Position-velocity diagram of the satellite system of the M 81 group. Blue denotes a satellite moving toward us, and red denotes a satellite moving away from us, relative to the mean group velocity (v = 29 km s⁻¹). The gray symbols indicate the structure members without available line-of-sight velocities. The x-axis denotes the distance from the minor axis along the major axis. A negative sign on the distance is assigned based on their position on the left (positive x) of the minor axis. The circles highlight the dwarf spheroidals, and the squares show dwarfs of all other morphologies. The two stars indicate the two main galaxies M 81 and M 82.