The RR Lyrae population of the Galactic bulge from the macho database: Mean colors and magnitudes

被引:78
作者
Alcock, C
Allsman, RA
Alves, DR
Axelrod, TS
Becker, AC
Basu, A
Baskett, L
Bennett, DP
Cook, KH
Freeman, KC
Griest, K
Lehner, MJ
Marshall, SL
Minniti, D
Peterson, BA
Pratt, MR
Quinn, PJ
Rodgers, AW
Stubbs, CW
Sutherland, W
Vandehei, T
Welch, DL
机构
[1] Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA
[2] Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA
[3] Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Weston, ACT 2611, Australia
[4] Univ Calif Davis, Dept Phys, Davis, CA 95616 USA
[5] Univ Washington, Dept Astron, Seattle, WA 98195 USA
[6] Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA
[7] European So Observ, D-85748 Garching, Germany
[8] Univ Oxford, Dept Phys, Oxford OX1 3RH, England
[9] McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada
关键词
galaxy; halo; stellar content; structure; gravitational lensing; stars; variables; other (RR Lyrae);
D O I
10.1086/305017
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
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 degrees, b > -4 degrees) 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.
引用
收藏
页码:190 / 199
页数:10
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