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A complete survey of radio recombination lines (RRLs) near 327 MHz from the galactic plane (l = 330° − 0°-89°, b = 0°) was carried out using a section of the Ooty Radio Telescope (ORT) with an angular resolution of 2° × 2°. A subset of regions in the same area was observed using the whole telescope which has a beam of 2° × 6'. Hydrogen RRLs were detected in most of the positions that were observed. The lv diagram and radial distribution computed from the observed spectra and their comparison with other species in the galactic plane indicate that the low density gas detected in the survey is distributed similar to the star forming regions. For an assumed temperature of 7000 K, we estimate that the densities and sizes of the regions are in the range 1 — 10 cm−3 and 20 — 200 pc respectively. Our data suggests that the low density ionized gas is in the form of outer envelopes of normal HII regions.

The electron temperatures of the compact cores of the galactic HII regions S206 and S209 have been determined by radio continuum observations near 235, 327 and 610 MHz using the Giant Meterwave Radio Telescope (GMRT). The resolution of our maps are 11″ and 6″ at 327 and 610 MHz respectively. These are the highest resolution low frequency maps of these HII regions.

A pilot project to observe recombination lines of hydrogen and carbon from Galactic HII regions near 20cm (n = 168) and 49cm (n = 220) using the 30-station correlator at the Giant Metre-wave Radio Telescope was undertaken. The preliminary results from observations of the HII regions W3 and S106 are presented here.