WALLABY pilot survey: accurate and automated linewidth measurements from global H i profiles
Abstract Current-generation 21-cm surveys of extragalactic neutral hydrogen (H i) with instruments such as FAST and ASKAP are providing detailed spectral and spatial information for over 105 galaxies. Future H i surveys with next-generation radio telescopes could provide sample sizes larger by orders of magnitude. There is therefore a need for accurate, automated, and reliable parameterisation of the H i emission from galaxies. We have developed an automated estimator for H i global profile widths to better enable studies of, for example, dynamical masses and Tully-Fisher distances. Our estimator is based on an implementation of the BusyFit profile-fitting algorithm, and converges for 95 % of global profiles in the WALLABY pilot survey. Probability density functions are calculated for all profile parameters using Monte Carlo techniques, and example error parameterisations are given. We confirm that linewidth uncertainties depend primarily on the integrated signal-to-noise ratio, profile steepness, and the linewidth, consistent with previous studies. We compare several common linewidth definitions, and the width at 50 % of the mean flux density (Wm50) is found to be the most robust measure of linewidth. We provide examples of the baryonic Tully-Fisher relation drawn from the WALLABY pilot survey.
Authors
- Nathan Deg (ORCID: https://orcid.org/0000-0003-3523-7633)
- T. Westmeier (ORCID: https://orcid.org/0000-0002-5300-2486)
- Jonghwan Rhee (ORCID: https://orcid.org/0000-0001-8496-4306)
- Boyi Ding (ORCID: https://orcid.org/0009-0007-6458-1712)
- Barbara Catinella (ORCID: https://orcid.org/0000-0002-7625-562X)
- Lister Staveley‐Smith (ORCID: https://orcid.org/0000-0002-8057-0294)
- Kristine Spekkens (ORCID: https://orcid.org/0000-0002-0956-7949)
- Bumhyun Lee (ORCID: https://orcid.org/0000-0002-3810-1806)
- Matthew Colless (ORCID: https://orcid.org/0000-0001-9552-8075)
- K. Lee-Waddell (ORCID: https://orcid.org/0000-0003-4844-8659)
- Danail Obreschkow (ORCID: https://orcid.org/0000-0002-1527-0762)
- Shinna Kim (ORCID: https://orcid.org/0000-0003-3143-5624)
- O. Ivy Wong (ORCID: https://orcid.org/0000-0003-4264-3509)
- Hélène M. Courtois
Institutions
- Université Claude Bernard Lyon 1 (FR)
- Australian National University (AU)
- Australia Telescope National Facility (AU)
- The University of Western Australia (AU)
- Lyon College (US)
- Yonsei University (KR)
- Queen's University (CA)
- Mount Stromlo Observatory (AU)
- ASTRO-3D (AU)
- ARC Centre of Excellence for All-sky Astrophysics (AU)
- International Centre for Radio Astronomy Research (AU)
Publication Details
- Journal
- Monthly Notices of the Royal Astronomical Society
- Published
- 2026-10-16
- DOI
- https://doi.org/10.1093/mnras/stag1949
- Primary Topic
- Galaxies: Formation, Evolution, Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Science and Industry Endowment Fund
- Australian Government
- Commonwealth Scientific and Industrial Research Organisation
- Curtin University of Technology
- National Research Foundation of Korea
- Institut Universitaire de France
- Government of Western Australia
- Ministry of Science and ICT, South Korea