J/A+A/710/A217ivo://CDS.VizieR/J/A+A/710/A217CDSBruni G.Panessa F.Kammoun E.Thakur A. L.Reynolds C.Ricci R.,Wieringa M.Bianchi S.De Rosa A.Matt G.Nicastro F.Ursini F.2026-06-22T07:48:46Z2026-06-22T08:36:34ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleiradio-sourcesx-ray-sourcesLow-luminosity active galactic nuclei (LLAGNs) often host weak radio jets whose propagation and impact on their host galaxies are strongly influenced by the surrounding interstellar medium. Constraining the connection between nuclear activity, radio variability, and large-scale radio structures in these systems remains a key observational challenge. We investigate the radio properties of the nearby LLAGN NGC 7213 to assess its ability to launch collimated outflows beyond the nuclear region and to characterise the nature, origin, and variability of newly identified radio components on parsec to kiloparsec scales. We present new radio observations obtained with MeerKAT, uGMRT, ATCA, and the Australian Long Baseline Array (LBA), covering frequencies from 300MHz to 9GHz. We analysed the morphology and spectra of the radio emission on kiloparsec scales and performed a dedicated LBA monitoring campaign to probe the parsec-scale core and its variability. We discovered a pair of compact radio knots located symmetrically at a projected distance of ~5 kpc north and south of the nucleus of NGC 7213. The two knots exhibit nearly identical flux densities and flat radio spectra from 300MHz up to at least 5.5GHz, with no significant spectral or geometric asymmetry. ATCA observations confirm the flat spectra at higher frequencies. The LBA monitoring shows that the nuclear radio source remains unresolved at all epochs, constraining the 8 GHz emission to sub-parsec scales. Significant variability is detected on both decade-long timescales, relative to archival LBA data, and on month-long timescales during our monitoring, with a flux-density increase of ~40mJy over six months. The symmetry, spectra, and physical properties of the kiloparsec-scale knots strongly support their interpretation as compact termination shocks of a weak or intermittent jet launched by the LLAGN in NGC 7213 and confined by the dense, disturbed interstellar medium of the host galaxy. The unresolved yet variable parsec-scale core traced by the LBA indicates that the observed high-frequency radio variability originates in the innermost jet region, which is likely linked to the recent increase in nuclear activity. NGC 7213 thus provides a nearby example of how weak jets in low-accretion AGN can produce both compact nuclear variability and symmetric kiloparsec-scale structures when interacting with complex environments.2026A&A...710A.217Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/710/A217CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/710/A217https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/710/A217http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/710/A217https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/710/A217https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/710/A217http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/710/A217GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tap3.644338263669406e-24 5.963462613277209e-24X-rayRadiodefaultJ/A+A/710/A217/tablec1ATCA radio monitoring of NGC 7213 at 5.5 and 9.0GHz. 27 epochs from 2024 July to 2025 FebruaryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintEpochEpoch number (1-27)meta.id;meta.mainintMJDModified Julian Datedtime.epochdoubleS5.5GHzFlux density at 5.5GHzmJyphot.flux.density;em.radio.3-6GHzinte_S5.5GHz1-sigma error on S5.5GHz (G1)mJystat.errorintS9.0GHzFlux density at 9.0GHzmJyphot.flux.density;em.radio.6-12GHzinte_S9.0GHz1-sigma error on S9.0GHz (G1)mJystat.errorintJ/A+A/710/A217/tabled1*Swift/XRT spectral fitting results (2-10 keV). 79 observations from 2024 March to 2025 DecemberrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJDModified Julian Datedtime.epochfloatNetExpNet exposure timestime.duration;src.net;obs.exposureintF2-10Absorbed 2-10 keV flux (in 10^-11^erg/cm^2^/s)1e-14W.m**-2phot.flux;em.X-ray.mediumfloate_F2-101-sigma error on F2-10 (in 10^-11^erg/cm^2^/s) (G1)1e-14W.m**-2stat.errorfloatGammaPhoton indexmeta.code;spect.indexfloate_Gamma1-sigma error on Gamma (G1)stat.errorfloatC/dofCash statistic / degrees of freedomstat.fit.dofchar