A puzzling non-detection of [O III] and [C II] from a z ≈ 7.7 galaxy observed with ALMA
Artikel i vetenskaplig tidskrift, 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



C. Binggeli

Uppsala universitet

A. K. Inoue

Osaka Sangyo University

Waseda University

T. Hashimoto

University of Tsukuba

Osaka Sangyo University

Waseda University

Maria Carmen Toribio Perez

Chalmers, Rymd-, geo- och miljövetenskap, Onsala rymdobservatorium

Erik Zackrisson

Uppsala universitet

S. Ramstedt

Uppsala universitet

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


University of Tokyo

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 646 A26


Astronomi, astrofysik och kosmologi

Atom- och molekylfysik och optik

Den kondenserade materiens fysik



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