J/A+A/710/A15ivo://CDS.VizieR/J/A+A/710/A15CDSHovatta T.Lindfors E.Korhonen H.Kharb P.Wittkowski M.Labdon A.,Pursimo T.Wiik K.2026-05-28T07:52:57Z2026-05-28T08:51:07ZCDS support team

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

cds-question@unistra.frpolarimetryquasarsvisible-astronomyParsec-scale jets of blazars have so far been spatially resolved only in millimeter and submillimeter wavelengths, where very long baseline interferometry can be used to obtain milliarcsecond-scale images of the jets. We have attempted to spatially resolve the near-infrared emission in jet-dominated blazars for the first time. We used the VLTI-GRAVITY instrument to obtain milliarcsecond-scale near-infrared interferometric observations of a flaring blazar Ton 599. Additionally, we observed four non-flaring blazars using the GRAVITY-wide mode, where a nearby bright star is used as a fringe tracker. We modeled the squared visibilities of Ton 599 and found that they are incompatible with a single unresolved point source unless there is a significant amount of additional unknown coherence loss in the instrument. With the present data, we cannot distinguish between a model with an unresolved point source and extended emission or coherence loss and a model with a single Gaussian component. This suggests that we are seeing the unresolved or only partially resolved jet-base in near-infrared wavelengths. The wide-field mode of GRAVITY was challenging for the additional relatively faint targets, resulting in either non-detections or poor-quality data that could not be modeled. Our observations demonstrate that it is possible to detect the compact jet emission in blazars with near-infrared interferometry, suggesting that with the improved GRAVITY+ instrument it will be possible to spatially resolve and image the near-infrared emission of blazar jets.2026A&A...710A..15Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/710/A15CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/703/A259 : Multiband optical variability of blazar Ton 599 (Vince+, 2025)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/710/A15https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/710/A15http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/710/A15https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/710/A15https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/710/A15http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/710/A15GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/710/A15/vis2Squared visibilities (Fig. 2)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMlambdaBaseline lengthinstr.baselinefloatV2Visibility squared, V^2^phot.flux;arith.ratiofloate_V21-sigma uncertainty of V2stat.errorfloat