Оглавление
Изображения
Загрузить ваше изображение
DSS Images Other Images
Публикации по объекту
Faint Blue Objects at High Galactic Latitude. VIII. Performance Characteristics of the US Survey
The US survey has cataloged 3987 objects in seven high Galactic latitudefields according to their optical colors, magnitudes, and morphologiesusing photographic techniques. This paper analyzes the effectiveness ofthe survey at producing finding lists for complete samples of hot starsand quasars that exhibit blue and/or ultraviolet excess (B-UVX) relativeto the colors of halo F and G subdwarf stars. A table of 599spectroscopic identifications summarizes the spectroscopic coverage ofthe US objects that has been accomplished to date. In addition, some ofthe survey plates have been reexamined for objects missed during theoriginal selection, and the literature has been searched for all otherspectroscopically identified blue stars and quasars with z<2.2 thathave been selected by other surveys within the US survey areas. Theseresults are used to estimate empirically both the accuracy of the USsurvey selection boundaries (in color, morphology, and brightness) andthe completeness of the resulting samples of B-UVX US objects withinthose boundaries. In particular, it is shown that the reliability of theUS color classifications is high and that the previously derived USmorphological boundary for the complete selection of unresolved quasarsis accurate. The contribution of color and morphological classificationerrors to B-UVX sample incompleteness is therefore correspondinglysmall. The empirical tests indicate high levels of completeness(95+1-2%) for the samples of US quasars and hotstars isolated within the stated survey selection limits. Errata andimprovements to some of the published catalog data are presented inAppendices.
| Detection of the Halo Component of the Field sdB Population
A new, complete sample of 20 faint sdB stars isolated from the US surveyis reported. Because the sample contains stars with magnitudes as faintas B = 18, it is uniquely situated to probe the field sdB spatialdistribution at relatively large distances out of the Galactic plane. AV/Vmax analysis provides strong evidence that the majority of thesestars are not part of a disklike stellar density distribution. Using astatistical treatment for population membership, a further V/Vmaxanalysis shows that the spatial distribution of the US sdB stars isconsistent with a combined disk-plus-halo stellar density law. Thisanalysis also provides a preliminary value for the sdB halo-to-diskdensity ratio in the solar neighborhood that is larger by a factor of>~7 than that for the field stars in general. It is likely that evenrelatively bright samples of sdB stars, such as those isolated from thePG survey, contain significant numbers of halo stars.
| Photometric Survey Near the Main Galactic Meridian - Part One - Photoelectric Stellar Magnitudes and Colours in the UBVR System
Not Available
| Faint blue objects at high Galactic latitude. V - Palomar Schmidt field centered on selected area 71
Starlike objects with both blue and ultraviolet excess have beenselected from a Palomar 1.2 m Schmidt field centered on Kapteyn SelectedArea 71. The method of selection is that used in the previous papers ofthis series, but modified to account for the differential reddening thatoccurs across the field. The authors list color classes, colorsubclasses, positions, and magnitudes of the selected objects.
| UBV sequences in selected star fields
Not Available
|
Добавить новую статью
Внешние ссылки
- - Внешних ссылок не найдено -
Добавить внешнюю ссылку
Группы:
|
Наблюдательные данные и астрометрия
| Созвездие: | Овен |
| Прямое восхождение: | 03h15m08.15s |
| Склонение: | +14°53'47.8" |
| Видимая звёздная величина: | 10.975 |
| Собственное движение RA: | 3.2 |
| Собственное движение Dec: | -7.1 |
| B-T magnitude: | 10.938 |
| V-T magnitude: | 10.972 |
Каталоги и обозначения:
|
