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Precision reconstruction of the cold dark matter-neutrino relative velocity fromN-body simulations

Inman, D, Emberson, JD, Pen, U-L, Farchi, A, Yu, H-R and Harnois-Déraps, J (2015) Precision reconstruction of the cold dark matter-neutrino relative velocity fromN-body simulations. Physical Review D, 92 (2). ISSN 1550-7998

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Abstract

Discovering the mass of neutrinos is a principle goal in high energy physics and cosmology. In addition to cosmological measurements based on two-point statistics, the neutrino mass can also be estimated by observations of neutrino wakes resulting from the relative motion between cold dark matter (CDM) and neutrinos. Such a detection relies on an accurate reconstruction of the CDM-neutrino relative velocity which is affected by nonlinear structure growth and galaxy bias. We investigate our ability to reconstruct this relative velocity using large N-body simulations where we evolve neutrinos as distinct particles alongside the CDM. We find that the CDM velocity power spectrum is overpredicted by linear theory whereas the neutrino velocity power spectrum is underpredicted. The magnitude of the relative velocity observed in the simulations is found to be lower than what is predicted in linear theory. Since neither the CDM nor the neutrino velocity fields are directly observable from galaxy or 21 cm surveys, we test the accuracy of a reconstruction algorithm based on halo density fields and linear theory. Assuming prior knowledge of the halo bias, we find that the reconstructed relative velocities are highly correlated with the simulated ones with correlation coefficients of 0.94, 0.93, 0.92 and 0.88 for neutrinos of mass 0.05, 0.1, 0.2 and 0.4 eV. We confirm that the relative velocity field reconstructed from large scale structure observations such as galaxy or 21 cm surveys can be accurate in direction and, with appropriate scaling, magnitude.

Item Type: Article
Additional Information: Derek Inman, J. D. Emberson, Ue-Li Pen, Alban Farchi, Hao-Ran Yu, and Joachim Harnois-Déraps. Precision reconstruction of the cold dark matter-neutrino relative velocity from N-body simulations. Phys. Rev. D 92, 023502 – Published 2 July 2015
Uncontrolled Keywords: 0201 Astronomical and Space Sciences, 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics, 0206 Quantum Physics
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: American Physical Society (APS)
Date Deposited: 24 Jul 2020 10:49
Last Modified: 24 Jul 2020 11:00
DOI or Identification number: 10.1103/physrevd.92.023502
URI: http://researchonline.ljmu.ac.uk/id/eprint/13367

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