Investigating the H I distribution and kinematics of ESO444-G084 and [KKS2000]23: New insights from the MHONGOOSE survey
Bibliographic record
Abstract
We present the neutral atomic hydrogen (H I) distribution, kinematics, mass modelling, and gravitational stability of the dwarf irregular galaxies ESO444–G084 and [KKS2000]23 using high spatial, spectral, and column density sensitivity data from the MeerKAT H I observations of nearby galactic objects: Observing Southern Emitters (MHONGOOSE) survey obtained with MeerKAT. ESO444–G084 exhibits centrally concentrated H I emission, while [KKS2000]23 has irregularly distributed high-density pockets. The total H I fluxes measured down to column density thresholds of 1019 cm−2 and 1018 cm−2 are nearly the same, suggesting that the increase in the H I diameter at lower column densities is primarily due to the larger beam size, and that no significant additional emission is detected. The total H I masses are (1.1±0.1)×108 M⊙ for ESO444–G084 and (6.1±0.3)×108 M⊙ for [KKS2000]23. We derived rotation curves using 3D kinematic modelling tools Python fully automated TiRiFiC (PyFAT) and tilted ring fitting code (TiRiFiC), which allow us to fully capture the gas kinematics. Both galaxies exhibit disk-like rotation, with ESO444–G084 showing a kinematic warp beyond ∼1.8 kpc. Its relatively fast-rising rotation curve suggests a more centrally concentrated dark matter distribution, whereas [KKS2000]23's more gradual rise indicates a more extended mass distribution. Mass modelling with an isothermal halo and stellar mass-to-light ratio $ (M/L)^{*}_{3.4\,\upmu {\mathrm {m}}} = 0.20 $ for ESO444–G084 and 0.18 for [KKS2000]23 yields physically consistent results. We further analyse disk stability using spatially resolved maps of the Toomre Q parameter and Σgas/Σcrit, linking these with recent star formation traced by hydrogen-alpha (Hα) and far-ultraviolet (FUV) emission. ESO444–G084 supports localised star formation despite global stability, while [KKS2000]23 is gravitationally unstable yet lacks strong Hα emission, suggesting that turbulence, gas depletion, or past feedback suppresses star formation. The absence of detectable inflows or outflows implies that internal processes regulate star formation. This study highlights the interplay between H I morphology, kinematics, dark matter distribution, and disk stability, demonstrating how internal mechanisms shape dwarf galaxy evolution.
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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 | 0.000 |
| 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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".