2 micron Narrow-Band Imaging of the Sagittarius D H II Region

R. D. Blum(1,3) A. Damineli(2,4)

(1) Cerro Tololo Interamerican Observatory, Casilla 603, La Serena, Chile, rblum@noao.edu
(2) JILA, University of Colorado,Campus Box 440, Boulder, CO, 80309,damineli@casa.colorado.edu
(3) Hubble Fellow
(4) Permanent address: IAG-USP, Av. Miguel Stefano 4200, 04301-904, Sao Paulo, Brazil

Paper: to appear in the ApJ Feb 1999

Weblink: http://www.ctio.noao.edu/ftp/pub/blum/sgrd.ps

EPrint Server: astro-ph/9809345


We present 2 micron narrow-band images of the core H II region in the Galactic star forming region Sagittarius D. The emission-line images are centered on 2.17 micron (Br gamma ) and 2.06 micron (He I). The H II region appears at the edge of a well defined dark cloud, and the morphology suggests a blister geometry as pointed out in earlier radio continuum work. There is a deficit of stars in general in front of the associated dark cloud indicating the H II region is located in-between the Galactic center and the sun. The lesser spatial extent of the He I line emission relative to Br gamma places the effective temperature of the ionizing radiation field below 40,000 K. The He I 2.06 micron to Br gamma ratio and Br gamma / far infrared dust emission put T_eff at about 36,500 K to 40,000 K as derived from ionization models.

Preprints available from the authors at blum@ctiowe.ctio.noao.edu , or the raw TeX (no figures) if you click here.

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