A charge-coupled device study of high-latitude Galactic structure: testing the model parameters

Karaali S., Ak S., Bilir S., Karatas Y., Gilmore G.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, vol.343, no.3, pp.1013-1024, 2003 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 343 Issue: 3
  • Publication Date: 2003
  • Doi Number: 10.1046/j.1365-8711.2003.06743.x
  • Journal Name: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1013-1024
  • Keywords: methods : data analysis, stars : luminosity function, mass function, Galaxy : abundances, Galaxy : structure, PHOTOMETRIC SPACE-DENSITIES, THICK DISK COMPONENT, METAL-POOR STARS, BASLE HALO PROGRAM, STELLAR LUMINOSITY FUNCTION, PROPER-MOTION STARS, MILKY-WAY, FE/H DETERMINATIONS, EARLY EVOLUTION, CCD PHOTOMETRY
  • Istanbul University Affiliated: Yes

Abstract

We interpret published charge-coupled device (CCD) UBVI data to deduce the stellar density distribution and metallicity distribution function in the region of 2-8 kpc from the Galactic plane, and compare our results to several star-count models. A feature of extant star-count models is degeneracy between the adopted scaleheights of the thin and thick discs, and their local normalization. We illustrate the utility of this small data set, and future larger sets (e.g. Sloan Digital Sky Survey, SDSS), by explicitly considering consistency between the derived density laws, and the implied solar neighbourhood luminosity function. Our data set, from Hall et al.'s 1996 paper (l = 52degrees, b =-39degrees), contains 566 stars, selected to be consistent with stellar loci in colour-colour diagrams. The effective apparent V -magnitude interval is 15.5 less than or equal toV (o) less than or equal to 20.5<. Our analysis supports the parametrization of the recent (SDSS) galaxy model of Chen et al., except in preferring the stellar halo axial ratio to be η= 0.84.