Friday. The meeting at Leiden was not nearly as bad as I expected it to be. Konrad did a great job, as did Peter and Thomas and even Ed. Met Yannick for the first time, I like him.
1111.0290
Cosmological evolution of warm dark matter fluctuations I: Efficient computational framework with Volterra integral equations
de Vega, Sanchez
* Boltzmann-Vlasov equations: Boltzmann: statistical distribution of one particle in rarified gas (non-equilibrium statistical mechanics). Vlasov: differential equation describing time evolution of the distribution function of plasma consisting of charged particles with long-range (e.g., Coulomb) interaction (Boltzmann is standard kinetic approach).
* Volterra equations: special type of integral equations where one limit of integration is variable, there are first and second kinds; application in the study of viscoelastic materials.
Study complete cosmological evolution of DM density fluctuations for particles that decoupled being ultrarelativistic during the RD era (case of keV scale WDM). Collisionless and linearized B-V equations for WDM and neutrinos in the presence of photons and coupled to the linearized Einstein equations are studied in detail in the presence of anisotropic stress with the Newtonian potential generically different from the spatial curvature perturbations. Recast full system of B-V equations for DM and neutrinos into a system of coupled Volterra integral equations. Generalizes the so-called Gilbert integral equation which is only valid for NR particles in the MD era, into both RD and MD for relativistic and NR particles. Reduce system of four Volterra integral equations for the density and anisotropic stress fluctuations of DM and neutrinos into a system of only two coupled Volterra equations. The kernels and inhomogeneities in these equations are explicitly given functions. Combine B-V equations and the linearized Einstein equations constrain the initial conditions on the distribution functions and gravitational potentials [IC constraints come from coupling diff-eqs?]. In the absence of neutrinos, the anisotropic stress vanishes and the Volterra-type equations reduce to a single integral equation [is this the case of reducing to CDM?]. These Volterra integral equations provide a useful and precise framework to compute the primordial WDM fluctuations over a wide range of scales including small scales up to k~1/5 kpc.
1111.0300
Cosmological evolution of WDM fluctuations II: solution from small to large scales and keV sterile neutrinos
deVega, Sanchez
Solve the WDM cosmo evolution by solving the Volterra integral equations of paper I. Derive exact analytic solution for the density fluctuations and gravitatonal potential at zero wavenumber [isn't this just the average density?]. Compute density contrast: at fixed a, density contrast grows for k<k_c and decreases for k>k_c (k_c~1.6Mpc). The density contrast depends on k & a, exhibit a self-similar behavior in product of k a. For small k, the contrast gently appropaches analytic solution for k=0. for k>1/(60kpc) contrast exhibits oscillations since hte RD era which become stronger as k grows. compute transfer function of the density contrast for thermal fermions and for sterile neutrinos in two models. Transfer function grows with k for mall k, and then decreases after reaching a maximum at k=k_c reflecting the time evoultion of the density contrast. Integral kernels in the Volterra equations are nonlocal in time and their falloff determine the memory of the past evolution since decoupling. This falloff is faster when DM decouples at equilibrium than when it decouples out of equilibrium. Although neutrinos and photons can be neglected in the MD era, they contribute in the MD era through their memory from the RD era.
1111.0320
Constraining DM signal from a combined analysis of MW satellites with the Fermi-LAT
Garde, Conrad, Cohen-Tanugi, Fermi-LAT collaboration, Kaplinghat, Martinez
Promising targets for DM searches in the gamma-ray band: dwarf spheroidals (large mass-to-light ratio, low astrophysical background). Apply joint likelihood analysis to apply constraints in case of no detection; present results from a combined analysis of 10 dwarf spheroidal galaxies using Fermi-LAT data. Different annihilation channels analyzed and uncertainties from astrophysical properties have been taken into account.
Cosmological evolution of WDM fluctuations II: solution from small to large scales and keV sterile neutrinos
deVega, Sanchez
Solve the WDM cosmo evolution by solving the Volterra integral equations of paper I. Derive exact analytic solution for the density fluctuations and gravitatonal potential at zero wavenumber [isn't this just the average density?]. Compute density contrast: at fixed a, density contrast grows for k<k_c and decreases for k>k_c (k_c~1.6Mpc). The density contrast depends on k & a, exhibit a self-similar behavior in product of k a. For small k, the contrast gently appropaches analytic solution for k=0. for k>1/(60kpc) contrast exhibits oscillations since hte RD era which become stronger as k grows. compute transfer function of the density contrast for thermal fermions and for sterile neutrinos in two models. Transfer function grows with k for mall k, and then decreases after reaching a maximum at k=k_c reflecting the time evoultion of the density contrast. Integral kernels in the Volterra equations are nonlocal in time and their falloff determine the memory of the past evolution since decoupling. This falloff is faster when DM decouples at equilibrium than when it decouples out of equilibrium. Although neutrinos and photons can be neglected in the MD era, they contribute in the MD era through their memory from the RD era.
1111.0320
Constraining DM signal from a combined analysis of MW satellites with the Fermi-LAT
Garde, Conrad, Cohen-Tanugi, Fermi-LAT collaboration, Kaplinghat, Martinez
Promising targets for DM searches in the gamma-ray band: dwarf spheroidals (large mass-to-light ratio, low astrophysical background). Apply joint likelihood analysis to apply constraints in case of no detection; present results from a combined analysis of 10 dwarf spheroidal galaxies using Fermi-LAT data. Different annihilation channels analyzed and uncertainties from astrophysical properties have been taken into account.
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