A low-frequency pilot survey of southern H II regions in the vela constellation

Atomic ionized regions with strong continuum emission are often associated with regions of high-mass star formation and low-frequency (<2 GHz) observations of these regions are needed to help build star formation models. The region toward the Vela Supernova Remnant is particularly interesting as it is a complex structure of recent supernova explosions and molecular clouds containing a number of H II regions that are not well characterized. We searched publicly available catalogues for H II regions, both candidate and identified, which also have low-frequency emission. In the area of ∼400 square degrees toward the Vela Supernova remnant, we found 10 such H II regions, some of which have multiple components in catalogues. In this work we use data from the Australian Square Kilometre Array Pathfinder and previously unpublished data from the Murchison Widefield Array and the Australian Telescope Compact Array to analyse these sources. The high-mass star forming region RCW 38, with observations specifically targeted on the source, is used as a pilot study to demonstrate how low-frequency, wide-field continuum observations can identify and study H II regions in our Galaxy. For the nine other H II regions, we discuss their properties; including information about which clouds are interacting, their ages, whether they are dominated by infrared or optical H α lines, distances, ionizing photon flux, and upper limits on the infrared luminosity. In future work, these nine regions will be analysed in more detail, similar to the result for RCW 38 presented here.