| Abstract | A structure that is likely associated with the Sagittarius dwarf galaxy (Sgr) is identified in a new sample of 1466 RR Lyrae stars of Bailey type ab (RRab). These stars were discovered in a 25 deg2 field, centered at the Galactic coordinates b = -7 deg, l = 3 deg, using 154 B and R photographic Schmidt plates taken for the DUO project. A significant extension of Sgr into this region is not expected from the Ibata, Gilmore, & Irwin projected density. After correction for extinction, the distribution of magnitudes corresponds to a bimodal distance modulus distribution, with peaks at the distance of the Galactic center and Sgr (24 +/- 2 kpc). The distribution on the sky of the 313 stars concentrated near 24 kpc is consistent with an extension of the structure found by Ibata and coworkers. Also, the period histogram of the distant RRab is quite different from that of stars at smaller distances. This is evidence that, at large distance, we suddenly cross a population that is different from the Galactic RRab. All of this evidence demonstrates that the observed density is likely an extension of the dwarf galaxy discovered by Ibata and coworkers. |
