WALLABY pilot survey: accurate and automated linewidth measurements from global HI profiles

Abstract

Current-generation 21-cm surveys of extragalactic neutral hydrogen (HI) with instruments such as FAST and ASKAP are providing detailed spectral and spatial information for over 10^5 galaxies. Future HI 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 HI emission from galaxies. We have developed an automated estimator for HI 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.

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Cite

BibTeX RIS

BibTeX

@misc{kim2026wallaby,
  title = {{WALLABY pilot survey: accurate and automated linewidth measurements from global HI profiles}},
  author = {Shinna Kim and Tobias Westmeier and Lister Staveley-Smith and Danail Obreschkow and Barbara Catinella and Nathan Deg and Karen Lee-Waddell and Jonghwan Rhee and Kristine Spekkens and O. Ivy Wong and Matthew Colless and Hélène M Courtois and Boyi Ding and Bumhyun Lee},
  howpublished = {HAL},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.16057},
  eprint = {2610.16057},
  archivePrefix = {arXiv},
  url = {https://hal.science/hal-05830004v1},
  note = {CC BY 4.0},
}

RIS

TY  - UNPB
TI  - WALLABY pilot survey: accurate and automated linewidth measurements from global HI profiles
AU  - Shinna Kim
AU  - Tobias Westmeier
AU  - Lister Staveley-Smith
AU  - Danail Obreschkow
AU  - Barbara Catinella
AU  - Nathan Deg
AU  - Karen Lee-Waddell
AU  - Jonghwan Rhee
AU  - Kristine Spekkens
AU  - O. Ivy Wong
AU  - Matthew Colless
AU  - Hélène M Courtois
AU  - Boyi Ding
AU  - Bumhyun Lee
PY  - 2026
DA  - 2026/10/12
PB  - HAL
DO  - 10.48550/arxiv.2610.16057
UR  - https://hal.science/hal-05830004v1
AB  - Current-generation 21-cm surveys of extragalactic neutral hydrogen (HI) with instruments such as FAST and ASKAP are providing detailed spectral and spatial information for over 10^5 galaxies. Future HI 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 HI emission from galaxies. We have developed an automated estimator for HI 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.
ER  -

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