We make a comprehensive study of H I absorption toward H II regions located within |l| < 10°. Structures in the extreme inner Galaxy are traced using the longitude-velocity space distribution of this absorption. We find significant H I absorption associated with the Near and Far 3 kpc Arms, the Connecting Arm, Bania's Clump 1, and the H I Tilted Disk. We also constrain the line-of-sight distances to H II regions, by using H I absorption spectra together with the H II region velocities measured by radio recombination lines.
Bibliographical noteCopyright 2013 The American Astronomical Society. First published in the Astrophysical Journal, 774(2), 117, 2013. The original publication is available at https://doi.org/10.1088/0004-637X/774/2/117, published by IOP Publishing. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.
- Galaxy: structure
- Hii regions