J/A+A/657/A122ivo://CDS.VizieR/J/A+A/657/A122doi:10.26093/cds/vizier.36570122CDSKollatschny W.Ochmann M.W.Kaspi S.Schumacher C.Behar E.,Chelouche D.Horne K.Mueller B.Rafter S.E.Chini R.Haas M.,Probst M.A.2022-05-18T14:36:15Z2022-01-21T09:43:30ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleispectroscopyspectrophotometryMrk926 is known to be a highly-variable AGN. Furthermore, it is known to show very broad-line profiles. We intended to study the continuum and line profile variations of this object with high temporal resolution in order to determine its broad-line region (BLR) structure, and to derive its black hole (BH) mass. We carried out a high-cadence spectroscopic variability campaign of Mrk926 with the 10m HET telescope, aided by photometric V-band data taken with the C18 telescope at the Wise Observatory, over a period of about five months. We extracted spectroscopic continuum and line light curves, and computed cross-correlation functions (CCFs) as well as velocity-resolved CCFs with respect to the combined spectroscopic and photometric V-band light curve. The continuum luminosity of Mrk926 showed a drastic decrease during our campaign. The luminosity dropped to less than 50% of its original luminosity within 2.5 months only. Furthermore, the spectra of Mrk926 show complex and very broad Balmer line profiles including outer Balmer satellites ranging from +/-5000 to +/-13000km/s. The integrated H{alpha}, H{beta} and HeI_5876_ line light curves are delayed relative to the continuum light curve. The Ha and Hb lines show two velocity-delay structures in the central part of their line profile (within +/-5000km/s) at ~10 and ~57 light-days, and at ~5 and ~48 light-days, respectively. These structures might be interpreted as the upper and lower half of an ellipse in the velocity-delay plane, that might be the signature of a line-emitting ring, inclined by ~50{deg} to the line of sight, orbiting the black hole at radii R of 33.5 and 26.5 light-days. We determined continuum luminosities log({lambda}*L_({lambda})_/erg/s) of 43.68 to 44.13 which are in good agreement with the established R_(BLR)-L_(AGN) relation. Adopting delays of 33.5 and 26.5 days for Ha and Hb, respectively, we derive a black hole mass of 1.1+/-0.2*10^8^M_{sun}_ which indicates a low Eddington ratio decreasing from 8 to 3 percent during our campaign. The Balmer satellite components show a higher correlation coefficient with respect to the continuum than the central line profile, and their response to the continuum variations is of the order of only 3-5 days. We attribute this to the central line segment and the Balmer satellites having different, spatially distinct regions of origin.2022A&A...657A.122Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/657/A122CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/657/A122https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/657/A122http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/657/A122https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/657/A122https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/657/A122http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/657/A122GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/657/A122/wisevmodPhotometric light curverecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJDJulian datedtime.epochdoubleFluxFlux in Bessell V band (arbitrary unit)phot.fluxdoublee_FluxFlux error (arbitrary unit)stat.error;phot.fluxdoubleJ/A+A/657/A122/listList of fits spectrarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNxNumber of pixels along X-axismeta.numberintObs.dateObservation datetime.epoch;obsnullableblambdaLower value of wavelength interval0.1nmem.wlintBlambdaUpper value of wavelength interval0.1nmem.wlfloatdlambdaWavelegnth resolution0.1nmpos.angResolutionfloatsizeSize of FITS fileKibytephys.size;meta.fitsintspShow the spectrummeta.ref.urlcharFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitschar