The VST Optical Imaging of the CDFS and ES1 Fields (VOICE) Survey is a Guaranteed Time program carried out with the ESO/VST telescope to provide deep optical imaging over two 4 deg\(^2\) patches of ...the sky centred on the CDFS and ES1 pointings. We present the cosmic shear measurement over the 4 deg\(^2\) covering the CDFS region in the \(r\)-band using LensFit. Each of the four tiles of 1 deg\(^2\) has more than one hundred exposures, of which more than 50 exposures passed a series of image quality selection criteria for weak lensing study. The \(5\sigma\) limiting magnitude in \(r\)- band is 26.1 for point sources, which is \(\sim\)1 mag deeper than other weak lensing survey in the literature (e.g. the Kilo Degree Survey, KiDS, at VST). The photometric redshifts are estimated using the VOICE \(u,g,r,i\) together with near-infrared VIDEO data \(Y,J,H,K_s\). The mean redshift of the shear catalogue is 0.87, considering the shear weight. The effective galaxy number density is 16.35 gal/arcmin\(^2\), which is nearly twice the one of KiDS. The performance of LensFit on such a deep dataset was calibrated using VOICE-like mock image simulations. Furthermore, we have analyzed the reliability of the shear catalogue by calculating the star-galaxy cross-correlations, the tomographic shear correlations of two redshift bins and the contaminations of the blended galaxies. As a further sanity check, we have constrained cosmological parameters by exploring the parameter space with Population Monte Carlo sampling. For a flat \(\Lambda\)CDM model we have obtained \(\Sigma_8\) = \(\sigma_8(\Omega_m/0.3)^{0.5}\) = \(0.68^{+0.11}_{-0.15}\).
The VST Optical Imaging of the CDFS and ES1 Fields (VOICE) Survey is proposed to obtain deep optical \(ugri\) imaging of the CDFS and ES1 fields using the VLT Survey Telescope (VST). At present, the ...observations for the CDFS field have been completed, and comprise in total about 4.9 deg\(^2\) down to $r_\mathrm{AB}$$\sim\(26 mag. In the companion paper by Fu et al. (2018), we present the weak lensing shear measurements for \)r\(-band images with seeing \)\le\( 0.9 arcsec. In this paper, we perform image simulations to calibrate possible biases of the measured shear signals. Statistically, the properties of the simulated point spread function (PSF) and galaxies show good agreements with those of observations. The multiplicative bias is calibrated to reach an accuracy of \)\sim\(3.0%. We study the bias sensitivities to the undetected faint galaxies and to the neighboring galaxies. We find that undetected galaxies contribute to the multiplicative bias at the level of \)\sim\(0.3%. Further analysis shows that galaxies with lower signal-to-noise ratio (SNR) are impacted more significantly because the undetected galaxies skew the background noise distribution. For the neighboring galaxies, we find that although most have been rejected in the shape measurement procedure, about one third of them still remain in the final shear sample. They show a larger ellipticity dispersion and contribute to \)\sim$0.2% of the multiplicative bias. Such a bias can be removed by further eliminating these neighboring galaxies. But the effective number density of the galaxies can be reduced considerably. Therefore efficient methods should be developed for future weak lensing deep surveys.
A dark-matter-only Horizon Project simulation is used to investigate the environment- and redshift- dependence of accretion onto both halos and subhalos. These objects grow in the simulation via ...mergers and via accretion of diffuse non-halo material, and we measure the combined signal from these two modes of accretion. It is found that the halo accretion rate varies less strongly with redshift than predicted by the Extended Press-Schechter (EPS) formalism and is dominated by minor-merger and diffuse accretion events at z=0, for all halos. These latter growth mechanisms may be able to drive the radio-mode feedback hypothesised for recent galaxy-formation models, and have both the correct accretion rate and form of cosmological evolution. The low redshift subhalo accretors in the simulation form a mass-selected subsample safely above the mass resolution limit that reside in the outer regions of their host, with ~70% beyond their host's virial radius, where they are probably not being significantly stripped of mass. These subhalos accrete, on average, at higher rates than halos at low redshift and we argue that this is due to their enhanced clustering at small scales. At cluster scales, the mass accretion rate onto halos and subhalos at low redshift is found to be only weakly dependent on environment and we confirm that at z~2 halos accrete independently of their environment at all scales, as reported by other authors. By comparing our results with an observational study of black hole growth, we support previous suggestions that at z>1, dark matter halos and their associated central black holes grew coevally, but show that by the present day, dark matter halos could be accreting at fractional rates that are up to a factor 3-4 higher than their associated black holes.
The validity of psychological profiling was examined by manipulating the amount of case and profiling information that was provided to introductory psychology students (N = 120). Overall, ...participants who viewed a homicide case were unable to create more accurate profiles than those participants who did not view a homicide case. However, the manipulation of profiling information did have an effect on the participant's ability to create accurate profiles. Participants who were given base rates and a sample profile or base rates only were able to create more accurate profiles when compared to participants who were given no extra information. These results may suggest that criminal profilers may simply be using published base rates to create profiles rather than special skills or years of experience as they claim to do.
This paper provides the first known exact general solutions of Painlevé's sixth equation (PVI) and the exact general solutions of the Navier Stokes equations and Prandtl's boundary layer equations.
An Adaptive Mesh Refinement cosmological resimulation is analyzed in order to test whether filamentary flows of cold gas are responsible for the build-up of angular momentum within a Milky Way like ...disk at z>=3. A set of algorithms is presented that takes advantage of the high spatial resolution of the simulation (12 pc) to identify: (i) the central gas disk and its plane of orientation; (ii) the complex individual filament trajectories that connect to the disk, and; (iii) the infalling satellites. The results show that two filaments at z>5.5, which later merge to form a single filament at z<4, drive the angular momentum and mass budget of the disk throughout its evolution, whereas luminous satellite mergers make negligible fractional contributions. Combined with the ubiquitous presence of such filaments in all large-scale cosmological simulations that include hydrodynamics, these findings provide strong quantitative evidence that the growth of thin disks in haloes with masses below 10^{12} M_{sun}, which host the vast majority of galaxies, is supported via inflowing streams of cold gas at intermediate and high redshifts.
The $F$-pure threshold is a numerical invariant of prime characteristic
singularities, that constitutes an analogue of the log canonical thresholds in
characteristic zero. We compute the $F$-pure ...thresholds of determinantal
ideals, i.e., of ideals generated by the minors of a generic matrix.
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