J0107a: A Barred Spiral Dusty Star-forming Galaxy at z = 2.467

• Published in: Astrophysical journal. Letters 2023-12, Vol.958 (2), p.L26
• Main Authors: Huang, Shuo, Kawabe, Ryohei, Kohno, Kotaro, Saito, Toshiki, Mizukoshi, Shoichiro, Iono, Daisuke, Michiyama, Tomonari, Tamura, Yoichi, Hayward, Christopher C., Umehata, Hideki
• Format: Article
• Language: English
• Subjects: Barred spiral galaxies; CO line emission; Dust emission; Emission; Emission lines; Galaxies; Galaxy formation; High-redshift galaxies; Molecular gases; Radio telescopes; Rotating disks; Star & galaxy formation; Star formation; Star formation rate; Stars; Stellar mass; Stellar models; Three dimensional models; Ultraluminous infrared galaxies
• ISSN: 2041-8205; 2041-8213
• DOI: 10.3847/2041-8213/acff63

Dusty star-forming galaxies (DSFGs) are among the most massive and active star-forming galaxies during the cosmic noon. Theoretical studies have proposed various formation mechanisms of DSFGs, including major merger-driven starbursts and secular star-forming disks. Here, we report J0107a, a bright (∼8 mJy at observed-frame 888 μ m) DSFG at z = 2.467 that appears to be a gas-rich massive disk and might be an extreme case of the secular disk scenario. J0107a has a stellar mass M ⋆ ∼ 5 × 10 11 M ⊙ , molecular gas mass M mol ≳ 10 11 M ⊙ , and a star formation rate of ∼500 M ⊙ yr −1 . J0107a does not have a gas-rich companion. The rest-frame 1.28 μ m JWST NIRCam image of J0107a shows a grand-design spiral with a prominent stellar bar extending ∼15 kpc. The Atacama Large Millimeter/submillimeter Array Band 7 continuum map reveals that the dust emission originates from both the central starburst and the stellar bar. 3D disk modeling of the CO(4–3) emission line indicates a dynamically cold disk with rotation-to-dispersion ratio V max / σ ∼ 8 . The results suggest a bright DSFG may have a nonmerger origin, and its vigorous star formation may be triggered by the bar and/or rapid gas inflow.