高红移星系的观测研究

Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,高红移星系的观测研究,王 俊 贤,University of Science & Technology of China,9/14/2024,1,2,3,The Hubble Law,4,Redshift z =,/,0,Require at least 2 lines,5,quasar spectra,Zheng et al (1997), Francis et al (1991), Cristiani and Vio (1990),Ly,a,H,a,C,IV,6,z = 0.5,z = 2.6,Photometric redshift,7,8,9,How to find high redshift galaxies?,Look very hard,get some help,Get lucky,Watch the fireworks,Look next to something else,Look smart (LBG, Lyman- Galaxies, photo-z, SMG),etc,Credit: Mark Dickinson,10,Long slit spectroscopy,11,Hubble Ultra Deep Field,12,Multi-slit spectroscopy,13,14,15,美国斯隆巡天望远镜,(Sloan Digital Survey-SDSS),：打孔式光纤定位系统，完成所有的观测任务需要约,2000,块焦面板。每块焦面板上根据星表数据预先打有,640,个孔，观测前将光纤植入孔中，,每次观测任务都需要新创建一块焦面板。,16,LAMOST,17,18,How to find high redshift galaxies?,Look very hard,get some help,Get lucky,Watch the fireworks,Look next to something else,Look smart (LBG, Lyman- Galaxies, photo-z, SMG),etc,Credit: Mark Dickinson,19,Galaxy Clusters as a“Cosmic Telescopes”,20,21,How to find high redshift galaxies?,Look very hard,get some help,Get lucky,Watch the fireworks,Look next to something else,Look smart (LBG, Lyman- Galaxies, photo-z, SMG),etc,Credit: Mark Dickinson,22,Dawson et al. 2002: A galaxy Serendipitously Detected at z=5.19,23,Blank sky search for high z sources,24,Grism Spectra,Spectra contaminated,Direct image (filter B,V, i, z or others),(For alignment and cataloging),Grism image taken with G800L,25,How to find high redshift galaxies?,Look very hard,get some help,Get lucky,Watch the fireworks,Look next to something else,Look smart (LBG, Lyman- Galaxies, photo-z, SMG),etc,Credit: Mark Dickinson,26,SDSS high-z quasar,Quasars are much more luminous than normal galaxies, and could be detected at larger distances. However they are rare.,27,28,Ly,a,29,SDSS high-z quasar and Gunn-Peterson Trough,Quasars are much more luminous than normal galaxies, and could be detected at larger distances. However they are rare.,30,A -ray burst at a redshift of z8.2,31,How to find high redshift galaxies?,Look very hard,get some help,Get lucky,Watch the fireworks,Look next to something else,Look smart (LBG, Lyman- Galaxies, photo-z, SMG,BzK, etc),etc,Credit: Mark Dickinson,32,Sub-mm galaxies,33,34,35,Star-forming galaxies & the IGM,*,Star-forming galaxies,spectral energy distributions,(SEDs) are approximately,flat,in F,vs . (What colors?),* The intergalactic opacity,suppresses flux below 912,* Therefore, use broadband,observations shortward and,longward of the break.,36,An imaging LBG demonstration,LBGs are star forming galaxies at z 2, identified by the color signature of the Lyman limit and Ly-,a,breaks.,First studied in large numbers by Steidel et al. (1995-2001).,Now 1000 with measured redshifts.,37,Lyman breaks in high redshift objects,Strong breaks across the redshifted Ly,line (SDSS quasars),38,39,LBG,in E-CDFS, R=22.8, z=3.38,strong Ly,emission (EW=60, SFR,UV,350 M,/yr) numerous chemical absorption features (6 hr IMACS exposure),Ly,SiII,OI/SiII,CII,FeII,SiIV,SiII,CIV,MUSYC,Gawiser et al 2005,40,Case B : 2/3 of the re-combinations lead to the emission of a Ly,photon,In principle, up to 6-7% of a young galaxys luminosity may emerge in the Lyman line (for a Salpeter IMF).,Young galaxies forming their first stars produce copious ionizing radiation, hence strong Lyman-, emission.,(Partridge and Peebles 1967),41,Wang et al. 2009,Spectra of high redshift Lyman Alpha Emitting Galaxies,42,Ly,is affected by1. ISM kinematics2. HI geometry3. dustbut the order of importance remains unclear,43,Tenorio-Tagle et al. 1999,44,Ly,in z3 LBGs,(Shapley et al. 2003),45,The Narrowband Search Method,take images in both broad and narrow filters.,Emission line sources appear faint or absent in broad filter,An important tool to detect high-z galaxies,46,The Narrowband Search Method,take images in both broad and narrow filters.,Emission line sources appear faint or absent in broad filter,47,Windows for Narrowband Surveys,Z=6.9,48,LBG (broad band dropout),LAE (narrow band excess),Large volume,Small volume,continuous redshift,certain redshifts, but deeper,Hard to identify,Easy to identify,sensitive to UV continuum + Ly,line,sensitive to Ly,line,Luminous galaxies,Fainter galaxies,trace the large scale structure,49,Blank sky spectroscopic search for Lyman alpha lines,50,Selection criteria (Wang et al. 2005),51,52,Sample Lyman-, Spectra,Note prominent asymmetry.,Spectra from Dawson et al 2005; six among 80 confirmed LALA z = 4.5 galaxies.,Keck+DEIMOS data.,53,Sample LAE spectra,Magellan IMACS spectra, Wang et al. 2009,54,Iye et al. 2006,55,LBG (broad band dropout),LAE (narrow band excess),Large volume,Small volume,continuous redshift,certain redshifts, but deeper,Hard to identify,Easy to identify,sensitive to UV continuum + Ly,line,sensitive to Ly,line,Luminous galaxies,Fainter and smaller galaxies,trace the large scale structure,56,Large scale structure of Ly,emitters at z5.7,Deep narrow band images on Chandra Deep Field South, using the two z=5.7 filters,Obtained Dec. 2003, with CTIO 4m telescope,A total of 24 candidate Ly,emitters at z=5.7 were selected, 18 in 823 nm band, and 6 in 815 nm band,Wang, Malhotra, Rhoads, ApJ letter 2005,57,Ouchi et al. 2005,58,59,60,61,Thank you!,62,