Near-infrared spectroscopy of Seyfert galaxies
Results from near-infrared 1.5 - 2.5 micron long-slit spectroscopy of 14 nearby Seyfert galaxies are presented.
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aActiveGalacticNuclei:fromCentralEnginetoHostGalaxyASPConferenceSeries,Vol.xxx,2003S.Collin,F.Combes,andI.ShlosmanNear–infraredspectroscopyofSeyfertgalaxiesJ.K.KotilainenandJ.ReunanenTuorlaObservatory,Piikki¨o,FinlandM.A.PrietoESO,Garching,GermanyAbstract.Resultsfromnear-infrared1.5–2.5µmlong-slitspectroscopyof14nearbySeyfertgalaxiesarepresented.1.IntroductionIntheAGNuni edmodels(Antonucci1993),amoleculartorusobscuresthenucleusandtheBLRinSeyfert2(S2)galaxies,whileinSeyfert1(S1)galaxiestheyaredirectlyvisible.Adequatespatialresolutiontosearchforthemoleculartorus,withpredictedsize<100pc(Pier&Krolik1993)canbeachievedinthenear-infrared(NIR).However,suchNIRspectroscopicstudieshavesofarbeenmadeatonlymoderatespatialresolutionand/oronlyalongtheradioor[Oiii]axis(Veilleuxetal.1997;Wingeetal.2000).WepresentNIR1.5–2.5µmlong-slitspectroscopyof14nearby(0.002<z<0.010)Seyferts(3S1s,2intermediateSeyfertsand9S2s),bothparallelandperpendiculartotheionizationcone.Forfulldiscussion,seeReunanen.Kotilainen&Prieto(2002a,b).2.ResultsThestrongestemissionlineisBrγ2.166µmin2S1s,2intermediateSeyferts
and2S2s;[Feii]1.644µmin3S2s;H21-0S(1)2.122µmin1S1and1S2;andacoronalline([Sivi]1.964µmor[Sivii]2.483µm)in3S2s.
BroadBrγisdetectedin9Seyferts,ofwhich5areopticallyclassi edasS2s.ThedetectionofbroadBrγinmorethanhalfoftheS2sisduetothelowernuclearextinctionintheNIR.Thisextinctionisunlikelytoberelatedtothemoleculartorus,asitsopticaldepthislikelytobehighenoughtoobscuretheBLR.Theextinctionismorelikelycausedbyforegrounddustymaterialintheformofstarforming(SF)clouds,whichfrequentlycoexistwiththeAGN.Spatiallyresolvednuclear[Feii]emissionwasdetectedin8Seyferts(1S1,2intermediateSeyferts,and5S2s).TheextendedemissionispatchyandfollowscloselytheSFcomplexesas[Feii]iscorrelatedwithBrγ.Thenuclear[Feii]emissioninafewSeyfertsisconsistentwithX-rayexcitationintheNLR,butappearspredominantlytobeshock-excited.
ThenuclearH2surfacedensityishigherinS2sthaninS1s.Thisquantityis,however,correlatedwiththedetectionofbroadBrγ,indicatingextinction
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