The SUBARU Deep Field Project: Lymanα Emitters at a Redshift of 6.6

[摘要] Wepresentnewresultsofadeepopticalimagingsurveyusinganarrowbandfilter(NB921)centeredat$${lambda=9196,mbox{Ã…}}$$togetherwith$$B,V,R,i^prime$$,and$$z^prime$$broadbandfiltersintheskyareaoftheSubaruDeepField,whichhasbeenpromotedasoneoflegacyprogramsofthe8.2mSubaruTelescope.Weobtainedaphotometricsampleof58$$mathrm{Ly},alpha$$emittercandidatesat$$zapprox6.5hbox{--}6.6$$among$$sim180$$strongNB921-excess($$z^prime-mathit{NB921}gt1.0z^prime-mathit{NB921}gt;1.0$$)objectstogetherwithacolorcriterionof$$i^prime-z^primegt1.3i^prime-z^primegt;1.3$$.Wethenobtainedopticalspectraof20objectsinourNB921-excesssample,andidentifiedatleastnine$$mathrm{Ly},alpha$$emittersat$$zsim6.5hbox{--}6.6$$,includingthetwoemittersreportedbyKodairaetal.(2003,PASJ,55,L17).Sinceour$$mathrm{Ly},alpha$$-emittercandidatesarefreefromstrongamplificationofgravitationallensing,weareabletodiscusstheirobservationalpropertiesfromastatisticalpointofview.Basedonthesenewresults,weobtainedalowerlimitofthestar-formationratedensityof$$ho_mathrm{SFR}simeq5.7imes10^{-4},h_{0.7},{{{M}_{odot}}},mathrm{yr}^{-1},mathrm{Mpc}^{-3}$$at$$zapprox6.6$$,beingconsistentwithourpreviousestimate.Wediscussthenatureofstar-formationactivityingalaxiesbeyond$$z=6$$.

[学科分类] 天文学(综合)

[关键词] "cosmology: observations";"early universe";"galaxies: formation";"galaxies: evolution";"galaxies: starburst"