First Results from the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) Survey: Cosmological Reionization at z?~?7 | |
Zheng,Zhen-Ya1,2,3; Wang,Junxian4; Rhoads,James5,6; Infante,Leopoldo2; Malhotra,Sangeeta5,6; Hu,Weida4; Walker,Alistair R.7; Jiang,Linhua8; Jiang,Chunyan1,3,9; Hibon,Pascale10 | |
刊名 | The Astrophysical Journal Letters |
2017-06-21 | |
卷号 | 842期号:2 |
关键词 | cosmology: observations dark ages, reionization, first stars galaxies: high-redshift galaxies: luminosity function, mass function |
ISSN号 | 2041-8205 |
DOI | 10.3847/2041-8213/aa794f |
英文摘要 | Abstract We present the first results from the ongoing Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) project, which is the largest narrowband survey for z ~ 7 galaxies to date. Using a specially built narrowband filter NB964 for the superb large-area Dark Energy Camera (DECam) on the NOAO/CTIO 4 m Blanco telescope, LAGER has collected 34 hr NB964 narrowband imaging data in the 3 deg2 COSMOS field. We have identified 23 Lyα Emitter candidates at z = 6.9 in the central 2-deg2 region, where DECam and public COSMOS multi-band images exist. The resulting luminosity function (LF) can be described as a Schechter function modified by a significant excess at the bright end (four galaxies with LLyα ~ 1043.4±0.2 erg s?1). The number density at LLyα?~?1043.4±0.2 erg s?1 is little changed from z?=?6.6, while at fainter LLyα it is substantially reduced. Overall, we see a fourfold reduction in Lyα luminosity density from z?=?5.7 to z?= 6.9. Combined with a more modest evolution of the continuum UV luminosity density, this suggests a factor of ~3 suppression of Lyα by radiative transfer through the z?~?7 intergalactic medium (IGM). It indicates an IGM neutral fraction of xH i?~?0.4–0.6 (assuming Lyα velocity offsets of 100–200 km s?1). The changing shape of the Lyα LF between z ? 6.6 and z?=?6.9 supports the hypothesis of ionized bubbles in a patchy reionization at z ~ 7. |
语种 | 英语 |
出版者 | The American Astronomical Society |
WOS记录号 | IOP:2041-8205-842-2-aa794f |
内容类型 | 期刊论文 |
源URL | [http://119.78.226.72/handle/331011/32123] |
专题 | 中国科学院上海天文台 |
作者单位 | 1.CAS Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Shanghai 200030, China; zhengzy@shao.ac.cn 2.Institute of Astrophysics and Center for Astroengineering, Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile; linfante@astro.puc.cl 3.Chinese Academy of Sciences South America Center for Astronomy, Santiago 7591245, Chile 4.CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei, Anhui 230026, China; jxw@ustc.edu.cn 5.School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, USA; Sangeeta.Malhotra@asu.edu, James.Rhoads@asu.edu 6.Astrophysics Science Division, Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771, USA 7.Cerro Tololo Inter-American Observatory, Casilla 603, La Serena, Chile 8.The Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, China 9.Núcleo de Astronomía, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Av. Ejército 441, Santiago, Chile 10.European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Santiago, Chile |
推荐引用方式 GB/T 7714 | Zheng,Zhen-Ya,Wang,Junxian,Rhoads,James,等. First Results from the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) Survey: Cosmological Reionization at z?~?7[J]. The Astrophysical Journal Letters,2017,842(2). |
APA | Zheng,Zhen-Ya.,Wang,Junxian.,Rhoads,James.,Infante,Leopoldo.,Malhotra,Sangeeta.,...&Barrientos,L. Felipe.(2017).First Results from the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) Survey: Cosmological Reionization at z?~?7.The Astrophysical Journal Letters,842(2). |
MLA | Zheng,Zhen-Ya,et al."First Results from the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) Survey: Cosmological Reionization at z?~?7".The Astrophysical Journal Letters 842.2(2017). |
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