Ýçindekiler
Görüntüler
Resim Yükleyin
DSS Images Other Images
Ýlgili Makaleler
The 1000 Brightest HIPASS Galaxies: Newly Cataloged Galaxies
The H I Parkes All-Sky Survey (HIPASS) is a blind 21 cm survey forextragalactic neutral hydrogen, covering the whole southern sky. TheHIPASS Bright Galaxy Catalog (BGC) is a subset of HIPASS and containsthe 1000 H I-brightest (peak flux density) galaxies. Here we present the138 HIPASS BGC galaxies that had no redshift measured prior to theParkes multibeam H I surveys. Of the 138 galaxies, 87 are newlycataloged. Newly cataloged is defined as having no optical (or infrared)counterpart in the NASA/IPAC Extragalactic Database. Using the DigitizedSky Survey, we identify optical counterparts for almost half of thenewly cataloged galaxies, which are typically of irregular or Magellanicmorphological type. Several H I sources appear to be associated withcompact groups or pairs of galaxies rather than an individual galaxy.The majority (57) of the newly cataloged galaxies lie within 10° ofthe Galactic plane and are missing from optical surveys as a result ofconfusion with stars or dust extinction. This sample also includes newlycataloged galaxies first discovered by Henning et al. in the H I shallowsurvey of the zone of avoidance. The other 30 newly cataloged galaxiesescaped detection because of their low surface brightness or opticalcompactness. Only one of these, HIPASS J0546-68, has no obvious opticalcounterpart, as it is obscured by the Large Magellanic Cloud. We findthat the newly cataloged galaxies with |b|>10° are generally lowerin H I mass and narrower in velocity width compared with the totalHIPASS BGC. In contrast, newly cataloged galaxies behind the Milky Wayare found to be statistically similar to the entire HIPASS BGC. Inaddition to these galaxies, the HIPASS BGC contains four previouslyunknown H I clouds.
| Two-colour photometry for 9473 components of close Hipparcos double and multiple stars
Using observations obtained with the Tycho instrument of the ESAHipparcos satellite, a two-colour photometry is produced for componentsof more than 7 000 Hipparcos double and multiple stars with angularseparations 0.1 to 2.5 arcsec. We publish 9473 components of 5173systems with separations above 0.3 arcsec. The majority of them did nothave Tycho photometry in the Hipparcos catalogue. The magnitudes arederived in the Tycho B_T and V_T passbands, similar to the Johnsonpassbands. Photometrically resolved components of the binaries withstatistically significant trigonometric parallaxes can be put on an HRdiagram, the majority of them for the first time. Based on observationsmade with the ESA Hipparcos satellite.
| The chemical evolution of the solar neighborhood. I - A bias-free reduction technique and data sample
The possible ways of measuring the age-metallicity relation for thegalactic disk in the neighborhood of the sun are discussed. It is shownthat the use of a field star sample chosen on the basis of effectivetemperature introduces a bias which results in a monotonic increase inthe metal abundance of the disk with time. However, if theage-metallicity relation for the disk can be shown to satisfy certaincriteria, the bias introduced in such a sample can be neglected: thegalactic disk apparently satisfies the criteria. It is concluded that asample analyzed through the use of uvby and H(beta) photometry inconjunction with a self-consistent set of theoretical isochronesprovides the least biased, most accurate estimate of the age-metallicityrelation for the disk.
|
Yeni bir Makale Öner
Ýlgili Baðlantýlar
Yeni Bir Baðlantý Öner
sonraki gruplarýn üyesi:
|
Gözlemler ve gökölçümü verileri
| Takýmyýldýz: | Hintli |
| Sað Açýklýk: | 22h00m53.85s |
| Yükselim: | -56°28'16.2" |
| Görünürdeki Parlaklýk: | 8.442 |
| Uzaklýk: | 333.333 parsek |
| özdevim Sað Açýklýk: | 15.6 |
| özdevim Yükselim: | 2.8 |
| B-T magnitude: | 8.647 |
| V-T magnitude: | 8.459 |
Kataloglar ve belirtme:
|
INHABITED SKY
