AAS 195th Meeting, January 2000
Session 53. ISM: Ionized Gas
Display, Thursday, January 13, 2000, 9:20am-6:30pm, Grand Hall

[Previous] | [Session 53] | [Next]

[53.14] Evidence of Ionized Winds in W49N on 0.0025 pc Scales

C. G. De Pree (Agnes Scott College), D. J. Wilner (CfA), W. M. Goss (NRAO), Elizabeth McGrath (Vassar), W. J. Welch (UC Berkeley)

We have observed the ionized gas in W49N with the Very Large Array (VLA) at 13 mm and 7 mm, and with the Berkeley Illinois Maryland Association (BIMA) Array at 3.3 mm. These observations vary in resolution from 0.35\arcsec~to 0.045\arcsec~(0.019 to 0.0025 pc at a distance of 11.4 kpc). In addition, we have used the VLA to observe water maser emission towards the bright G sources over a wide velocity range from -256 to 271 km s-1. The high resolution continuum observations reveal the morphologies in the ultracompact sources; most of the sources at 0.045\arcsec~resolution appear to have shell or ring morphologies. Of the seven bright sources in W49N for which multifrequency flux densities have been measured, four are observed to have rising spectral indices, with values ranging from \alpha=0.3 to 1.1 and three are observed to be flat (S\nu\propto\nu\alpha). Those sources with rising spectral indices (A, B1, B2, G1 and G2) also have the broadest radio recombination lines, with \DeltaVFWHM>45 km s-1 in the H66\alpha line (De Pree et al. 1996). The water maser postions have been aligned with the high resolution 7 mm continuum to within 0.05\arcsec, and appear to be closely associated with the G1/G2 sources. The outflow discussed in Gwinn et al. (1992) and Mac Low & Elitzur (1992) is centered within 0.2\arcsec~of the bright G2 continuum peak, but is not clearly associated with any one of the 7 mm continuum sources. We present the high resolution images and an interpretation of the distribution of ionized gas and water maser positions.

CGD acknowledges the support of a AAS Small Research Grant.

[Previous] | [Session 53] | [Next]