J/A+A/698/A157ivo://CDS.VizieR/J/A+A/698/A157doi:10.26093/cds/vizier/bc-nt/lbfhCDSOrienti M.D'Ammando F.Dallacasa D.Migliori G.Rossi P.Bodo G.2026-08-03T06:54:52Z2025-06-13T09:02:38ZCDS support team

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

cds-question@unistra.frradio-continuum-emissionactive-galactic-nucleiCompact symmetric objects (CSOs) are intrinsically compact extragalactic radio sources that are thought to be the progenitors of classical radio galaxies. To date, evolutionary models have mainly focused on the formation and growth of high-power radio sources, leaving unanswered many questions related to low-power objects, whose relativistic jets are likely more prone to instabilities. We present a new sample of candidate low-power CSOs selected from the Faint Images of the Radio Sky at Twenty-cm (FIRST) survey. The main selection criteria are (i) a parsec-scale double radio morphology from archival Very Long Baseline Array (VLBA) images and (ii) a VLBA total flux density consistent with that from the FIRST survey, which rules out the presence of significant radio emission extending beyond the parsec scale. The final sample consists of 60 sources with radio luminosities between 10^24^ and 10^27^W/Hz at 1.4GHz and projected linear sizes between 45 and 430pc, which fill a region in the radio power-size plane that is currently underpopulated. We carried out VLBA observations at 4.98GHz of a sub-sample of 20 sources among the brightest candidate CSOs with the aim of confirming their classification. We classify 12 sources as CSOs on the basis of their radio structure and spectral index distribution. In two out of the four CSOs with core identification, the asymmetry in the flux density of the outer components is in agreement with light travel time effects, and there is no evidence of jet-cloud interaction. If we assume a simplistic parametric model, most of the sources in the total sample have a jet power of ~10^44^-10^45^erg/s , making their evolutionary paths sensitive to the individual conditions of the jet and its environment.2025A&A...698A.157Ohttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/698/A157CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/698/A157https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/698/A157http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/698/A157https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/698/A157https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/698/A157http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/698/A157GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/698/A157/list (List of fits images)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/698/A157/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/698/A157/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/698/A157/list?GETtext/xml+votable180.050000true128.7424341.192430.0055555555555555566/4572 4695 5295 6501 8526 9381 9402-9403 10798 10802 11234 11276 11418 26887 27581 28216 28380 28514 28625 31663https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/698/A157?format=asciiRadiodefaultJ/A+A/698/A157/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.numberintObs.dateObservation date'Y:M:D'time.epoch;obsnullableFreqObserved frequencyGHzem.freqdoublesizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitschar