ИСТИНА

KDG64 (UGC5442) is a relatively large (Reff = 1.05 kpc) and luminous (MV=-13.6 mag) dwarf spheroidal galaxy residing in the M81 group that bridges the dE and dSph classes in terms of size and mass. With recent advances in studies of ultra-diffuse galaxies in Coma cluster it became a promising target as one of the closest analogues to UDGs in the Local Volume. Here we present spatially resolved velocity and velocity dispersion profiles along both major and minor axes of KDG64 from deep intermediate-resolution integrated-light spectra obtained with Binospec, the MMT’s new high-throughput optical spectrograph. We derive dark matter fraction within the half-light radius of about 90% and high level of the vertical orbital anisotropy (beta_z=0.75) using axisymmetric Jeans dynamical models, which is consistent with some of the Coma UDGs. The shape of the dispersion profile with central elevation cannot be precisely described by a constant M/L model, which may be explained using a cuspy dark matter profile. While the exact shape of DM halo is beyond our grasp, we could still put some limitations to address the cusp/core issue in dwarf spheroidals. KDG64 sits on the mass metallicity relation formed by somewhat fainter dSphs in the Local Group and more luminous UDGs and dEs in clusters and its internal dynamics also bridges the gap between them. Overall, there seems to be a continuum of structural and dynamical properties including dark matter contents for dEs, UDGs, and dSphs, hence we should think how to build a general scenario of dwarf galaxy formation and evolution that explains the full variety of observed characteristics.