SERENADE. II. An ALMA Multiband Dust Continuum Analysis of 28 Galaxies at 5 < z < 8 and the Physical Origin of the Dust Temperature Evolution
Journal article, 2024
We present an analysis of the Atacama Large Millimeter-submillimeter Array (ALMA) multiband dust continuum observations for 28 spectroscopically confirmed bright Lyman break galaxies at 5 < z < 8. Our sample consists of 11 galaxies at z ∼ 6 newly observed in our ALMA program, which substantially increases the number of 5 < z < 8 galaxies with both rest-frame 88 and 158 μm continuum observations, allowing us to simultaneously measure the IR luminosity and dust temperature for a statistical sample of z ≳ 5 galaxies for the first time. We derive the relationship between the ultraviolet (UV) slope (β UV) and infrared excess (IRX) for the z ∼ 6 galaxies, and find a shallower IRX-β UV relation compared to the previous results at z ∼ 2-4. Based on the IRX-β UV relation consistent with our results and the β UV-M UV relation including fainter galaxies in the literature, we find a limited contribution of the dust-obscured star formation to the total star formation rate density, ∼30% at z ∼ 6. Our measurements of the dust temperature at z ∼ 6-7, T dust = 40.9 − 9.1 + 10.0 K on average, support a gentle increase of T dust from z = 0 to z ∼ 6-7. Using an analytic model with parameters consistent with recent James Webb Space Telescope results, we discuss that the observed redshift evolution of the dust temperature can be reproduced by an ∼0.6 dex decrease in the gas depletion timescale and ∼0.4 dex decrease in the metallicity. The variety of T dust observed at high redshifts can also be naturally explained by scatters around the star formation main sequence and average mass-metallicity relation including an extremely high dust temperature of T dust > 80 K observed in a galaxy at z = 8.3.
Author
Ikki Mitsuhashi
University of Tokyo
National Astronomical Observatory of Japan
Waseda University
Yuichi Harikane
University of Tokyo
F. E. Bauer
Millennium Institute of Astrophysics
Space Science Institute
Pontificia Universidad Catolica de Chile
Tom Bakx
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Andrea Ferrara
Scuola Normale Superiore di Pisa
S. Fujimoto
The University of Texas at Austin
Takuya Hashimoto
University of Tsukuba
Akio K. Inoue
Waseda University
K. Iwasawa
Catalan Institution for Research and Advanced Studies
University of Barcelona
Y. Nishimura
University of Tokyo
M. Imanishi
National Astronomical Observatory of Japan
Yoshiaki Ono
University of Tokyo
T. Saito
National Astronomical Observatory of Japan
Yuma Sugahara
Waseda University
National Astronomical Observatory of Japan
H. Umehata
California Institute of Technology (Caltech)
Nagoya University
L. Vallini
Istituto nazionale di astrofisica (INAF)
T. Wang
Nanjing University
J. A. Zavala
National Astronomical Observatory of Japan
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 971 2 161Subject Categories
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
DOI
10.3847/1538-4357/ad5675