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Related papers: Mapping the Galactic Halo VIII: Quantifying substr…

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We develop an explicit model for the formation of the stellar halo from tidally disrupted, accreted dwarf satellites in the cold dark matter (CDM) framework, focusing on predictions testable with the Sloan Digital Sky Survey (SDSS) and…

Astrophysics · Physics 2009-10-31 James S. Bullock , Andrey V. Kravtsov , David H. Weinberg

We introduce a new maximum likelihood method to model the density profile of Blue Horizontal Branch and Blue Straggler stars and apply it to the Sloan Digital Sky Survey Data Release 8 (DR8) photometric catalogue. There are a large number…

Astrophysics of Galaxies · Physics 2015-05-27 A. J. Deason , V. Belokurov , N. W. Evans

In L\"ovdal et al, we presented a data-driven method for clustering in Integrals of Motion space and applied it to a large sample of nearby halo stars with 6D phase-space information. We identified a large number of clusters, many of which…

Astrophysics of Galaxies · Physics 2022-09-14 Tomás Ruiz-Lara , Tadafumi Matsuno , S. Sofie Lövdal , Amina Helmi , Emma Dodd , Helmer H. Koppelman

If the favored hierarchical cosmological model is correct, then the Milky Way system should have accreted ~100-200 luminous satellite galaxies in the past \~12 Gyr. We model this process using a hybrid semi-analytic plus N-body approach…

Astrophysics · Physics 2008-11-26 James S. Bullock , Kathryn V. Johnston

The hierarchical structure formation model predicts that stellar halos should form, at least partly, via mergers. If this was a predominant formation channel for the Milky Way's halo, imprints of this merger history in the form of moving…

Astrophysics of Galaxies · Physics 2017-02-01 Amina Helmi , Jovan Veljanoski , Maarten A. Breddels , Hao Tian , Laura V. Sales

As one of the most massive Milky Way satellites, the Sagittarius dwarf galaxy has played an important role in shaping the Galactic disk and stellar halo morphologies. The disruption of Sagittarius over several close-in passages has…

Astrophysics of Galaxies · Physics 2017-10-04 Marion I. P. Dierickx , Abraham Loeb

The last 10-20 years has seen a profound shift in views of how the Galaxy's halo formed. The idea of a monolithic early collapse of a single system (Eggen, Lynden-Bell and Sandage 1962) has been challenged by observations at high redshift…

We provide new constraints on the connection between galaxies in the local universe, identified by the Sloan Digital Sky Survey (SDSS), and dark matter halos and their constituent substructures in the $\Lambda$CDM model using WMAP7…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-20 Rachel M. Reddick , Risa H. Wechsler , Jeremy L. Tinker , Peter S. Behroozi

Aims: Develop a data-driven and statistically based method for finding such clumps in Integrals of Motion space for nearby halo stars and evaluating their significance robustly. Methods: We use data from Gaia EDR3 extended with radial…

Astrophysics of Galaxies · Physics 2022-09-14 S. Sofie Lövdal , Tomás Ruiz-Lara , Helmer H. Koppelman , Tadafumi Matsuno , Emma Dodd , Amina Helmi

We propose and test a method for applying statistical photometric parallax to main sequence turn off (MSTO) stars in the Sloan Digital Sky Survey (SDSS). Using simulated data, we show that if our density model is similar to the actual…

Astrophysics of Galaxies · Physics 2018-10-10 Jake Weiss , Heidi Jo Newberg , Matthew Newby , Travis Desell

Using the stellar photometry catalogue based on the latest data release (DR4) of the Sloan Digital Sky Survey (SDSS), a study of the Galactic structure using star counts is carried out for selected areas of the sky. The sample areas are…

Astrophysics · Physics 2009-11-11 Y. Xu , L. C. Deng , J. Y. Hu

We use the Pristine survey CaHK narrow-band photometry, combined with the SDSS ugr photometry, to provide a cleaner sample of blue horizontal branch stars in the Galactic halo out to large distances. We demonstrate a completeness of 91% and…

Abridged: We estimate the distances to ~48 million stars detected by the Sloan Digital Sky Survey and map their 3D number density distribution in 100 < D < 20 kpc range over 6,500 deg^2 of sky. The data show strong evidence for a Galaxy…

In hierarchical structure formation, dark matter halos that merge with larger halos can persist as subhalos. These subhalos are likely hosts of visible galaxies. While the dense halo environment rapidly strips subhalos of their dark mass,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Andrew R. Wetzel , Martin White

Modern Galactic surveys have revealed an ancient merger that dominates the stellar halo of our Galaxy (\textit{Gaia}-Sausage-Enceladus, GSE). Using chemical abundances and kinematics from the H3 Survey, we identify 5559 halo stars from this…

We study numerical simulations of satellite galaxy disruption in a potential resembling that of the Milky Way. Our goal is to assess whether a merger origin for the stellar halo would leave observable fossil structure in the phase-space…

Astrophysics · Physics 2009-05-11 Amina Helmi , Simon D. M. White

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…

I review recent SDSS results related to galaxies and large scale structure, including: (1) discovery of coherent, unbound structures in the stellar halo, (2) demonstration that Pal 5 has tidal tails and Draco doesn't, (3) precise…

Astrophysics · Physics 2007-05-23 David H. Weinberg

We characterise the radial density, metallicity and flattening profile of the Milky Way's stellar halo, based on the large sample of 1757 spectroscopically confirmed giant stars from SDSS/SEGUE-2 after excising stars that were…

Astrophysics of Galaxies · Physics 2015-08-26 Xiang-Xiang Xue , Hans-Walter Rix , Zhibo Ma , Heather Morrison , Jo Bovy , Branimir Sesar , William Janesh

We present the latitude-normalized radial velocity (vb) distribution of 3318 subsolar metallicity, V<13.5 stars from the Grid Giant Star Survey (GGSS) in Southern Hemisphere fields. The sample includes giants mostly within ~5 kpc from the…