First Spectroscopic Confirmations of z ∼ 7.0 Ly α Emitting Galaxies in the LAGER Survey
- CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei, Anhui 230026 (China)
- CAS Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Shanghai 200030 (China)
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States)
- Las Campanas Observatory, Carnegie Institution for Science, Casilla 601, La Serena (Chile)
- Cerro Tololo Inter-American Observatory, Casilla 603, La Serena (Chile)
- The Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)
- European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Santiago (Chile)
- Centro de Astroingeniería, Facultad de Física, Pontificia Universidad Católica de Chile, Santiago (Chile)
- Department of Astronomy, The University of Texas at Austin, Austin, TX 78712 (United States)
- Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)
Narrowband imaging is a highly successful approach for finding large numbers of high-redshift Ly α 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. Ly α emission lines are identified in six sources (yielding a success rate of 2/3), including three luminous LAEs with Ly α luminosities of L {sub Lyα} ∼ 10{sup 43.5} erg s{sup −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 Ly α 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{sup −1}. They likely sit in a common ionized bubble produced by themselves or with close neighbors, which reduces the intergalactic medium attenuation of Ly α . A tentative narrow N v λ 1240 line is seen in one source, hinting at activity of a central massive black hole with metal-rich line-emitting gas.
- OSTI ID:
- 22654398
- Journal Information:
- Astrophysical Journal Letters, Vol. 845, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
Similar Records
Lyalpha-EMITTING GALAXIES AT REDSHIFT zapprox 4.5 IN THE LALA CETUS FIELD
THE REST-FRAME OPTICAL SPECTROSCOPIC PROPERTIES OF LY α -EMITTERS AT z ∼ 2.5: THE PHYSICAL ORIGINS OF STRONG LY α EMISSION