Characterizing Star Formation Processes in Clumpy Turbulent Disk Galaxies with DYNAMO
Bibliographic record
Abstract
The redshift range 1 < z < 3 (referred to as “cosmic noon”) defines a characteristic epoch for the formation of stars and heavy elements in galaxies. Understanding the processes that drive and regulate star formation at this period is essential for linking the earliest phases of galaxy evolution with those observed in the local Universe and remains a key missing component of a comprehensive evolution model for galaxies. The population of systems dominating this era of massive galaxy assembly and disk growth are particularly important in that they are responsible for the majority of stellar mass density in the Universe. However, efforts to directly resolve star formation in z > 1 galaxies are substantially challenged by redshift and resolution effects. This doctoral thesis aims to investigate the mechanisms driving clumpy star formation in turbulent, high-z disks using a subset of galaxies from the DYnamics of Newly-Assembled Massive Objects (DYNAMO) sample. DYNAMO comprises a sample of extremely rare, nearby (z ∼ 0.07 & 0.12) galaxies whose system properties closely resemble those observed in z ∼ 1 − 2 main-sequence galaxies. Using a combination of CO[1-0] NOEMA-PdBI observations and blackbody modeling of infrared Herschel data we assess the molecular gas content and explore the state of the ISM in DYNAMO. Coupling these measurements with resolved kinematics, we test predictions from Toomre instability theory and find the first direct observational evidence indicating the role the internal gas velocity dispersion plays in the formation of massive star forming clumps within galaxies. Using high-resolution imaging from Keck Telescope we discover 32 stellar clumps in 5 DYNAMO targets via KP -band maps of star light and perform robust stellar mass estimates for these clump-like structures. For one galaxy in DYNAMO, G04-1, we present a detailed case study of stellar clumps using multi-filter follow-up observations from Hubble Space Telescope and find evidence of radial gradients in clump mass and color. These findings provide new, crucial insight into the global and resolved star formation properties of z ∼ 1 − 2 galaxies and underscore how advantageous high-z analogue samples are for obtaining the high-resolution imaging and kinematics necessary for a comprehensive study of star formation at cosmic noon.
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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 | 0.001 | 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) | 0.000 | 0.000 |
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".