Related papers: Still at Odds with Conventional Galaxy Evolution: …
We use the Keck Cosmic Web Imager integral-field unit spectrograph to: 1) measure the global stellar population parameters for the ultra-diffuse galaxy (UDG) Dragonfly 44 (DF44) to much higher precision than previously possible for any UDG,…
Many ultra-diffuse galaxies (UDGs) have been discovered in the Coma cluster, and there is evidence that some, notably Dragonfly 44, have Milky Way-like dynamical masses despite dwarf-like stellar masses. We used X-ray, UV, and optical data…
The observed line-of-sight velocity dispersion $\sigma_{los}$ of the ultra diffuse galaxy Dragonfly 44 (DF44) requires a Newtonian dynamical mass-to-light ratio of $M_{dyn}/L_I=26^{+7}_{-6}$ Solar units. This is well outside the acceptable…
Understanding the peculiar properties of Ultra Diffuse Galaxies (UDGs) via spectroscopic analysis is a challenging task requiring very deep observations and exquisite data reduction. In this work we perform one of the most complete…
Recently a population of large, very low surface brightness, spheroidal galaxies was identified in the Coma cluster. The apparent survival of these Ultra Diffuse Galaxies (UDGs) in a rich cluster suggests that they have very high masses.…
Due to the peculiar properties of ultra-diffuse galaxies (UDGs), understanding their origin presents a major challenge. Previous X-ray studies demonstrated that the bulk of UDGs lack substantial X-ray emission, implying that they reside in…
We present spatially-resolved stellar kinematics of the well-studied ultra diffuse galaxy (UDG) Dragonfly 44, as determined from 25.3 hrs of observations with the Keck Cosmic Web Imager. The luminosity-weighted dispersion within the…
There is a growing consensus that the vast majority of ultra-diffuse galaxies (UDGs) are dwarf galaxies. However, there remain a few UDGs that seem to be special in terms of their globular cluster (GC) systems. In particular, according to…
We examine the star formation properties of galaxies with very thin disks selected from the Revised Flat Galaxy Catalog (RFGC). The sample contains 333 ultra-flat galaxies (UFG) at high Galactic latitudes, $|b|>10^{\circ}$, with a blue…
Low-mass early-type galaxies, including dwarf spheroidals (dSph) and brighter dwarf ellipticals (dE), dominate the galaxy population in groups and clusters. Recently, an additional early-type population of more extended ultradiffuse…
We test if the cosmological zoom-in simulations of isolated galaxies from the FIRE project reproduce the properties of ultra diffuse galaxies. We show that stellar feedback-generated outflows that dynamically heat galactic stars, together…
We derive the stellar population parameters of 11 quiescent ultra-diffuse galaxies (UDGs) from Keck/KCWI data. We supplement these with 14 literature UDGs, creating the largest spectroscopic sample of UDGs to date (25). We find a strong…
We use spectral energy distribution (SED) fitting to place constraints on the stellar population properties of 29 quiescent ultra-diffuse galaxies (UDGs) across different environments. We use the fully Bayesian routine PROSPECTOR coupled…
In addition to occupying the extreme, diffuse tail of the dwarf galaxy population, Ultra-Diffuse Galaxies (UDGs) are themselves a key laboratory in which to study star formation in extreme low-density environments. In the second paper of…
Given the absence of directly detected dark matter (DM) as weakly interacting massive particles, there is strong interest in the possibility that DM is an ultra-light scalar field, here denoted as fuzzy DM. Ultra-diffuse galaxies, with the…
We investigate the nature of the newly discovered Ultra Faint dwarf spheroidal galaxies (UF dSphs) in a general cosmological context simultaneously accounting for various ``classical`` dSphs and Milky Way properties including their…
Observations of nearby galaxy clusters at low surface brightness have identified galaxies with low luminosities, but sizes as large as L* galaxies, leading them to be dubbed "ultra-diffuse galaxies" (UDGs). The survival of UDGs in dense…
Observational studies of ultra-diffuse galaxies (UDGs) represent a significant challenge because of their very low surface brightnesses. A feasible approach is to identify "future" UDGs when their stars are still young. Using data mining,…
Ultra-Diffuse galaxies are gravitational systems with quite varied properties. On one hand we have cases like DF2 and DF4, both observed by the Dragonfly Array Telescope, claimed to be highly-deficient in dark matter. On the other hand, we…
The formation and evolution of the ultra-diffuse galaxies (UDGs) continues to remain a puzzle. Similarities and differences in the morphological and the kinematical properties of the UDGs with their possible precursors, namely low-surface…