Article

# Halo concentration and the dark matter power spectrum

Department of Physics, Jadwin Hall, Princeton University, Princeton, NJ 08544, USA

Monthly Notices of the Royal Astronomical Society (Impact Factor: 5.52). 03/2003; 340(4):1199 - 1204. DOI: 10.1046/j.1365-8711.2003.06372.x Source: arXiv

- [Show abstract] [Hide abstract]

**ABSTRACT:**In this paper I generalize the halo model for the clustering of dark matter in order to produce the power spectra of the two main baryonic matter components in the Universe: stars and hot gas. As a natural extension, this can be also used to describe the clustering of all mass. According to the design of the halo model, the large-scale power spectra of the various matter components are physically connected with the distribution of each component within bound structures and thus, ultimately, with the complete set of physical processes that drive the formation of galaxies and galaxy clusters. Besides being practical for cosmological and parametric studies, the semi-analytic model presented here has also other advantages. Most importantly, it allows one to understand on physical ground what is the relative contribution of each matter component to the total clustering of mass as a function of scale, and thus it opens an interesting new window to infer the distribution of baryons through high precision cosmic shear measurements. This is particularly relevant for future wide-field photometric surveys such as Euclid. In this work the concept of the model and its uncertainties are illustrated in detail, while in a companion paper we use a set of numerical hydrodynamic simulations to show a practical application and to investigate where the model itself needs to be improved.Journal of Cosmology and Astroparticle Physics 01/2014; 2014(04). · 6.04 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**We study how parameter error forecasts for tomographic cosmic shear observations are affected by sky coverage, density of source galaxies, inclusion of cosmic microwave background experiments, simultaneous fitting of nondark energy parameters, and the parametrization of the history of the dark energy equation-of-state parameter w(z). We find tomographic shear-shear power spectra on large angular scales (l<1000) inferred from all-sky observations, in combination with Planck, can achieve σ(w0)=0.06 and σ(wa)=0.09 assuming the equation-of-state parameter is given by w(z)=w0+wa[1-a(z)] and that nine other matter content and primordial power spectrum parameters are simultaneously fit. Taking parameters other than w0, wa, and Ωm to be completely fixed by the cosmic microwave background (CMB), we find errors on w0 and wa that are only 10% and 30% better, respectively, justifying this common simplifying assumption. We also study “dark energy tomography” : reconstruction of w(z) assumed to be constant within each of five independent w bins. With smaller-scale information included by use of the Jain and Taylor ratio statistic, we find σ(wi)<0.1 for all five w bins and σ(wi)<0.02 for both w bins at z<0.8. Finally, addition of cosmic shear can also reduce errors on quantities already determined well by the CMB. We find the sum of neutrino masses can be determined to ±0.013 eV and that the primordial power spectrum power-law index, nS, as well as dns/dlnk, can be determined more than a factor of 2 better than by Planck alone. These improvements may be highly valuable since the lower bound on the sum of neutrino masses is 0.06 eV as inferred from atmospheric neutrino oscillations, and slow-roll models of inflation predict nonzero dnS/dlnk at the forecasted error levels when |nS-1|>0.04.Physical Review D 01/2004; 70(6). · 4.69 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**We consider constraints on a phenomenological dark-matter model consisting of two nearly degenerate particle species using observed properties of the Milky Way satellite galaxy population. The two parameters of this model, assuming the particle masses are ≳ GeV, are vk, the recoil speed of the daughter particle, and τ, the lifetime of the parent particle. The satellite constraint that spans the widest range of vk is the number of satellites that have a mass within 300 pc M300>5×106M⊙, although constraints based on M300 in the classical dwarfs and the overall velocity function are competitive for vk≳50 km s-1. In general, we find that τ≲30 Gyr is ruled out for 20 km s-1≲vk≲200 km s-1, although we find that the limits on τ for fixed vk can change by a factor of ∼3 depending on the star-formation histories of the satellites. We advocate using the distribution of M300 in Milky Way satellites, determined by next-generation all-sky surveys and follow-up spectroscopy, as a probe of dark-matter physics.Physical review D: Particles and fields 12/2010; 82(12).

Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.