A Near‐Infrared Photometric Study of the Low‐Latitude Globular Clusters Liller 1, Djorgovski 1, HP 1, and NGC 6528
Notice bibliographique
Résumé
Images recorded through J , H , Ks ,2.2 μm continuum, and 2.3 μm CO filters are used to investigate the stellar contents of the low Galactic latitude globular clusters NGC 6528, Liller 1, Djorgovski 1, and HP 1, as well as surrounding bulge fields. Metallicities are estimated for the latter three clusters by comparing the colors and CO indexes of giant branch stars with those in other clusters and the bulge, while reddenings are estimated from the colors of bright bulge stars in the surrounding fields. In some cases the metallicities and reddenings are significantly different from previous estimates. The horizontal branch (HB) in NGC 6528 occurs at K = 13.2, and the K luminosity function of HB stars in this cluster is not significantly different from those in the moderately metal-rich clusters NGC 6304 and NGC 6316. R ', the ratio of HB to bright red giant branch (RGB) and asymptotic giant branch (AGB) stars, is 1.25 ± 0.25, in good agreement with its value in other globular clusters. The RGB bump in NGC 6528 is detected at K = 13.8, and the relative brightness of this feature with respect to the HB is consistent with the cluster being very metal rich. The HB in Liller 1 occurs at K = 14.4. Stars in Liller 1 have smaller J-K colors and CO indexes than bulge giants with the same brightness, and a comparison between the Liller 1 and NGC 6528 sequences on the ( K , J-K ), and ( K ,CO) color-magnitude diagrams (CMDs) indicates that Liller 1 has a metallicity comparable to, and perhaps even slightly lower than, that of NGC 6528. Stars in Liller 1 and NGC 6528 occupy the same region of the ( J-H , H-K ) two-color diagram as bulge giants, which is consistent with these clusters forming as part of the bulge. Stars in Djorgovski 1 and HP 1 have significantly smaller CO indexes than stars with the same brightness in the surrounding bulge fields, and CMDs for these clusters are constructed by selecting objects according to CO index. After adjusting for differences in distance and reddening, the Djorgovski 1 giant branch on the ( K , J-K ) CMD is well matched by that of the [Fe/H] = -2.2 cluster M92, while the giant branch of HP 1 follows that of the [Fe/H] = -1.6 globular cluster M13. The metallicities inferred for both clusters are consistent with integrated J-K colors and CO indexes measured through moderately large (∼35''-45'') apertures. Based on the brightness of the RGB tip, it is concluded that Djorgovski 1 has a distance modulus μ 0 = 15.4, while the distance modulus of HP 1 is μ 0 = 14.7. The brightest stars in the fields surrounding Liller 1, Djorgovski 1, and HP 1 follow the same relation between M K and CO index as M giants in Baade's window. Stars as faint as the HB have been detected in the field surrounding HP 1, and the relative numbers of HB and upper giant branch stars indicate that R ' = 1.14 ± 0.11. This relatively low value reinforces earlier studies, which found that R ', and hence the helium abundance, likely does not vary with radius in the innermost regions of the Galactic bulge.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,002 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».