J/MNRAS/473/1685ivo://CDS.VizieR/J/MNRAS/473/1685doi:10.26093/cds/vizier.74731685CDSCavallaro F.Trigilio C.Umana G.Franzen T.M.O.Norris R.P.Leto P.,Ingallinera A.Buemi C.S.Marvil J.Agliozzo C.Bufano F.,Cerrigone L.Riggi S.2024-08-17T20:21:20Z2020-09-17T11:31:22ZCDS support team

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

cds-question@unistra.frgalaxy-planesmilky-way-galaxyradio-sourcesinterferometryIn the next few years the classification of radio sources observed by the large surveys will be a challenging problem and spectral index is a powerful tool for addressing it. Here we present an algorithm to estimate the spectral index of sources from multiwavelength radio images. We have applied our algorithm to SCORPIO, a Galactic plane survey centred around 2.1GHz carried out with Australian Telescope Compact Array and found we can measure reliable spectral indices only for sources stronger than 40 times the rms noise. Above a threshold of 1mJy, the source density in SCORPIO is 20 per cent greater than in a typical extragalactic field, like Australia Telescope Large Area Survey because of the presence of Galactic sources. Among this excess population, 16 sources per square degree have a spectral index of about zero suggesting optically thin thermal emission such as HII regions and planetary nebulae, while 12 per square degree present a rising spectrum, suggesting optically thick thermal emission such as stars and UCHII regions.2018MNRAS.473.1685Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/473/1685CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/454/902 : SCORPIO 1 catalogue of compact radio sources (Umana+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/473/1685https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/473/1685http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/473/1685https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/473/1685https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/473/1685http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/473/1685GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/473/1685/tablea1 (Spectral indices catalogue)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/473/1685/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/473/1685/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/473/1685/tablea1?GETtext/xml+votable180.050000true252.550863-41.815640.0055555555555555566/42381 42383 42392-42394 42405 424161.3914745465735584e-24 1.3914745465735584e-24https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/473/1685?format=asciiRadiodefaultJ/MNRAS/473/1685/tablea1Spectral indices cataloguerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintScorpio1Scorpio1 designation (NNNa)meta.id;meta.maincharGLONGalactic longitudedegpos.galactic.lonGLATGalactic latitudedegpos.galactic.latS2.1GHzFlux density at 2.1GHzmJyphot.flux.density;em.radio.1500-3000MHzfloate_S2.1GHzrms uncertainty on flux density at 2.1GHzmJystat.errorfloatalphaSpectral indexspect.indexfloate_alpharms uncertainty on alphastat.error;pos.eq.rafloat_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.decnullableindexed