2022MNRAS.516.4220L

Ultra-diffuse galaxies (UDGs) are as faint as dwarf galaxies but whose sizes are similar to those of spiral galaxies. A variety of formation mechanisms have been proposed, some of which could result in different disc thicknesses. In this study, we measure the radial profile of the H I scale height (h_g) and flaring angle (h_g/R) of AGC 242019 through the joint Poisson-Boltzmann equation based on its well spatially-resolved H I gas maps. The mean H I scale height of AGC 242019 is $\langle h_{\rm g}\rangle \approx 537.15 \pm 89.4\,{\rm pc}$, and the mean flaring angle is $\langle h_{\rm g}/R \rangle\approx 0.19 \pm 0.03$. As a comparison, we also derive the disc thickness for a sample of 14 dwarf irregulars. It is found that the H I disc of AGC 242019 has comparable thickness to dwarfs. This suggests that AGC 242019 is unlikely to experience much stronger stellar feedback than dwarf galaxies, which otherwise leads to a thicker disc for this galaxy.