J/A+A/642/A136ivo://CDS.VizieR/J/A+A/642/A136doi:10.26093/cds/vizier.36420136CDSBenaglia P.Ishwara-Chandra C.H.Intema H.Colazo M.E.Gaikwad M.2021-04-27T11:58:14Z2020-10-13T10:29:30ZCDS support team

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

cds-question@unistra.frradio-continuum-emissionradio-sourcesObservations at the radio continuum band below the gigahertz band are key when the nature and properties of non-thermal sources are investigated because their radio radiation is strongest at these frequencies. The low radio frequency range is therefore the best to spot possible counterparts to very high-energy (VHE) sources: relativistic particles of the same population are likely to be involved in radio and high-energy radiation processes. Some of these counterparts to VHE sources can be stellar sources. The Cygnus region in the northern sky is one of the richest in this type of sources that are potential counterparts to VHEsources. We surveyed the central ~15 sq deg of the Cygnus constellation at the 325 and 610MHz bands with angular resolutions and sensitivities of 10" and 6", and 0.5 and 0.2mJy/beam, respectively. The data were collected during 172 hours in 2013-2017, using the Giant Metrewave Radio Telescope (GMRT) with 32MHz bandwidth, and were calibrated using the SPAM routines. The source extraction was carried out with the PyBDSF tool,followed by verification through visual inspection of every putative catalog candidate source in order to determine its reliability. In this first paper we present the catalog of sources, consisting of 1048 sources at 325MHz and 2796 sources at 610MHz. By cross-matching the sources from both frequencies with the objects of the SIMBAD database, we found possible counterparts for 143 of them. Most of the sources from the 325MHz catalog (993) were detected at the 610MHz band, and their spectral index alpha was computed adopting S(nu){prop.to}nu^alpha^. The maximum of the spectral index distribution is at alpha=-1, which is characteristic of non-thermal emitters and might indicate an extragalactic population.2020A&A...642A.136Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/642/A136CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/107/1433 : Cygnus OB2 polarimetry (Kobulnicky+, 1994)J/ApJ/643/238 : Chandra/2MASS sources in Cygnus OB2 (Butt+, 2006)J/A+A/464/211 : Cyg OB2 Chandra and near-IR obs. (Albacete Colombo+, 2007)J/A+A/472/557 : Cygnus OB2 region 610MHz sources (Marti+, 2007)J/ApJS/184/84 : X-ray sources in Cyg OB2 region (Wright+, 2009)J/ApJ/713/871 : X-ray sources in star-forming region Cyg-OB2 (Wright+, 2012)J/ApJS/202/19 : riz photometry in Cyg OB2 (Guarcello+, 2012)J/MNRAS/460/2593 : Cygnus OB2 DANCe: Proper motion study (Wright+, 2016)J/A+A/603/A106 : Rotational periods in Cygnus OB2 (Roquette+, 2017)J/A+A/612/A50 : New massive members of Cygnus OB2 (Berlanas+, 2018)J/MNRAS/484/1838 : Spatial substructure of Cygnus OB2 (Berlanas+, 2019)J/A+A/637/A64 : Cygnus OB2 e-MERLIN 21cm survey (COBRaS) (Morford+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/642/A136https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/642/A136http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/642/A136https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/642/A136https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/642/A136http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/642/A136GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/642/A136/table4 (Detected sources at 610MHz above 7sigma)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/642/A136/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/642/A136/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/642/A136/table4?GETtext/xml+votable180.050000true302.883416740.88634440.005555555555555556Cone search capability for table J/A+A/642/A136/table5 (Spectral index of sources detected at both bands)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/642/A136/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/642/A136/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/642/A136/table5?GETtext/xml+votable180.050000true303.485208341.55168610.005555555555555556Cone search capability for table J/A+A/642/A136/table3 (Detected sources at 325MHz above 7sigma)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/642/A136/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/642/A136/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/642/A136/table3?GETtext/xml+votable180.050000true303.477291741.5422250.0055555555555555565/3667 3673-3675 3678 6/14653-14655 14682 14689-14691 14704 14740-14741 14784-14785 14788-14789 148002.1534725313611987e-25 4.0419025326745717e-25https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/642/A136?format=asciiRadiodefaultJ/A+A/642/A136/table4Detected sources at 610MHz above 7sigmarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSource610Source Designation for 610MHz, BIC610-NNNNmeta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.maine_RAJ2000Error on RAsarcsecstat.error;pos.eq.rafloatDEJ2000Declination (J2000)pos.eq.dec;meta.maine_DEJ2000Error on DEsarcsecstat.error;pos.eq.decfloatFTotIntegrated flux at 610MHzmJyphot.flux.density;em.radio.400-750MHzfloate_FTotError on integrated flux at 610MHzmJystat.errorfloatFPeakPeak flux at 610MHzmJy/beamphot.flux.density;em.radio.400-750MHzfloate_FPeakError on peak flux at 610MHzmJy/beamstat.errorfloatMajMajor axis at 610MHzarcsecphys.angSize;em.radio.400-750MHzfloate_MajError on major axis at 610MHzarcsecstat.errorfloatMinMinor axis at 610MHzarcsecphys.angSize;srcfloate_MinError on minor axis at 610MHzarcsecstat.error;stat.minfloatPAPosition angle at 610MHzdegpos.posAngfloate_PAError on position angle at 610MHzdegstat.errorfloatJ/A+A/642/A136/table5Spectral index of sources detected at both bandsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSource325Source Designation for 325MHz, BIC325-NNNNmeta.id;meta.maincharRAJ2000Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainSource610Source Designation(s) for 610MHz, BIC610-NNNNmeta.idcharSp+IndexSpectral index 325/610spect.indexfloate_Sp+IndexError on Spectral indexstat.errorfloatJ/A+A/642/A136/table3Detected sources at 325MHz above 7sigmarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSource325Source Designation for 325MHz, BIC325-NNNNmeta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.maine_RAJ2000Error on RAsarcsecstat.error;pos.eq.rafloatDEJ2000Declination (J2000)pos.eq.dec;meta.maine_DEJ2000Error on DEsarcsecstat.error;pos.eq.decfloatFTotIntegrated flux at 325MHzmJyphot.flux.density;em.radio.200-400MHzfloate_FTotError on integrated flux at 325MHzmJystat.errorfloatFPeakPeak flux at 325MHzmJy/beamphot.flux.density;em.radio.200-400MHzfloate_FPeakError on peak flux at 325MHzmJy/beamstat.errorfloatMajMajor axis at 325MHzarcsecphys.angSize;em.radio.200-400MHzfloate_MajError on major axis at 325MHzarcsecstat.errorfloatMinMinor axis at 325MHzarcsecphys.angSize;srcfloate_MinError on minor axis at 325MHzarcsecstat.error;stat.minfloatPAPosition angle at 325MHzdegpos.posAngfloate_PAError on position angle at 325MHzdegstat.errorfloat