-ray-astronomyastronomical-object-identificationWe present a method to assess the reliability of the identification of EGRET sources with extragalactic radio sources. We verify that EGRET is detecting the blazar class of active galactic nuclei (AGNs). However many published identifications are found to be questionable. We provide a table of 42 blazars that we expect to be robust identifications of EGRET sources. This includes one previously unidentified EGRET source, the lensed AGN PKS 1830-210, near the direction of the Galactic center. We provide the best available positions for 16 more radio sources that are also potential identifications for previously unidentified EGRET sources. All high Galactic latitude EGRET sources (|b|>3) that demonstrate significant variability can be identified with flat-spectrum radio sources. This suggests that EGRET is not detecting any type of AGN other than blazars. This identification method has been used to establish with 99.998% confidence that the peak gamma-ray flux of a blazar is correlated with its average 5GHz radio flux. An even better correlation is seen between gamma-ray flux and the 2.29GHz flux density measured with VLBI at the base of the radio jet. Also, using high-confidence identifications, we find that the radio sources identified with EGRET sources have greater correlated VLBI flux densities than the parent population of flat radio spectrum sources.1997ApJ...481...95Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/481/95CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJS/101/259 : The second EGRET catalog (Thompson+ 1995)J/ApJS/107/227 : Supplement to Second EGRET Catalog (Thompson+ 1996)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/481/95https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/481/95http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/481/95https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/481/95https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/481/95http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/481/95GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/481/95/table2 (Potential radio identifications of EGRET sources in the supplement to the second EGRET catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/481/95/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/481/95/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/481/95/table2?GETtext/xml+votable180.050000true66.662516.61050.005555555555555556Cone search capability for table J/ApJ/481/95/table1 (Potential radio identifications of sources in the second EGRET catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/481/95/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/481/95/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/481/95/table1?GETtext/xml+votable180.050000true0.066620.69340.005555555555555556CGRO6/329 515 556 582 909 1085 1214 1313 1362 1899 2019 2411 3145 3477 3819 4820 5423 5816 6112 6640 6646 7004 7426 7576 7592 7896 7968 8514 9442 9460 9723 10200 10251 10340 11063 11407 12286 12461 12467 12671 15310 15646 17411 18208 18718 19398 19421 20099 20225 20472 21371 21393 21769 21974 22517 22919 22947 23124 23411 23518 23526 23545 23588 23995 24081 24261 24308 25022 25068 25214 25864 26131 26156 26245 26292 26340 26611 26944 26983 28086 28479 28492 28675 28767 28935 29016 29072 29252 29570 29593 29836 30388 30746 30806 31015 31665 32614 33100 34123 34259 35079 35305 36958 39023 39130 40760 41089 41334 42188 42874 42945 42958 43262 43366 43822 44331 44629 44813 44908 45218 46066 47862 47873 47893 48685 48874 490703.213643678408261e-24 3.213643678408261e-24https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/481/95?format=asciiGamma-rayRadiodefaultJ/ApJ/481/95/table2Potential radio identifications of EGRET sources in the supplement to the second EGRET catalogrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint2EGJ2000 position name of the EGRET sourcemeta.id;meta.maincharn_2EG[cfj] Note (1)meta.notecharGLONGalactic longitudedegpos.galactic.lonGLATGalactic latitudedegpos.galactic.latn_GLAT[km] Note on GLAT (2)meta.notecharVI? Variability index (3)meta.code;src.var.indexfloatnullableID? EGRET catalogue identification (OtherName in EGRET catalog description)meta.idcharu_ID[?] ?: lower confidence level, else high-confidence levelmeta.code.errorcharRadioIDPossible radio counterpart (4)meta.id.assoccharn_RadioID[abdginxy] Note (5)meta.notecharNamesOther name of counterpartmeta.idcharn_Names[hlew] Note (6)meta.notecharS5GHz? Density flux at 4.85GHzmJyphot.flux.density;em.radio.3-6GHzintnullableSI? Radio spectral indexspect.index;em.radiofloatnullabler0? Characteristic angle between confusing sources that are at least as bright and flat as this radio sourcearcminphys.angSize;srcfloatnullableeta? a priori probability {eta} = p(id) that the source is a {gamma}-ray sourcestat.fit.goodnessdoublenullabler? Angle between the EGRET position estimate and the radio positionarcminpos.angDistancefloatnullabler95? Radius of the 95% confidence contour in the direction of the radio sourcearcminphys.angSizefloatnullableContour? Position contour at the radio position%pos;arith.ratiofloatnullableLR? Likelihood ratio indicating the strength of the indication for the determinationstat.likelihood;phys.atmol.collStrength;arith.ratiodoublenullablep(id/r)? a posteriori probability that the identification is correctmeta.id;stat.probabilitydoublenullable_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data)degpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data)degpos.eq.decnullableindexedJ/ApJ/481/95/table1Potential radio identifications of sources in the second EGRET catalogn_2EG[cfj] Note (1)meta.notecharSI? Radio spectral indexspect.index;em.radiofloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint2EGJ2000 position name of the EGRET sourcemeta.id;meta.maincharGLONGalactic longitudedegpos.galactic.lonGLATGalactic latitudedegpos.galactic.latn_GLAT[km] Note on GLAT (2)meta.notecharVI? Variability index (3)meta.code;src.var.indexfloatnullableID? EGRET catalogue identification (OtherName in EGRET catalog description)meta.idcharu_ID[?] ?: lower confidence level, else high-confidence levelmeta.code.errorcharRadioIDPossible radio counterpart (4)meta.id.assoccharn_RadioID[abdginxy] Note (5)meta.notecharNamesOther name of counterpartmeta.idcharn_Names[hlew] Note (6)meta.notecharS5GHz? Density flux at 4.85GHzmJyphot.flux.density;em.radio.3-6GHzintnullabler0? Characteristic angle between confusing sources that are at least as bright and flat as this radio sourcearcminphys.angSize;srcfloatnullableeta? a priori probability {eta} = p(id) that the source is a {gamma}-ray sourcestat.fit.goodnessdoublenullabler? Angle between the EGRET position estimate and the radio positionarcminpos.angDistancefloatnullabler95? Radius of the 95% confidence contour in the direction of the radio sourcearcminphys.angSizefloatnullableContour? Position contour at the radio position%pos;arith.ratiofloatnullableLR? Likelihood ratio indicating the strength of the indication for the determinationstat.likelihood;phys.atmol.collStrength;arith.ratiodoublenullablep(id/r)? a posteriori probability that the identification is correctmeta.id;stat.probabilitydoublenullable_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data)degpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data)degpos.eq.decnullableindexed