The MUSE eXtremely deep field: first panoramic view of an Mg II emitting intragroup medium
Bibliographic record
Abstract
Using the exquisite data from the MUSE eXtremely Deep Field (MXDF), we report the discovery of an Mg IIemission nebula with an area above a 2σsignificance level of 1000 proper kpc2. This provides the first panoramic view of the spatial distribution of magnesium in the intragroup medium of a low-mass group of five star-forming galaxies atz = 1.31. The galaxy group members are separated by less than 50 physical kpc in projection and ≈120 km s−1in velocity space. The most massive galaxy has a stellar mass of 109.35 M⊙and shows an Mg IIP-Cygni line profile, indicating the presence of an outflow, which is consistent with the spatially resolved spectral analysis showing ≈+120 km s−1shift of the Mg IIemission lines with respect to the systemic redshift. The other galaxies are less massive and only show Mg IIin emission. The detected Mg IInebula has a maximal projected extent of ≈70 kpc, including a low-surface-brightness (≈2 × 10−19erg s−1cm−2arcsec−2) gaseous bridge between two subgroups of galaxies. The presence of absorption features in the spectrum of a background galaxy located at an impact parameter of 19 kpc from the closest galaxy of the group indicates the presence of gas enriched in magnesium even beyond the detected nebula seen in emission, which suggests that we are observing the tip of a larger intragroup medium. The observed Mg IIvelocity gradient suggests an overall rotation of the structure along the major axis of the most massive galaxy. Our MUSE data also reveal extended Fe II* emission in the vicinity of the most massive galaxy, aligned with its minor axis and pointing towards a neighboring galaxy. Extended [O II] emission is found around the galaxy group members and at the location of the Mg IIbridge. Our results suggest that both tidal stripping effects from galaxy interactions and outflows are enriching the intragroup medium of this system.
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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 | 0.003 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.002 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".