Related papers: Triangulum II: Not Especially Dense After All
[abridged] We present the results of a spectroscopic survey of the recently discovered faint Milky Way satellites Boo, UMaI, UMaII and Wil1. Using the DEIMOS spectrograph on Keck, we have obtained samples that contain from 15 to 85 probable…
This article summarizes recent work on the luminosity and mass distribution of the Galactic bulge and disk, and on the mass of the Milky Way's dark halo. A new luminosity model consistent with the COBE NIR data and the apparent magnitude…
We present a chemodynamical analysis of the Leo~V dwarf galaxy, based on Keck II DEIMOS spectra of 8 member stars. We find a systemic velocity for the system of $\langle v_r\rangle = 170.9^{+ 2.1}_{-1.9}$kms$^{-1}$, and barely resolve a…
We present Magellan/IMACS and Magellan/MIKE spectroscopy of the ultra-faint dwarf (UFD) galaxy Pictor~II (Pic~II) that is located only 12 kpc from the Large Magellanic Cloud (LMC). From the IMACS spectroscopy, we identify 13 member stars…
We present the discovery of a faint Milky Way satellite, Laevens 2/Triangulum II, found in the Panoramic Survey Telescope And Rapid Response System (Pan-STARRS 1) 3 pi imaging data and confirmed with follow-up wide-field photometry from the…
While most dwarf galaxies are strongly dark matter dominated, two remarkable objects in the NGC 1052 field, DF2 and DF4, appear to lack dark matter. DF2 and DF4 were recently found to be part of a trail of low luminosity galaxies that…
Velocity dispersion measurements of recently discovered Milky Way satellites with $M_V\gtrsim-7$ imply they posses high mass-to-light ratios. The expected velocity dispersions due to their baryonic mass are $\sim0.2$\,km\,s$^{-1}$, but…
The amount of dark matter in the four galactic dwarf spheroidals with large mass-to-light ratios is investigated. Sextans has a cut-off radius which is equal to the expected tidal radius, assuming a high mass-to-light ratio. This satellite…
A wealth of recent observational studies shows the dark matter in the Milky Way to have the following fundamental properties: 1) there is no detectable dark matter associated with the Galactic disk -- the dark matter is distributed in a…
It is widely established that a lower bound on the dark matter particle mass, $m$, can be obtained by demanding that the de Broglie wavelength in a given galaxy must be smaller than the virial radius of the galaxy, leading to $m\gtrsim…
The High Resolution Echelle Spectrometer on the Keck I telescope has been used to measure nine radial velocities having a median precision of 2 km/s for seven red giants belonging to the isolated dwarf spheroidal galaxy Andromeda II. We…
A sample of 11 thousand galaxies with radial velocities V_ LG < 3500 km/s is used to study the features of the local distribution of luminous (stellar) and dark matter within a sphere of radius of around 50 Mpc around us. The average…
The recently discovered stellar system Ursa Major III/UNIONS 1 (UMa3/U1) is the faintest known Milky Way satellite to date. With a stellar mass of $16^{+6}_{-5}\,\rm M_\odot$ and a half-light radius of $3\pm1$pc, it is either the darkest…
Milky Way dwarf spheroidal galaxies are the tiniest observed galaxies and are currently associated with the largest fractions of dark matter, which is revealed by their too large velocity dispersions. However, most of them are found near…
We present an extensive study of the Sagittarius II (Sgr II) stellar system using MegaCam g and i photometry, narrow-band, metallicity-sensitive Calcium H&K doublet photometry, augmented with Keck II/DEIMOS multi-object spectroscopy. We are…
The ultra-diffuse galaxy NGC1052-DF2 has a very low velocity dispersion, indicating that it has little or no dark matter. Here we report the discovery of a second galaxy in this class, residing in the same group. NGC1052-DF4 closely…
Dwarf galaxies have a wide variety of structures, such as dark matter (DM) distribution, stellar-to-halo mass ratio, and stellar density. Recent high-resolution simulations have shown a variety of stellar-to-halo mass ratios for dwarf…
We report the discovery of a Milky Way satellite in the constellation of Antlia. The Antlia 2 dwarf galaxy is located behind the Galactic disc at a latitude of $b\sim 11^{\circ}$ and spans $1.26$ degrees, which corresponds to $\sim2.9$ kpc…
The lowest luminosity (L < 10^5 L_sun) Milky Way satellite galaxies represent the extreme lower limit of the galaxy luminosity function. These ultra-faint dwarfs are the oldest, most dark matter-dominated, most metal-poor, and least…
Reticulum II (Ret II) is a satellite galaxy of the Milky Way and presents a prime target to investigate the nature of dark matter (DM) because of its high mass-to-light ratio. We evaluate a dedicated INTEGRAL observation campaign data set…