GMRT and VLA Observations at 49 cm and 20 cm of the HII Region near l = 24.8°, b = 0.1°

Abstract

International audienceWe report multi-frequency radio continuum and hydrogen radio recombination line observations of HII regions near l = 24.8°, b = 0.1° using the Giant Metrewave Radio Telescope(GMRT) at 1.28 GHz (n = 172), 0.61 GHz (n = 220) and the Very Large Array (VLA) at 1.42 GHz (n = 166). The region consists of a large number of resolved HII regions and a few compact HII regions as seen in our continuum maps, many of which have associated infrared (IR) point sources. The largest HII region at l = 24.83° and b = 0.1° is a few arcmins in size and has a shell-type morphology. It is a massive HII region enclosing ˜550M with a linear size of 7 pc and an rms electron density of ˜110 cm-3 at a kinematic distance of 6 kpc. The required ionization can be provided by a single star of spectral type Omicr 5.5