J/A+A/608/A36ivo://CDS.VizieR/J/A+A/608/A36doi:10.26093/cds/vizier.36080036CDSTovmassian G.H.Gonzalez-Buitrago D.Thorstensen J.Kotze E.,Breytenbach H.Schwope A.Bernardini F.Zharikov S.V.Hernandez M.S.,Buckley D.A.H.de Miguel E.Hambsch F.-J.Myers G.Goff W.Cejudo D.,Starkey D.Campbell T.Ulowetz J.Stein W.Nelson P.Reichart D.E.,Haislip J.B.Ivarsen K.M.LaCluyze A.P.Moore J.P.Miroshnichenko A.S.2017-12-13T19:31:54Z2017-12-05T11:14:32ZCDS support team

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

cds-question@unistra.frcataclysmic-variable-starsphotometryspectroscopyBased on XMM-Newton X-ray observations IGR J19552+0044 appears to be either a pre-polar or an asynchronous polar. Aims. We conducted follow-up optical observations to identify the sources and periods of variability precisely and to classify this X-ray source correctly. Extensive multicolor photometric and medium- to high-resolution spectroscopy observations were performed and period search codes were applied to sort out the complex variability of the object. We found firm evidence of discording spectroscopic (81.29+/-0.01m) and photometric (83.599+/-0.002m) periods that we ascribe to the white dwarf (WD) spin period and binary orbital period, respectively. This confirms that IGR J19552+0044 is an asynchronous polar. Wavelength dependent variability and its continuously changing shape point at a cyclotron emission from a magnetic WD with a relatively low magnetic field below 20MG. The difference between the WD spin period and the binary orbital period proves that IGR J19552+0044 is a polar with the largest known degree of asynchronism (0.97 or 3%).2017A&A...608A..36Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/608/A36CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/608/A36https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/608/A36http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/608/A36https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/608/A36https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/608/A36http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/608/A36GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/608/A36/listList of spectraTitleTitle of the filemeta.title;meta.fileNspSpectrum number within the observation datemeta.id;meta.mainintspShow the spectrummeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFileNameName of the spectrum file in subdirectory spmeta.id;meta.filecharObs.DateObservation datetime.epoch;obsnullableJ/A+A/608/A36/ibandI band photometry of IGR J19552+0044recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian date (HJD-2450000)time.epochdoublemagMagnitude in Bandmagphot.magfloate_magrms uncertainty on magmagstat.error;phot.magfloatBand[IV] Observed band (Johnson)instr.bandpasscharJ/A+A/608/A36/vbandV band photometry of IGR J19552+0044recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian date (HJD-2450000)time.epochdoublemagMagnitude in Bandmagphot.magfloate_magrms uncertainty on magmagstat.error;phot.magfloatBand[IV] Observed band (Johnson)instr.bandpasschar