J/A+A/704/A245ivo://CDS.VizieR/J/A+A/704/A245CDSBruno L.Botteon A.Dallacasa D.Venturi T.Balboni M.Biava N.,Brienza M.Brueggen M.Brunetti G.de Gasperin F.De Rubeis E.,Di Gennaro G.Gastaldello F.Ignesti A.Pasini T.Rajpurohit K.,Shulevski A.Srikanth K.S.L.van Weeren R.J.Zhang X.2026-03-20T07:08:39Z2025-12-15T09:07:05ZCDS support team

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

cds-question@unistra.frgalaxy-clustersradio-galaxiesComplex energy transfer processes in the intracluster medium (ICM) can revive fossil (with spectral ages >>100Myr) plasma initially generated by radio galaxies. This leads to the re-ignition of faint radio sources with irregular and filamentary morphologies, and ultra-steep (alpha>1.5) synchrotron spectra, which can be more easily detected at low frequencies (~100MHz). These sources offer the opportunity to investigate the microphysics of the ICM and its interplay with radio galaxies, the origin of seed relativistic electrons, the merging history of the host cluster, and the phenomenology of radio filaments. The study of revived sources has so far been hampered by the requirement of sensitive and high-resolution multi-frequency radio data at low frequencies to characterise their spatial properties and provide a proper classification. We aim to perform the analysis of a sample of candidate revived sources identified among nearby (z<=0.35) and low-mass (M_500_<=5x10^14^M_{sun}_) Planck clusters in the footprint of the Second Data Release of the LOw Frequency ARray (LOFAR) Two Metre Sky Survey (LoTSS-DR2). By inspecting LoTSS-DR2 images at 144MHz, we identified 7 targets with patchy and filamentary morphologies, which have been followed-up with the upgraded Giant Metrewave Radio Telescope (uGMRT) at 400MHz. By combining LOFAR and uGMRT data, we obtained high-resolution images and spectral index maps, which we used to interpret the nature of the sources. All targets show regions with very steep spectra, confirming the effectiveness of our morphology-based selection in identifying fossil plasma. Based on their morphology, spectral properties, and optical associations, we investigated the origin of the targets. We found a variety of promising revived fossil sources, while also showing that apparently intricate structures can be easily misclassified in the absence of high-resolution and multi-band data.2025A&A...704A.245Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/704/A245CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/704/A245https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/704/A245http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/704/A245https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/704/A245https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/704/A245http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/704/A245GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/704/A245/table1 (Properties of the clusters hosting the candidate revived sources analysed in this work)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/704/A245/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/704/A245/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/704/A245/table1?GETtext/xml+votable180.050000true266.825745.18990.005555555555555556Cone search capability for table J/A+A/704/A245/list (List of fits images)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/704/A245/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/704/A245/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/704/A245/list?GETtext/xml+votable180.050000true266.8075445.121020.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/704/A2456/2173 5438 5468 5524 7243 9593 11537 20335https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/704/A245?format=asciiRadiodefaultJ/A+A/704/A245/table1Properties of the clusters hosting the candidate revived sources analysed in this workrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSimbadSimbad column added by the CDSmeta.ref.urlcharPSZ2PSZ2 host clustermeta.id;meta.maincharAbellAbell host cluster namemeta.idcharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainzCluster redshiftsrc.redshiftfloatM500Cluster mass19+14solMassphys.massfloate_M500Cluster mass error19+14solMassstat.errorfloatR500Cluster radiuskpcphys.size.radiusinte_R500Cluster radius errorkpcstat.errorintScaleAngular to linear scale conversionkpc/arcsecinstr.scalefloatClassCluster classification as No Diffuse Emission (NDE) or Uncertain (U)meta.code.classcharC? Concentrationphys.size;arith.ratiofloatnullablee_C? Concentration errorstat.errorfloatnullableW? Centroid shift morphological X-ray parameters (1)stat.fit.paramfloatnullablee_W? Centroid shift morphological X-ray parameters errorstat.error;pos.cartesian.zfloatnullableJ/A+A/704/A245/listList of fits imagesDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintObs.dateObservation datestime.epoch;obsnullableFreqObserved frequencyMHzem.freqfloatsizeSize of FITS fileKibytephys.size;meta.fitsintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitscharAssocDataAssociated Data web pagemeta.ref.urlchar