http://arxiv.org/abs/1910.07463
By means of interferometic 21-cm observations and a 3D kinematic modeling technique, we study the gas kinematics of six HI-rich ultra-diffuse galaxies (UDGs). We derive robust circular velocities and baryonic masses, that allow us to study the position of our UDGs with respect to the baryonic Tully-Fisher relation (BTFR). Somewhat surprisingly, we find that these galaxies are strong outliers from the BTFR, rotating too slowly for their baryonic mass. Moreover, their position in the circular velocity–baryonic mass plane implies that they have a baryon fraction inside their virial radii compatible with the cosmological mean, meaning that they have no “missing baryons”. Unexpectedly, the dynamics of our galaxies are dominated by the baryons, leaving small room for dark matter inside their discs.
P. Piña, F. Fraternali, E. Adams, et. al.
Thu, 17 Oct 19
32/62
Comments: Proceedings of IAU Symposium 355, “The Realm of the Low-Surface-Brightness Universe”. Based on Mancera Pi\~na et al. 2019, ApJL, 883, L33 (this https URL, arXiv:1909.01363)