(DOI: will be inserted by hand later) Multiple merging events in Abell 521 ⋆
Bibliographic record
Abstract
Abstract. We present a detailed spatial and dynamical analysis of the central ∼ 2.2 h75 −1 Mpc region of the galaxy cluster Abell 521 (z=0.247), based on 238 spectra (of which 191 new measurements) obtained at the 3.6 m Telescope of the European Southern Observatory and at the Canada-France-Hawaii Telescope. From the analysis of the 125 galaxies that are confirmed members of the cluster, we derive a location (“mean ” velocity) of CBI = 74019 +112 −125 km/s and detect a complex velocity distribution with high velocity scale (“dispersion”, SBI = 1325+145 −100 km/s), but clear departure from a single Gaussian component. When excluding a possible background group of four galaxies, the velocity dispersion remains still large ( ∼ 1200 km/s). The general structure of the cluster follows a North-West/South-East direction, crossed by a perpendicular high density “ridge ” of galaxies in the core region. The Northern region of the cluster is characterized by a lower velocity dispersion as compared to the whole cluster value; it hosts the BCG and a dynamically bound complex of galaxies, and it is associated with a group detected in X-ray (Arnaud et al. 2000). This region could be in a stage of pre-merger onto the main cluster. The small offset ( ∼ + 250 km/s) in the mean velocity of the northern region as compared to the whole cluster suggests that the merging occurs partly in the plane of the sky. These results, taken together with the fact that most of the
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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 | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.026 | 0.005 |
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".