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1、大样本巡天中类星体测光红移的确定吴学兵（北京大学天文学系）wuxb@bac.pku.edu.cnContentIntroduction:quasarsinlargeskysurveysPhotometricredshiftsofquasarsinSDSSHowtofindhigh-zquasarsDiscussion:BATC&LAMOST...1.Introduction类星体（quasars）Originallydiscoveredinradiosurvey(3C)in1950s;firstidentifiedasstar-li
2、keopticalsourceswithemissionlinesin1963;MaartenSchmidt(1963)realizedtheredshiftof3C273(z=0.158)Firstnamedsimplyas“quasi-stellarradiosources”,shortento“quasars”byH.-Y.Chiu(邱宏义)(1964),acceptedbyApJin1970Morethan100,000discovered;thelargestredshiftis6.4(Fan(樊晓晖),etal.2003
3、)MaartenSchmidt类星体3C273的谱线红移量达到0.16类星体光谱中有强而宽的未知发射线。1963年MaartenSchmidt证认出它们实际上是红移了的H和其它元素的发射线。Examplesofquasarsdiscoveredwiththelargestopticaltelescope(2.16m)inChina(Wu,Bade&Beckmann1999,A&A,347,63)Spectraofthreemostdistantquasars(Fanetal.2003)LargeOpticalSkyQuasarSur
4、veysPalomar-Green(PG)BrightQuasarSurvey(BQS):B<16,10000deg^2,~120Quasars(~7%)LargeBrightQuasarSurvey(LBQS):B<17.5,~10^3quasars2dF:200deg^2,U-V<-0.3,~2.610^4quasarsSloanDigitalSkySurvey(SDSS):eventual10000deg^2,ugrizselection,~10^5quasarsDataRelease5(2006):Spectroscopic
5、area:5740deg^2.79,394Quasars(redshift<2.3)11,217Quasars(redshift>2.3)UnderstandingthedistributionandevolutionofquasarsDetectionofACompleteGunn-PetersonTrough:VLTobservationHigh-redshiftquasarsprobetheendofreionizationepochThefirstquasarandthecosmicreionizationPhysicsMo
6、delfortheCentralEngineofQuasarsSupermassiveblackholeAccretiondiskBroadlineregionDustytorusNarrowlineregionJet2.PhotometricredshiftsofquasarsinSDSSSloanDigitalSkySurveyIPhotometry:~3x108objectsLimitingmagnitudesatthedetectionlimit,S/N5:1Spectroscopy:>106objects(106galax
7、ies;105quasars)Galaxies:r<17.77;Quasars:i<19.1OnlyphotometricredshiftsforfainterobjectsSpectroscopy:Thebestwaytodeterminetheredshiftofquasars,thoughnotalwayspossible,esp.forfainterquasarsPhotometricSystemsofSDSSSDSScompositequasarspectrum(EDR2200quasars)Predictedmagnit
8、udeandcolorofquasarsQuasarspectrumf(),SDSStransmissionefficiencys()(u,g,r,i,z)Comparisonwiththedataof18678quasarsin
