TY - JOUR
T1 - Anomalous motion of ionized gas in the Sickle (G0.18-0.04) near the Galactic center
AU - Yusef-Zadeh, F.
AU - Roberts, D. A.
AU - Wardle, M.
N1 - Funding Information:
1 The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under a cooperative agreement by Associated Universities, Inc.
Funding Information:
We thank the referee for useful comments. The work of F. Y.-Z. was supported in part by NASA grant NAGW-2518. D.R. acknowledges support from the NSF grant AST94-19227. The SRCfTA is funded by the Australian Research Council under the Special Research Centres program.
PY - 1997
Y1 - 1997
N2 - We present VLA measurements of H92α radio recombination line emission from the unusual H II region G0.18-0.04, the "Sickle," with spatial and spectral resolutions of 27″.8 × 24″.9 and 14 km s-1, respectively. These observations detected two new kinematic components of ionized gas whose velocities differ greatly from the +25 km s-1 molecular cloud surrounding the Sickle. One component is highly redshifted with a peak velocity of about +150 km s-1, and the other is a blueshifted velocity feature peaking near -35 km s-1. Neither of these high-velocity features have molecular counterparts. The blueshifted feature is forbidden in the sense of Galactic rotation and coincides with the prominent nonthermal filaments crossing the Sickle, thus suggesting that they are physically associated with each other. The results presented here are interpreted in terms of ionized gas being accelerated away from the surface of the cloud associated with the Sickle region, either by the magnetic field associated with the nonthermal filaments or by the stellar winds from the hot helium stars near G0.18-0.04.
AB - We present VLA measurements of H92α radio recombination line emission from the unusual H II region G0.18-0.04, the "Sickle," with spatial and spectral resolutions of 27″.8 × 24″.9 and 14 km s-1, respectively. These observations detected two new kinematic components of ionized gas whose velocities differ greatly from the +25 km s-1 molecular cloud surrounding the Sickle. One component is highly redshifted with a peak velocity of about +150 km s-1, and the other is a blueshifted velocity feature peaking near -35 km s-1. Neither of these high-velocity features have molecular counterparts. The blueshifted feature is forbidden in the sense of Galactic rotation and coincides with the prominent nonthermal filaments crossing the Sickle, thus suggesting that they are physically associated with each other. The results presented here are interpreted in terms of ionized gas being accelerated away from the surface of the cloud associated with the Sickle region, either by the magnetic field associated with the nonthermal filaments or by the stellar winds from the hot helium stars near G0.18-0.04.
KW - Galaxies: ISM
KW - Galaxy: center
KW - ISM: individual (Sagittarius A East, Sagittarius A West)
KW - ISM: magnetic fields
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U2 - 10.1086/310997
DO - 10.1086/310997
M3 - Article
AN - SCOPUS:0242455840
SN - 0004-637X
VL - 490
SP - L83-L86
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1 PART II
ER -