Absolute proper motions to B ∼ 22.5. V. Detection of sagittarius dwarf spheroidal debris in the direction of the galactic anticenter

We have detected a population of predominantly blue (B-V ≤ 1.1) stars in the direction l = 167°, b = -35° (Kapteyn Selected Area [SA] 71) that cannot be accounted for by standard star count models. Down to V ∼20 mag, the colors and magnitudes of these stars are similar to those of the southern overdensity detected by the Sloan Digital Sky Survey (SDSS) at l = 167°, b = -54° and identified as stripped material from the Sagittarius dwarf spheroidal (Sgr dSph) galaxy. We present absolute proper motions of the stars in SA 71, and we find that the excess blue stars represent a distinct, kinematically cooler component than the Galactic field, in reasonable agreement with predictions of Sgr dSph disruption models. The density of the excess SA 71 stars at V ∼ 18.8 mag and B-V ≤ 1.1 is within a factor of 2 of the density of the SDSS-south Sgr dSph stripped material and of that predicted by the Helmi & White disruption model. Three additional anticenter fields (SA 29, 45, and 118) show very good agreement with standard star count models.