KINEMATICS OF STARS IN KAPTEYN SELECTED AREA 71: SAMPLING THE MONOCEROS AND SAGITTARIUS TIDAL STREAMS
Bibliographic record
Abstract
We present a 3D kinematical analysis of stars located in Kapteyn Selected Area 71 ( l = 167.1°, b = −34.7°), where previously a stellar excess was found by Dinescu et al. in (2002). Previous findings indicated that the stellar excess has a cold kinematical signature as inferred from proper motions, and was initially associated with debris from the Sagittarius dwarf galaxy (Sgr)—namely the southern trailing tail. We have obtained radial velocities using the Hydra multi-object spectrograph on the WIYN 3.5 m telescope. Results for 183 proper-motion-selected stars indicate that the dominant population in this stellar excess is not debris from Sgr, but rather a population that kinematically belongs to the ring-like stream that is now known as the Monoceros (Mon) stream. The orbit determined for this population agrees very well with the predictions for the Mon stream from Peñarrubia et al. in (2005). The radial-velocity dispersion of this population is between 20 and 30 km s −1 , lower than that of the Galactic field. Also, the shape of the radial-velocity distribution shows a sharp cut-off on one side, which is more in line with model predictions of the disruption of a satellite rather than with the distribution of the Galactic field. Despite the fact that we now believe most of the stars in the stellar excess to be a part of Mon, about ten stars in this stellar excess have highly negative radial velocities, which is a clear indication of their membership to the Sgr trailing tidal tail.
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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".