ANOMALOUS MOTION OF IONIZED-GAS IN THE SICKLE (G0.18-0.04) NEAR THE GALACTIC-CENTER

We present VLA measurements of H92 alpha radio recombination line emis sion from the unusual H Il region G0.18-0.04, the ''Sickle,'' with spa tial and spectral resolutions of 27.'' 8 x 24.'' 9 and 14 km s(-1), re spectively. These observations detected two new kinematic components o f ionized gas whose velocities differ greatly from the +25 km s(-1) mo lecular cloud surrounding the Sickle. One component is highly redshift ed with a peak velocity of about + 150 km s(-1), and the other is a bl ueshifted velocity feature peaking near -35 km s(-1). Neither of these high-velocity features have molecular counterparts. The blueshifted f eature is forbidden in the sense of Galactic rotation and coincides wi th the prominent nonthermal filaments crossing the Sickle, thus sugges ting that they are physically associated with each other. The results presented here are interpreted in terms of ionized gas being accelerat ed away from the surface of the cloud associated with the Sickle regio n, either by the magnetic held associated with the nonthermal filament s or by the stellar winds from the hot helium stars near G0.18-0.04.