Large-Scale Coherent Dipole Anisotropy ?

We have reanalyzed and compared the dipoles of the 1.2 Jy and 0.6 Jy (QDOT) IRAS galaxy samples. We find strong indications from both samples for (a) significant contributions to the gravitational field that shapes the Local Group motion from depths up to $\sim 170$ $h^{-1}$ Mpc and (b) a large-scale coherence of the dipole anisotropy, indications provided mainly by the fact that the differential dipoles of large equal volume shells are aligned with the CMB dipole and exhibit significant dipole signals. The two IRAS dipoles are indistinguishable within 50 $h^{-1}$ Mpc and beyond $\sim 130$ $h^{-1}$ Mpc while the QDOT dipole, having a lower flux limit, continues growing with respect to the 1.2 Jy sample up to $\sim 100$ $h^{-1}$ Mpc in agreement with Rowan-Robinson et al (1990). The most probable cause of these deep dipole contributions is the Shapley mass concentration.