J/A+A/370/468ivo://CDS.VizieR/J/A+A/370/468doi:10.26093/cds/vizier.33700468CDSTorres D.F.Romero G.E.Combi J.A.Benaglia P.Andernach H.Punsly B.2012-09-24T07:14:56Z2001-04-30T11:49:59ZCDS support team

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

cds-question@unistra.frgamma-ray-astronomyradio-sourcesWe present a study of 40 low-latitude unidentified 3EG gamma-ray sources which were found to be not positionally coincident with any known class of potential gamma-ray emitters in the Galaxy (Romero et al., 1999A&A...348..868R). We have performed a variability analysis which reveals that many of these 40 sources are variable. These sources have, in addition, a steep mean value of the gamma-ray spectral index, <{Gamma}>=2.41+/-0.2, which, combined with the high level of variability, seems to rule out a pulsar origin. The positional coincidences with uncatalogued candidates to supernova remnants were also studied. Only 7 sources in the sample are spatially coincident with these candidates, a result that is shown to be consistent with the expected level of pure chance association. A complementary search for weak radio counterparts was also conducted and the results are presented as an extensive table containing all significant point-like radio sources within the 40 EGRET fields. We argue that in order to produce the high variability, steep gamma-ray spectra, and absence of strong radio counterparts observed in some of the gamma-ray sources of our sample, a new class of objects should be postulated, and we analyze a viable candidate.2001A&A...370..468Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/370/468CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJS/123/79 : Third EGRET catalog (3EG) (Hartman+, 1999)J/A+AS/131/11 : Radio sources related to gamma-ray emission (Reich+ 1998)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/370/468https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/370/468http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/370/468https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/370/468https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/370/468http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/370/468GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/370/468/table7 (Statistical variability of AGNs.)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/370/468/table7?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/370/468/table7?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/370/468/table7?GETtext/xml+votable180.050000true31.085915.00860.005555555555555556Cone search capability for table J/A+A/370/468/table1 (Unidentified 3EG sources without known possible galactic counterparts)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/370/468/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/370/468/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/370/468/table1?GETtext/xml+votable180.050000true40.418361.06190.005555555555555556Cone search capability for table J/A+A/370/468/table5a (Gamma-source positions)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/370/468/table5a?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/370/468/table5a?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/370/468/table5a?GETtext/xml+votable180.050000true40.4161.070.005555555555555556Cone search capability for table J/A+A/370/468/table5b (Possible radio-counterparts for each 3EG source.)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/370/468/table5b?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/370/468/table5b?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/370/468/table5b?GETtext/xml+votable180.050000true40.430583361.2015750.005555555555555556Cone search capability for table J/A+A/370/468/table6 (SNRs candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/370/468/table6?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/370/468/table6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/370/468/table6?GETtext/xml+votable180.050000true271.0655-29.91750.0055555555555555565/839 9341 10688 10701 6/556 579 1128 1141 1143 1149 1257 1259-1260 1262 1312 1314 1320 1349 1351 1360-1362 1487 1498 1509 1899 1902 1985 1988 2414 3144-3145 3147-3148 3308 4695 4822 5423 7004 7255 7576 7896 7969 8514 9442 9460 9723 12467 12671 12935 13687 13927 14340 14413 14418 14424-14425 14707 14710 14713 14716 15567 15578 15589 15600 15761-15764 15766 15768-15769 15772 18718 19398 20097 20226 21035 21324 21974 22519 22917 22947 23022 23099 23121 23410 23566 23588 23954 23960 24084 24260 24262 24283 24286 24299 24302 24304-24305 24308 25625 25864 26118 26131 26245 26292 26620 26826 28083 28479 28493 28675 28718 28722 28765 28767 28778 28799 28817 28837 28842 28847-28850 28869 28969 29016 29056 29061 29065 29069 29072 29080 29187-29188 29190 29216 29249 29252 29255 29259 29261 29266 29272 29310-29311 29396-29397 29468-29469 29482 29538-29539 29570 29587 29592-29593 29635 29641 29644 29686 29692-29694 29714 29833 29835-29836 29838 29897 30241 30244 30366 30388-30389 30476 30536 30616 30707 30713 30715-30716 30718 31044 31187 31665 31830 32037 32054 32066 32113 34123 34178 35078 36187 37212 37246 37342 37373-37374 37828 37869 37874 37912 37920 37936-37938 38032 38036 38046 38048 38050 38400 38449 39224 39235 39266 39284 39311 39891 39960 39962-39963 39984 40762 41201 41375 41556 41581 41583 41587 41594 41616 41659 41710 41717 41720 41749 41756 41760 41800 41802 41806 41809 41816 41859 41876 41886 41895 41913 42098 42141 42143 42149 42160 42164-42165 42172 42186 42197 42199 42221 42232 42235 42283 42294 42334-42335 42356-42357 42368 42370 42384 42411 42414 42448 42455 42481 42497 42592 42756 42763 42775 42812-42813 42901 42980 43011 43028 43049 43118-43119 43262 43270 43366 46055 47014 47531 48875 49065https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/370/468?format=asciiGamma-rayRadiodefaultJ/A+A/370/468/table7Statistical variability of AGNs.NvpNumber of viewing periodsmeta.numberintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint3EGJ3EG source designation ("J" omitted)meta.id;meta.maincharprimaryAGNAGN Namemeta.id.crosscharGLONGalactic longitudedegpos.galactic.lonGLATGalactic latitudedegpos.galactic.latSI? Spectral index, {Gamma} (N(E) {prop.to} E^-{Gamma}^)spect.index;em.IR.8-15umfloatnullableFgamma{gamma}-ray flux1e-08cm**-2.s**-1phot.flux.density;em.gamma.hardfloate_Fgammarms uncertainty on Fgamma1e-08cm**-2.s**-1stat.errorfloatmuFluctuation index, {mu}=100{sigma}/<Fgamma>%src.var.indexfloatIAverage statistical index of variability, I=mu/26.9src.var.indexfloat_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/A+A/370/468/table8Variability index I for all low latitude unidentified sourcesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint3EGJ3EG source designation ("J" omitted)meta.id;meta.maincharprimaryIAverage statistical index of variability, I=mu/26.9src.var.indexfloatJ/A+A/370/468/table1Unidentified 3EG sources without known possible galactic counterpartsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint3EGJ3EG source designation ("J" omitted)meta.id;meta.maincharn_3EGJ[+*] Note on 3EG source (1)meta.notecharGLONGalactic longitudedegpos.galactic.lonGLATGalactic latitudedegpos.galactic.late_PosError in the position (2)degstat.errorfloatSISpectral index, {Gamma} (N(E) {prop.to} E^-{Gamma}^)spect.index;em.IR.8-15umfloate_SIrms uncertainty on SIstat.errorfloatFgamma{gamma}-ray flux1e-08cm**-2.s**-1phot.flux.density;em.gamma.hardfloatsigmaStandard deviation of the flux measurements1e-08cm**-2.s**-1stat.stdev;phot.fluxfloatNvpNumber of viewing periodsmeta.numberintmuFluctuation index, {mu}=100{sigma}/<Fgamma>%src.var.indexfloatIAverage statistical index of variability, I={mu}/26.9src.var.indexfloat_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/A+A/370/468/table5aGamma-source positions3EGJGamma-ray 3EG source designation ("J" omitted)meta.id;meta.maincharprimaryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000.0)pos.eq.ra;meta.mainDEJ2000Declination (J2000.0)pos.eq.dec;meta.mainJ/A+A/370/468/table5bPossible radio-counterparts for each 3EG source.recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint3EGJGamma-ray 3EG source name ("J" omitted)meta.id;meta.maincharSeqSequential number (or letter) for group of radio source around gamma-ray sourcemeta.recordcharSurveyRadio survey used (ref. in surveys.dat file)meta.idcharRSourceRadio source namemeta.id.crosscharRAJ2000? Right ascension (J2000)pos.eq.ra;meta.mainnullablee_RAJ2000? rms uncertainty on right ascensionsstat.error;pos.eq.rafloatnullablen_RAJ2000[?n] Note (1)meta.notecharDEJ2000? Declination (J2000)pos.eq.dec;meta.mainnullablee_DEJ2000? rms uncertainty on declinationarcsecstat.error;pos.eq.decdoublenullablen_DEJ2000[?n] Note (1)meta.notecharFreq? Observed frequencyMHzem.freqfloatnullableu_Freq[?n] Note (1)meta.code.errorcharl_FluxLimit flag on Fluxmeta.code.error;phot.fluxcharFlux? Flux at the observed frequencyJyphot.flux.density;em.radiodoublenullablen_Flux[pn] Note (1)meta.notechare_Flux? rms uncertainty on FluxJystat.error;phot.fluxdoublenullablen_e_Flux[?np] Note (1)meta.notecharComComments (2)meta.notecharJ/A+A/370/468/surveySurvey referencesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSurveySurvey designationmeta.idcharprimaryn_Survey? Part of the surveymeta.noteintnullableBibCodeBibCodemeta.bib.bibcodecharAutAuthor's namesmeta.bib.authorcharComCommentsmeta.notecharJ/A+A/370/468/table6SNRs candidatesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGLONGalactic longitudedegpos.galactic.lonGLATGalactic latitudedegpos.galactic.latThetaDiameter of the extended sourcearcminphys.angSizefloat_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