Bar-induced gas velocities in the bulge of M31

Interstellar gas on closed orbits in a weak barlike potential, when viewed from an appropriate angle, will generate a velocity field similar to what is observed in the bulge of M31. Three phenomena observed in the inner kiloparsec of M31 are best explained by a central bar: (I) the tilt of the inner isophotes, (2) gas velocities in the inner kiloparsec, (3) the "face-on spiral" pattern seen in dust and ionized gas. Models that fit the data have the near end of the bar south of the nucleus, and the long axis of the bar at an angle of about 20^deg^ to the projection of the line of sight onto the plane of M31.