Observations of the giant H II region complex W51 at decameter wavelengths

Abstract

Radio continuum absorption observations at 34.5 MHz with a spatial resolution of 34 x 48 arcmin have been obtained for the giant H II region complex W 51 with the decameter-wave radio telescope at Gauribidanur, India (13 deg 36 min N and long 77 deg 27 min E). A mean electron temperature of 9500 + or - 600 K and a background temperature of 28,000 + or - 2600 K have been derived. The proportion of nonthermal emission originating on the near side of W51 corresponds to a mean emissivity of 2 K/pc. The present observations also indicate that the ring towards the east of the nebula (W 51 C) is nonthermal.