Studies of Extragalactic Nebulae.IV. Preliminary Spectroscopic Observations of NGC 4258

Spectroscopic observations have been obtained in P.A. = 148 and P.A. = 58 near the major and minor axes of NGC 4258, respectively The observations in P A. = 148 show the presence of a velocity maximum at a distance of about 6" from the center, followed by a very pronounced minimum at about 16", after which the curve rises to a second maximum at about 40" from the center. In P A. = 58 the velocity curve is generally bow-shaped, confirming the presence of pronounced non-circular motions. No satisfactory model of the observed motions has been found In the nucleus, an emission cloud measuring 9"4 X 5"8 (300 X 186 pc) has been detected. This cloud has about the same sixe and mass as the nuclear clouds in NGC 1068 but, unlike those clouds, has no kinetic energy with respect to the surrounding material and has very low turbulent energy; the turbulence within the cloud is much lower than in the surrounding material.