A Low Frequency Pilot Survey of Southern HII Regions in the Vela Constellation

Abstract

Atomic ionised regions with strong continuum emission are often associated with regions of high-mass star formation and low-frequency (<2GHz) 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 HII regions that are not well characterised. We searched publicly available catalogues for HII 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 HII 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 In this work we use data from the Australian Square Kilometre Array Pathfinder and previously unpublished data from the Murchison Widefield Array and the Australian Telescope Compact Array to analyse these sources.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 HII regions in our Galaxy. For the 9 other HII regions, we discuss their properties; including information about which clouds are interacting, their ages, whether they are dominated by infrared or optical H$\alpha$ lines, distances, ionising photon flux, and upper limits on the infrared luminosity. In future work, these 9 regions will be analysed in more detail, similar to the result for RCW 38 presented here.

18 pages, 19 Figures, Accepted by MNRAS

References in corpus (23)

• WSClean: an implementation of a fast, generic wide-field imager for radio astronomy
• GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey I: A low-frequency extragalactic catalogue
• An optimized algorithm for multi-scale wideband deconvolution of radio astronomical images
• The Rapid ASKAP Continuum Survey I: Design and First Results
• The observed spiral structure of the Milky Way
• A Compendium of Distances to Molecular Clouds in the Star Formation Handbook
• IR Dust Bubbles: Probing the Detailed Structure and Young Massive Stellar Populations of Galactic HII Regions
• The low-frequency environment of the Murchison Widefield Array: radio-frequency interference analysis and mitigation
• High-resolution radio continuum survey of M33 II. Thermal and nonthermal emission
• The $AKARI$ Far-Infrared All-Sky Survey Maps
• X-ray and IR Point Source Identification and Characteristics In the Embedded, Massive Star-Forming Region RCW 38
• GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey II: Galactic Plane $345^{\circ }<l<67^{\circ }$, $180^{\circ }<l<240^{\circ }$
• Science with the Murchison Widefield Array: Phase I Results and Phase II Opportunities
• Star formation in the Vela Molecular Ridge. Large scale mapping of cloud D in the mm continuum
• GEMINI near-infrared spectroscopic observations of young massive stars embedded in molecular clouds
• A young stellar cluster within the RCW41 HII region: deep NIR photometry and Optical/NIR polarimetry
• Spectral energy distribution modelling of Southern candidate massive protostars using the Bayesian inference method
• A Large Scale, Low Frequency Murchison Widefield Array Survey of Galactic HII regions between 260< l <\340
• Deep near-infrared adaptive optics observations of a young embedded cluster at the edge of the RCW 41 HII region
• Observations of the [CI] (${}^3{P}_1$-${}^3{P}_0$) emission toward the massive star-forming region RCW38: further evidence for highly-clumped density distribution of the molecular gas
• IRAS 09002-4732: A Laboratory for the Formation of Rich Stellar Clusters
• Radio Spectral Index Analysis of Southern Hemisphere Symbiotic Stars
• Twenty years of observations of PM 1-188: Its chemical abundances and extraordinary kinematics

Cited by in corpus (3)

• The Rapid ASKAP Continuum Survey IV: continuum imaging at 1367.5 MHz and the first data release of RACS-mid
• Physical Properties and Kinematics of Dense Cores Associated with Regions of Massive Star Formation from the Southern Sky
• GaLactic and Extragalactic All-sky Murchison Widefield Array survey eXtended (GLEAM-X) I: Survey Description and Initial Data Release