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Related papers: Ursa Major: a missing low-mass CDM halo?

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According to the Cold Dark Matter (CDM) hierarchical clustering theory of galaxy and large scale structure formation, there should be numerous low mass dark matter haloes present in the Universe today. If these haloes contain sufficient…

Astrophysics · Physics 2009-11-10 S. Roberts , J. Davies , S. Sabatini , W. van Driel , K. O'Neil , M. Baes , S. Linder , R. Smith , Rh. Evans

Ursa Minor (UMi) is one of the closest satellites of the Milky Way (d=69 kpc). It is possibly a disrupted dSph interacting with the external Galactic halo. This makes its study quite necessary in the forementioned context. In this paper we…

Astrophysics · Physics 2007-05-23 D. Martinez-Delgado , A. Aparicio

Low-mass stars, those with main-sequence lifetimes that are of order the age of the Universe, provide unique constraints on the Initial Mass Function (IMF) when they formed. Star counts in systems with simple star-formation histories are…

Astrophysics · Physics 2007-05-23 Rosemary F. G. Wyse , Gerard Gilmore , Sofia Feltzing , Mark Houdashelt

Dark matter is a key piece of the current cosmological scenario, with weakly interacting massive particles (WIMPs) a leading dark matter candidate. WIMPs have not been detected in their conventional parameter space (100 GeV $\lesssim…

With the HDS (High Dispersion Spectrograph) on the Subaru telescope, we obtained high resolution optical region spectra of three red giant stars (cos 4, cos 82, and cos 347) in the Ursa Minor dwarf spheriodal galaxy. Chemical abundances in…

Astrophysics · Physics 2015-06-24 K. Sadakane , N. Arimoto , C. Ikuta , W. Aoki , P. Jablonka , A. Tajitsu

We investigate the mass distributions within eight classical Milky Way dwarf spheroidal galaxies (MW dSphs) using an equilibrium Jeans analysis and we compare our results to the mass distributions predicted for subhalos in dissipationless…

Cosmology and Nongalactic Astrophysics · Physics 2012-03-21 Joe Wolf , James S. Bullock

Ultra-compact dwarf galaxies (UCDs) are stellar systems with masses of around 10^7 to 10^8 Msun and half mass radii of 10-100 pc. They have some properties in common with massive globular clusters, however dynamical mass estimates have…

Astrophysics · Physics 2009-11-13 Holger Baumgardt , Steffen Mieske

Extremely low mass white dwarfs are very rare objects likely formed in compact binary systems. We present MMT optical spectroscopy of 42 low mass white dwarf candidates serendipitously discovered in a survey for hypervelocity B-type stars.…

Astrophysics · Physics 2011-02-11 Mukremin Kilic , Carlos Allende Prieto , Warren R. Brown , D. Koester

The recently discovered stellar system, Ursa Major III/UNIONS 1, may be the faintest and densest dwarf spheroidal satellite galaxy of the Milky Way. Owing to its close proximity and substantial dark matter (DM) component, Ursa Major III…

High Energy Physics - Phenomenology · Physics 2024-09-20 Peng-Long Zhang , Xiao-Jun Bi , Qin Chang , Peng-Fei Yin , Yi Zhao

We establish new dynamical constraints on the mass and abundance of compact objects in the halo of dwarf spheroidal galaxies. In order to preserve kinematically cold the second peak of the Ursa Minor dwarf spheroidal (UMi dSph) against…

Astrophysics · Physics 2009-11-13 F. J. Sanchez-Salcedo , V. Lora

Dwarf spheroidal galaxies (dSphs) are promising targets of indirect detection experiments searching for dark matter (DM) at present universe. Toward robust prediction for the amount of signal flux originating in DM annihilation inside…

Astrophysics of Galaxies · Physics 2020-09-30 Shun-ichi Horigome , Kohei Hayashi , Masahiro Ibe , Miho N. Ishigaki , Shigeki Matsumoto , Hajime Sugai

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

We present a homogeneous kinematic analysis of red giant branch stars within 18 of the 28 Andromeda dwarf spheroidal (dSph) galaxies, obtained using the Keck I LRIS and Keck II DEIMOS spectrographs. Based on their g-i colors (taken with the…

We use RR Lyrae stars identified by the Gaia third data release (DR3) to explore the outskirts of the Ursa Minor (UMi) dwarf spheroidal galaxy (dSph) and update the census of its variable star population. We adopted different tools based on…

Astrophysics of Galaxies · Physics 2025-03-12 A. Garofalo , G. Clementini , F. Cusano , T. Muraveva , L. Monti

Two low surface brightness (LSB) dwarf galaxies were identified recently as having little or no dark matter (DM), provoking widespread interest in their formation histories. These galaxies also host populous systems of star clusters that…

Astrophysics of Galaxies · Physics 2024-08-26 Aaron J. Romanowsky , Enrique Cabrera , Steven R. Janssens

Low-mass early-type galaxies, including dwarf spheroidals (dSph) and brighter dwarf ellipticals (dE), dominate the galaxy population in groups and clusters. Recently, an additional early-type population of more extended ultradiffuse…

A particular population of galaxies have drawn much interest recently, which are as faint as typical dwarf galaxies but have the sizes as large as $L^*$ galaxies, the so called "ultra-diffuse galaxie" (UDGs). The lack of tidal features of…

Astrophysics of Galaxies · Physics 2017-08-02 Yu Rong , Qi Guo , Liang Gao , Shihong Liao , Lizhi Xie , Thomas H. Puzia , Shuangpeng Sun , Jun Pan

We present a new mass estimate for the Hercules dwarf spheroidal galaxy (dSph), based on the revised velocity dispersion obtained by Aden et al. (2009, arXiv:0908.3489). The removal of a significant foreground contamination using newly…

Astrophysics of Galaxies · Physics 2014-11-20 D. Adén , M. I. Wilkinson , J. I. Read , S. Feltzing , A. Koch , G. F. Gilmore , E. K. Grebel , I. Lundström

We consider the hypothesis that galactic dark matter is composed of ultra-light scalar particles and use internal properties of dwarf spheroidal galaxies to establish a preferred range for the mass m of these bosonic particles. We…

Astrophysics of Galaxies · Physics 2015-05-30 V. Lora , Juan Magana , Argelia Bernal , F. J. Sanchez-Salcedo , E. K. Grebel