The importance and signatures of cosmic tau-(anti)neutrinos have been studied for upward-and downward-going µ − + µ + and hadronic shower event rates relevant for present and future underground water or ice detectors, utilizing the unique and reliable ultrasmall-x predictions of the dynamical (radiative) parton model. The upward-going µ − + µ + event rates calculated just from cosmic ν µ + νµ fluxes are sizeably enhanced by taking into account cosmic ν τ + ντ fluxes and their associated τ − + τ + fluxes as well. The coupled transport equations for the upward-going (−) ν τ flux traversing the Earth imply an enhancement of the attenuated and regenerated (−) ν τ flux typically around 10 4 − 10 5 GeV with respect to the initial cosmic flux.This enhancement turns out to be smaller than obtained so far, in particular for flatter initial cosmic fluxes behaving like E −1 ν . Downward-going µ − +µ + events and in particular the background-free and unique hadronic 'double bang' and 'lollipop' events allow to test downward-going cosmic ν τ + ντ fluxes up to about 10 9 GeV.

Context. Weak gravitational lensing is one of the most promising tools to investigate the equation-of-state of dark energy. In order to obtain reliable parameter estimations for current and future experiments, a good theoretical understanding of dark matter clustering is essential. Of particular interest is the statistical precision to which weak lensing observables, such as cosmic shear correlation functions, can be determined. Aims. We construct a fitting formula for the non-Gaussian part of the covariance of the lensing power spectrum. The Gaussian contribution to the covariance, which is proportional to the lensing power spectrum squared, and optionally shape noise can be included easily by adding their contributions. Methods. Starting from a canonical estimator for the dimensionless lensing power spectrum, we model first the covariance in the halo model approach including all four halo terms for one fiducial cosmology and then fit two polynomials to the expression found. On large scales, we use a first-order polynomial in the wave-numbers and dimensionless power spectra that goes asymptotically towards 1.1 C pt for → 0, i.e., the result for the non-Gaussian part of the covariance using tree-level perturbation theory. On the other hand, for small scales we employ a second-order polynomial in the dimensionless power spectra for the fit. Results. We obtain a fitting formula for the non-Gaussian contribution of the convergence power spectrum covariance that is accurate to 10% for the off-diagonal elements, and to 5% for the diagonal elements, in the range 50 < ∼ < ∼ 5000 and can be used for single source redshifts z s ∈ [0.5, 2.0] in WMAP5-like cosmologies.

Context. Halo models and halo occupation distributions (HODs) are important tools to model the distribution of galaxies and matter. Aims. We present and assess a new method for constraining the parameters of HODs using the mean gravitational lensing shear around galaxy pairs, so-called galaxy-galaxy-galaxy lensing (G3L). In contrast to galaxy-galaxy lensing, G3L is also sensitive to the correlations between the per-halo numbers of galaxies from different populations. We employed our G3L halo model to probe these correlations and test the default hypothesis that they are negligible. Methods. We derived a halo model for G3L and validated it with realistic mock data from the Millennium Simulation and a semianalytic galaxy model. Then, we analysed public data from the Kilo-Degree Survey (KiDS), the VISTA Infrared Kilo-Degree Galaxy Survey (VIKING) and data from the Galaxy And Mass Assembly Survey (GAMA) to infer the HODs of galaxies at z < 0.5 in five different stellar mass bins between 10 8.5 h −2 M and 10 11.5 h −2 M and two colours (red and blue), as well as correlations between satellite numbers. Results. The analysis accurately recovers the true HODs in the simulated data for all galaxy samples within the 68% credibility range. The model best fits agree with the observed G3L signal on the 95% confidence level. The inferred HODs vary significantly with colour and stellar mass. In particular, red galaxies prefer more massive halos 10 12 M , while blue galaxies are present in halos 10 11 M . There is strong evidence (> 3σ) for a high correlation, increasing with halo mass, between the numbers of red and blue satellites and between galaxies with stellar masses below 10 10 M . Conclusions. Our G3L halo model accurately constrains galaxy HODs for lensing surveys of up to 10 3 deg 2 and redshift below 0.5 probed here. Analyses of future surveys may need to include non-Poisson variances of satellite numbers or a revised model for central galaxies. Correlations between satellite numbers are ubiquitous between various galaxy samples and are relevant for halos with masses 10 13 M , that is, of galaxy-group scale and more massive. Possible causes of these correlations are the selection of similar galaxies in different samples, the survey flux limit, or physical mechanisms such as a fixed ratio between the satellite numbers of distinct populations. The decorrelation for halos with smaller masses is probably an effect of shot noise by low-occupancy halos. The inferred HODs can be used to complement galaxy-galaxy lensing or galaxy-clustering HOD studies or as input to cosmological analyses and improved mock galaxy catalogues.