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Related papers: Stellar Substructures around the Hercules Dwarf Sp…

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Two studies have recently reported the discovery of pronounced Halo substructure in the Sloan Digital Sky Survey (SDSS) commissioning data. Here we show that this Halo substructure is almost in its entirety due to the expected tidal stream…

Astrophysics · Physics 2009-05-29 Rodrigo Ibata , Michael Irwin , Geraint Lewis , Andrea Stolte

Our aim is to provide as clean and as complete a sample as possible of red giant branch stars that are members of the Hercules dSph galaxy. With this sample we explore the velocity dispersion and the metallicity of the system. Stromgren…

We report the detection of main-sequence and blue horizontal-branch stars of the Ursa Minor dwarf spheroidal galaxy beyond its tidal radius, indicating the existence of a possible tidal extension in this satellite of the Milky Way. This…

Astrophysics · Physics 2009-11-06 D. Martinez-Delgado , J. Alonso-Garcia , A. Aparicio , M. A. Gomez-Flechoso

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

A new overdensity of A-colored stars in distant parts of the Milky Way's stellar halo, at a dereddened SDSS magnitude of g_0 = 20.3, is presented. Identification of associated variable RR Lyrae candidates supports the claim that these are…

We investigate the possibility that the dwarf galaxies Crater II and Hercules have previously been tidally stripped by the Milky Way. We present Magellan/IMACS spectra of candidate member stars in both objects. We identify 37 members of…

Astrophysics of Galaxies · Physics 2019-09-25 Sal Wanying Fu , Joshua D. Simon , Alex G. Alarcón Jara

In the past decade, surveys of the stellar component of the Galaxy have revealed a number of streams from tidally disrupted dwarf galaxies and globular clusters. Simulations of hierarchical structure formation in LCDM cosmologies predict…

Astrophysics · Physics 2010-11-05 Jennifer M. Siegal-Gaskins , Monica Valluri

We identify new structures in the halo of the Milky Way Galaxy from positions, colors and magnitudes of five million stars detected in the Sloan Digital Sky Survey. Most of these stars are within 1.26 degrees of the celestial equator. We…

The Eastern Banded Structure (EBS) and Hydra~I halo overdensity are very nearby (d $\sim$ 10 kpc) objects discovered in SDSS data. Previous studies of the region have shown that EBS and Hydra I are spatially coincident, cold structures at…

Astrophysics of Galaxies · Physics 2016-02-17 Jonathan R. Hargis , B. Kimmig , B. Willman , N. Caldwell , M. G. Walker , J. Strader , D. J. Sand , C. J. Grillmair , J. H. Yoon

We test whether the structural properties of the nearby dwarf spheroidal (dSph) galaxy Draco, a well-studied Milky Way companion, can be reconciled with the suggestion that dSphs are unbound tidal remnants with a large depth extent along…

Astrophysics · Physics 2009-11-07 Ralf Klessen , Eva Grebel , Daniel Harbeck

We use analytical and N-body methods to examine the survival of wide stellar binaries against repeated encounters with dark substructures orbiting in the dark matter haloes of dwarf spheroidal galaxies (dSphs). Our models adopt…

Astrophysics of Galaxies · Physics 2010-06-01 Jorge Penarrubia , Sergey E. Koposov , Matthew G. Walker , Gerry Gilmore , N. Wyn Evans , Craig D. Mackay

To place the highly substructured stellar halos of the Milky Way and M31 in a larger context of hierarchical galaxy formation, it is necessary to understand the prevalence and properties of tidal substructure around external galaxies. This…

Astrophysics of Galaxies · Physics 2016-03-23 Jeffrey L. Carlin , Rachael L. Beaton , David Martinez-Delgado , R. Jay Gabany

We present six simulations of galactic stellar haloes formed by the tidal disruption of accreted dwarf galaxies in a fully cosmological setting. Our model is based on the Aquarius project, a suite of high resolution N-body simulations of…

Dwarf galaxies are valuable laboratories for dynamical studies related to dark matter and galaxy evolution, yet it is currently unknown just how physically extended their stellar components are. Satellites orbiting the Galaxy's potential…

As part of our survey for substructure in the Milky Way halo as traced by giant stars, and to look for tidal stellar debris in the halo viable for measurement of the Galactic mass potential with SIM, we explore the distribution of stars…

We use deep V-band surface photometry of five of the brightest elliptical galaxies in the Virgo cluster to search for diffuse tidal streams, shells, and plumes in their outer halos (r > 50 kpc). We fit and subtract elliptical isophotal…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Steven Janowiecki , J. Christopher Mihos , Paul Harding , John J. Feldmeier , Craig Rudick , Heather Morrison

Using a sample of 407 RR Lyrae stars extracted from SDSS Stripe 82, we study the degree of substructure in the Galactic halo. We identify overdensities associated with the known substructures of the Hercules-Aquila Cloud and the Sagittarius…

Astrophysics of Galaxies · Physics 2015-06-03 Laura L. Watkins

Using the MIKE spectrograph, mounted on the 6.5 m Magellan/Clay telescope at the Las Campanas observatory in Chile, we have obtained high-resolution spectra for 60 F and G dwarf stars, all likely members of a density enhancement in the…

Astrophysics · Physics 2009-05-28 T. Bensby , M. S. Oey , S. Feltzing , B. Gustafsson

Recent years have seen a series of large-scale photometric surveys with the aim of detecting substructure in nearby dwarf galaxies. Some of these objects display a varying distribution of each stellar population, reflecting their star…

Astrophysics · Physics 2009-11-10 Matthew Coleman