VLA Observations of the Sagittarius D Star-Forming Region

David M. Mehringer(1), W. M. Goss(2), D. C. Lis(1), Patrick Palmer(3), and Karl M. Menten(4)

(1) California Institute of Technology, Downs Laboratory of Physics, MC 320-47, Pasadena, CA 91125
(2) National Radio Astronomy Observatory, Box O, Socorro, NM 87801
(3) University of Chicago, Department of Astronomy and Astrophysics, 5640 S. Ellis Ave., Chicago, IL 60637
(4) Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany

Paper: to appear in ApJ


We have carried out a program of VLA observations of the Sgr D (G1.13-0.10) star-forming region in order to gain a better understanding of this source. Continuum observations at 6 and 18 cm show a region which is dominated by a single compact source. This source is embedded in a halo of ionized gas and there are several compact continuum sources scattered about the field. The supernova remnant G1.05-0.15 is located 5' south of the main H II region. From the continuum observations we determined the physical conditions of the thermal sources in Sgr D. Observations of the 6 cm transition of H_2CO which appears in absorption were also carried out to study the distribution and kinematics of molecular material in this region. These data indicate that the distribution of molecular material is clumpy, with apparent optical depths varying by about one order of magnitude within single clouds. In addition, the line widths of the molecular clouds associated with the Sgr D H II region (G1.13-0.10) are ~3 km/sec n, which is more typical of Galactic disk than Galactic center sources. The narrow molecular lines and the presence of higher velocity, broader H_2CO absorption lines in the Sgr D spectrum indicate that this region is probably located on the far side of the Galactic center region. OH and H_2O maser observations indicate that there may be at least three sites of very recent star formation in this region.

Preprints available from the authors at dmehring@socrates.patnet.caltech.edu , or the raw TeX (no figures) if you click here.

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