The rr lyrae population of the galactic bulge from the macho database: mean colors and magnitudes

C. Alcock, R. A. Allsman, D. R. Alves, T. S. Axelrod, A. C. Becker, A. Basu, L. Baskett, D. P. Bennett, K. H. Cook, K. C. Freeman, K. Griest, M. J. Lehner, S. L. Marshall, D. Minniti, B. A. Peterson, M. R. Pratt, P. J. Quinn, A. W. Rodgers, C. W. Stubbs, W. SutherlandT. Vandehei, D. L. Welch

Research output: Contribution to journalArticlepeer-review

54 Citations (Scopus)

Abstract

Mean colors and magnitudes of RR Lyrae stars in 24 fields toward the Galactic bulge from the MACHO database are presented. Accurate mean reddenings are computed for these fields on the basis of the mean colors. The distribution along the line of sight of the RR Lyrae population is examined on the basis of the mean magnitudes, and it is shown that the bulk of the RR Lyrae population is not barred. Only the RR Lyrae stars in the inner fields closer to the Galactic center (l < 4°, b > -4°) show evidence for a bar. The red giant clump stars in the MACHO fields, however, clearly show a barred distribution, confirming the results of previous studies. Given the different spatial distribution, the RR Lyrae stars and the clump giants trace two different populations. The RR Lyrae variables would represent the inner extension of the Galactic halo in these fields.

Original languageEnglish
Pages (from-to)190-199
Number of pages10
JournalAstrophysical Journal
Volume492
Issue number1 PART I
DOIs
Publication statusPublished - 1998

Keywords

  • Galaxy: halo
  • Galaxy: stellar content
  • Galaxy: structure
  • Gravitational lensing
  • Stars: Variables: other (RR Lyrae)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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