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3rd of October 2019
An ATCA survey of HI absorption in the SMC
by Jameson et al.
Jameson et al. have presented the results from a new Australia Telescope Compact Array (ATCA) HI absorption survey towards 55 sources in the Small Magellanic Cloud. They combined the new ATCA (interferometric) data with archival Parkes (single-dish) data to produce a spectrum of the HI emission for each source, and the ATCA data to search for absorption features.

The plots above show an example of identified absorption features in absorption (left) and emission (right) spectra, in a more complex absorption spectrum source, 011049-731428. Individual absorption features are identified by color, with the dashed line of the respective color used to indicate the peak of each feature. The number of components (Ncomp) is indicated at the top right. The filled light gray area shows the 1-sigma uncertainty. From measurements of individual absorption components for a subset of sources, Jameson et al. find the average cold H i cloud temperature is ∼30 K in the SMC, which is lower than the ∼40 K found in the Milky Way. They estimate that the cold gas fraction in the SMC is ∼20%, which is similar to the average value for the Milky Way but larger than previously estimated for the SMC. More information is give in the the data in the paper to be published in the Astrophysical Journal Supplement Series.

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