Spatial and Velocity clumping in an SDSS blue horizontal branch star catalogue

Abstract

We present evidence for eight new clumps of blue horizontal branch (BHB) stars discovered in a catalogue of these stars compiled from the Sloan Digital Sky Survey (SDSS) by Sirko et al. published in 2004. Clumps are identified by selecting pairs of stars separated by distances <= 2 kpc and with differences in galactocentric radial velocities < 25 km/s. Each clump contains four or more stars. Four of the clumps have supporting evidence: two of them also contain overdensities of RR Lyrae stars which makes their reality very likely. At least one of the clumps is likely to be associated with the tidal debris of the Sagittarius dwarf spheroidal galaxy. We emphasize that more accurate observations of the radial velocities or proper motions of the stars in the clumps as well as the identification of other halo stars in these regions are required to establish the reality of the remaining clumps.

5 pages, 2 figures. Accepted for publication in MNRAS letters

References in corpus (3)

• A 22 Degree Tidal Tail for Palomar 5
• Formation and evolution of clumpy tidal tails around globular clusters
• Probing the Sagittarius stream with blue horizontal branch stars

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• The stellar halo of the Galaxy
• The Stellar Mass Density at z~6 from Spitzer Imaging of i-drop Galaxies
• Galactic Archaeology with Gaia
• The Century Survey Galactic Halo Project III: A Complete 4300 deg^2 Survey of Blue Horizontal Branch Stars in the Metal-Weak Thick Disk and Inner Halo
• Kinematic Structure in the Galactic Halo at the North Galactic Pole: RR Lyrae and BHB Stars show different kinematics
• A comprehensive view of the Virgo Stellar Stream
• Architecture of the Andromeda: a quantitative analysis of clustering in the inner stellar halo