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There has been a vast recent improvement in photometric and kinematic data for star clusters, Ultra Compact dwarfs, galactic nuclei, and local dSph galaxies, with Subaru contributing substantially to the photometric studies in particular.…

Subluminous B (sdB) stars can result from stable Roche lobe overflow or common envelope ejection in close binary systems. The companions are either low mass main sequence stars or white dwarfs. We discuss mass determinations for sdB stars…

Astrophysics · Physics 2007-05-23 U. Heber

Assuming spherical symmetry and dynamical equilibrium within a given gravitational potential, a dwarf spheroidal (dSph) galaxy's globally averaged stellar velocity dispersion depends entirely on the shape of its stellar density profile.…

Astrophysics of Galaxies · Physics 2026-02-13 Sofia L. Splawska , Raphaël Errani , Jorge Peñarrubia , Matthew G. Walker

The majority of the globular clusters associated with the Sagittarius dwarf galaxy are faint. In this respect it differs significantly from the globular cluster systems surrounding typical giant galaxies. The observation that most of…

Astrophysics · Physics 2009-06-23 Sidney van den Bergh

We identify SDSSJ121010.1+334722.9 as an eclipsing post-common-envelope binary, with an orbital period of P ~ 3 hrs, containing a very cool, low-mass, DAZ white dwarf and a low-mass main-sequence star of spectral type M5. A model atmosphere…

We report on the discovery of the companion star to the millisecond pulsar J1342+2822B in the globular cluster M3. We exploited a combination of near-ultraviolet and optical observations acquired with the Hubble Space Telescope in order to…

High Energy Astrophysical Phenomena · Physics 2019-04-17 M. Cadelano , F. R. Ferraro , A. G. Istrate , C. Pallanca , B. Lanzoni , P. C. C. Freire

We place observational constraints on a recently proposed Galactic population, dubbed the shroud (Gyuk & Gates 1999, Gates & Gyuk 2001). The shroud would be a very thick Galactic disk of low luminosity objects, most likely old white dwarfs,…

Astrophysics · Physics 2009-11-10 Janne Holopainen , Chris Flynn

Are dwarf spheroidal galaxies dark matter dominated? We present N-body simulations of the interaction between the Milky Way and its closest companion, the Sagittarius dwarf spheroidal galaxy, constrained by new kinematic, distance and…

Astrophysics · Physics 2009-10-30 Rodrigo Ibata , Geraint Lewis

Dwarf spheroidal (dSph) galaxies are considered the basic building blocks of the galaxy formation process in the LCDM (Lambda Cold Dark Matter) hierarchical cosmological model. These galaxies are believed to be the most dark matter (DM)…

Astrophysics of Galaxies · Physics 2015-06-16 P. Assmann , M. Fellhauer , M. I. Wilkinson , R. Smith , M. Blaña

We present a deep, wide-field photometric survey of the newly-discovered Hercules dwarf spheroidal galaxy, based on data from the Large Binocular Telescope. Images in B, V and r were obtained with the Large Binocular Camera covering a 23'…

We present deep CCD photometry of a field in the newly discovered dwarf spheroidal galaxy in Sagittarius (hereafter Sgr), and of a nearby control field. These data (totaling ~3.5 hrs exposure time in V and I) were used to produce…

Astrophysics · Physics 2009-10-22 Mario Mateo , A. Udalski , M. Szymanski , J. Kaluzny , M. Kubiak , W. Krzeminski

We investigate whether the oblate, spheroidal morphology of common dwarf spheroidal galaxies (dSph) may result from the slow relaxation of stellar orbits within a halo of Wave Dark Matter ($\psi$DM) when starting from an initial disk of…

Astrophysics of Galaxies · Physics 2023-08-29 Riccardo Della Monica , Ivan de Martino , Tom Broadhurst

The local group dwarf spheroidal galaxies (LG dSphs) are among the most promising astrophysical targets for probing the small scale structure of dark matter (DM) subhalos. We describe a method for testing the correspondence between proposed…

Astrophysics of Galaxies · Physics 2020-12-09 Sasha Brownsberger , Lisa Randall

This paper presents an alternative scenario to explain the observed properties of the Milky Way dwarf Spheroidals (MW dSphs). We show that instead of resulting from large amounts of dark matter (DM), the large velocity dispersions observed…

Astrophysics of Galaxies · Physics 2019-10-09 Francois Hammer , Yanbin Yang , Jianling Wang , Frederic Arenou , Mathieu Puech , Hector Flores

Numerical simulations of dwarf spheroidal galaxies undergoing several close encounters with the Milky Way are described. By comparing our models to observed properties of the recently discovered dwarf galaxy in Sagittarius (Sgr), we discuss…

Astrophysics · Physics 2016-08-30 Kathryn V. Johnston , David N. Spergel , Lars Hernquist

We present Keck/DEIMOS spectroscopy of Segue 1, an ultra-low luminosity (M_V = -1.5) Milky Way satellite companion. While the combined size and luminosity of Segue 1 are consistent with either a globular cluster or a dwarf galaxy, we…

The Solo (Solitary Local) Dwarf Galaxy survey is a volume limited, wide-field g- and i- band survey of all known nearby (<3 Mpc) and isolated (>300 kpc from the Milky Way or M31) dwarf galaxies. This set of 44 dwarfs are homogeneously…

Astrophysics of Galaxies · Physics 2021-01-20 C. R. Higgs , A. W. McConnachie , N. Annau , M. Irwin , G. Battaglia , P. Côté , G. F. Lewis , K. Venn

The system WDS 16329+0315 is an old, nearby quintuple physical system in the thick Galactic disc formed by a close-resolved, triple primary of solar metallicity, namely HD 149162, and a very wide, common proper motion, secondary pair,…

Solar and Stellar Astrophysics · Physics 2018-08-20 R. González-Peinado , J. A. Caballero , D. Montes , C. Cifuentes

In a search for eclipsing white dwarfs using the Zwicky Transient Facility lightcurves, we identified a deep eclipsing white dwarf with a dark, substellar companion. The lack of an infrared excess and an orbital period of 10 hours made this…