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[abridged] We present the results of a spectroscopic survey of the recently discovered faint Milky Way satellites Boo, UMaI, UMaII and Wil1. Using the DEIMOS spectrograph on Keck, we have obtained samples that contain from 15 to 85 probable…

Astrophysics · Physics 2010-03-01 N. F. Martin , R. A. Ibata , S. C. Chapman , M. Irwin , G. F. Lewis

White dwarfs are among the most common objects in the stellar halo; however, due to their low luminosity and low number density compared to the stars in the discs of the Milky Way, they are scarce in the observable volume. Hence, they are…

Astrophysics of Galaxies · Physics 2017-02-09 Marco C. Lam

We present results from MMT/Hectochelle spectroscopy of red giant candidate stars along the line of sight to the recently-discovered Galactic satellite Crater 2. Modelling the joint distribution of stellar positions, velocities and…

The dwarf spheroidal (dSph) satellites of the Local Group have long been thought to be simple spheroids of stars embedded within extended dark matter halos. Recently, however, evidence for the presence of spatially and kinematically…

Astrophysics · Physics 2009-11-11 Alan W. McConnachie , Jorge Penarrubia , Julio F. Navarro

Using collisionless N-body simulations of dwarf galaxies orbiting the Milky Way (MW) we construct realistic models of dwarf spheroidal (dSph) galaxies of the Local Group. The dwarfs are initially composed of stellar disks embedded in dark…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Klaudia Kowalczyk , Ewa L. Lokas , Stelios Kazantzidis , Lucio Mayer

We report the discovery of one possible neutron star binary ($P_{\rm orb} =$ 0.8666 day) by using the LAMOST low-resolution spectroscopic data. The visible companion is a late A-type dwarf ($T_{\rm eff} = 7900 \pm 200$ K; log$g$ $=$…

High Energy Astrophysical Phenomena · Physics 2022-12-06 Hailong Yuan , Song Wang , Zhongrui Bai , Yue Wang , Yiqiao Dong , Mengxin Wang , Sicheng Yu , Yongheng Zhao , Yaoquan Chu , Jifeng Liu , Haotong Zhang

We examine the prospects for detecting gamma-rays from dark matter annihilation in the six most promising dwarf spheroidal (dSph) satellite galaxies of the Milky Way. We use recently-measured velocity dispersion profiles to provide a…

We improve the earlier restrictions on parameters of the dark matter (DM) in the form of a sterile neutrino. The results were obtained from non-observing the DM decay line in the X-ray spectrum of the Milky Way (using the recent XMM-Newton…

Astrophysics · Physics 2008-11-26 Alexey Boyarsky , Jukka Nevalainen , Oleg Ruchayskiy

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

Based on the observed paucity of the dwarf spheroidal (dSph) satellites of the Milky Way at small Galactocentric distances, we put forward the hypothesis that subsequent to the formation of the Milky Way and its satellites, those dSphs that…

Astrophysics · Physics 2008-11-26 R. Cowsik , Charu Ratnam , Pijushpani Bhattacharjee , Subhabrata Majumdar

The distribution of dark matter in dwarf galaxies can have important implications on our understanding of galaxy formation as well as the particle physics properties of dark matter. However, accurately characterizing the dark matter content…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-01 Laura J. Chang , Lina Necib

Dwarf satellite galaxies are ideal laboratories for identifying particle Dark Matter signals. When setting limits on particle Dark Matter properties from null searches, it becomes however crucial the level at which the Dark Matter density…

Astrophysics of Galaxies · Physics 2016-07-26 Piero Ullio , Mauro Valli

The Milky Way dark matter halo is formed from the accretion of smaller subhalos. These sub-units also harbor stars---typically old and metal-poor---that are deposited in the Galactic inner regions by disruption events. In this Letter, we…

Astrophysics of Galaxies · Physics 2018-01-31 Jonah Herzog-Arbeitman , Mariangela Lisanti , Piero Madau , Lina Necib

The dwarf spheroidal galaxy Ursa Major II (UMaII) is believed to be one of the most dark-matter dominated systems among the Milky Way satellites and represents a suitable target for indirect dark matter (DM) searches. The MAGIC telescopes…

High Energy Astrophysical Phenomena · Physics 2018-03-12 MAGIC Collaboration , M. L. Ahnen , S. Ansoldi , L. A. Antonelli , C. Arcaro , D. Baack , A. Babić , B. Banerjee , P. Bangale , U. Barres de Almeida , J. A. Barrio , J. Becerra González , W. Bednarek , E. Bernardini , R. Ch. Berse , A. Berti , W. Bhattacharyya , A. Biland , O. Blanch , G. Bonnoli , R. Carosi , A. Carosi , G. Ceribella , A. Chatterjee , S. M. Colak , P. Colin , E. Colombo , J. L. Contreras , J. Cortina , S. Covino , P. Cumani , P. Da Vela , F. Dazzi , A. De Angelis , B. De Lotto , M. Delfino , J. Delgado , F. Di Pierro , A. Domínguez , D. Dominis Prester , D. Dorner , M. Doro , S. Einecke , D. Elsaesser , V. Fallah Ramazani , A. Fernández-Barral , D. Fidalgo , M. V. Fonseca , L. Font , C. Fruck , D. Galindo , R. J. García López , M. Garczarczyk , M. Gaug , P. Giammaria , N. Godinović , D. Gora , D. Guberman , D. Hadasch , A. Hahn , T. Hassan , M. Hayashida , J. Herrera , J. Hose , D. Hrupec , K. Ishio , Y. Konno , H. Kubo , J. Kushida , D. Kuveždić , D. Lelas , E. Lindfors , S. Lombardi , F. Longo , M. López , C. Maggio , P. Majumdar , M. Makariev , G. Maneva , M. Manganaro , K. Mannheim , L. Maraschi , M. Mariotti , M. Martínez , S. Masuda , D. Mazin , K. Mielke , M. Minev , J. M. Miranda , R. Mirzoyan , A. Moralejo , V. Moreno , E. Moretti , T. Nagayoshi , V. Neustroev , A. Niedzwiecki , M. Nievas Rosillo , C. Nigro , K. Nilsson , D. Ninci , K. Nishijima , K. Noda , L. Nogués , S. Paiano , J. Palacio , D. Paneque , R. Paoletti , J. M. Paredes , G. Pedaletti , M. Peresano , M. Persic , P. G. Prada Moroni , E. Prandini , I. Puljak , J. R. Garcia , I. Reichardt , W. Rhode , M. Ribó , J. Rico , C. Righi , A. Rugliancich , T. Saito , K. Satalecka , T. Schweizer , J. Sitarek , I. Šnidarić , D. Sobczynska , A. Stamerra , M. Strzys , T. Surić , M. Takahashi , L. Takalo , F. Tavecchio , P. Temnikov , T. Terzić , M. Teshima , N. Torres-Albà , A. Treves , S. Tsujimoto , G. Vanzo , M. Vazquez Acosta , I. Vovk , J. E. Ward , M. Will , D. Zarić

We develop, implement and characterise an enhanced data reduction approach which delivers precise, accurate, radial velocities from moderate resolution spectroscopy with the fibre-fed VLT/FLAMES+GIRAFFE facility. This facility, with…

We present (V,I) photometry of two wide (~25 X 25 arcmin^2) fields centered on the low surface brightness dwarf spheroidal galaxies Draco and Ursa Minor. New estimates of the distance to these galaxies are provided ((m-M)_0(UMi)=19.41 \pm…

Astrophysics · Physics 2009-11-07 M. Bellazzini , F. R. Ferraro , L. Origlia , E. Pancino , L. Monaco , E. Oliva

We have performed a search for halo white dwarfs as high proper motion objects in a second epoch WFPC2 image of the Groth-Westphal strip. We identify 24 high proper motion objects with mu > 0.014 ''/yr. Five of these high proper motion…

Astrophysics · Physics 2009-11-07 Cailin A. Nelson , Kem H. Cook , Tim S. Axelrod , Jeremy R. Mould , Charles Alcock

We re-analyse the recently published HARPS and PFS velocities of the nearby K dwarf GJ 221 that have been reported to contain the signatures of two planets orbiting the star. Our goal is to see whether the earlier studies discussing the…

Earth and Planetary Astrophysics · Physics 2015-06-18 Mikko Tuomi

We present evidence for a ring of stars in the plane of the Milky Way, extending at least from l = 180 deg to l = 227 deg with turnoff magnitude $g \sim 19.5$; the ring could encircle the Galaxy. We infer that the low Galactic latitude…

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…

Astrophysics · Physics 2007-05-23 Beth Willman