Host Galaxy 5 — Messier 83 (15 XGOs)
Photo: SSON Warrumbungle, 90 seconds on 2024-04-15 at 22:45:18.330 UTC.
Finding and annotating the H II regions on this photo of Messier 83 was a challenge. The earliest catalog / listing I found was Rumstay, K. S., & Kaufman, M. (1983). “H II Regions and Star Formation in M83 and M33.” The Astrophysical Journal, 274, 611–631, published on November 15, 1983. Unfortunately, the paper did not list its 296 M83 H II regions directly in modern J2000/ICRS RA and Dec. It used an offset calculation that was difficult for me to use.
A later paper, by Maragkoudakis, A., Ivkovich, N., Peeters, E., Stock, D. J., Hemachandra, D., & Tielens, A. G. G. M. (2018). “PAHs and star formation in the H II regions of nearby galaxies M83 and M33.” Monthly Notices of the Royal Astronomical Society, 481(4), 5370–5393 gave the J2000 positions for the H II regions identified in Rumstay and Kaufman. I was able to get the RA and Dec data for a number of H II regions (designated as RK regions), build a csv file, and use it in the AnnotateImage script in Pixinsight. That is how I generated the RK designations on the photo above. Here are the entries in the csv file:
NAME RA DEC
RK 209 204.2216667 -29.85861111
RK 137 204.2558333 -29.8575
RK 86 204.2795833 -29.82666667
RK 120 04.2645833 -29.90055556
RK 211 204.2204167 -29.85305556
RK 20 204.3204167 -29.88722222
RK 70 204.2858333 -29.86972222
RK 230 204.21125 -29.86722222
RK 69 204.2854167 -29.86777778
RK 198 204.22625 -29.84638889
RK 275 204.1679167 -29.85583333
RK 201 204.2245833 -29.815
RK 154 204.2445833 -29.80166667
RK 135 204.2583333 -29.92527778
RK 266 204.1808333 -29.87277778