TY - JOUR
T1 - First Spectroscopic Confirmations of z ∼ 7.0 Lyα Emitting Galaxies in the LAGER Survey
AU - Hu, Weida
AU - Wang, Junxian
AU - Zheng, Zhen Ya
AU - Malhotra, Sangeeta
AU - Infante, Leopoldo
AU - Rhoads, James
AU - Gonzalez, Alicia
AU - Walker, Alistair R.
AU - Jiang, Linhua
AU - Jiang, Chunyan
AU - Hibon, Pascale
AU - Barrientos, L. Felipe
AU - Finkelstein, Steven
AU - Galaz, Gaspar
AU - Kang, Wenyong
AU - Kong, Xu
AU - Tilvi, Vithal
AU - Yang, Huan
AU - Zheng, Xianzhong
N1 - Funding Information:
We thank the anonymous referee for useful comments that helped to improve the manuscript. We acknowledge financial support from the National Science Foundation of China (grant Nos. 11233002, 11421303, and 11773051) and the National Program for Support of Top-notch Young Professionals for
Funding Information:
covering the cost of the NB964 narrowband filter. J.X.W. thanks the National Basic Research Program of China (973 program, grant No. 2015CB857005) and CAS Frontier Science Key Research Program QYCDJ-SSW-SLH006 for support. Z.Y.Z. acknowledges support by the China-Chile Joint Research Fund (CCJRF No. 1503) and the CAS Pioneer Hundred Talents Program (C). The work of S.M., J.E.R., and A.G. on this project is supported in part by US National Science Foundation grant AST-1518057. L.I. is in part supported by CONICYT-Chile grants Basal-CATA PFB-06/ 2007, 3140542, and Conicyt-PIA-ACT 1417. C.J. acknowledges support by Shanghai Municipal Natural Science Foundation (15ZR1446600).
Funding Information:
This research uses data obtained partly through the Telescope Access Program (TAP), which is funded by the National Astronomical Observatories, Chinese Academy of Sciences, and the Special Fund for Astronomy from the Ministry of Finance. We thank the scientists and telescope operators at Magellan telescope for their help. Facility: Magellan:Baade (IMACS).
Publisher Copyright:
© 2017. The American Astronomical Society. All rights reserved..
PY - 2017/8/20
Y1 - 2017/8/20
N2 - Narrowband imaging is a highly successful approach for finding large numbers of high-redshift Lyα emitting galaxies (LAEs) up to z ∼ 6.6. However, at z ≳ 7 there are as of yet only three narrowband selected LAEs with spectroscopic confirmations (two at z ∼ 6.9-7.0, one at z ∼ 7.3), which hinders extensive studies on cosmic reionization and galaxy evolution at this key epoch. We have selected 23 candidate z ∼ 6.9 LAEs in COSMOS field with the large area narrowband survey Lyman-Alpha Galaxies at the End of Reionization (LAGER). In this work, we present spectroscopic follow-up observations of 12 candidates using the Inamori Magellan Areal Camera and Spectrograph on Magellan. For nine of these, the observations are sufficiently deep to detect the expected lines. Lyα emission lines are identified in six sources (yielding a success rate of 2/3), including three luminous LAEs with Lyα luminosities of L Lyα ∼ 1043.5 erg s-1, the highest among known spectroscopically confirmed galaxies at ≳7.0. This triples the sample size of spectroscopically confirmed narrowband selected LAEs at z ≳ 7, and confirms the bright-end bump in the Lyα luminosity function we previously derived based on the photometric sample, supporting a patchy reionization scenario. Two luminous LAEs appear physically linked with a projected distance of 1.1 pMpc and velocity difference of ∼170 km s-1. They likely sit in a common ionized bubble produced by themselves or with close neighbors, which reduces the intergalactic medium attenuation of Lyα. A tentative narrow N v λ1240 line is seen in one source, hinting at activity of a central massive black hole with metal-rich line-emitting gas.
AB - Narrowband imaging is a highly successful approach for finding large numbers of high-redshift Lyα emitting galaxies (LAEs) up to z ∼ 6.6. However, at z ≳ 7 there are as of yet only three narrowband selected LAEs with spectroscopic confirmations (two at z ∼ 6.9-7.0, one at z ∼ 7.3), which hinders extensive studies on cosmic reionization and galaxy evolution at this key epoch. We have selected 23 candidate z ∼ 6.9 LAEs in COSMOS field with the large area narrowband survey Lyman-Alpha Galaxies at the End of Reionization (LAGER). In this work, we present spectroscopic follow-up observations of 12 candidates using the Inamori Magellan Areal Camera and Spectrograph on Magellan. For nine of these, the observations are sufficiently deep to detect the expected lines. Lyα emission lines are identified in six sources (yielding a success rate of 2/3), including three luminous LAEs with Lyα luminosities of L Lyα ∼ 1043.5 erg s-1, the highest among known spectroscopically confirmed galaxies at ≳7.0. This triples the sample size of spectroscopically confirmed narrowband selected LAEs at z ≳ 7, and confirms the bright-end bump in the Lyα luminosity function we previously derived based on the photometric sample, supporting a patchy reionization scenario. Two luminous LAEs appear physically linked with a projected distance of 1.1 pMpc and velocity difference of ∼170 km s-1. They likely sit in a common ionized bubble produced by themselves or with close neighbors, which reduces the intergalactic medium attenuation of Lyα. A tentative narrow N v λ1240 line is seen in one source, hinting at activity of a central massive black hole with metal-rich line-emitting gas.
KW - cosmology: observations
KW - dark ages, reionization, first stars
KW - galaxies: formation
KW - galaxies: highredshift
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UR - http://www.scopus.com/inward/citedby.url?scp=85028451909&partnerID=8YFLogxK
U2 - 10.3847/2041-8213/aa8401
DO - 10.3847/2041-8213/aa8401
M3 - Article
AN - SCOPUS:85028451909
SN - 2041-8205
VL - 845
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2
M1 - L16
ER -