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Related papers: Local Group Analogs in $\Lambda$CDM cosmological s…

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We identify Local Group (LG) analogs in the IllustrisTNG cosmological simulation, and use these to study two mass estimators for the LG: one based on the timing argument (TA) and one based on the virial theorem (VT). Including updated…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-06 Odelia V. Hartl , Louis E. Strigari

In this work an ensemble of simulated Local Group analogues is used to constrain the properties of the mass assembly history of the Milky Way (MW) and Andromeda (M31) galaxies. These objects have been obtained using the constrained…

Space observatories like the Hubble Space Telescope and Gaia are providing unprecedented 6D phase space information of satellite galaxies. Such measurements can shed light on the structure and assembly history of the Local Group, but…

Astrophysics of Galaxies · Physics 2017-05-03 Ekta Patel , Gurtina Besla , Kaisey Mandel

The Local Group (LG) of galaxies is dominated by the M31 and Milky Way (MW) pair, a configuration which suggests that the mass distribution in the LG and its surroundings should be highly anisotropic. We use the APOSTLE cosmological…

Astrophysics of Galaxies · Physics 2023-10-05 Isabel M. E. Santos-Santos , Julio F. Navarro , Alan McConnachie

We use a large sample of isolated dark matter halo pairs drawn from cosmological N-body simulations to identify candidate systems whose kinematics match that of the Local Group of Galaxies (LG). We find, in agreement with the "timing…

The kinematics of the Milky Way (MW) and M31, the dominant galaxies in the Local Group (LG), can be used to estimate the LG total mass. New results on the M31 proper motion have recently been used to improve that estimate. Those results are…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-21 J. E. Forero-Romero , D. Sierra-Porta

We attempt to fit the observed radial velocities (RVs) of ${\,{\sim}\,}30$ Local Group (LG) galaxies using a 3D dynamical model of it and its immediate environment within the context of the standard cosmological paradigm, $\Lambda$CDM. This…

Astrophysics of Galaxies · Physics 2019-02-05 Indranil Banik , Hongsheng Zhao

We use Density Estimation Likelihood-Free Inference, $\Lambda$ Cold Dark Matter simulations of $\sim 2M$ galaxy pairs, and data from Gaia and the Hubble Space Telescope to infer the sum of the masses of the Milky Way and Andromeda (M31)…

Astrophysics of Galaxies · Physics 2021-01-20 Pablo Lemos , Niall Jeffrey , Lorne Whiteway , Ofer Lahav , Niam I Libeskind , Yehuda Hoffman

The mass of the Local Group (LG), comprising the Milky Way (MW), Andromeda (M31), and their satellites, is crucial for validating galaxy formation and cosmological models. Traditional virial mass estimates, which rely on line-of-sight (LoS)…

Astrophysics of Galaxies · Physics 2025-06-04 David Benisty , David Mota

The total mass of the Local Group (LG) is a fundamental quantity that enables interpreting the orbits of its constituent galaxies and placing the LG in a cosmological context. One of the few methods that allows inferring the total mass…

We attempt to understand the planes of satellite galaxies orbiting the Milky Way (MW) and M31 in the context of Modified Newtonian Dynamics (MOND), which implies a close MW-M31 flyby occurred ${\approx 8}$ Gyr ago. Using the timing…

Astrophysics of Galaxies · Physics 2018-06-05 Indranil Banik , David O'Ryan , Hongsheng Zhao

We make detailed theoretical predictions for the assembly properties of the Local Group (LG) in the standard LambdaCDM cosmological model. We use three cosmological N-body dark matter simulations from the CLUES project, which are designed…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 J. E. Forero-Romero , Y. Hoffman , G. Yepes , S. Gottoeber , R. Piontek , A. Klypin , M. Steinmetz

We use new measurements of the M31 proper motion to examine the Milky Way (MW) - M31 orbit and angular momentum. For Local Group (LG) mass consistent with measured values, and assuming the system evolves in isolation, we show a wide range…

Astrophysics of Galaxies · Physics 2025-04-23 Odelia V. Hartl , Louis E. Strigari

We recently showed that several Local Group (LG) galaxies have much higher radial velocities (RVs) than predicted by a 3D dynamical model of the standard cosmological paradigm. Here, we show that 6 of these 7 galaxies define a thin plane…

Astrophysics of Galaxies · Physics 2017-11-30 Indranil Banik , Hongsheng Zhao

In this work we study the dynamics of the Local Group (LG) within the context of cosmological models beyond General Relativity (GR). Using observable kinematic quantities to identify candidate pairs we build up samples of simulated LG-like…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-18 Edoardo Carlesi , David F. Mota , Hans Winther

We use the APOSTLE $\Lambda$CDM cosmological hydrodynamical simulations of the Local Group to study the recent accretion of massive satellites into the halo of Milky Way (MW)-sized galaxies. These systems are selected to be close analogues…

Astrophysics of Galaxies · Physics 2021-04-21 Isabel M. E. Santos-Santos , Azadeh Fattahi , Laura V. Sales , Julio F. Navarro

Using a large observational sample from the Sloan Digital Sky Survey, we investigate the spatial alignment between galaxy pairs and their local cosmic filaments. Focusing on pairs with stellar masses and separations comparable to the Milky…

Astrophysics of Galaxies · Physics 2025-10-28 Peng Wang

The structure, extent, and mass of the Milky Way's (MW) dark matter (DM) halo are observationally challenging to determine due to our position within the Galaxy. To overcome this limitation, we study a combined sample of 127 MW analogs from…

We introduce "Simulations Beyond The Local Universe" (SIBELIUS) that connect the Local Group to its cosmic environment. We show that introducing hierarchical small-scale perturbations to a density field constrained on large scales by…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-24 Till Sawala , Stuart McAlpine , Jens Jasche , Guilhem Lavaux , Adrian Jenkins , Peter H. Johansson , Carlos S. Frenk

We construct a Galacto-Local Group rotation curve, combining the Galactic rotation curve with a diagram, where galacto-centric radial velocities of outer globular clusters and member galaxies of the Local Group are plotted against their…

Astrophysics · Physics 2015-05-13 Yoshiaki Sofue