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MACHO Project Photometry of RR Lyrae Stars in the Sagittarius Dwarf Galaxy

Year: 1997
Type: article
Abstract: We report the discovery of 30 type a , b RR Lyrae (RR ab ) stars that are likely members of the Sagittarius dwarf galaxy (Sgr). Accurate positions, periods, amplitudes, and magnitudes are presented. Their distances are determined with respect to RR ab stars in the Galactic bulge found also in the MACHO 1993 data. For R ☉ = 8 kpc, the mean distance to these stars is D = 22 ± 1 kpc, smaller than previous determinations for this galaxy. This indicates that Sgr has an elongated main body extending for more than 10 kpc, which is inclined along the line of sight, with its northern part (in Galactic coordinates) closer to us. The size and shape of Sgr give clues about the past history of this galaxy. If the shape of Sgr follows the direction of its orbit, the observed spatial orientation suggests that Sgr is moving away from the Galactic plane. Also, Sgr stars may be the sources of some of the microlensing events seen toward the bulge.
DOI: 10.1086/303467
Authors: C. Alcock, R. A. Allsman, D. R. Alves, T. S. Axelrod, A. C. Becker, D. P. Bennett, K. H. Cook, K. C. Freeman, K. Griest, J. A. Guern, M. J. Lehner, S. L. Marshall, D. Minniti, B. A. Peterson, M. R. Pratt, P. J. Quinn, A. W. Rodgers, C. W. Stubbs, W. Sutherland, D. L. Welch
Institutions: Lawrence Livermore National Laboratory, University of California, Berkeley, Australian National University, University of California, Davis, University of Washington, University of California San Diego, University of California, Santa Barbara, University of Oxford, McMaster University
Language: English
Open Access status: bronze
OpenAlex ID: W2023880922
FWCI: 7.169
Cites: 27
Cited by: 47
Related to: 10