KAOSS: turbulent, but disc-like kinematics in dust-obscured star-forming galaxies at z ∼ 1.3–2.6

Birkin, Jack E; Puglisi, A; Swinbank, A M; Smail, Ian; An, Fang Xia; Chapman, S C; Chen, Chian-Chou; Conselice, C J; Dudzevičiūtė, U; Farrah, D; Gullberg, B; Matsuda, Y; Schinnerer, E; Scott, D; Wardlow, J L; van der Werf, P

Abstract

We present spatially resolved kinematics of 27 ALMA-identified dust-obscured star-forming galaxies (DSFGs) at z ∼ 1.3–2.6, as traced by Hα emission using VLT/KMOS near-infrared integral field spectroscopy from the ‘KMOS-ALMA Observations of Submillimetre Sources’ (KAOSS) Large Programme. We derive Hα rotation curves and velocity dispersion profiles for the DSFGs, and find that among the 27 sources with bright, spatially extended Hα emission, 24 display evidence for disc-like kinematics. We measure a median inclination-corrected velocity at 2.2 Rd of vrot = 190 ± 40 km s−1 and intrinsic velocity dispersion of σ0 = 87 ± 6 km s−1 for these disc-like sources. The kinematics yield median circular velocities of vcirc = 230 ± 20 km s−1 and dynamical masses within 2Re (∼ 7 kpc radius) of Mdyn = (1.1 ± 0.2) × 1011 M⊙. Compared to less actively star-forming galaxies, KAOSS DSFGs are both faster rotating with higher intrinsic velocity dispersions, but have similar vrot/σ0 ratios, median v/σ0 = 2.5 ± 0.5. We suggest that the kinematics of the DSFGs are primarily rotation supported but with a non-negligible contribution from pressure support, which may be driven by star formation or mergers/interactions. We estimate the normalization of the stellar mass Tully–Fisher relation (sTFR) for the disc-like DSFGs and compare it with local studies, finding no evolution at fixed slope between z ∼ 2 and z ∼ 0. Finally, we show that the kinematic properties of the DSFG population are consistent with them evolving into massive early-type galaxies, the dominant z ∼ 0 population at these masses.

Citation

Birkin, J. E., Puglisi, A., Swinbank, A. M., Smail, I., An, F. X., Chapman, S. C., …van der Werf, P. (2024). KAOSS: turbulent, but disc-like kinematics in dust-obscured star-forming galaxies at z ∼ 1.3–2.6. Monthly Notices of the Royal Astronomical Society, 531(1), 61-83. https://doi.org/10.1093/mnras/stae1089

• Journal Article Type: Article
• Acceptance Date: Apr 12, 2024
• Online Publication Date: Apr 23, 2024
• Publication Date: 2024-06
• Deposit Date: Jul 4, 2024
• Publicly Available Date: Jul 4, 2024
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 531
• Issue: 1
• Pages: 61-83
• DOI: https://doi.org/10.1093/mnras/stae1089
• Public URL: https://durham-repository.worktribe.com/output/2516916