scholarly journals Dynamical friction from scalar dark matter in the relativistic regime

2021 ◽  
Vol 104 (10) ◽  
Author(s):  
Dina Traykova ◽  
Katy Clough ◽  
Thomas Helfer ◽  
Emanuele Berti ◽  
Pedro G. Ferreira ◽  
...  
Keyword(s):  
Dark Matter ◽  
Dynamical Friction ◽  
Relativistic Regime

scholarly journals Dynamical friction in a Fuzzy Dark Matter universe

2020 ◽  
Vol 2020 (01) ◽  
pp. 001-001 ◽  
Author(s):  
Lachlan Lancaster ◽  
Cara Giovanetti ◽  
Philip Mocz ◽  
Yonatan Kahn ◽  
Mariangela Lisanti ◽  
...  
Keyword(s):  
Dark Matter ◽  
Dynamical Friction

scholarly journals Dark Matter Substructure and Dwarf Galactic Satellites

2010 ◽  
Vol 2010 ◽  
pp. 1-21 ◽  
Author(s):  
Andrey Kravtsov
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Luminosity Function ◽  
Cold Dark Matter ◽  
Dynamical Friction ◽  
Density Profiles ◽  
Tidal Forces ◽  
Central Regions ◽  
Galactic Satellites ◽  
Virial Mass

A decade ago cosmological simulations of increasingly higher resolution were used to demonstrate that virialized regions of Cold Dark Matter (CDM) halos are filled with a multitude of dense, gravitationally bound clumps. These dark mattersubhalosare central regions of halos that survived strong gravitational tidal forces and dynamical friction during the hierarchical sequence of merging and accretion via which the CDM halos form. Comparisons with observations revealed that there is a glaring discrepancy between abundance of subhalos and luminous satellites of the Milky Way and Andromeda as a function of their circular velocity or bound mass within a fixed aperture. This large discrepancy, which became known as the “substructure” or the “missing satellites” problem, begs for an explanation. In this paper, the author reviews the progress made during the last several years both in quantifying the problem and in exploring possible scenarios in which it could be accommodated and explained in the context of galaxy formation in the framework of the CDM paradigm of structure formation. In particular, he shows that the observed luminosity function, radial distribution, and the remarkable similarity of the inner density profiles of luminous satellites can be understood within hierarchical CDM framework using a simple model in which efficiency of star formation monotonically decreases with decreasing virial mass satellites had before their accretionwithout any actual sharp galaxy formation threshold.

scholarly journals Constraints from Dynamical Friction on the Dark Matter Content of Barred Galaxies

2000 ◽  
Vol 543 (2) ◽  
pp. 704-721 ◽  
Author(s):  
Victor P. Debattista ◽  
J. A. Sellwood
Keyword(s):  
Dark Matter ◽  
Matter Content ◽  
Dynamical Friction ◽  
Barred Galaxies

scholarly journals Fast galaxy bars continue to challenge standard cosmology

2021 ◽  
Vol 508 (1) ◽  
pp. 926-939
Author(s):  
Mahmood Roshan ◽  
Neda Ghafourian ◽  
Tahere Kashfi ◽  
Indranil Banik ◽  
Moritz Haslbauer ◽  
...  
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Dark Matter Halo ◽  
Dynamical Friction ◽  
Statistical Population ◽  
Barred Galaxies ◽  
Corotation Radius ◽  
Pattern Speeds ◽  
Hydrodynamical Simulations ◽  
Disc Galaxies

ABSTRACT Many observed disc galaxies harbour a central bar. In the standard cosmological paradigm, galactic bars should be slowed down by dynamical friction from the dark matter halo. This friction depends on the galaxy’s physical properties in a complex way, making it impossible to formulate analytically. Fortunately, cosmological hydrodynamical simulations provide an excellent statistical population of galaxies, letting us quantify how simulated galactic bars evolve within dark matter haloes. We measure bar strengths, lengths, and pattern speeds in barred galaxies in state-of-the-art cosmological hydrodynamical simulations of the IllustrisTNG and EAGLE projects, using techniques similar to those used observationally. We then compare our results with the largest available observational sample at redshift z = 0. We show that the tension between these simulations and observations in the ratio of corotation radius to bar length is 12.62σ (TNG50), 13.56σ (TNG100), 2.94σ (EAGLE50), and 9.69σ (EAGLE100), revealing for the first time that the significant tension reported previously persists in the recently released TNG50. The lower statistical tension in EAGLE50 is actually caused by it only having five galaxies suitable for our analysis, but all four simulations give similar statistics for the bar pattern speed distribution. In addition, the fraction of disc galaxies with bars is similar between TNG50 and TNG100, though somewhat above EAGLE100. The simulated bar fraction and its trend with stellar mass both differ greatly from observations. These dramatic disagreements cast serious doubt on whether galaxies actually have massive cold dark matter haloes, with their associated dynamical friction acting on galactic bars.

scholarly journals A new calibration method of sub-halo orbital evolution for semi-analytic models

2020 ◽  
Vol 498 (3) ◽  
pp. 3902-3913
Author(s):  
Shengqi Yang ◽  
Xiaolong Du ◽  
Andrew J Benson ◽  
Anthony R Pullen ◽  
Annika H G Peter
Keyword(s):  
Dark Matter ◽  
High Resolution ◽  
Cold Dark Matter ◽  
Maximum Velocity ◽  
Parameter Tuning ◽  
Dynamical Friction ◽  
Dynamical Models ◽  
Non Linear ◽  
Tidal Heating ◽  
Analytic Models

ABSTRACT Understanding the non-linear dynamics of satellite haloes (a.k.a. ‘sub-haloes’) is important for predicting the abundance and distribution of dark matter sub-structures and satellite galaxies, and for distinguishing among microphysical dark matter models using observations. Typically, modelling these dynamics requires large N-body simulations with high resolution. Semi-analytic models can provide a more efficient way to describe the key physical processes such as dynamical friction, tidal mass loss, and tidal heating, with only a few free parameters. In this work, we present a fast Markov chain Monte Carlo fitting approach to explore the parameter space of such a sub-halo non-linear evolution model. We use the dynamical models described in an earlier work and calibrate the models to two sets of high-resolution cold dark matter N-body simulations, ELVIS and Caterpillar. Compared to previous calibrations that used manual parameter tuning, our approach provides a more robust way to determine the best-fitting parameters and their posterior probabilities. We find that jointly fitting for the sub-halo mass and maximum velocity functions can break the degeneracy between tidal stripping and tidal heating parameters, as well as providing better constraints on the strength of dynamical friction. We show that our semi-analytic simulation can accurately reproduce N-body simulations statistics, and that the calibration results for the two sets of N-body simulations agree at 95 per cent confidence level. Dynamical models calibrated in this work will be important for future dark matter sub-structure studies.

scholarly journals Tidal forces from the wake of dynamical friction: warps, lopsidedness, and kinematic misalignment

2020 ◽  
Vol 498 (1) ◽  
pp. 1080-1092
Author(s):  
Rain Kipper ◽  
María Benito ◽  
Peeter Tenjes ◽  
Elmo Tempel ◽  
Roberto de Propris
Keyword(s):  
Dark Matter ◽  
Velocity Dispersion ◽  
Position Angle ◽  
Back Reaction ◽  
Dynamical Friction ◽  
Matter Distribution ◽  
Tidal Forces ◽  
Isolated Galaxies ◽  
The Galaxy ◽  
Dark Matter Distribution

ABSTRACT A galaxy moving through a background of dark matter particles induces an overdensity of these particles or a wake behind it. The back reaction of this wake on the galaxy is a force field that can be decomposed into an effective deceleration (called dynamical friction) and a tidal field. In this paper, we determine the tidal forces, thus generated on the galaxy, and the resulting observables, which are shown to be warps, lopsidedness, and/or kinematic-photometric position angle misalignments. We estimate the magnitude of the tidal-like effects needed to reproduce the observed warp and lopsidedness on the isolated galaxy IC 2487. Within a realistic range of dark matter distribution properties, the observed, warped, and lopsided kinematical properties of IC 2487 are possible to reproduce (the background medium of dark matter particles has a velocity dispersion of $\lesssim 80\, {\rm km\, s^{-1}}$ and the density $10^4{\!-\!}10^5\, {\rm M_\odot \, kpc^{-3}}$, more likely at the lower end). We conclude that the proposed mechanism can generate warps, lopsidedness, and misalignments observed in isolated galaxies or galaxies in loose groups. The method can be used also to constrain dark matter spatial and velocity distribution properties.

scholarly journals Dynamical Friction and the Distribution of Dark Matter in Barred Galaxies

1998 ◽  
Vol 493 (1) ◽  
pp. L5-L8 ◽  
Author(s):  
Victor P. Debattista ◽  
J. A. Sellwood
Keyword(s):  
Dark Matter ◽  
Dynamical Friction ◽  
Barred Galaxies

scholarly journals Constraints on the astrophysical environment of binaries with gravitational-wave observations

2020 ◽  
Vol 644 ◽  
pp. A147
Author(s):  
Vitor Cardoso ◽  
Andrea Maselli
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Neutron Star ◽  
Gravitational Wave ◽  
Accretion Disks ◽  
Environmental Effects ◽  
Surrounding Medium ◽  
Future Generations ◽  
Dynamical Friction ◽  
Compact Binaries

Aims. The dynamics of coalescing compact binaries can be affected by the environment in which the systems evolve, leaving detectable signatures in the emitted gravitational signal. In this paper, we investigate the ability of gravitational-wave detectors to constrain the nature of the environment in which compact binaries merge. Methods. We parametrized a variety of environmental effects by modifying the phase of the gravitational signal emitted by black hole and neutron star binaries. We infer the bounds on such effects by current and future generations of interferometers, studying their dependence on the binary’s parameters. Results. We show that the strong dephasing induced by accretion and dynamical friction can constrain the density of the surrounding medium to orders of magnitude below those of accretion disks. Planned detectors, such as LISA or DECIGO, will be able to probe densities typical of those of dark matter.

scholarly journals Spatially offset black holes in the Horizon-AGN simulation and comparison to observations

2020 ◽  
Vol 500 (4) ◽  
pp. 4639-4657 ◽  
Author(s):  
Deaglan J Bartlett ◽  
Harry Desmond ◽  
Julien Devriendt ◽  
Pedro G Ferreira ◽  
Adrianne Slyz
Keyword(s):  
Black Holes ◽  
Dark Matter ◽  
Friction Force ◽  
Cosmic Time ◽  
Supermassive Black Holes ◽  
Dynamical Friction ◽  
Orbital Radius ◽  
Hydrodynamical Simulation ◽  
The Galaxy

ABSTRACT We study the displacements between the centres of galaxies and their supermassive black holes (BHs) in the cosmological hydrodynamical simulation Horizon-AGN, and in a variety of observations from the literature. The BHs in Horizon-AGN feel a subgrid dynamical friction force, sourced by the surrounding gas, which prevents recoiling BHs being ejected from the galaxy. We find that (i) the fraction of spatially offset BHs increases with cosmic time, (ii) BHs live on prograde orbits in the plane of the galaxy with an orbital radius that decays with time but stalls near z = 0, and (iii) the magnitudes of offsets from the galaxy centres are substantially larger in the simulation than in observations. We attribute the stalling of the infall and excessive offset magnitudes to the fact that dynamical friction from stars and dark matter is not modelled in the simulation, and hence provide a way to improve the BH dynamics of future simulations.

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