J/MNRAS/462/2695ivo://CDS.VizieR/J/MNRAS/462/2695doi:10.26093/cds/vizier.74622695CDSIlkiewicz K.Mikolajewska J.Stoyanov K.Manousakis A.Miszalski B.2024-08-16T20:18:23Z2018-04-10T15:32:08ZCDS support team

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

cds-question@unistra.frnovaecataclysmic-variable-starsline-intensitiesT CrB is a symbiotic recurrent nova known to exhibit active phases, characterized by apparent increases in the hot component temperature and the appearance of flickering, i.e. changes in the observed flux on the time-scale of minutes. Historical UV observations have ruled out orbital variability as an explanation for flickering and instead suggest flickering is caused by variable mass transfer. We have analysed optical and X-ray observations to investigate the nature of the flickering as well as the active phases in T CrB. The spectroscopic and photometric observations confirm that the active phases follow two periods of ~1000d and ~5000d. Flickering in the X-rays is detected and follows an amplitude-flux relationship similar to that observed in the optical. The flickering is most prominent at harder X-ray energies, suggesting that it originates in the boundary layer between the accretion disc and the white dwarf. The X-ray radiation from the boundary layer is then reprocessed by a thick accretion disc or a nebula into UV radiation. A more detailed understanding of flickering would benefit from long-term simultaneous X-ray and optical monitoring of the phenomena in symbiotic recurrent novae and related systems such as Z And type symbiotic stars.2016MNRAS.462.2695Ihttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/462/2695CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/462/2695https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/462/2695http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/462/2695https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/462/2695https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/462/2695http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/462/2695GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/MNRAS/462/2695/tablea2Emission line fluxesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJDModified Julian datedtime.epochintDateObservation datetime.epoch;obsnullablePhasePhase (1)time.phasefloatVmagV magnitudemagphot.mag;em.opt.VfloatFHeII? Emission line flux of HeII 46861e-16W.m**-2phot.flux;spect.linefloatnullableFHb? Emission line flux of H{beta}1e-16W.m**-2phot.flux;em.line.HbetafloatnullableFHa? Emission line flux of H{alpha}1e-16W.m**-2phot.flux;em.line.HalphaintnullableFHeI? Emission line flux of HeI 58761e-16W.m**-2phot.flux;spect.linefloatnullableJ/MNRAS/462/2695/tablea3Equivalent widths of emission linesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJDModified Julian datedtime.epochintDateObservation datetime.epoch;obsnullablePhasePhase (1)time.phasefloatEWHeII? Equivalent width of HeII 46860.1nmspect.line.eqWidthfloatnullableEWHb? Equivalent width of H{beta}0.1nmspect.line.eqWidth;em.line.HbetafloatnullableEWHa? Equivalent width of H{alpha}0.1nmspect.line.eqWidth;em.line.HalphafloatnullableEWHeI? Equivalent width of HeI 58760.1nmspect.line.eqWidthfloatnullableJ/MNRAS/462/2695/tableb1Swift UVOT observations of T CrBrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateObservation datetime.epoch;obsnullableExpTimeExposure timestime.duration;obs.exposureintFiltUVOT filtermeta.notecharmagMagnitude in filtermagphot.magfloate_magrms uncertainty on magmagstat.error;phot.magfloat