天文学-天体光谱学第七章

第七章光致电 - Ly/H515,H/H46，与CaseB复合理论(LyH30,HH 及AGN内红BLR比较高密度下辐射转移效应不可略（n2系列光深不谱线宽度较大范围：500kms1104kms1，大的DopplerLy1026,OVI1032,1038; SIV1394,1403,OIV]1402;CIV1549,HeII1640,

第七章光致电 -碰撞激发线CIVλ1549发射率j(CIV)n q(2s2S,2p2P)

(ergss-1cm3str1) C e T20000K,q2.6109cm3e

（对

L(CIV)

j(CIV)dVd

n q(2s2S,2p2P)h

Cer3n24.61023ergsse为简单见，假定宇宙丰度log[CH]

，且所有C为C3对半径为l

Nc(4l

/3)Nl

r2第七章光致电 - 由reverberation r21016hL1/2(CIV) 0 为以100kms10

2.7107h3L1/2(CIV

假定 1011cm3ee

l3NN

4r3N 1.51041 L(CIV)g10-3 (CIV)N NeCoveringfactor宽线区对连续辐射的吸收光厚宽线云，coving

f/

(电离连续谱被宽

第七章光致电 -

9121(H)1

1

d

OXd

)

F

cF(Ly)(H)

(

)OX1216

W(Ly)

F(LyF

1216

1.4W(Ly)~f

第七章光致电 -BLR 宽线区成分，其中氢完全电离，对Lyman连续谱光薄单位时间中心源发射能光致电离的光子数：(H

uQ(H

1Theratioofthephotonnumberdensitytoparticledensityattheincidentfaceofthecloud“singlezone”model:计算谱线强度比对u的依赖关

第七章光致电 -CIII]/CIV 的指示（因对u敏感，对元素丰度不敏感 NGC5548:n1011cm3,u

电离复合平

Q(H)

n2 Be Be

r1

/Ac

T20000K,

2.521013cm3s1r4.81010cm (extendedpartialionizedzone)，即云厚度rr1，原因在于：

第七章光致电 -因在Lyman(/13对热谱：绝大部分被吸收光子~Lyman系限，当邻近 量较高能的光子，产生大的PIZ，其中，H/H00.1。同时， ，导致n2大布居（亚稳态）。电子的碰撞激发至更高激发态，导致Balmer线发射，Ly/H

第七章光致电 -6.NarrowLineGeneralLine 200700kmAllowedlines Forbiddenlines:strongest[OIII]4959,5005,StudiesforSy1problematicasnarrowandbroadlinesGasdiagnosticsfrom[OIII]5007/4959and4363and[SIIratios:T~

and

3103cm3,possibledensitygradientNLRmassfromHβemissivityandassumingsphericalLH2108 M~7105(104/Ne)M

,

R~20f1/3(104/Ne)2/3i.e.,90pcwithanestimatedfillingfactor

f102

第七章光致电 -StrongNarrowLinesSeyfert

第七章光致电 -

第七章光致电 -Note:TypicaltemperaturesinAGN

104

第七章光致电 -LineDiagnostics:

第第七章致电-第七章光致电 -NLR特征：有一宽的电子密度范围(102104cm3)。相对强度依赖于Te和Ne。所以[OIII]线得到的不一 的发射，不能代表λ4959，5007的发射 离级的谱线，ne,Te也不一定相同。如O,O

第七章光致电 -选氢Hβ线（复合线）：因为初级近似，窄险的线强比为典型CaseHβ h h nneff n2eff e1.241025ergss1cm3str

为Hβ有效复合系数，反映了所有复合至n 致n4n

T104T10431014cm3ne

第七章光致电 - L(H)jHdVd4n21.241025 3其中，为窄线云的体积填充因子，云数目 ，云半径l，则cNl3rc

r19(L41(H))1/333L41(H

为NLR的Hβ1041ergss1为单位，n3

103为单位的ne在Seyfert2星系中，典型L(H)为10391042ergss1，对邻近

r100 某些情况下，可能比102估算NLR质量

4r3n

7105L41(H 第七章光致电 -ModelsoftheNLRaimDeterminefluxofReproducelineratiosandequivalentwidthsofnarrowprovideestimatesfortheline(Kewleyetal.,Nature(Kewleyetal.,LineratiosareusedtodefinedifferenttypesofSeyfert(Kewleyetal.,

第七章光致电 -(Allenetal.,1999,Fig.

Photoionizationmodelscanreproduceratiosofstrongobservedlinessuchas[OIII5007]/Hβratioandabsoluteluminosityoftheselines.BUT:Strengthsofhighandlowionizationstagescannotbereproduced→rulesoutthesimplestphotoionizationPotentialsolution:shock(Allenetal.,1999,andtherein)!Photonsproducedafterashock(whereT~106K)canionizepre-shockgas→combinationofcollisionalandShockpossiblyrelatedtojet/radio 第七章光致电 -Natureofthe

Alternativeexplanationofunusualratios:twoandmultiplezoneNLRmodels.Triggered,e.g.,bytoostrongFelineemissionForexample:Highionizationnuclearemissionregion(HINER)models(Murayama&Taniguchi,1998):10%ofNLRemissionfromhighdensity(ne~109cm3)photoionizedregionwithinFig.

whichisresponsibleforemissionfromhighionizedspecies.Similarmodelshavealsobeenproposed,e.g,byKomossa&Schulz(1997)andbymanyotherProblem:ToomanyfreeparametersSearchforphysicalE.g.,matterboundedvs.ionizationclouds,locallyoptimallyemittingclouds,.. 第七章光致电 -ImagingoftheLinediagnostics:sizeofNLR~90pcor→forthenearestAGNimagingis(e.g.,Circinusgalaxy:d=4Mpc→1=19ImagingofNLRpossibleeitherusingintegralfieldspectroscopyornarrow-Oftenused:narrow-bandHand[OIII]Results(see,e.g.,Poggeionization→ExtendedNarrowLineRegionInthefollowing:twotypicalexamples:NGC1068(=M77)andCircinusSimilarstudieshavebeenperformedformorethan30nearby

第七章光致电 -NGC1068,NGC1068(M77),NOAO

第七章光致电 -NGC1068,NGC1068(M77):Seyfert2nucleusatz=0:003(d~15Mpc),oneofthebeststudiedgalaxiesinthesky.NGC1068(M77)(Bill

第七章光致电 -NGC1068,NGC1068(M77):Seyfertnucleusatz=0:003(d~15Mpc),oneofthebeststudiedgalaxiesinthesky.Pogge(1988):ExtendedionizingradiationconefromthenucleusofNGC1068,alongthedirectionoftheradiojet.NGC1068(M77)corewithHSTinO

第七章光致电 -NGC1068:FunnelinIRoverlaidtoOIIIimage:Highlystructured

第七章光致电 -Circinusd~4Mpc(1~19pc2ndnearestAGNonsouthernhemisphereafterCenASAbSeyfert2

第七章光致电 -(HSTWilsonetal.,2000,Fig.[OIII] F814W

第七章光致电 -(HSTandVLT(IR)Prietoetal.,2004,Fig.

第七章光致电 -X-raysCircinusgalaxy:AlignmentbetweenhardX-emittinggasandopticalionization

Optical

第八章冷星际介质光HubbleDiameterof35HubbleDiameterof35Thicknessof6Thicknessof1Diameterof≥50MeanDensity 0.1M⊙pc-3 larmassfraction Gasmass

第八章冷星际介质光TheISMoftheMilkyWayconsistsofthefollowing n(cm3 T(K

Fill

102 106 20 SNR，wind, 101 1 byO/B 1 20 20 21cm 10 10 20 HIenvelopes, 102 40 IR,HIM:HotIonizedMedium；WIM:WarmIonizedMedium；WNM:

第八章冷星际介质光Humansobservedstarsforthousandsofyear.OnlyIsaacNewtonrealisedthatstarsaresimilartoourSun,butmuchfurtheraway；In17th-19thcenturies,itwasassumedthatthevastbetweenthestarsiscompleyemptyInthebeginningof20thcentury,usingspectral Hartmannfoundstaticlinesof Cainthespectraofdoublestarswhichheattributedtointers larmedium(ISM).Doppler v/c ,causesvariationsofs larlines,butnotofISMabsorptionlines。

第八章冷星际介质光第八章冷星际介质光WhyCa(alsoNa)wasobserved,butnotHorHelines?MostatomsintheISMareontheirgroundstateTheycanabsorbs larradiationinresonancelines(strongest).CaandNahavetheselinesintheopticalband,whileHandHehavethemintheultraviolet(UV)band(Lyα1216Åand586Å,respectively).Earthatmosphereabsorbsradiationwithλ<2900Å.Beforespace escopes,itwasimpossibletoobserveintheUVband。In larspectra,ofcourse,oneobservesH,He,Oofexcitedstates.E.g.Balmerlinesof

lar

第八章冷星际介质光Copernicussa lite(1980s)studiednearbystarsandmeasuredLyαofH,aswellaslinesofC,N,O,Mg,Si,S,Ar,MnMoleculesofCH,CH,CNwerealsodiscoveredin1938inoptics.Normallyonelineisobserved(notlikeinlaboratorieswhe