Detection of 21-CENTIMETER Hydrogen Absorption in the High-Velocity Component of the Radio Galaxy Perseus a

Neutral-hydrogen absorption has been detected in the radio source Perseus A (NGC 1275). Several narrow absorption features are seen. They cluster about a recession velocity of 8120 km , which is 3000 km 1 larger than the systemic velocity. It is shown that these hydrogen clouds lie in front of or within the 0'!02 continuum source located in the nucleus of NUC 1275. Models implied by these observations are considered and include (1) superposition of two galaxies, (2) a "nuclear wind," and (3) radiatively driven mass loss through "line locking." Subject headings: galaxies, individual - redshifts - Seyfert galaxies - 21-cm radiation