Vol. 565
In section 1. Letters

Planck confirmation of the disk and halo rotation of M31

It is possible to detect the rotation of a nearby galaxy through a temperature difference in the cosmic microwave background (CMB) between the receding and approaching side; this is a Doppler-induced effect. The authors have studied the first 15.4 months of Planck observations and detected the rotation in the disk of M31, which was previously detected with the seven-year WMAP data. They also detected the rotation of the M31 halo for the first time in the CMB, which is interesting for constraining models of galaxy formation. In addition, they succeeded to measure a temperature asymmetry, which is expected from the kinetic Sunyaev-Zeldovich effect in the diffuse hot gas of the Local Group: a hot spot of a few degrees in size is located in the direction of M31 in the CMB maps, and a cold spot in the opposite direction, as predicted by Rubin & Loeb (2014, JCAP, 01, 051).