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Related papers: Revisiting the Tale of Hercules: how stars orbitin…

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We report a measurement of the streaming motion of the stars in the Galactic bar with the Red Clump Giants (RCGs) using the data of the Optical Gravitational Lensing Experiment II (OGLE-II). We measure the proper motion of 46,961 stars and…

Astrophysics · Physics 2009-11-07 T. Sumi , L. Eyer , P. R. Wozniak

We report the discovery of 15 stars in the H3 survey that lie, in projection, near the tip of the trailing gaseous Magellanic Stream (MS). The stars have Galactocentric velocities $< -155$ km s$^{-1}$, Galactocentric distances of $\approx…

Context. The Sagittarius (Sgr) dwarf spheroidal galaxy is currently being disrupted under the strain of the Milky Way. A reliable reconstruction of Sgr star formation history can only be obtained by combining core and stream information.…

Astrophysics · Physics 2009-11-11 L. Monaco , M. Bellazzini , P. Bonifacio , A. Buzzoni , F. R. Ferraro , G. Marconi , L. Sbordone , S. Zaggia

Recent years have seen the discovery of an ever growing number of stellar debris streams and clouds. These structures are typically detected as extended and often curvilinear overdensities of metal-poor stars that stand out from the…

Astrophysics of Galaxies · Physics 2016-04-06 Carl J. Grillmair , Jeffrey L. Carlin

We show that there is a low metallicity tidal stream that runs along l=143 deg. in the South Galactic Cap, about 34 kpc from the Sun, discovered from SEGUE stellar velocities. Since the most concentrated detections are in the Cetus…

Astrophysics of Galaxies · Physics 2009-07-22 Heidi Jo Newberg , Brian Yanny , Benjamin A. Willett

Using high-resolution spectroscopy, we provide a determination of [Fe/H] and [Ca/H] for confirmed red-giant branch member stars of the Hercules dwarf spheroidal galaxy. Based on this we explore the ages of the prevailing stellar populations…

Astrophysics of Galaxies · Physics 2015-05-20 D. Adén , K. Eriksson , S. Feltzing , E. K. Grebel , A. Koch , M. I. Wilkinson

Stellar streams in the Milky Way are promising detectors of low-mass dark matter (DM) subhalos predicted by $\Lambda$CDM. Passing subhalos induce perturbations in streams that indicate the presence of the subhalos. Understanding how known…

We measure the escape speed curve of the Milky Way based on the analysis of the velocity distribution of $\sim 2850$ counter-rotating halo stars from the Gaia DR2. The distances were estimated through the StarHorse code, and only stars with…

We perform a search for stellar streams around the Milky Way using the first three years of multi-band optical imaging data from the Dark Energy Survey (DES). We use DES data covering $\sim 5000$ sq. deg. to a depth of $g > 23.5$ with a…

We analyse a 10,000 star spectroscopic survey, focused on Galactic thick disk stars typically 2-5 kpc from the Sun, carried out using the AAOmega Spectrograph on the AAT. We develop methods for completeness-correction of the survey based on…

Astrophysics of Galaxies · Physics 2015-06-15 Apoorva Jayaraman , Gerard Gilmore , Rosemary F. G. Wyse , John E. Norris , Vasily Belokurov

We present mass models of the Milky Way created to fit observational constraints and to be consistent with expectations from theoretical modelling. The method used to create these models is that demonstrated in McMillan (2011), and we…

Astrophysics of Galaxies · Physics 2016-12-07 Paul J. McMillan

Until the recent advent of $Gaia$ Data Release 2 (DR2) and deep multi-object spectroscopy, it has been difficult to obtain 6-D phase space information for large numbers of stars beyond 4 kpc, in particular towards the Galactic centre, where…

Halo stars with unusually high radial velocity ("hypervelocity" stars, or HVS) are thought to be stars unbound to the Milky Way that originate from the gravitational interaction of stellar systems with the supermassive black hole at the…

Astrophysics · Physics 2009-11-13 Mario G. Abadi , Julio F. Navarro , Matthias Steinmetz

Using star counts in both color and magnitude from the Two Micron All Sky Survey (2MASS) Second Incremental Release Point Source Catalog we search for evidence of non-uniform extinction and stellar population density changes in the Galactic…

Astrophysics · Physics 2009-11-07 A. C. Quillen

Motivated by the vast gap between photometric and spectroscopic data volumes, there is great potential in using 5D kinematic information to identify and study substructures of the Milky Way. We identify substructures in the Galactic halo…

Providing a detailed picture of the Sagittarius (Sgr) stream offers important constraints on the build-up of the Galactic halo as well as its gravitational potential at large radii. While several attempts have been made to model the…

We present the results of a new sensitive survey of neutral hydrogen above and below the Galactic Center with the Green Bank Telescope. The observations extend up to Galactic latitude | b | < 10 deg with an effective angular resolution of…

The hierarchical model of galaxy formation predicts that the Milky Way halo is populated by tidal debris of dwarf galaxies and globular clusters. Due to long dynamical times, debris from the lowest mass objects remains coherent as thin and…

Astrophysics of Galaxies · Physics 2024-05-31 Ana Bonaca , Adrian M. Price-Whelan

We present trigonometric parallax and proper motion measurements toward 22 GHz water and 6.7 GHz methanol masers in 16 high-mass star-forming regions. These sources are all located in the Scutum spiral arm of the Milky Way. The observations…

Astrophysics of Galaxies · Physics 2020-01-08 K. Immer , J. Li , L. H. Quiroga-Nuñez , M. J. Reid , B. Zhang , L. Moscadelli , K. L. J. Rygl

We present the analysis of 1,207 RR Lyrae found in photometry taken by the Catalina Survey's Mount Lemmon telescope. By combining accurate distances for these stars with measurements for ~14,000 type-AB RR Lyrae from the Catalina Schmid…