J/A+AS/129/577ivo://CDS.VizieR/J/A+AS/129/577CDSTakalo L.O.Sillanpaa A.Valtaoja E.Katajainen S.Nilsson K.Pursimo T.Heinamaki P.Villata M.Raiteri C.M.Ghisellini G.,De Francesco G.Lanteri L.Chiaberge M.Peila A.Boltwood P.,Tosti G.Fiorucci M.Terasranta H.Tornikoski M.Teerikorpi P.1998-06-22T07:34:17Z1998-06-22T07:34:13ZCDS support team

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

cds-question@unistra.frbl-lacertae-objectsinfrared-photometryvisible-astronomyWide-band photometryWe present the results of the optical and radio monitoring of the BL Lac object AO 0235+164 during a faint state. In both optical and radio bands the source has been observed at the faintest ever recorded levels, reaching V=19.80 and F_22GHz_=0.34Jy. In the optical bands we still see variability with amplitudes up to 1.5 magnitudes on timescales from days to weeks. The radio variability is less dramatic, but in general follows the optical behaviour. A correlation between general trends in the optical and radio behaviour of AO 0235+164 may be recognized in the data from the present monitoring as well as in the historical light curves, suggesting a `base' mechanism responsible for the emission at both frequencies. A good candidate is a synchrotron process in the relativistic jet. Optical flares with no corresponding radio counterparts have been observed too. These events may be interpreted in terms of microlensing by a foreground galaxy.1998A&AS..129..577Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+AS/129/577CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+AS/129/577https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+AS/129/577http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+AS/129/577https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+AS/129/577https://vizier.iucaa.in/viz-bin/votable?-source=J/A+AS/129/577http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+AS/129/577GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalInfrareddefaultJ/A+AS/129/577/table2The optical observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian datedtime.epochdoubleBmag? B magnitudemagphot.mag;em.opt.Bfloatnullablee_Bmag? rms uncertainty on Bmagmagstat.errorfloatnullableVmag? V magnitudemagphot.mag;em.opt.Vfloatnullablee_Vmag? rms uncertainty on Vmagmagstat.errorfloatnullableRmag? R magnitudemagphot.mag;em.opt.Rfloatnullablee_Rmag? rms uncertainty on Rmagmagstat.errorfloatnullableImag? I magnitudemagphot.mag;em.opt.Ifloatnullablee_Imag? rms uncertainty on Imagmagstat.errorfloatnullableObsObserver (1)obs.observerchar