The QUEST RR Lyrae Survey: Confirmation of the Clump at 50 kpc and Other Over-Densities in the Outer Halo

Abstract

We have measured the periods and light curves of 148 RR Lyrae variables from V=13.5 to 19.7 from the first 100 sq. degrees of the QUEST RR Lyrae survey. Approximately 55% of these stars belong to the clump of stars detected earlier by the Sloan Digital Sky Survey. According to our measurements, this feature has ~10 times the background density of halo stars, spans at least 37.5 deg by 3.5 deg in right ascension and declination (>=30 by >=3 kpc), lies ~50 kpc from the Sun, and has a depth along the line of sight of ~5 kpc (1 sigma). These properties are consistent with the recent models that suggest it is a tidal stream from the Sgr dSph galaxy. The mean period of the type ab variables, 0.58 d, is also consistent. In addition, we have found two smaller over-densities in the halo, one of which may be related to the globular cluster Pal 5.

12 pages (including 4 figures). Accepted for publication in the ApJ Letters

References in corpus (13)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• Dwarf Galaxies of the Local Group
• Debris streams in the solar neighbourhood as relicts from the formation of the Milky Way
• Detection of massive tidal tails around the globular cluster Pal 5 with SDSS commissioning data
• Great Circle tidal streams: evidence for a nearly spherical massive dark halo around the Milky Way
• Building up the Stellar Halo of the Galaxy
• Identification of A-colored Stars and Structure in the Halo of the Milky Way from SDSS Commissioning Data
• A Prescription for Building the Milky Way's Halo from Disrupted Satellites
• Candidate RR Lyrae Stars Found in Sloan Digital Sky Survey Commissioning Data
• Mapping the Galactic Halo I. The `Spaghetti' Survey
• Simple dynamical models of the Sagittarius dwarf galaxy
• Tidal streams in the Galactic halo: Evidence for the Sagittarius northern stream or traces of a new nearby dwarf galaxy
• The Metallicity Dependence of RR Lyrae Absolute Magnitudes from Synthetic Horizontal-Branch Models

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