J/A+A/700/A63ivo://CDS.VizieR/J/A+A/700/A63doi:10.26093/cds/vizier.37000063CDSKutkin A.M.Morganti R.Oosterloo T.A.Adams E.A.K.Denes H.,van Leeuwen J.Norden M.J.Orru E.2025-08-27T20:01:22Z2025-08-06T08:56:13ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleiradio-sourcesWe present two new radio continuum images obtained with Apertif at 1.4GHz. The images, produced with a direction-dependent calibration pipeline, cover 136 square degrees of the Lockman Hole and 24 square degrees of the ELAIS-N fields, with an average resolution of 17x12" and residual noise of 33uJy/beam. With the improved depth of the images we found in total 63692 radio sources, many of which are detected for the first time at this frequency. With the addition of the previously published Apertif catalog for the Bootes field, we cross-match with the LOFAR deep-fields value-added catalogs at 150MHz, resulting in a homogeneous sample of 10196 common sources with spectral index estimates, one of the largest to date. We analyze and discuss the correlations between spectral index, redshift, linear sources size, and radio luminosity, taking into account biases of flux-density-limited surveys. Our results suggest that the observed correlation between spectral index and redshift of active galactic nuclei can be attributed to the Malmquist bias reflecting an intrinsic relation between radio luminosity and the spectral index. We also find a correlation between spectral index and linear source size with more compact sources having steeper spectra.2025A&A...700A..63Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/700/A63CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/700/A63https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/700/A63http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/700/A63https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/700/A63https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/700/A63http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/700/A63GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/700/A63/table1a (Apertif source list for the ELAIS-N field)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/700/A63/table1a?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/700/A63/table1a?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/700/A63/table1a?GETtext/xml+votable180.050000true237.828154.95930.005555555555555556Cone search capability for table J/A+A/700/A63/table1b (Apertif source list for the Lockman Hole field)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/700/A63/table1b?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/700/A63/table1b?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/700/A63/table1b?GETtext/xml+votable180.050000true151.264757.0020.005555555555555556Cone search capability for table J/A+A/700/A63/list (List of fits images)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/700/A63/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/700/A63/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/700/A63/list?GETtext/xml+votable180.050000true242.6110954.458880.0055555555555555564/373-374 377 379-380 382 465 634 5/1487 1491 1500 1502 1515 1524 1526 1532 1857 1859 1868 1872 2837 2880 6/5626-5628 5630 5941-5943 5945-5947 5957-5959 5961-5963 6004-6006 6021 6023 6029 6031 6053-6055 6057 6059 6100 6102 6108 6110 6132 6136 7427 7461 7476 7492 7496 9975 9981-9983 10123 10126-10127 10160 10162 10168 10170 11357 11524-11526 11528-115298.945194077893623e-25 8.945194077893623e-25https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/700/A63?format=asciiRadiodefaultJ/A+A/700/A63/table1aApertif source list for the ELAIS-N fieldrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource name, APTF_JHHMMSS+DDMMSSmeta.id;meta.maincharRAICRSRight ascension (ICRS, J2000)degpos.eq.ra;meta.maine_RAICRSRight ascension errorarcsecstat.error;pos.eq.rafloatDEICRSDeclination (ICRS, J2000)degpos.eq.dec;meta.maine_DEICRSDeclination errorarcsecstat.error;pos.eq.decfloatSCodeSource type as classified by PyBDSF (1)meta.codecharFtotTotal flux density at 1350MHz or 1375MHzmJyphot.flux.density;em.radio.750-1500MHzdoublee_FtotTotal flux density errormJystat.errorfloatFpeakPeak flux density at 1350MHz or 1375MHzmJy/beamphot.flux.density;em.radio.750-1500MHzdoublee_FpeakPeak flux density errormJy/beamstat.errorfloatIslrmslocal background noise RMSuJy/beaminstr.background;pos.lg;pos.lsrfloatJ/A+A/700/A63/table1bApertif source list for the Lockman Hole fieldrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource name, APTF_JHHMMSS+DDMMSSmeta.id;meta.maincharRAICRSRight ascension (ICRS, J2000)degpos.eq.ra;meta.mainindexede_RAICRSRight ascension errorarcsecstat.error;pos.eq.rafloatDEICRSDeclination (ICRS, J2000)degpos.eq.dec;meta.mainindexede_DEICRSDeclination errorarcsecstat.error;pos.eq.decfloatFtotTotal flux density at 1350MHz or 1375MHzmJyphot.flux.density;em.radio.750-1500MHzdoublee_FtotTotal flux density errormJystat.errorfloatFpeakPeak flux density at 1350MHz or 1375MHzmJy/beamphot.flux.density;em.radio.750-1500MHzdoublee_FpeakPeak flux density errormJy/beamstat.errorfloatIslrmslocal background noise RMSuJy/beaminstr.background;pos.lg;pos.lsrfloatSCodeSource type as classified by PyBDSF (1)meta.codecharJ/A+A/700/A63/table3Spectral indices of sources at 1400-150MHzrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintApertifApertif source name (ICRS, J2000), APTF_JHHMMSS+DDMMSSmeta.id;meta.maincharLOFARLOFAR HBA source name (ICRS, J2000), ILTJHHMMSS.ss+DDMMSS.smeta.idcharSIAptHBASpectral index between 1400 and 150MHzphot.flux.density;em.radio.100-200MHzfloate_SIAptHBASpectral index uncertaintystat.errorfloatzbest? Redshift estimate from the LOFAR value-added catalogsrc.redshift;pos.heliocentricfloatnullablelogL150? Luminosity density at 150MHzlog(W.Hz**-1)phys.luminosity;em.radio.100-200MHzfloatnullablen_logL150[i] i for -{infinity}meta.notecharSize150? Linear source size at 150MHzkpcphys.size.radiusfloatnullableJ/A+A/700/A63/listList of fits imagesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintsizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitschar