  A subset of the RR Lyrae (RRL) candidates identified from the Southern
Edgeworth-Kuiper Belt Object (SEKBO) survey data has been followed up
photometrically (n=106) and spectroscopically (n=51). Period and light curve
fitting reveals a 24 +/_ 7% contamination of SEKBO survey data by non-RRLs.
This paper focuses on the region of the Virgo Stellar Stream (VSS),
particularly on its extension to the South of the declination limits of the
SDSS and of the QUEST RRL survey. The distribution of radial velocities in the
Galactic standard of rest frame (V_GSR) for the 11 RRLs observed in the VSS
region has two apparent peaks. The larger peak coincides with the four RRLs
having <V_GSR>=127 +/_ 10 kms-1 and dispersion sigma=27 kms-1, marginally
larger than that expected from the errors alone. The two type ab RRLs in this
group have <[Fe/H]>=-1.95 +/_ 0.1. Both the radial velocities and metal
abundances are consistent with membership in the VSS. The second velocity peak,
which occurs at <V_GSR>=-175 +/_ 10 kms-1 may indicate the presence of stars
from the Sgr leading tidal tail, which is expected to have large negative
velocities in this region. We explore the extent of the VSS by constructing
luminosity functions from the SEKBO data and comparing them to data synthesized
with the Besancon Galactic model. Analysis of the excess over the model
predictions reveals the VSS as a large (~760 deg^2) overdensity centered at
roughly (RA, Dec) ~ (186deg, -4deg), spanning a length of ~15 kpc in
projection, assuming a heliocentric distance of 19kpc. The data reveal for the
first time the more southern regions of the stream and trace it to Dec ~ -15deg
and Galactic latitudes as low as b ~ 45deg.

Astrophysics