Article

The Non-Linear Matter Power Spectrum in Warm Dark Matter Cosmologies

INAF -Osservatorio Astronomico di Trieste, I-34131, Trieste, Italy; INFN/National Institute for Nuclear Physics, I-34127, Trieste, Italy; University Observatory Munich, Ludwig-Maximilian University, 81679, Munich, Germany; Germany Excellence Cluster Universe, 85748, Munich, Garching, Germany; Max-Planck-Institut for Extraterrestrial Physics, 85748, Garching, Germany
Monthly Notices of the Royal Astronomical Society (Impact Factor: 5.52). 07/2011; 000. DOI: 10.1111/j.1365-2966.2011.19910.x
Source: arXiv

ABSTRACT We investigate the non-linear evolution of the matter power spectrum by using
a large set of high-resolution N-body/hydrodynamic simulations. The linear
matter power in the initial conditions is consistently modified to accommodate
warm dark matter particles which induce a small scale cut-off in the power as
compared to standard cold dark matter scenarios. The impact of such thermal
relics is addressed at small scales with k > 1 h/Mpc and at z < 5, which are
particularly important for the next generation of Lyman-alpha forest, weak
lensing and galaxy clustering surveys. We quantify the mass and redshift
dependence of the warm dark matter non-linear matter power and we provide a
fitting formula which is accurate at the ~2% level below z=3 and for masses
m_wdm > 0.5 keV. The role of baryonic physics (cooling, star formation and
feedback recipes) on the warm dark matter induced suppression is also
quantified. Furthermore, we compare our findings with the halo model and show
their impact on the cosmic shear power spectra.

0 Bookmarks
 · 
91 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We review the status of sterile neutrino dark matter and discuss astrophysical and cosmological bounds on its properties as well as future prospects for its experimental searches. We argue that if sterile neutrinos are the dominant fraction of dark matter, detecting an astrophysical signal from their decay (the so-called 'indirect detection') may be the only way to identify these particles experimentally. However, it may be possible to check the dark matter origin of the observed signal unambiguously using its characteristic properties and/or using synergy with accelerator experiments, searching for other sterile neutrinos, responsible for neutrino flavor oscillations. We argue that to fully explore this possibility a dedicated cosmic mission - an X-ray spectrometer - is needed.
    Physics of the Dark Universe. 06/2013; 1(s 1–2).
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present updated constraints on the free-streaming of warm dark matter (WDM) particles derived from an analysis of the Lya flux power spectrum measured from high-resolution spectra of 25 z > 4 quasars obtained with the Keck High Resolution Echelle Spectrometer (HIRES) and the Magellan Inamori Kyocera Echelle (MIKE) spectrograph. We utilize a new suite of high-resolution hydrodynamical simulations that explore WDM masses of 1, 2 and 4 keV (assuming the WDM consists of thermal relics), along with different physically motivated thermal histories. We carefully address different sources of systematic error that may affect our final results and perform an analysis of the Lya flux power with conservative error estimates. By using a method that samples the multi-dimensional astrophysical and cosmological parameter space, we obtain a lower limit mwdm > 3.3 keV (2sigma) for warm dark matter particles in the form of early decoupled thermal relics. Adding the Sloan Digital Sky Survey (SDSS) Lya flux power spectrum does not improve this limit. Thermal relics of masses 1 keV, 2 keV and 2.5 keV are disfavoured by the data at about the 9sigma, 4sigma and 3sigma C.L., respectively. Our analysis disfavours WDM models where there is a suppression in the linear matter power spectrum at (non-linear) scales corresponding to k=10h/Mpc which deviates more than 10% from a LCDM model. Given this limit, the corresponding "free-streaming mass" below which the mass function may be suppressed is 2x10^8 Msun/h. There is thus very little room for a contribution of the free-streaming of WDM to the solution of what has been termed the small scale crisis of cold dark matter.
    Physical review D: Particles and fields 06/2013; 88(4).
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We re-evaluate the extragalactic gamma-ray flux prediction from dark matter annihilation in the approach of integrating over the nonlinear matter power spectrum, extrapolated to the free-streaming scale. We provide an estimate of the uncertainty based entirely on available N-body simulation results and minimal theoretical assumptions. We illustrate how an improvement in the simulation resolution, exemplified by the comparison between the Millennium and Millennium II simulations, affects our estimate of the flux uncertainty and we provide a "best guess" value for the flux multiplier, based on the assumption of stable clustering for the dark matter perturbations described as a collision-less fluid. We achieve results comparable to traditional Halo Model calculations, but with a much simpler procedure and a more general approach, as it relies only on one, directly measurable quantity. In addition we discuss the extension of our calculation to include baryonic effects as modeled in hydrodynamical cosmological simulations and other possible sources of uncertainty that would in turn affect indirect dark matter signals. Upper limit on the integrated power spectrum from supernovae lensing magnification are also derived and compared with theoretical expectations.
    01/2014; 441(3).

Full-text (3 Sources)

View
41 Downloads
Available from
Jun 2, 2014