Detailed Study of Stars and Gas in a <i>z</i> = 8.3 Massive Merger with Extreme Dust Conditions
Abstract 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, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>12</mml:mn> <mml:mo>+</mml:mo> <mml:mi>log</mml:mi> <mml:mi mathvariant="normal">(O/H)</mml:mi> <mml:mo>=</mml:mo> <mml:mn>7.76</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.03</mml:mn> </mml:math> , ionization parameter, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>log</mml:mi> <mml:mi>U</mml:mi> <mml:mo>=</mml:mo> <mml:mo>−</mml:mo> <mml:mn>2.48</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.03</mml:mn> </mml:math> , 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.
Authors
- Gaël Noirot
- Anishya Harshan (ORCID: https://orcid.org/0000-0001-9414-6382)
- Jasleen Matharu (ORCID: https://orcid.org/0000-0002-7547-3385)
- Maruša Bradač (ORCID: https://orcid.org/0000-0001-5984-0395)
- Vladan Markov (ORCID: https://orcid.org/0000-0002-5694-6124)
- G. Desprez (ORCID: https://orcid.org/0000-0001-8325-1742)
- Adam Muzzin (ORCID: https://orcid.org/0000-0002-9330-9108)
- Chris J. Willott (ORCID: https://orcid.org/0000-0002-4201-7367)
- Ghassan T. E. Sarrouh (ORCID: https://orcid.org/0000-0001-8830-2166)
- Vicente Estrada-Carpenter (ORCID: https://orcid.org/0000-0001-8489-2349)
- Yoshihisa Asada (ORCID: https://orcid.org/0000-0003-3983-5438)
- Roberta Tripodi (ORCID: https://orcid.org/0000-0002-9909-3491)
- Marcin Sawicki (ORCID: https://orcid.org/0000-0002-7712-7857)
- Nicholas S. Martis (ORCID: https://orcid.org/0000-0003-3243-9969)
- Victoria Strait (ORCID: https://orcid.org/0000-0002-6338-7295)
- Lamiya Mowla (ORCID: https://orcid.org/0000-0002-8530-9765)
- Gabriel Brammer (ORCID: https://orcid.org/0000-0003-2680-005X)
- Gregor Rihtaršič (ORCID: https://orcid.org/0009-0009-4388-898X)
Institutions
- Herzberg Institute of Astrophysics (CA)
- University of Copenhagen (DK)
- University of Ljubljana (SI)
- Wellesley College (US)
- York University (CA)
- Kyoto University (JP)
- Saint Mary's University (CA)
- University of California, Davis (US)
Publication Details
- Journal
- The Astrophysical Journal Letters
- Published
- 2024-12-12
- DOI
- https://doi.org/10.3847/2041-8213/ad9741
- Citations
- 9
- Primary Topic
- Galaxies: Formation, Evolution, Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 2.98
Funders
- National Science Foundation
- National Aeronautics and Space Administration
- Canadian Foundation for AIDS Research
- Canarie
- Space Telescope Science Institute
- National Radio Astronomy Observatory
- National Research Foundation
- Danmarks Grundforskningsfond
- Korea Astronomy and Space Science Institute
- Javna Agencija za Raziskovalno Dejavnost RS
- National Astronomical Observatory of Japan
- National Science and Technology Council
- Alliance de recherche numérique du Canada
- Canadian Space Agency
- Natural Sciences and Engineering Research Council of Canada
- National Institutes of Natural Sciences