Massimo Meneghetti

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Aims. We investigate how ellipticity, asymmetries and substructures separately affect the ability of galaxy clusters to produce strong lensing events, i.e. gravitational arcs, and how they influence the arc morphologies and fluxes. This is important for those studies aiming, for example, at constraining cosmological parameters from statistical lensing, or(More)
We compare the statistical properties of giant gravitationally lensed arcs produced in matched simulated and observed cluster samples. The observed sample consists of 10 X-ray selected clusters at redshifts z c ∼ 0.2 imaged with HST by Smith et al.. The simulated dataset is produced by lensing the Hubble Deep Field, which serves as a background source(More)
Previous studies of strong gravitational lensing by galaxy clusters have neglected the potential impact of the intra-cluster gas. Here, we compare simulations of strong cluster lensing including gas physics at increasing levels of complexity, i.e. with adiabatic, cooling, star-forming, feedback-receiving, and thermally conducting gas, along with different(More)
We present the results of a set of numerical simulations evaluating the effect of cluster galaxies on arc statistics. We perform a first set of gravitational lensing simulations using three independent projections for each of nine different galaxy clusters obtained from N-body simulations. The simulated clusters consist of dark matter only. We add a(More)
The circulating immunoreactive atrial natriuretic peptide (C-terminal; alpha-ANP) increases during exercise to become suppressed in the first hours of the recovery. The response of the N-terminal ANP fragments to acute exercise is not known while proANP (31-67) appears to be elevated with chronic exercise. We evaluated the plasma concentrations of the(More)
Re-ionization of the intergalactic medium occurred in the early Universe at redshift z ≈ 6-11, following the formation of the first generation of stars. Those young galaxies (where the bulk of stars formed) at a cosmic age of less than about 500 million years (z ≲ 10) remain largely unexplored because they are at or beyond the sensitivity limits of existing(More)
Using the results of a high-resolution, cosmological hydrodynamical re-simulation of a supercluster-like region we investigate the physical properties of the gas located along the filaments and bridges which constitute the so-called cosmic web. First we analyze the main characteristics of the density, temperature and velocity fields, which have quite(More)
We make an exploratory study of how well dark energy models can be constrained using lensed arcs at different redshifts behind cluster lenses. Arcs trace the critical curves of clusters , and the growth of critical curves with source redshift is sensitive to the dark-energy equation of state. Using analytical models and numerically simulated clusters, we(More)
Aims. We discuss the applicability and reliability of the shapelet technique for scientific image analysis. Methods. We quantify the effects of non-orthogonality of sampled shapelet basis functions and misestimation of shapelet parameters. We perform the shapelet decomposition on artificial galaxy images with underlying shapelet models and galaxy images(More)
We construct a linear filter optimised for detecting dark-matter halos in weak-lensing data. The filter assumes a mean radial profile of the halo shear pattern and modifies that shape by the noise power spectrum. Aiming at separating dark-matter halos from spurious peaks caused by large-scale structure lensing, we model the noise as being composed of weak(More)