Resolved H I in two ultra-diffuse galaxies from contrasting non-cluster environments

T. C. Scott, Chandreyee Sengupta, P. Lagos, Aeree Chung, O. Ivy Wong

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3 Citations (Scopus)


We report on the first resolved H I observations of two blue ultra-diffuse galaxies (UDGs), using the Giant Metrewave Radio Telescope (GMRT). These observations add to the so-far limited number of UDGs with resolved H I data. The targets are from contrasting non-cluster environments: UDG-B1 is projected in the outskirts of Hickson Compact Group 25 and Secco-dI-2 (SdI-2) is an isolated UDG. These UDGs also have contrasting effective radii with Re of 3.7 kpc (similar to the Milky Way) and 1.3 kpc, respectively. SdI-2 has an unusually large MMHI ratio = 28.9, confirming a previous single dish H I observation. Both galaxies display H I morphological and kinematic signatures consistent with a recent tidal interaction, which is also supported by observations from other wavelengths, including optical spectroscopy. Within the limits of the observations' resolution our analysis indicates that SdI-2 is dark matter dominated within its H I radius and this is also likely to be the case for UDG-B1. Our study highlights the importance of high spatial and spectral resolution H I observations for the study of the dark matter properties of UDGs.

Original languageEnglish
Pages (from-to)3953-3964
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
Publication statusPublished - 2021 May 1

Bibliographical note

Funding Information:
The present investigation was carried out by funds made available by MIUR (PRIN Project).

Publisher Copyright:
© 2021 The Author(s)

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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