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IONIZED GAS KINEMATICS AND MORPHOLOGY IN Sgr B2 Main ON 1000 AU SCALES
被引:6
|作者:
De Pree, C. G.
[1
]
Wilner, D. J.
[2
]
Goss, W. M.
[3
]
机构:
[1] Agnes Scott Coll, Dept Phys & Astron, Decatur, GA 30030 USA
[2] Harvard Ctr Astrophys, Cambridge, MA USA
[3] Natl Radio Astron Observ, Socorro, NM 87801 USA
基金:
美国国家科学基金会;
关键词:
H II regions;
ISM: kinematics and dynamics;
stars: formation;
RADIO RECOMBINATION LINE;
STAR-FORMING REGION;
H II REGIONS;
CONTINUUM OBSERVATIONS;
SAGITTARIUS B2;
RESOLUTION;
D O I:
10.1088/0004-6256/142/5/177
中图分类号:
P1 [天文学];
学科分类号:
0704 ;
摘要:
We have imaged the Sgr B2 Main region with the Very Large Array in the BnA configuration (theta(beam) = 0 ''.13) in both the H52 alpha (45.453 GHz) radio recombination line and 7mm continuum emission. At a distance of 8500 pc, this spatial resolution corresponds to a physical scale of 0.005 pc (similar to 1100 AU). The current observations detect H52 alpha emission in 12 individual ultracompact and hypercompact H II regions. Two of the sources with detected H52 alpha emission have broad (Delta V-FWHM similar to 50 km s(-1)) recombination lines, and two of the sources show lines with peaks at more than one velocity. We use line parameters from the H52 alpha lines and our previous H66 alpha line observations to determine the relative contribution of thermal, pressure, and kinematic broadening, and electron density. These new observations suggest that pressure broadening can account for the broad lines in some of the sources, but that gas motions (e.g., turbulence, accretion, or outflow) contribute significantly to the broad lines in at least one of the sources (Sgr B2 F3).
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