A puzzling non-detection of [O III] and [C II] from a z ≈ 7.7 galaxy observed with ALMA
Journal article, 2021
Context. Characterizing the galaxy population in the early Universe holds the key to understanding the evolution of these objects and the role they played in cosmic reionization. However, there have been very few observations at the very highest redshifts to date. Aims. In order to shed light on the properties of galaxies in the high-redshift Universe and their interstellar media, we observe the Lyman-α emitting galaxy z7_GSD_3811 at z = 7.664 with bands 6 and 8 at the Atacama Large Millimeter/submillimeter Array (ALMA). Methods. We target the far-infrared [O iii] 88 µm and [C ii] 158 µm emission lines and dust continuum in the star-forming galaxy z7_GSD_3811 with ALMA. We combine these measurements with earlier observations in the rest-frame ultraviolet (UV) in order to characterize the object and compare the results to those of earlier studies that observed [O iii] and [C ii] emission in high-redshift galaxies. Results. The [O iii] 88 µm and [C ii] 158 µm emission lines are undetected at the position of z7_GSD_3811, with 3σ upper limits of 1.6 × 108 L and 4.0 × 107 L, respectively. We do not detect any dust continuum in band 6 nor band 8. The measured rms in the band 8 and band 6 continua are 26 and 9.9 µJy beam−1, respectively. Similar to several other high-redshift galaxies, z7_GSD_3811 exhibits low [C ii] emission for its star formation rate compared to local galaxies. Furthermore, our upper limit on the [O iii] line luminosity is lower than the previously observed [O iii] lines in high-redshift galaxies with similar UV luminosities. Our ALMA band 6 and 8 dust continuum observations imply that z7_GSD_3811 likely has a low dust content, and our non-detections of the [O iii] and [C ii] lines could indicate that z7_GSD_3811 has a low metallicity (Z. 0.1 Z).
Galaxies: High-Redshift
Dark ages
Galaxies: Evolution
Galaxies: ISM
First stars
Reionization
Author
C. Binggeli
Uppsala University
A. K. Inoue
Osaka Sangyo University
Waseda University
T. Hashimoto
University of Tsukuba
Osaka Sangyo University
Waseda University
Maria Carmen Toribio Perez
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Erik Zackrisson
Uppsala University
S. Ramstedt
Uppsala University
Ken Mawatari
Osaka Sangyo University
University of Tokyo
Yuichi Harikane
National Astronomical Observatory of Japan
University College London (UCL)
H. Matsuo
National Astronomical Observatory of Japan
The Graduate University for Advanced Studies (SOKENDAI)
Takashi Okamoto
Hokkaido University
Kazuaki Ota
Kyoto University
Ikkoh Shimizu
National Astronomical Observatory of Japan
Shikoku Gakuin University
Y. Tamura
Nagoya University
Y. Taniguchi
The Open University of Japan
H. Umehata
RIKEN
University of Tokyo
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 646 A26Subject Categories
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
Condensed Matter Physics
DOI
10.1051/0004-6361/202038180