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Related papers: A Magellanic origin for the Virgo substructure

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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…

We show that tagging RR Lyrae stars according to their location in the period-amplitude diagram can be used to shed light on the genesis of the Galactic stellar halo. The mixture of RR Lyrae of ab type, separated into classes along the…

Astrophysics of Galaxies · Physics 2018-03-21 V. Belokurov , A. J. Deason , S. E. Koposov , M. Catelan , D. Erkal , A. J. Drake , N. W. Evans

We present results from an analysis of $\sim$ 29,000 RR Lyrae stars located in the Large Magellanic Cloud (LMC). For these objects, near-infrared time-series photometry from the VISTA survey of the Magellanic Clouds system (VMC) and optical…

We examine whether the Large Magellanic Cloud (LMC) is currently losing its stellar halo to Milky Way (MW) tides. We present a live $N$-body model for the ongoing MW-LMC interaction that predicts a prominent stream of stars tidally stripped…

Astrophysics of Galaxies · Physics 2022-06-01 Michael S. Petersen , Jorge Peñarrubia , Ella Jones

In this contribution we discuss the expected properties of our halo if our Galaxy had been built from mergers of smaller systems. Using both analytic arguments and high-resolution simulations, we find that the Galactic halo in the Solar…

Astrophysics · Physics 2007-05-23 Amina Helmi

Many properties of the Milky Way's dark matter halo, including its mass assembly history, concentration, and subhalo population, remain poorly constrained. We explore the connection between these properties of the Milky Way and its…

We discuss a sample of over 3000 candidate RR Lyrae stars selected by various methods using Sloan Digital Sky Survey data for about 1000 deg^2 of sky. These stars probe the halo structure out to ~100 kpc from the Galactic center. Their…

We discuss the density and radial velocity distributions of over 3000 candidate RR Lyrae stars selected by various methods using Sloan Digital Sky Survey data for about 1000 deg^2 of sky. This is more than 20 times larger sample than…

We use a new panoramic imaging survey, conducted with the Dark Energy Camera, to map the stellar fringes of the Large and Small Magellanic Clouds to extremely low surface brightness V $\gtrsim$ 32 mag arcsec$^{-2}$. Our results starkly…

Astrophysics of Galaxies · Physics 2018-05-23 Dougal Mackey , Sergey E. Koposov , Gary Da Costa , Vasily Belokurov , Denis Erkal , Pete Kuzma

The assembly process of our Galaxy can be retrieved using the motions and chemistry of individual stars. Chemo-dynamical studies of the nearby halo have long hinted at the presence of multiple components such as streams, clumps, duality and…

Astrophysics of Galaxies · Physics 2018-11-14 Amina Helmi , Carine Babusiaux , Helmer H. Koppelman , Davide Massari , Jovan Veljanoski , Anthony G. A. Brown

Based on the \textit{Gaia} DR3 RR Lyrae catalog, we use two methods to fit the density profiles with an improved broken power law, and find that there are two break radii coinciding with the two apocenter pile-ups of high-eccentricity…

Astrophysics of Galaxies · Physics 2023-08-09 Dashuang Ye , Cuihua Du , Jianrong Shi , Jun Ma

We identify shell structures in the Milky Way for the first time. We find 2 shells in the Virgo Overdensity (VOD) region and 2 shells in the Hercules Aquila Cloud (HAC) region using Sloan Digital Sky Survey, Gaia, and LAMOST data. These…

Astrophysics of Galaxies · Physics 2020-10-28 Thomas Donlon , Heidi Jo Newberg , Robyn Sanderson , Lawrence M. Widrow

Standard cosmology predicts that dwarfs were the first galaxies to be formed in the Universe and that many of them merge afterwards to form bigger galaxies such as the Milky Way. This process would have left behind traces such as tidal…

Thanks to modern sky surveys, over twenty stellar streams and overdensity structures have been discovered in the halo of the Milky Way. In this paper, we present an analysis of spectroscopic observations of individual stars from one such…

Our Galaxy is thought to have undergone an active evolutionary history dominated by star formation, the accretion of cold gas, and, in particular, mergers up to 10 gigayear ago. The stellar halo reveals rich fossil evidence of these…

We report the discovery of high velocity candidates among RR~Lyrae stars found in the Milky Way halo. We identified 9 RR~Lyrae stars with Galactocentric velocities exceeding the local escape velocity based on the assumed Galaxy potential.…

We present observations obtained with the AAT's 2dF wide field spectrograph AAOmega of K-type stars located within a region of the sky which contains the Virgo Over-Density and the leading arm of the Sagittarius Stream. On the basis of the…

Solar and Stellar Astrophysics · Physics 2015-06-04 A. R. Casey , S. C. Keller , G. Da Costa

The Next Generation Virgo Cluster Survey (NGVS) is a deep $u^*giz$ survey targeting the Virgo cluster of galaxies at 16.5~Mpc. This survey provides high-quality photometry over an $\sim$ 100 deg$^2$ region straddling the constellations of…

Recent analyses of the stellar stream of the Sagittarius dwarf galaxy have claimed that the kinematics and three-dimensional location of the M-giant stars in this structure constrain the dark matter halo of our Galaxy to possess a triaxial…

Astrophysics of Galaxies · Physics 2015-06-12 Rodrigo Ibata , Geraint F. Lewis , Nicolas F. Martin , Michele Bellazzini , Matteo Correnti

We present an N-body model that reproduces the morphology and kinematics of the Magellanic Stream (MS), a vast neutral hydrogen (HI) structure that trails behind the Large and Small Magellanic Clouds (LMC and SMC, respectively) in their…

Astrophysics of Galaxies · Physics 2015-06-03 Jonathan D. Diaz , Kenji Bekki