An∼600 pc View of the Strongly Lensed, Massive Main-sequence Galaxy J0901: A Baryon-dominated, Thick Turbulent Rotating Disk with a Clumpy Cold Gas Ring at z=2.259
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Date
2023
Journal Title
Journal ISSN
Volume Title
Publisher
Institute of Physics
Abstract
We present a high-resolution kinematic study of the massive main-sequence star-forming galaxy (SFG)
SDSS J090122.37+181432.3 (J0901) at z = 2.259, using ∼0 36 Atacama Large Millimeter/submillimeter Array
CO(3–2) and ∼0 1–0 5 SINFONI/VLT Hα observations. J0901 is a rare, strongly lensed but otherwise normal
massive (log(M M) ~ 11) main-sequence SFG, offering a unique opportunity to study a typical massive SFG
under the microscope of lensing. Through forward dynamical modeling incorporating lensing deflection, we fit the
CO and Hα kinematics in the image plane out to about one disk effective radius (Re ∼ 4 kpc) at an ∼600 pc
delensed physical resolution along the kinematic major axis. Our results show high intrinsic dispersions of the cold
molecular and warm ionized gas (σ0,mol. ∼ 40 km s−1 and σ0,ion. ∼ 66 km s−1) that remain constant out to Re; a
moderately low dark matter fraction ( fDM ∼ 0.3–0.4) within Re; and a centrally peaked Toomre Q parameter—
agreeing well with the previously established σ0 versus z, fDM versus Σbaryon, and Qʼs radial trends using largesample
non-lensed main-sequence SFGs. Our data further reveal a high stellar mass concentration within ∼1–2 kpc
with little molecular gas, and a clumpy molecular gas ring-like structure at R ∼ 2–4 kpc, in line with the inside-out
quenching scenario. Our further analysis indicates that J0901 had assembled half of its stellar mass only ∼400 Myr
before its observed cosmic time, and the cold gas ring and dense central stellar component are consistent with
signposts of a recent wet compaction event of a highly turbulent disk found in recent simulations.
Description
Keywords
Northern Extended Millimeter Array (NOEMA), Cold gas kinematics, Velocity
Citation
Liu, D., et al. (2023). An ∼600 pc view of the strongly lensed, massive main-sequence galaxy J0901: A baryon-dominated, thick turbulent rotating disk with a clumpy cold gas ring at z = 2.259. Astrophysical Journal, 942(2) doi:10.3847/1538-4357/aca46b