Systematically asymmetric: a comparison of H I profile asymmetries in real and simulated galaxies
Abstract
We examine different measures of asymmetry for galaxy H I velocity profiles. We introduce the channel-by-channel asymmetry and the velocity-of-equality statistics to quantify profile asymmetries. Using a sample of simulated galaxies, we examine how these and the standard lopsidedness morphometric statistic depend on a variety of observational effects, including the viewing angle and inclination. We find that our newly introduced channel-by-channel asymmetry is less sensitive to the effects of viewing angle and inclination than other morphometrics. Applying our statistics to the WHISP (Westerbork H I survey of Irregular and SPiral galaxies) H I galaxy sample, we also find that the channel-by-channel asymmetry is a better indicator of visually classified asymmetric profiles. In addition, we find that the lopsidedness-velocity of equality space can be used to identify profiles with deep central dips without visual inspection.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- June 2020
- DOI:
- 10.1093/mnras/staa1368
- arXiv:
- arXiv:2005.06453
- Bibcode:
- 2020MNRAS.495.1984D
- Keywords:
-
- galaxies: evolution;
- galaxies: interactions;
- radio lines: galaxies;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 21 pages, 16 figures, accepted to MNRAS