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An all-sky list of 88 nearby dwarf spheroidal (dSph) galaxies with distances D < 10 Mpc is considered. Most of the objects have recently been found by Karachentseva & Karachentsev based on POSSII/ESO-SERC survey. A hundred more dSph…

Astrophysics · Physics 2009-11-11 I. D. Karachentsev , V. E. Karachentseva , M. E. Sharina

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

We study the formation histories and present-day structure of satellite galaxies formed in a high resolution hydrodynamic simulation of a Milky Way-like galaxy. The simulated satellites span nearly 4 orders of magnitude in luminosity but…

Cosmology and Nongalactic Astrophysics · Physics 2009-10-06 Takashi Okamoto , Carlos S. Frenk

The discovery of $19$ dwarf galaxies without dark matter provides, counter-intuitively, strong support for the $\Lambda$CDM standard model of cosmology. Their presence is well accommodated in a scenario where the dark matter is in the form…

General Relativity and Quantum Cosmology · Physics 2022-01-24 Ali Rida Khalifeh , Raul Jimenez

Gravitational microlensing, the lensing of stars in the Milky Way galaxy with other stars, has been used for exploring compact dark matter objects, exoplanets, and black holes. The duration of microlensing events, the so-called Einstein…

Solar and Stellar Astrophysics · Physics 2022-08-31 Sedighe Sajadian , Sohrab Rahvar , Fatemeh Kazemian

We use VLT/FLAMES intermediate resolution (R~6500) spectra of individual red giant branch stars in the near-infrared CaII triplet (CaT) region to investigate the wide-area metallicity properties and internal kinematics of the Sextans dwarf…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 G. Battaglia , E. Tolstoy , A. Helmi , M. Irwin , P. Parisi , V. Hill , P. Jablonka

Velocity dispersion ($\sigma$) is a key driver for galaxy structure and evolution. We here present a comprehensive semi-empirical approach to compute $\sigma$ via detailed Jeans modelling assuming both a constant and scale-dependent…

Astrophysics of Galaxies · Physics 2022-01-05 Christopher Marsden , Francesco Shankar , Mariangela Bernardi , Ravi Sheth , Hao Fu , Andrea Lapi

We report the discovery of clear observational signs of past accretion/merger events in one of the Milky Way satellite galaxies, the Sextans dwarf spheroidal (dSph). These were uncovered in the spatial distribution, internal kinematics and…

Astrophysics of Galaxies · Physics 2018-07-18 Luis Cicuendez , Giuseppina Battaglia

We present results from a pilot observation of nearby (~20 Mpc) galaxies with mass similar to that of the Milky Way (MW) to address the missing satellite problem. This is the first paper from an on-going project to address the problem with…

Distinguishing a core and a cusp within dark matter halos is complexified by the existence of mass-anisotropy degeneracy, where various combinations of velocity anisotropy ($\beta$) and inner density slope ($\gamma$) yield similar…

Astrophysics of Galaxies · Physics 2025-02-21 Dafa Wardana , Masashi Chiba , Kohei Hayashi

Dwarf spheroidal galaxies (dSphs) are extremely gas-poor, dark matter-dominated galaxies, which make them ideal to test the predictions of the cold dark matter (CDM) model. We argue that the removal of the baryonic component from gas-rich…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Kenza S. Arraki , Anatoly Klypin , Surhud More , Sebastian Trujillo-Gomez

The N-body dark matter (DM) simulations point that DM density profiles, e.g. the NFW halo, should be cuspy in its center, but observations disfavour this kind of DM profile. Here we consider whether the observed rotation curves "close" to…

Astrophysics of Galaxies · Physics 2014-11-04 Davi C. Rodrigues , Paulo L. de Oliveira , Julio C. Fabris , Gianfranco Gentile

The mass of the Local Group (LG), comprising the Milky Way (MW), Andromeda (M31), and their satellites, is crucial for validating galaxy formation and cosmological models. Traditional virial mass estimates, which rely on line-of-sight (LoS)…

Astrophysics of Galaxies · Physics 2025-06-04 David Benisty , David Mota

Kinematic surveys of the dwarf spheroidal (dSph) satellites of the Milky Way are revealing tantalising hints about the structure of dark matter (DM) haloes at the low-mass end of the galaxy luminosity function. At the bright end, modelling…

We predict the spatial distribution and number of Milky Way dwarf galaxies to be discovered in the DES and LSST surveys, by completeness correcting the observed SDSS dwarf population. We apply most massive in the past, earliest forming, and…

Astrophysics of Galaxies · Physics 2015-06-22 Jonathan R. Hargis , Beth Willman , Annika H. G. Peter

Galaxies are thought to grow through accretion; as less massive galaxies are disrupted and merge over time, their debris results in diffuse, clumpy stellar halos enveloping the central galaxy. Here we present a study of the variation in the…

Astrophysics of Galaxies · Physics 2016-10-19 Allison Merritt , Pieter van Dokkum , Roberto Abraham , Jielai Zhang

Aims: We aim to compute the binary fraction of "classical" dwarf spheroidal galaxies (dSphs) that are satellites of the Milky Way (MW). This value can offer insights into the binary fraction in environments that are less dense and more…

Dark matter annihilation in dwarf spheroidal (dSph) galaxies near the Milky Way has the potential to produce a detectable signature in gamma-rays. The amplitude of this signal depends on the dark matter density in a dSph, the dark matter…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-09 Eric J. Baxter , Jason Kumar , Andrew B. Pace , Jack Runburg

We derive the mass weighted total density slopes within the effective (half-light) radius, $\gamma'$, for more than 2000 nearby galaxies from the SDSS-IV MaNGA survey using Jeans-anisotropic-models applied to IFU observations. Our galaxies…

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…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Alan W. McConnachie , Patrick Cote