Stellar over-densities in the halo: the extent of the Virgo over-density

Understand

We map the three dimensional extent of the Virgo Over-density by combining distance information from RR Lyrae variables and projected spatial information from SEKBO (Keller et al.

• 2008) and Sloan Digital Sky Survey (SDSS) DR6 photometry.
• The Virgo Over-density is seen to comprise two filaments 14.5 x 3 degrees and 10 x 3 degrees and a circular structure 3 degrees in diameter.
• Together the three features span 38 degrees of right ascension and declinations of +2 to -15 degrees.