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

ABSTRACT We present new multifrequency Atacama Large Millimeter/submillimeter Array (ALMA) continuum observations of the massive [$\log _{10}(M_\star /\mathrm{M}_\odot) = 10.3_{-0.2}^{+0.1}$], UV-luminous [$M_\mathrm{UV} = -21.7 \pm 0.2$] $z=7.31$ galaxy REBELS-25 in Bands 3, 4, 5, and 9. Combining the new observations with previously taken data in Bands 6 and 8, we cover the dust continuum emission of the galaxy in six distinct bands – spanning rest-frame $50-350\, \mu$m – enabling simultaneous constraints on its dust mass ($M_\mathrm{dust}$), temperature ($T_\mathrm{dust}$), and emissivity index ($\beta _\mathrm{IR}$) via modified blackbody fitting. Given a fiducial model of optically thin emission, we infer a cold dust temperature of $T_\mathrm{dust} = 32_{-6}^{+9}\,$ K and a high dust mass of $\log _{10}(M_\mathrm{dust}/\mathrm{M}_\odot) = 8.2_{-0.4}^{+0.6}$, 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, $y = 0.7_{-0.4}^{+2.3}\, \mathrm{M}_\odot$ 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 $\beta _\mathrm{IR} = 2.5 \pm 0.4$ 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.

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Journal
Monthly Notices of the Royal Astronomical Society
Published
2024-08-20
DOI
https://doi.org/10.1093/mnras/stae1994
Citations
14
Primary Topic
Galaxies: Formation, Evolution, Phenomena
Type
article
Field-Weighted Citation Impact
4.64

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article

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

Pratika Dayal, A. Pallottini, Ilse De Looze, A. P. S. Hygate et al.
14 citations
Monthly Notices of the Royal Astronomical Society
Galaxies: Formation, Evolution, Phenomena
4.64
article

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

Pratika Dayal, A. Pallottini, Ilse De Looze, A. P. S. Hygate, Jacqueline Hodge, Andrea Ferrara, Marco Palla, Aswin P. Vijayan, Mauro Stefanon, Themiya Nanayakkara, Hanae Inami, Ivana van Leeuwen, Lucie E. Rowland, Hiddo Algera, Yoshinobu Fudamoto, R. A. A. Bowler, Elisabete da Cunha, Manuel Aravena, Renske Smit, Laura Sommovigo, Tom J. L. C. Bakx, Hiroyuki Hirashita, Rychard Bouwens, P. van der Werf
article en
14 citations

Abstract

ABSTRACT We present new multifrequency Atacama Large Millimeter/submillimeter Array (ALMA) continuum observations of the massive [$\log _{10}(M_\star /\mathrm{M}_\odot) = 10.3_{-0.2}^{+0.1}$], UV-luminous [$M_\mathrm{UV} = -21.7 \pm 0.2$] $z=7.31$ galaxy REBELS-25 in Bands 3, 4, 5, and 9. Combining the new observations with previously taken data in Bands 6 and 8, we cover the dust continuum emission of the galaxy in six distinct bands – spanning rest-frame $50-350\, \mu$m – enabling simultaneous constraints on its dust mass ($M_\mathrm{dust}$), temperature ($T_\mathrm{dust}$), and emissivity index ($\beta _\mathrm{IR}$) via modified blackbody fitting. Given a fiducial model of optically thin emission, we infer a cold dust temperature of $T_\mathrm{dust} = 32_{-6}^{+9}\,$ K and a high dust mass of $\log _{10}(M_\mathrm{dust}/\mathrm{M}_\odot) = 8.2_{-0.4}^{+0.6}$, 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, $y = 0.7_{-0.4}^{+2.3}\, \mathrm{M}_\odot$ 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 $\beta _\mathrm{IR} = 2.5 \pm 0.4$ 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.

Monthly Notices of the Royal Astronomical SocietyVol. 533(3)
Hiroshima University (JP), Leiden University (NL), Institute of Astronomy and Astrophysics, Academia Sinica (TW), Waseda University (JP), Scuola Normale Superiore (IT), Universitat de València (ES), University of Groningen (NL), The University of Western Australia (AU), University of Manchester (GB), Ghent University (BE), DAWN Center for Independent Living (US), Instituto de Física de Cantabria (ES), Flatiron Health (United States) (US), ARC Centre of Excellence for All-sky Astrophysics (AU), National Astronomical Observatory of Japan (JP), International Centre for Radio Astronomy Research (AU), Osservatorio di Astrofisica e Scienza dello Spazio, Flatiron Institute (US), Swinburne University of Technology (AU), Liverpool John Moores University (GB), Chalmers University of Technology (SE), Universidad Diego Portales (CL), Technical University of Denmark (DK), The University of Osaka (JP)
National Science Foundation, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Ministry of Science and Technology, Korea Astronomy and Space Science Institute, National Astronomical Observatory of Japan, ARC Centre of Excellence for All-Sky Astrophysics, National Research Council Canada, Science and Technology Facilities Council, National Institutes of Natural Sciences
Openalex Percentile: Top 5%
Galaxies: Formation, Evolution, Phenomena
4.64
DOIOpen Access PDFOpenAlex
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