Related papers: Evidence for Substructure in Ursa Minor Dwarf Sphe…
Context. In the Local Group, dwarf spheroidal galaxies (dSphs) and ultra-faint dwarf galaxies (UFDs) exhibit large velocity dispersions. These values are generally attributed to the presence of substantial amounts of dark matter (DM), in…
We present the first spectroscopic analysis of the faint and compact stellar system Draco II (Dra II, M_V=-2.9+/-0.8, r_h=19^{+8}_{-6} pc), recently discovered in the Pan-STARRS1 3{\pi} survey. The observations, conducted with DEIMOS on the…
The spatial distributions of the most recently discovered ultra faint dwarf satellites around the Milky Way and the Andromeda galaxy are compared to the previously reported discs-of-satellites (DoS) of their host galaxies. In our…
We compute the spatial velocity components and the galactic orbital elements for 209 metal-poor $([Fe/H] < -1.0)$ RRLyrae (ab) variable stars in the solar neighborhood using proper motions, radial velocities, and photometric distances…
The masses of compact objects like white dwarfs, neutron stars and black holes are fundamental to astrophysics, but very difficult to measure. We present the results of an analysis of subluminous B (sdB) stars in close binary systems with…
The project Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS (MUCHFUSS) aims at finding hot subdwarf stars with massive compact companions like massive white dwarfs (M > 1.0 Msun), neutron stars or stellar mass black…
The cold dark matter scenario predicts that a large number of dark subhalos should be located within the halo of each Milky-way sized galaxy. One tell-tale signature of such dark subhalos could be additional milliarcsecond-scale image…
As is usual in dwarf spheroidal galaxies, today the Local Group galaxy Ursa Minor is depleted of its gas content. How this galaxy lost its gas is still a matter of debate. To study the history of gas loss in Ursa Minor, we conducted the…
The highly organised distribution of satellite galaxies surrounding the Milky Way is a serious challenge to the concordance cosmological model. Perhaps the only remaining solution, in this framework, is that the dwarf satellite galaxies…
We determine the total dynamical matter density in the solar neighbourhood using the second Gaia data release (DR2). The dynamical matter density distribution is inferred in a framework of a Bayesian hierarchical model, which accounts for…
With the inception of gravitational wave astronomy, astrophysical studies using interferometric techniques have begun to probe previously unknown parts of the universe. In this work, we investigate the potential of a new interferometric…
We present a study of the recently discovered compact stellar system Triangulum II. From observations conducted with the DEIMOS spectrograph on Keck II, we obtained spectra for 13 member stars that follow the CMD features of this very faint…
We use FIRE-2 zoom simulations of Milky Way size disk galaxies to derive easy-to-use relationships between the observed circular speed of the Galaxy at the Solar location, $v_\mathrm{c}$, and dark matter properties of relevance for direct…
Dwarf spheroidal galaxies (dSphs) have been extensively investigated in the Local Group, but their low luminosity and surface brightness make similar work in more distant galaxy groups challenging. Modern instrumentation unlocks the…
We study the distribution of dark matter in dwarf spheroidal galaxies by modelling the moments of their line-of-sight velocity distributions. We discuss different dark matter density profiles, both cuspy and possessing flat density cores.…
We present the results of the analysis of deep archival \sat\ observations towards the dwarf spheroidal galaxies Draco, Leo I, Ursa Major II and Ursa Minor in the Milky Way neighbourhood. The X-ray source population is characterized and…
The Laser Interferometer Space Antenna (LISA) will detect and characterize $\sim10^4$ Galactic Binaries consisting predominantly of two White Dwarfs (WD). An interesting prospect within this population is a third object--another WD star, a…
Photometry alone is not sufficient to unambiguously distinguish between ultra-faint star clusters and dwarf galaxies because of their overlap in morphological properties. Here we report on VLT/GIRAFFE spectra of candidate member stars in…
Recent observations have led to the discovery of numerous optically selected binaries containing an undetected component with mass consistent with a compact object (neutron star or white dwarf). Using the the Neil Gehrels Swift Observatory…
High resolution N-body simulations of galactic cold dark matter haloes indicate that we should expect to find a few satellite galaxies around the Milky Way whose haloes have a maximum circular velocity in excess of 40 kms. Yet, with the…