The outer regions of the Galactic bulge - I. Observations
Abstract
An observational survey of stars selected from the region of sky in the direction of the Galactic bulge is presented. We discuss the choice of tracer populations for this study. Digitized UK Schmidt plate photometry, calibrated with CCD photometry, is obtained in 18 regions over the bulge. Stars are selected for spectroscopic follow-up from within a carefully chosen colour-magnitude selection window, optimized for efficient detection of bulge K giants. Some 1500 stellar spectra are obtained, with the AAT AUTOFIB facility, giving the largest data set yet obtained in this region of the Galaxy, by a factor of ~=10. We derive a radial velocity and metallicity for each star, and quantify the uncertainties in these measurements. Luminosity classification is derived both by visual classification and by using an automated routine based on Principal Component Analysis. There are two basic results from this survey: the discovery of the Sagittarius dwarf galaxy, which is described by Ibata, Gilmore & Irwin, and a study of the Galactic bulge, which is presented in an accompanying paper.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- August 1995
- DOI:
- 10.1093/mnras/275.3.591
- arXiv:
- arXiv:astro-ph/9502036
- Bibcode:
- 1995MNRAS.275..591I
- Keywords:
-
- STARS: ABUNDANCES;
- STARS: POPULATION II;
- GALAXY: ABUNDANCES;
- GALAXY: KINEMATICS AND DYNAMICS;
- GALAXY: STELLAR CONTENT;
- GALAXIES: EVOLUTION;
- Astrophysics
- E-Print:
- MNRAS in press, 13pp, 11figs uuencoded, compressed tarred .ps files