We use a sample of blue horizontal branch ( BHB ) stars from the Sloan Digital Sky Survey Data Release 7 to explore the structure of the tidal tails from the Sagittarius Dwarf Galaxy .
We use a method yielding BHB star candidates with up to \sim 70 % purity from photometry alone .
The resulting sample has a distance precision of roughly 5 % and can probe distances in excess of 100 kpc .
Using this sample , we identify a possible extension to the trailing arm at distances of 60 - 80 kpc from the Sun with an estimated significance of at least 3.8 \sigma .
Current models predict that a distant ‘ returning ’ segment of the debris stream should exist , but place it substantially closer to the Sun where no debris is observed in our data .
Exploiting the distance precision of our tracers , we estimate the mean line-of-sight thickness of the leading arm to be \sim 3 kpc , and show that the two ‘ bifurcated ’ branches of the debris stream differ by only 1 - 2 kpc in distance .
With a spectroscopic very pure BHB star subsample , we estimate the velocity dispersion in the leading arm , 37 km s ^ { -1 } , which is in reasonable agreement with models of Sgr disruption .
We finally present a sample of high-probability Sgr BHB stars in the leading arm of Sgr , selected to have distances and velocities consistent with Sgr membership , to allow further study .