| DOI | Resolve DOI: https://doi.org/10.3847/1538-4365/abf4d4 |
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| Author | Search for: Wenger, Trey V.1ORCID identifier: https://orcid.org/0000-0003-0640-7787; Search for: Dawson, J. R.ORCID identifier: https://orcid.org/0000-0003-0235-3347; Search for: Dickey, John M.1ORCID identifier: https://orcid.org/0000-0002-6300-7459; Search for: Jordan, C. H.ORCID identifier: https://orcid.org/0000-0002-1220-2940; Search for: McClure–Griffiths, N. M.ORCID identifier: https://orcid.org/0000-0003-2730-957X; Search for: Anderson, L. D.ORCID identifier: https://orcid.org/0000-0001-8800-1793; Search for: Armentrout, W. P.ORCID identifier: https://orcid.org/0000-0002-7045-9277; Search for: Balser, Dana S.ORCID identifier: https://orcid.org/0000-0002-2465-7803; Search for: Bania, T. M.ORCID identifier: https://orcid.org/0000-0003-4866-460X |
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| Affiliation | - National Research Council of Canada. Herzberg Astronomy and Astrophysics
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| Funder | Search for: National Science Foundation; Search for: National Science Foundation; Search for: Australian Research Council |
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| Format | Text, Article |
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| Subject | H II regions; surveys; radio spectroscopy; radio continuum emission; galaxy structure; Milky Way dynamics; Milky Way galaxy; interstellar medium |
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| Abstract | The Southern H ii Region Discovery Survey (SHRDS) is a 900 hr Australia Telescope Compact Array 4–10 GHz radio continuum and radio recombination line (RRL) survey of Galactic H ii regions and infrared-identified H ii region candidates in the southern sky. For this data release, we reprocess all previously published SHRDS data and include an additional ∼450 hr of observations. The search for new H ii regions is now complete over the range 259° < ℓ < 346°, ∣b∣ < 4° for H ii region candidates with predicted 6 GHz continuum peak brightnesses ≳30 mJy beam⁻¹. We detect radio continuum emission toward 730 targets altogether including previously known nebulae and H ii region candidates. By averaging ∼18 RRL transitions, we detect RRL emission toward 206 previously known H ii regions and 436 H ii region candidates. Including the northern sky surveys, over the last decade the H ii Region Discovery Surveys have more than doubled the number of known Galactic H ii regions. The census of H ii regions in the Wide-field Infrared Survey Explorer (WISE) Catalog of Galactic H ii Regions is now complete for nebulae with 9 GHz continuum flux densities ≳250 mJy. We compare the RRL properties of the newly discovered SHRDS nebulae with those of all previously known H ii regions. The median RRL FWHM line width of the entire WISE Catalog H ii region population is 23.9 km s⁻¹ and is consistent between Galactic quadrants. The observed Galactic longitude–velocity asymmetry in the population of H ii regions probably reflects underlying spiral structure in the Milky Way. |
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| Publication date | 2021-06-07 |
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| Publisher | IOP |
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| In | |
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| Language | English |
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| Peer reviewed | Yes |
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| Export citation | Export as RIS |
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| Report a correction | Report a correction (opens in a new tab) |
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| Record identifier | d628ca32-48e4-41c8-8c07-1d9171e2f578 |
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| Record created | 2023-05-11 |
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| Record modified | 2023-05-11 |
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