With the help of Gaia DR2 , we are able to obtain the full 6-D phase space information for stars from LAMOST DR5 .
With high precision of position , velocity , and metallicity , the rotation of the local stellar halo is presented using the K giant stars with [ Fe/H ] < -1 dex within 4 kpc from the Sun .
By fitting the rotational velocity distribution with three Gaussian components , stellar halo , disk , and a counter-rotating hot population , we find that the local halo progradely rotates with V _ { T } = +27 ^ { +4 } _ { -5 } km s ^ { -1 } providing the local standard of rest velocity of V _ { LSR } = 232 km s ^ { -1 } .
Meanwhile , we obtain the dispersion of rotational velocity is \sigma _ { T } = 72 ^ { +4 } _ { -4 } km s ^ { -1 } .
Although the rotational velocity strongly depends on the choice of V _ { LSR } , the trend of prograde rotation is substantial even when V _ { LSR } is set at as low as 220 km s ^ { -1 } .
Moreover , we derive the rotation for subsamples with different metallicities and find that the rotational velocity is essentially not correlated with [ Fe/H ] .
This may hint a secular evolution origin of the prograde rotation .
It shows that the metallicity of the progradely rotating halo is peaked within -1.9 < [ Fe/H ] < -1.6 without considering the selection effect .
We also find a small fraction of counter-rotating stars with larger dispersion and lower metallicity .
Finally , the disk component rotates with V _ { T } = +182 ^ { +6 } _ { -6 } km s ^ { -1 } and \sigma _ { T } = 45 ^ { +3 } _ { -3 } km s ^ { -1 } , which is quite consistent with the metal-weak thick disk population .