J/A+A/486/99ivo://CDS.VizieR/J/A+A/486/99doi:10.26093/cds/vizier.34860099CDSShapovalova A.I.Popovic L.C.Collin S.Burenkov A.N.Chavushyan V.H.,Bochkarev N.G.Benitez E.Dultzin-Hacyan D.Kovacevic A.Borisov N.,Carrasco L.Leon-Tavares J.Mercado A.Valdes J.R.Vlasuyk V.V.,Zhdanova V.E.2017-07-04T07:09:27Z2008-09-14T17:53:04ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleigalaxiesspectroscopyResults of a long-term spectral monitoring of the active galactic nucleus of NGC 4151 are presented (11 years, from 1996 to 2006). High quality spectra (S/N>50 in the continuum near H{alpha} and H{beta}) were obtained in the spectral range ~4000 to 7500{AA}, with a resolution between 5 and 15 {AA}, using the 6-m and the 1-m SAO's telescopes (Russia), the GHAO's 2.1-m telescope (Cananea, Mexico), and the OAN-SPM's 2.1-m telescope (San-Pedro, Mexico). The observed fluxes of the H{alpha}, H{beta}, H{gamma} and HeII{lambda}4686 emission lines and of the continuum at the observed wavelength 5117{AA}, were corrected for the position angle, the seeing and the aperture effects. We found that the continuum and line fluxes varied strongly (up to a factor 6) during the monitoring period. The emission was maximum in 1996-1998, and there were two minima, in 2001 and in 2005. As a consequence, the spectral type of the nucleus changed from a Sy1.5 in the maximum activity state to a Sy1.8 in the minimum state. The H{alpha}, H{gamma} and He{lambda}4686 fluxes were well correlated with the H{beta} flux. The line profiles were strongly variable, showing changes of the blue and red asymmetry. The flux ratios of the blue/red wings and of the blue (or red) wing/core of H{alpha} and H{beta} varied differently. We considered three characteristic periods during which the H{beta} and H{alpha} profiles were similar: 1996-1999, 2000-2001 and 2002-2006. The line to continuum flux ratios were different; in particular during the first period (1996-2001), the lines were not correlated with the continuum and saturated at high fluxes. In the second and third period (2002-2006), where the continuum flux was small, the H{alpha} and H{beta} fluxes were well correlated to the continuum flux, meaning that the ionizing continuum was a good extrapolation of the optical continuum. The CCFs are often asymmetrical and the time lags between the lines and the continuum are badly defined indicating the presence of a complex BLR, with dimensions from a 1 to 50 light-days. We discuss the different responses of H{beta} and H{alpha} to the continuum during the monitoring period.2008A&A...486...99Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/486/99CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/AZh/71/189 : Gas Kinematics from Halpha line in NGC 4151 (Sergeev, 1994)J/A+A/324/904 : NGC 4151 line-continuum diagram sequences (Malkov+ 1997)J/PAZh/25/403 : Optical variability of NGC 4151 (Lyuty+, 1999)J/PAZh/27/83 : Nuclear activity of NGC 4151 in 1989-2000 (Doroshenko+, 2001)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/486/99https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/486/99http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/486/99https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/486/99https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/486/99http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/486/99GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/486/99/fluxesObserved continuum, H{alpha}, H{beta}, H{gamma} and HeII{4686} fluxes, reduced to the 6m telescope aperture (2"x6"), with observation characteristicsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJDJulian datedtime.epochdoubleResSpectral resolution0.1nmspect.resolutionfloatF(cont)Continuum flux at 5117{AA} (2)(1)fW.m**-2.nm**-1phot.fluxfloate_F(cont)Estimated continuum flux error (2)fW.m**-2.nm**-1stat.errorfloatF(Ha)? H{alpha} total flux (3)fW.m**-2phot.flux;em.line.Halphafloatnullablee_F(Ha)? H{alpha} flux error (1)(3)fW.m**-2stat.errorfloatnullableF(Hb)? H{beta} total flux (3)fW.m**-2phot.flux;em.X-rayfloatnullablee_F(Hb)? H{beta} flux error (3)fW.m**-2stat.errorfloatnullableF(Hg)? H{gamma} total flux (1)(3)fW.m**-2phot.fluxfloatnullablee_F(Hg)? H{gamma} flux error (3)fW.m**-2stat.errorfloatnullableF(HeII)? HeII{lambda}4686{AA} total flux (1)(3)fW.m**-2phot.fluxfloatnullablee_F(HeII)? HeII{lambda}4686{AA} flux error (3)fW.m**-2stat.errorfloatnullableObsDateUT-date of the observationobs.param;obsnullableTelCode assigned to each telescope+equipment (1)meta.code;instr.telcharAperWThe projected spectrograph entrance apertures (Slit Width)arcsecinstr.fovfloatAperLThe projected spectrograph entrance apertures (along Slit)arcsecinstr.fovfloatlam1Lower wavelength of the spectral range0.1nminstr.bandwidthintlam2Upper wavelength of the spectral range0.1nminstr.bandwidthintPA? Slit position angledegobs.paramintnullableSeeing? Mean seeingarcsecinstr.obsty.seeing;stat.meanfloatnullableJ/A+A/486/99/table3Corrections for the position angle effectrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPASlit position angle in degreesdegobs.paramintAperWThe projected spectrograph entrance apertures (Slit Width)arcsecinstr.fovfloatAperLThe projected spectrograph entrance apertures (along Slit)arcsecinstr.fovfloatkp(H{beta})Slit position angle corrections for emission lines (H{beta}) (1)instr.paramfloate_kp(H{beta})? Estimated PA correction error for emission linestat.errorfloatnullablekp(cnt)Position angle (PA) corrections (1) for continuum fluxinstr.paramfloate_kp(cnt)? Estimated PA correction error for continuum fluxstat.errorfloatnullableJ/A+A/486/99/table45Correction for seeing effectsapGsAperture for Gsinstr.fovcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeeingL? Lower value of the interval of seeingsarcsecinstr.obsty.seeingfloatnullableSeeingU? Upper value of the interval of seeingsarcsecinstr.obsty.seeingfloatnullableSeeing? Mean seeingarcsecinstr.obsty.seeingfloatnullableksHb? Our seeing correction for the emission lines flux (H{beta})instr.paramfloatnullableapksHbAperture for ksHbinstr.fovchare_ksHb? Estimated seeing correction errorstat.errorfloatnullableksHbP? Peterson's seeing correction for the emission lines flux (H{beta}) (2)instr.paramfloatnullableapksHbPAperture for ksHPinstr.fovcharGs? Our host galaxy seeing correction for the continuum flux (1)1e-16W.m**-2.nm**-1instr.paramfloatnullablee_Gs? Estimated host galaxy seeing correction error (1)1e-16W.m**-2.nm**-1stat.errorfloatnullableGsP? Peterson's host galaxy seeing correction for the continuum flux (2)1e-16W.m**-2.nm**-1instr.paramfloatnullableapGsPAperture for GsPinstr.fovchar