We present kinematical profiles and metallicity for the M31 dwarf spheroidal ( dSph ) satellite galaxy Andromeda II ( And II ) based on Keck DEIMOS spectroscopy of 531 red giant branch stars .
Our kinematical sample is among the largest for any M31 satellite and extends out to two effective radii ( r _ { eff } = 5.3 ^ { \prime } = 1.1 kpc ) .
We find a mean systemic velocity of - 192.4 \pm 0.5  km s ^ { -1 }  and an average velocity dispersion of \sigma _ { v } = 7.8 \pm 1.1  km s ^ { -1 } .
While the rotation velocity along the major axis of And II is nearly zero ( < 1  km s ^ { -1 } ) , the rotation along the minor axis is significant with a maximum rotational velocity of v _ { max } = 8.6 \pm 1.8  km s ^ { -1 } .
We find a kinematical major axis , with a maximum rotational velocity of v _ { max } = 10.9 \pm 2.4  km s ^ { -1 } , misaligned by 67 ^ { \circ } to the isophotal major axis .
And II is thus the first dwarf galaxy with evidence for nearly prolate rotation with a v _ { max } / \sigma _ { v } = 1.1 , although given its ellipticity of \epsilon = 0.10 , this object may be triaxial .
We measured metallicities for a subsample of our data , finding a mean metallicity of [ Fe/H ] = -1.39 \pm 0.03 dex and an internal metallicity dispersion of 0.72 \pm 0.03 dex .
We find a radial metallicity gradient with metal-rich stars more centrally concentrated , but do not observe a significant difference in the dynamics of two metallicity populations .
And II is the only known dwarf galaxy to show minor axis rotation making it a unique system whose existence offers important clues on the processes responsible for the formation of dSphs .