We discuss the detection limits and current status of a uniform survey of SDSS I for ultra-faint Milky Way dwarf galaxies. We present the properties of two new, low surface brightness Milky Way companions discovered as a result of this survey. One of these companions is the Ursa Major dwarf, the newest dwarf spheroidal companion to the Milky Way and the lowest luminosity galaxy yet known. Ursa ...

The dwarf satellite galaxies in the Local Group are generally considered to be hosted in dark matter subhalos that survived the disruptive processes during infall onto their host halos. It has recently been argued that if the majority of satellites entered the Milky Way halo in a group rather than individually, this could explain the spatial and dynamical peculiarities of its satellite distribu...

The Sloan Digital Sky Survey has been immensely successful in detecting new Milky Way satellite galaxies over the past seven years. It was instrumental in finding examples of the least luminous galaxies we know in the Universe, uncovering apparent inconsistencies between cold dark matter theory and dwarf galaxy properties, providing first evidence for a possible lower mass limit for dark matter...

A very large body of information has been collected on the structure of the Galaxy. Here we can only concentrate on a small selection of the most recent and most important observational facts and theoretical findings. The MILKY WAY GALAXY belongs to the Local Group, a smaller group of three large and over 30 small galaxies, and is the second largest (after the Andromeda Galaxy M31) but perhaps ...

We report on the discovery of three new dwarf galaxies in the Local Group. These galaxies are found in new CFHT/MegaPrime g, i imaging of the southwestern quadrant of M31, extending our extant survey area to include the majority of the southern hemisphere of M31’s halo out to 150 kpc. All these galaxies have stellar populations which appear typical of dwarf spheroidal (dSph) systems. The first ...

It has been known that recent microlensing results towards the bulge imply mass densities that are surprisingly high given dynamical constraints on the Milky Way mass distribution. We derive the maximum optical depth towards the bulge that may be generated by axisymmetric structures in the Milky Way, and show that observations are close to surpassing these limits. This result argues in favor of...

We use the clump giants of the disk as standard candles calibrated from Hipparcos parallaxes in order to map their distribution with two new near-IR surveys of the Galactic plane: UKIDSS-GPS and VVV. We explore different selection cuts of clump giants. We conclude that there is an edge of the stellar disk of the Milky Way at R = 13.9±0.5 kpc along various lines of sight across the galaxy. The e...

The spiral galaxies, including our galaxy, are created by the gravito-radiative forces generated by colliding black holes at the center of quasars. The gravito-radiative force is predicted by Einstein’s general theory of relativity. A quasar is assumed to have a circular disk of highly compressed neutrons (ylem) orbiting around black holes. The collision of two black holes at the center generat...

We build a stellar-dynamical model of the Milky Way barred bulge and disk, using a newly implemented adaptive particle method. The underlying mass model has been previously shown to match the Galactic near-infrared surface brightness as well as gas-kinematic observations. Here we show that the new stellar-dynamical model also matches the observed stellar kinematics in several bulge fields, and ...

We present a scenario for the production of dynamically cold rings around the Milky Way via a high– eccentricity, flyby encounter. These initial conditions are more cosmologically motivated than those considered in previous works. We find that the encounters we examine generically produce a series of nearly dynamically cold ring–like features on low–eccentricity orbits that persist over timesca...