The H I gas disc thickness of the ultra-diffuse galaxy AGC 242019

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 < h(g)> approximate to 537.15 +/- 89.4 pc, and the mean flaring angle is < hg/R > approximate to 0.19 +/- 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.

Automated summary

In this study, the radial profile of the H I scale height and flaring angle of the ultra-diffuse galaxy AGC 242019 were measured, and it was found that its disc thickness is comparable to that of dwarf galaxies. This suggests that AGC 242019 is unlikely to experience strong stellar feedback.