scholarly journals Constraining the warm dark matter particle mass with Milky Way satellites

2014 ◽  
Vol 442 (3) ◽  
pp. 2487-2495 ◽  
Author(s):  
Rachel Kennedy ◽  
Carlos Frenk ◽  
Shaun Cole ◽  
Andrew Benson
Keyword(s):  
Dark Matter ◽  
Milky Way ◽  
Dark Matter Particle ◽  
Particle Mass

scholarly journals Heating of Milky Way disc stars by dark matter fluctuations in cold dark matter and fuzzy dark matter paradigms

2019 ◽  
Vol 485 (2) ◽  
pp. 2861-2876 ◽  
Author(s):  
Benjamin V Church ◽  
Philip Mocz ◽  
Jeremiah P Ostriker
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Quantum Interference ◽  
Cold Dark Matter ◽  
Milky Way ◽  
Velocity Dispersion ◽  
Formation Rate ◽  
Density Fluctuations ◽  
Particle Mass ◽  
Small Scale

ABSTRACT Although highly successful on cosmological scales, cold dark matter (CDM) models predict unobserved overdense ‘cusps’ in dwarf galaxies and overestimate their formation rate. We consider an ultralight axion-like scalar boson which promises to reduce these observational discrepancies at galactic scales. The model, known as fuzzy dark matter (FDM), avoids cusps, suppresses small-scale power, and delays galaxy formation via macroscopic quantum pressure. We compare the substructure and density fluctuations of galactic dark matter haloes comprised of ultralight axions to conventional CDM results. Besides self-gravitating subhaloes, FDM includes non-virialized overdense wavelets formed by quantum interference patterns, which are an efficient source of heating to galactic discs. We find that, in the solar neighbourhood, wavelet heating is sufficient to give the oldest disc stars a velocity dispersion of ${\sim } {30}{\, \mathrm{km\, s}^{-1}}$ within a Hubble time if energy is not lost from the disc, the velocity dispersion increasing with stellar age as σD ∝ t0.4 in agreement with observations. Furthermore, we calculate the radius-dependent velocity dispersion and corresponding scaleheight caused by the heating of this dynamical substructure in both CDM and FDM with the determination that these effects will produce a flaring that terminates the Milky Way disc at $15\!-\!20{\, \mathrm{kpc}}$. Although the source of thickened discs is not known, the heating due to perturbations caused by dark substructure cannot exceed the total disc velocity dispersion. Therefore, this work provides a lower bound on the FDM particle mass of ma > 0.6 × 10−22 eV. Furthermore, FDM wavelets with this particle mass should be considered a viable mechanism for producing the observed disc thickening with time.

scholarly journals Energy equipartition between stellar and dark matter particles in cosmological simulations results in spurious growth of galaxy sizes

2019 ◽  
Vol 488 (1) ◽  
pp. L123-L128 ◽  
Author(s):  
Aaron D Ludlow ◽  
Joop Schaye ◽  
Matthieu Schaller ◽  
Jack Richings
Keyword(s):  
Dark Matter ◽  
Dark Matter Particle ◽  
Mass Resolution ◽  
Particle Mass ◽  
Cosmological Simulations ◽  
Massive Particles ◽  
Energy Equipartition ◽  
Mass Segregation ◽  
Baryonic Mass ◽  
The Impact

ABSTRACTThe impact of 2-body scattering on the innermost density profiles of dark matter haloes is well established. We use a suite of cosmological simulations and idealized numerical experiments to show that 2-body scattering is exacerbated in situations where there are two species of unequal mass. This is a consequence of mass segregation and reflects a flow of kinetic energy from the more to less massive particles. This has important implications for the interpretation of galaxy sizes in cosmological hydrodynamic simulations, which nearly always model stars with less massive particles than are used for the dark matter. We compare idealized models as well as simulations from the eagle project that differ only in the mass resolution of the dark matter component, but keep subgrid physics, baryonic mass resolution, and gravitational force softening fixed. If the dark matter particle mass exceeds the mass of stellar particles, then galaxy sizes – quantified by their projected half-mass radii, R50 – increase systematically with time until R50 exceeds a small fraction of the redshift-dependent mean interparticle separation, l (${\rm R_{50}} \gtrsim 0.05\times l$). Our conclusions should also apply to simulations that adopt different hydrodynamic solvers, subgrid physics, or adaptive softening, but in that case may need quantitative revision. Any simulation employing a stellar-to-dark matter particle mass ratio greater than unity will escalate spurious energy transfer from dark matter to baryons on small scales.

scholarly journals A Limit on the Warm Dark Matter Particle Mass from the Redshifted 21 cm Absorption Line

2018 ◽  
Vol 859 (2) ◽  
pp. L18 ◽  
Author(s):  
Mohammadtaher Safarzadeh ◽  
Evan Scannapieco ◽  
Arif Babul
Keyword(s):  
Dark Matter ◽  
Absorption Line ◽  
Dark Matter Particle ◽  
Particle Mass

scholarly journals Remnants of Galactic Subhalos and Their Impact on Indirect Dark-Matter Searches

Galaxies ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 65 ◽  
Author(s):  
Martin Stref ◽  
Thomas Lacroix ◽  
Julien Lavalle
Keyword(s):  
Dark Matter ◽  
Computer Simulations ◽  
Gamma Rays ◽  
Cold Dark Matter ◽  
Milky Way ◽  
Dark Matter Particle ◽  
Cosmic Ray ◽  
Tidal Disruption ◽  
Large Numbers ◽  
Boost Factor

Dark-matter subhalos, predicted in large numbers in the cold-dark-matter scenario, should have an impact on dark-matter-particle searches. Recent results show that tidal disruption of these objects in computer simulations is overefficient due to numerical artifacts and resolution effects. Accounting for these results, we re-estimated the subhalo abundance in the Milky Way using semianalytical techniques. In particular, we showed that the boost factor for gamma rays and cosmic-ray antiprotons is increased by roughly a factor of two.

scholarly journals CONSTRAINING THE WARM DARK MATTER PARTICLE MASS THROUGH ULTRA-DEEP UV LUMINOSITY FUNCTIONS ATz= 2

2016 ◽  
Vol 818 (1) ◽  
pp. 90 ◽  
Author(s):  
N. Menci ◽  
N. G. Sanchez ◽  
M. Castellano ◽  
A. Grazian
Keyword(s):  
Dark Matter ◽  
Dark Matter Particle ◽  
Particle Mass ◽  
Luminosity Functions ◽  
Deep Uv

scholarly journals High-resolution simulations of dark matter subhalo disruption in a Milky-Way-like tidal field

2020 ◽  
Vol 499 (1) ◽  
pp. 116-128
Author(s):  
Jeremy J Webb ◽  
Jo Bovy
Keyword(s):  
Dark Matter ◽  
High Resolution ◽  
Galaxy Formation ◽  
Cold Dark Matter ◽  
Milky Way ◽  
Initial Conditions ◽  
Dark Matter Particle ◽  
Dark Matter Halo ◽  
Isotropic Distribution ◽  
Stellar Component

ABSTRACT We compare the results of high-resolution simulations of individual dark matter subhaloes evolving in external tidal fields with and without baryonic bulge and disc components, where the average dark matter particle mass is three orders of magnitude smaller than cosmological zoom-in simulations of galaxy formation. The Via Lactea II simulation is used to setup our initial conditions and provides a basis for our simulations of subhaloes in a dark-matter-only tidal field, while an observationally motivated model for the Milky-Way is used for the tidal field that is comprised of a dark matter halo, a stellar disc, and a stellar bulge. Our simulations indicate that including stellar components in the tidal field results in the number of subhaloes in Milky-Way-like galaxies being only $65{{\ \rm per\ cent}}$ of what is predicted by Λ cold dark matter (ΛCDM). For subhaloes with small pericentres (rp ≲ 25 kpc), the subhalo abundance is reduced further to $40{{\ \rm per\ cent}}$, with the surviving subhaloes being less dense and having a tangentially anisotropic orbital distribution. Conversely, subhaloes with larger pericentres are minimally affected by the inclusion of a stellar component in the tidal field, with the total number of outer subhaloes $\approx 75{{\ \rm per\ cent}}$ of the ΛCDM prediction. The densities of outer subhaloes are comparable to predictions from ΛCDM, with the subhaloes having an isotropic distribution of orbits. These ratios are higher than those found in previous studies that include the effects baryonic matter, which are affected by spurious disruption caused by low resolution.

scholarly journals Determining the dark matter particle mass through antler topology processes at lepton colliders

2014 ◽  
Vol 90 (11) ◽  
Author(s):  
Neil D. Christensen ◽  
Tao Han ◽  
Zhuoni Qian ◽  
Josh Sayre ◽  
Jeonghyeon Song ◽  
...  
Keyword(s):  
Dark Matter ◽  
Dark Matter Particle ◽  
Particle Mass ◽  
Lepton Colliders
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