Kinematic Analysis of z = 4.3 Galaxies in the SPT2349–56 Protocluster Core
Bibliographic record
Abstract
Abstract SPT2349−56 is a protocluster discovered in the 2500 deg 2 South Pole Telescope (SPT) survey. In this paper, we study the kinematics of the galaxies found in the core of SPT2349−56 using high-resolution (1.55 kpc spatial resolution at z = 4.303) redshifted [C ii ] 158 μ m data. Using the publicly available code 3D BAROLO , we analyze the seven far-infrared brightest galaxies within the protocluster core. Based on conventional definitions for the detection of rotating disks, we classify six sources to be rotating disks in an actively star-forming protocluster environment, with weighted mean V rot / σ disp = 4.5 ± 1.3. The weighted mean rotation velocity ( V ro t ) and velocity dispersion ( σ disp ) for the sample are 357.1 ± 114.7 km s −1 and 43.5 ± 23.5 km s −1 , respectively. We also assess the disk stability of the galaxies and find a mean Toomre parameter of Q T = 0.9 ± 0.3. The galaxies show a mild positive correlation between disk stability and dynamical support. Using the position–velocity maps, we find that five sources further classify as disturbed disks, and one classifies as a strictly rotating disk. Our sample joins several observations at similar redshift with high V / σ values, with the exception that they are morphologically disturbed, kinematically rotating, and interacting galaxies in an extreme protocluster environment.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".