RRL OBSERVATIONS USING ORT AT 328 MHz AND WSRT AT 1.4 GHz FROM ELDWIM

Abstract

Radio recombination line (RRL or RL for short) observations from 10 Galactic positions using the Ooty Radio Telescope (ORT) at 328 MHz and the Westerbork Synthesis Radio Telescope (WSRT) at 1.4 GHz have been presented. ORT observations were made using a recently augmented New Digital Backend (NDB). NDB offered a bandwidth of 1 MHz that was used to observe H271α RL. The eight intermediate-frequency bands offered by WSRT in the incoherent addition mode were used to detect the seven H/Henα RLs with n = 165-171 and the H208β RL. RL observations common to WSRT and ORT have been put together to model the diffuse low-density ionized gas (extended low density warm ionized medium, ELDWIM). This modeling constrains the electron number density in ELDWIM to 1.0 cm–3 33,000 K for the obtained ratios of N He +/N H + toward these directions.