Stellar overdensities in the halo: the extent of the Virgo overdensity

Abstract

We map the three-dimensional extent of the Virgo overdensity by combining distance information from RR Lyrae variables and projected spatial information from the Southern Edgeworth-Kuiper Belt Object Survey and Sloan Digital Sky Survey Data Release 6 photometry. The Virgo overdensity is seen to comprise two filaments and 10° × 3°, and a circular structure 3° in diameter. Together, the three features span 38° of right ascension and declinations of 2° to -15°. RR Lyrae variables place the two filamentary features at heliocentric distances of 20 and 17 kpc, respectively, with projected dimensions of 5 × 1 and 3 × 1 kpc. Show more