Planetary nebulae in local group galaxies. IX - Velocity modulated photographs of the center of M31

Arecibo telescope observations of high-velocity, infalling neutral hydrogen clouds in the Galaxy's anticenter and inner direction exhibit direct evidence, at the anticenter, for the collision of a -210 km/sec velocity cloud with Milky Way material. The energy transfer of the high velocity cloud complex which has reached the outer Galaxy is estimated at 10 to the 53rd to 10 to the 54th ergs, with phenomena resulting from galactic accretion of neutral hydrogen clouds that are subjected to examination. It is also indicated by the observations that the cloud complex at the anticenter is a fragment of the Magellanic Stream which has fallen as far as a few kiloparsecs from the sun, while the complex in the direction of the inner Galaxy is located beyond the galactic center and may be a part of a distinct, southern hemisphere Magellanic Stream.