J/A+A/690/A129ivo://CDS.VizieR/J/A+A/690/A129doi:10.26093/cds/vizier.36900129CDSKim J.-S.Nikonov A.S.Roth J.Ensslin T.A.Janssen M.Arras P.,Mueller H.Lobanov A.P.2025-02-12T20:01:08Z2024-10-02T09:11:43ZCDS support team

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

cds-question@unistra.frgalaxiesinterferometrypolarimetryradio-sourcesSelf-calibration methods with the CLEAN algorithm have been widely employed in Very Long Baseline Interferometry (VLBI) data processing in order to correct antenna-based amplitude and phase corruptions present in the data. However, human interaction during the conventional CLEAN self-calibration process can impose a strong effective prior, which in turn may produce artifacts within the final image and hinder the reproducibility of final results. In this work, we aim to demonstrate a combined self-calibration and imaging method for VLBI data in a Bayesian inference framework. The method corrects for amplitude and phase gains for each antenna and polarization mode by inferring the temporal correlation of the gain solutions. We use Stokes I data of M87 taken with the Very Long Baseline Array (VLBA) at 43 GHz, pre-calibrated using the rPICARD CASA-based pipeline. For antenna-based gain calibration and imaging, we use the Bayesian imaging software resolve. To estimate gain and image uncertainties, we use a Variational Inference method. We obtain a high-resolution M87 Stokes I image at 43GHz in conjunction with antenna-based gain solutions using our Bayesian self-calibration and imaging method. The core with counter-jet structure is better resolved, and extended jet emission is better described compared to the CLEAN reconstruction. Furthermore, uncertainty estimation of the image and antenna-based gains allows us to quantify the reliability of the result. Our Bayesian self-calibration and imaging pipeline is able to reconstruct robust and reproducible Stokes I images with gain solutions without the need of human interaction.2024A&A...690A.129Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/690/A129CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/616/A188 : M87 jet VLBI images (Kim+, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/690/A129https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/690/A129http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/690/A129https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/690/A129https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/690/A129http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/690/A129GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/690/A129/list (List of fits images)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/690/A129/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/690/A129/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/690/A129/list?GETtext/xml+votable180.050000true187.7059312.391120.0055555555555555566/27765https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/690/A129?format=asciiRadiodefaultJ/A+A/690/A129/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.mainNyNumber 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.fitscharNxNumber of pixels along X-axismeta.numberint