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The formation of globular clusters and their relation to the distribution of dark matter have long puzzled astronomers. One of the most recently-proposed globular cluster formation channels ties ancient star clusters to the large-scale…

Astrophysics of Galaxies · Physics 2021-12-08 Anna T. P. Schauer , Volker Bromm , Michael Boylan-Kolchin , Simon C. O. Glover , Ralf S. Klessen

The local velocity distribution of dark matter plays an integral role in interpreting the results from direct detection experiments. We previously showed that metal-poor halo stars serve as excellent tracers of the virialized dark matter…

Astrophysics of Galaxies · Physics 2019-01-09 Jonah Herzog-Arbeitman , Mariangela Lisanti , Lina Necib

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

Dark matter comprises the bulk of the matter in the universe but its particle nature and cosmological origin remain mysterious. Knowledge of the dark matter density distribution in the Milky Way Galaxy is crucial to both our understanding…

(Abridged) This paper presents the first connections made between two local features in velocity-space found in a survey of M giant stars and stellar spatial inhomogeneities on global scales. Comparison to cosmological, chemodynamical…

Astrophysics of Galaxies · Physics 2015-06-04 Kathryn V. Johnston , Allyson A. Sheffield , Steven R. Majewski , Sanjib Sharma

Recent observations have revealed a trove of unexpected morphological features in many of the Milky Way's stellar streams. Explanations for such features include time-dependent deformations of the Galactic gravitational potential, local…

Astrophysics of Galaxies · Physics 2022-12-22 Tomer D. Yavetz , Kathryn V. Johnston , Sarah Pearson , Adrian M. Price-Whelan , Chris Hamilton

The measurements of the possible gravitational microlensing events are analysed with a simple yet accurate disc--halo model of the Milky Way Galaxy. This comprises a luminous exponential disc embedded in a flattened dark matter halo with…

Astrophysics · Physics 2016-06-08 N. W. Evans , J. Jijina

Detection of bending waves is a highly challenging task even in nearby disc galaxies due to their sub-kpc bending amplitudes. However, simulations show that the harmonic bending of a Milky Way like disc galaxy is associated with a harmonic…

Astrophysics of Galaxies · Physics 2022-04-20 Meera Nandakumar , Chaitra Narayan , Prasun Dutta

Modeling the Milky Way stellar halo requires well-determined density and velocity anisotropy profiles. However, it has been challenging to gather a large sample of stars with six-dimensional data that extend beyond 40 kpc to map the outer…

We consider the process of stellar binaries tidally disrupted by a supermassive black hole. For highly eccentric orbits, as one star is ejected from the three-body system, the companion remains bound to the black hole. Hypervelocity stars…

Astrophysics of Galaxies · Physics 2015-06-16 Elena M. Rossi , Shiho Kobayashi , Re'em Sari

An accurate knowledge of the dark matter distribution in the Milky Way is of crucial importance for galaxy formation studies and current searches for particle dark matter. In this paper we set new dynamical constraints on the Galactic dark…

Astrophysics of Galaxies · Physics 2015-12-03 Miguel Pato , Fabio Iocco , Gianfranco Bertone

Increasing attention has recently focused on non-traditional dark-matter production mechanisms which result in primordial dark-matter velocity distributions with highly non-thermal shapes. In this paper, we undertake an assessment of how…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-14 Keith R. Dienes , Fei Huang , Jeff Kost , Kevin Manogue , Brooks Thomas

Directionally sensitive dark matter (DM) direct detection experiments present the only way to observe the full three-dimensional velocity distribution of the Milky Way halo local to Earth. In this work we compare methods for extracting…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-10 Bradley J. Kavanagh , Ciaran A. J. O'Hare

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…

The Gaia mission has provided the largest ever astrometric chart of the Milky Way. Using it to map the Galactic halo is helpful for disentangling its merger history. The identification of halo stars in Gaia DR2 with reliable distance…

Astrophysics of Galaxies · Physics 2021-11-25 Helmer H. Koppelman , Amina Helmi

Stellar streams are sensitive tracers of the gravitational potential, which is typically assumed to be static in the inner Galaxy. However, massive mergers like Gaia-Sausage-Enceladus can impart torques on the stellar disk of the Milky Way…

Astrophysics of Galaxies · Physics 2023-12-18 Jacob Nibauer , Ana Bonaca , Mariangela Lisanti , Denis Erkal , Zoe Hastings

Ample observational capabilities exist today to detect the small density perturbations that low-mass dark matter subhaloes impart on stellar streams from disrupting Galactic satellites. In anticipation of these observations, we investigate…

Astrophysics of Galaxies · Physics 2016-08-17 Denis Erkal , Vasily Belokurov , Jo Bovy , Jason L. Sanders

The Hercules ultra-faint dwarf galaxy (UFD) has long been hypothesized to be tidally disrupting, yet no conclusive evidence has been found for tidal disruption owing partly to difficulties in identifying Hercules member stars. In this work,…

Astrophysics of Galaxies · Physics 2024-03-05 Xiaowei Ou , Anirudh Chiti , Nora Shipp , Joshua D. Simon , Marla Geha , Anna Frebel , Mohammad K. Mardini , Denis Erkal , Lina Necib

Using the first 25% of DEEP2 Redshift Survey data, we probe the line-of-sight velocity dispersion profile for isolated galaxies with absolute B-band magnitude -22<M_B-5log(h)<-21 at z=0.7-1.0, using satellite galaxies as luminous tracers of…

Stellar streams produced from dwarf galaxies provide direct evidence of the hierarchical formation of the Milky Way. Here, we present the first comprehensive study of the "LMS-1" stellar stream, that we detect by searching for wide streams…

Astrophysics of Galaxies · Physics 2021-10-20 Khyati Malhan , Zhen Yuan , Rodrigo Ibata , Anke Arentsen , Michele Bellazzini , Nicolas F. Martin