Detailed Study of Stars and Gas in a z = 8.3 Massive Merger with Extreme Dust Conditions

Anishya Harshan; Roberta Tripodi; Nicholas S. Martis; Gregor Rihtaršič; Maruša Bradač; Yoshihisa Asada; Gabe Brammer; Guillaume Desprez; Vince Estrada-Carpenter; Jasleen Matharu; Vladan Markov; Adam Muzzin; Lamiya Mowla; Gaël Noirot; Ghassan T. E. Sarrouh; Marcin Sawicki; Victoria Strait; Chris Willott

doi:10.3847/2041-8213/ad9741

The Astrophysical Journal Letters (Jan 2024)

Detailed Study of Stars and Gas in a z = 8.3 Massive Merger with Extreme Dust Conditions

Anishya Harshan,
Roberta Tripodi,
Nicholas S. Martis,
Gregor Rihtaršič,
Maruša Bradač,
Yoshihisa Asada,
Gabe Brammer,
Guillaume Desprez,
Vince Estrada-Carpenter,
Jasleen Matharu,
Vladan Markov,
Adam Muzzin,
Lamiya Mowla,
Gaël Noirot,
Ghassan T. E. Sarrouh,
Marcin Sawicki,
Victoria Strait,
Chris Willott

Affiliations

Anishya Harshan: ORCiD; University of Ljubljana , Department of Mathematics and Physics, Jadranska ulica 19, SI-1000 Ljubljana, Slovenia
Roberta Tripodi: ORCiD; University of Ljubljana , Department of Mathematics and Physics, Jadranska ulica 19, SI-1000 Ljubljana, Slovenia
Nicholas S. Martis: ORCiD; University of Ljubljana , Department of Mathematics and Physics, Jadranska ulica 19, SI-1000 Ljubljana, Slovenia
Gregor Rihtaršič: ORCiD; University of Ljubljana , Department of Mathematics and Physics, Jadranska ulica 19, SI-1000 Ljubljana, Slovenia
Maruša Bradač: ORCiD; University of Ljubljana , Department of Mathematics and Physics, Jadranska ulica 19, SI-1000 Ljubljana, Slovenia; Department of Physics and Astronomy, University of California Davis , 1 Shields Avenue, Davis, CA 95616, USA
Yoshihisa Asada: ORCiD; Department of Astronomy and Physics and Institute for Computational Astrophysics, Saint Mary’s University , 923 Robie Street, Halifax, Nova Scotia B3H 3C3, Canada; Department of Astronomy, Kyoto University , Sakyo-ku, Kyoto 606-8502, Japan
Gabe Brammer: ORCiD; Cosmic Dawn Center (DAWN) , Denmark; Niels Bohr Institute, University of Copenhagen , Jagtvej 128, DK-2200 Copenhagen N, Denmark
Guillaume Desprez: ORCiD; Department of Astronomy and Physics and Institute for Computational Astrophysics, Saint Mary’s University , 923 Robie Street, Halifax, Nova Scotia B3H 3C3, Canada
Vince Estrada-Carpenter: Department of Astronomy and Physics and Institute for Computational Astrophysics, Saint Mary’s University , 923 Robie Street, Halifax, Nova Scotia B3H 3C3, Canada
Jasleen Matharu: ORCiD; Cosmic Dawn Center (DAWN) , Denmark; Niels Bohr Institute, University of Copenhagen , Jagtvej 128, DK-2200 Copenhagen N, Denmark
Vladan Markov: ORCiD; University of Ljubljana , Department of Mathematics and Physics, Jadranska ulica 19, SI-1000 Ljubljana, Slovenia
Adam Muzzin: Department of Physics and Astronomy, York University , 4700 Keele St. Toronto, Ontario, M3J 1P3, Canada
Lamiya Mowla: ORCiD; Whitin Observatory , Department of Physics and Astronomy, Wellesley College, 106 Central Street, Wellesley, MA 02481, USA; Dunlap Institute for Astronomy and Astrophysics , 50 St. George Street, Toronto, Ontario M5S 3H4, Canada
Gaël Noirot: Department of Astronomy and Physics and Institute for Computational Astrophysics, Saint Mary’s University , 923 Robie Street, Halifax, Nova Scotia B3H 3C3, Canada
Ghassan T. E. Sarrouh: ORCiD; Department of Physics and Astronomy, York University , 4700 Keele St. Toronto, Ontario, M3J 1P3, Canada
Marcin Sawicki: ORCiD; Department of Astronomy and Physics and Institute for Computational Astrophysics, Saint Mary’s University , 923 Robie Street, Halifax, Nova Scotia B3H 3C3, Canada
Victoria Strait: ORCiD; Cosmic Dawn Center (DAWN) , Denmark; Niels Bohr Institute, University of Copenhagen , Jagtvej 128, DK-2200 Copenhagen N, Denmark
Chris Willott: ORCiD; NRC Herzberg , 5071 West Saanich Rd, Victoria, BC V9E 2E7, Canada

DOI: https://doi.org/10.3847/2041-8213/ad9741
Journal volume & issue: Vol. 977, no. 2
p. L36

Abstract

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We present galaxy MACS0416-Y1 at z _spec = 8.312 as observed by the CAnadian NIRISS Unbiased Cluster Survey. MACS0416-Y1 has been shown to have extreme dust properties; thus, we study the physical properties and star formation histories of its resolved components. Overall, we find that MACS0416-Y1 is undergoing a star formation burst in three resolved clumps. The central clump is less massive compared to the other clumps and possibly formed in the merging process of the two larger clumps. Although the star formation history indicates an ongoing star formation burst, this gas-rich galaxy shows comparable star formation efficiency to cosmic noon galaxies. Using NIRSpec prism spectroscopy, we measure metallicity, $12+\mathrm{log}{\rm{(O/H)}}=7.76\pm 0.03$ , ionization parameter, $\mathrm{log}U=-2.48\pm 0.03$ , and electron temperature T _e = 18000 ± 4000 K. The emission line ratios of the galaxy indicate an evolved interstellar medium similar to z ∼ 2 star-forming galaxies. Further, we find possible presence of ionization from an active galactic nucleus (AGN) using emission line diagnostics; however, we do not detect a broad-line component in the H β emission line. As this gas-rich galaxy is undergoing a major merger, we hypothesize that the high dust temperature in MACS0416-Y1 is caused by the star formation burst or a possible narrow-line AGN.

Published in The Astrophysical Journal Letters

ISSN: 2041-8205 (Print); 2041-8213 (Online)
Publisher: IOP Publishing
Country of publisher: United Kingdom
LCC subjects: Science: Astronomy: Astrophysics
Website: https://iopscience.iop.org/journal/2041-8205

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