Accurate simultaneous constraints on the dust mass, temperature, and emissivity index of a galaxy at redshift 7.31
Journal article, 2024

We present new multifrequency Atacama Large Millimeter/submillimeter Array (ALMA) continuum observations of the massive [ log 10 ( M∗ / M ⊙) = 10 . 3 + 0 . 1 -0. 2 ], UV-luminous [ M UV = -21 . 7 ±0 . 2] z = 7 . 31 galaxy REBELS-25 in Bands 3, 4, 5, and 9. Combining the new observations with previously taken data in Bands 6 and 8, we co v er the dust continuum emission of the galaxy in six distinct bands -spanning rest-frame 50 -350 μm -enabling simultaneous constraints on its dust mass ( M dust ), temperature ( T dust ), and emissivity index ( β IR ) via modified blackbody fitting. Given a fiducial model of optically thin emission, we infer a cold dust temperature of T dust = 32 + 9 -6 K and a high dust mass of log 10 ( M dust / M ⊙) = 8 . 2 + 0 . 6 -0 . 4 , and moderately optically thick dust does not significantly alter these estimates. If we assume dust production is solely through supernovae (SNe), the inferred dust yield would be high, y = 0 . 7 + 2 . 3 -0 . 4 M _per SN. Consequently, we argue grain growth in the interstellar medium of REBELS-25 also contributes to its dust build-up. This is supported by the steep dust emissivity index βIR = 2 . 5 ±0 . 4 we measure for REBELS-25, as well as by its high stellar mass, dense interstellar medium, and metal-rich nature. Our results suggest that constraining the dust emissivity indices of high-redshift galaxies is important not only to mitigate systematic uncertainties in their dust masses and obscured star formation rates, but also to assess if dust properties evolve across cosmic time. We present an efficient observing set-up to do so with ALMA, combining observations of the peak and Rayleigh-Jeans tail of the dust emission.

galaxies: high-redshift

galaxies: e volution

submillimetre: galaxies

Author

H. Algera

Hir oshima University

National Astronomical Observatory of Japan

H. Inami

Hir oshima University

I. De Looze

Ghent university

Andrea Ferrara

Scuola Normale Superiore di Pisa

Hiroyuki Hirashita

Osaka University

Academia Sinica

Manuel Aravena

Diego Portales University

Tom Bakx

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

Rychard Bouwens

Leiden University

Rebecca A.A. Bowler

University of Manchester

E. da Cunha

University of Western Australia

ARC Centre of Excellence for All-sky Astrophysics

Pratika Dayal

University of Groningen

Yoshinobu Fudamoto

Waseda University

National Astronomical Observatory of Japan

J. Hodge

Leiden University

Alexander Hygate

Leiden University

Ivana van Leeuwen

Leiden University

Themiya Nanayakkara

Swinburne University of Technology

Marco Palla

Istituto nazionale di astrofisica (INAF)

Ghent university

Andrea Pallottini

Scuola Normale Superiore di Pisa

Lucie Rowland

Leiden University

Renske Smit

Liverpool John Moores University

Laura Sommovigo

Flatir on Institute

Mauro Stefanon

Universitat de Valencia

A. P. Vijayan

Technical University of Denmark (DTU)

Cosmic Dawn Center (DAWN)

P. van der Werf

Leiden University

Monthly Notices of the Royal Astronomical Society

00358711 (ISSN) 13652966 (eISSN)

Vol. 533 3 3098-3113

Subject Categories

Astronomy, Astrophysics and Cosmology

DOI

10.1093/mnras/stae1994

More information

Latest update

9/17/2024