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Title: Dark matter direct detection signals inferred from a cosmological N-body simulation with baryons

Abstract

We extract at redshift z = 0 a Milky Way sized object including gas, stars and dark matter (DM) from a recent, high-resolution cosmological N-body simulation with baryons. Its resolution is sufficient to witness the formation of a rotating disk and bulge at the center of the halo potential, therefore providing a realistic description of the birth and the evolution of galactic structures in the ΛCDM cosmology paradigm. The phase-space structure of the central galaxy reveals that, throughout a thick region, the dark halo is co-rotating on average with the stellar disk. At the Earth's location, the rotating component, sometimes called dark disk in the literature, is characterized by a minimum lag velocity v{sub lag} ≅ 75 km/s, in which case it contributes to around 25% of the total DM local density, whose value is ρ{sub DM} ≅ 0.37GeV/cm{sup 3}. The velocity distributions also show strong deviations from pure Gaussian and Maxwellian distributions, with a sharper drop of the high velocity tail. We give a detailed study of the impact of these features on the predictions for DM signals in direct detection experiments. In particular, the question of whether the modulation signal observed by DAMA is or is not excludedmore » by limits set by other experiments (CDMS, XENON and CRESST...) is re-analyzed and compared to the case of a standard Maxwellian halo. We consider spin-independent interactions for both the elastic and the inelastic scattering scenarios. For the first time, we calculate the allowed regions for DAMA and the exclusion limits of other null experiments directly from the velocity distributions found in the simulation. We then compare these results with the predictions of various analytical distributions. We find that the compatibility between DAMA and the other experiments is improved. In the elastic scenario, the DAMA modulation signal is slightly enhanced in the so-called channeling region, as a result of several effects that include a departure from a Maxwellian distribution and anisotropies in the velocity dispersions due to the dark disk. For the inelastic scenario, the improvement of the fit is mainly attributable to the departure from a Maxwellian distribution at high velocity. It is correctly modeled by a generalized Maxwellian distribution with a parameter α ≅ 1.95, or by a Tsallis distribution with q ≅ 0.75.« less

Authors:
 [1]; ;  [2]
  1. Service de Physique Théorique, Université Libre de Bruxelles, CP225, Bld du Triomphe, 1050 Brussels (Belgium)
  2. Laboratoire d'Astrophysique de Marseille, Observatoire Astronomique de Marseille Provence, CNRS/Université de Provence, 38 rue Joliot Curie, 13388 Marseille (France)
Publication Date:
OSTI Identifier:
22272978
Resource Type:
Journal Article
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2010; Journal Issue: 02; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANISOTROPY; ASTROPHYSICS; BARYONS; CHANNELING; COMPARATIVE EVALUATIONS; COSMOLOGICAL CONSTANT; COSMOLOGY; ELASTIC SCATTERING; INELASTIC SCATTERING; MILKY WAY; MODULATION; NONLUMINOUS MATTER; PHASE SPACE; POTENTIALS; RED SHIFT; SPIN

Citation Formats

Ling, F. -S., Nezri, E., Athanassoula, E., and Teyssier, R., E-mail: fling@ulb.ac.be, E-mail: Emmanuel.Nezri@oamp.fr, E-mail: lia@oamp.fr, E-mail: romain.teyssier@gmail.com. Dark matter direct detection signals inferred from a cosmological N-body simulation with baryons. United States: N. p., 2010. Web. doi:10.1088/1475-7516/2010/02/012.
Ling, F. -S., Nezri, E., Athanassoula, E., & Teyssier, R., E-mail: fling@ulb.ac.be, E-mail: Emmanuel.Nezri@oamp.fr, E-mail: lia@oamp.fr, E-mail: romain.teyssier@gmail.com. Dark matter direct detection signals inferred from a cosmological N-body simulation with baryons. United States. https://doi.org/10.1088/1475-7516/2010/02/012
Ling, F. -S., Nezri, E., Athanassoula, E., and Teyssier, R., E-mail: fling@ulb.ac.be, E-mail: Emmanuel.Nezri@oamp.fr, E-mail: lia@oamp.fr, E-mail: romain.teyssier@gmail.com. 2010. "Dark matter direct detection signals inferred from a cosmological N-body simulation with baryons". United States. https://doi.org/10.1088/1475-7516/2010/02/012.
@article{osti_22272978,
title = {Dark matter direct detection signals inferred from a cosmological N-body simulation with baryons},
author = {Ling, F. -S. and Nezri, E. and Athanassoula, E. and Teyssier, R., E-mail: fling@ulb.ac.be, E-mail: Emmanuel.Nezri@oamp.fr, E-mail: lia@oamp.fr, E-mail: romain.teyssier@gmail.com},
abstractNote = {We extract at redshift z = 0 a Milky Way sized object including gas, stars and dark matter (DM) from a recent, high-resolution cosmological N-body simulation with baryons. Its resolution is sufficient to witness the formation of a rotating disk and bulge at the center of the halo potential, therefore providing a realistic description of the birth and the evolution of galactic structures in the ΛCDM cosmology paradigm. The phase-space structure of the central galaxy reveals that, throughout a thick region, the dark halo is co-rotating on average with the stellar disk. At the Earth's location, the rotating component, sometimes called dark disk in the literature, is characterized by a minimum lag velocity v{sub lag} ≅ 75 km/s, in which case it contributes to around 25% of the total DM local density, whose value is ρ{sub DM} ≅ 0.37GeV/cm{sup 3}. The velocity distributions also show strong deviations from pure Gaussian and Maxwellian distributions, with a sharper drop of the high velocity tail. We give a detailed study of the impact of these features on the predictions for DM signals in direct detection experiments. In particular, the question of whether the modulation signal observed by DAMA is or is not excluded by limits set by other experiments (CDMS, XENON and CRESST...) is re-analyzed and compared to the case of a standard Maxwellian halo. We consider spin-independent interactions for both the elastic and the inelastic scattering scenarios. For the first time, we calculate the allowed regions for DAMA and the exclusion limits of other null experiments directly from the velocity distributions found in the simulation. We then compare these results with the predictions of various analytical distributions. We find that the compatibility between DAMA and the other experiments is improved. In the elastic scenario, the DAMA modulation signal is slightly enhanced in the so-called channeling region, as a result of several effects that include a departure from a Maxwellian distribution and anisotropies in the velocity dispersions due to the dark disk. For the inelastic scenario, the improvement of the fit is mainly attributable to the departure from a Maxwellian distribution at high velocity. It is correctly modeled by a generalized Maxwellian distribution with a parameter α ≅ 1.95, or by a Tsallis distribution with q ≅ 0.75.},
doi = {10.1088/1475-7516/2010/02/012},
url = {https://www.osti.gov/biblio/22272978}, journal = {Journal of Cosmology and Astroparticle Physics},
issn = {1475-7516},
number = 02,
volume = 2010,
place = {United States},
year = {Mon Feb 01 00:00:00 EST 2010},
month = {Mon Feb 01 00:00:00 EST 2010}
}