WISDOM project -- XXIII. Star-formation efficiencies of eight early-type galaxies and bulges observed with SITELLE and ALMA
Bibliographic record
Abstract
Early-type galaxies (ETGs) are known to harbour dense spheroids of stars with scarce star formation (SF). Approximately a quarter of these galaxies have rich molecular gas reservoirs yet do not form stars efficiently. These gas-rich ETGs have properties similar to those of bulges at the centres of spiral galaxies. We use spatially-resolved observations (~ 100 pc resolution) of warm ionised-gas emission lines (Hbeta, [O III], [N II], Halpha and [S II]) from the imaging Fourier transform spectrograph SITELLE at the Canada-France-Hawaii Telescope and cold molecular gas (12CO(2-1) or 12CO(3-2)) from the Atacama Large Millimeter/submillimeter Array (ALMA) to study the SF properties of 8 ETGs and bulges. We use the ionised-gas emission lines to classify the ionisation mechanisms and demonstrate a complete absence of regions dominated by SF ionisation in these ETGs and bulges, despite abundant cold molecular gas. The ionisation classifications also show that our ETGs and bulges are dominated by old stellar populations. We use the molecular gas surface densities and Halpha-derived SF rates (in spiral galaxies outside of the bulges) or upper limits (in ETGs and bulges) to constrain the depletion times (inverse of the SF efficiencies), suggesting again suppressed SF in our ETGs and bulges. Finally, we use the molecular gas velocity fields to measure the gas kinematics, and show that bulge dynamics, particularly the strong shear due to the deep and steep gravitational potential wells, is an important SF-regulation mechanism for at least half of our sample galaxies.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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 teacher head, 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".