Ikerbasque

About: Ikerbasque is a other organization based out in Bilbao, Spain. It is known for research contribution in the topics: Graphene & Quantum. The organization has 713 authors who have published 7967 publications receiving 231990 citations. The organization is also known as: Basque Foundation for Science.

Clash: weak-lensing shear-and-magnification analysis of 20 galaxy clusters*

Abstract: We present a joint shear-and-magnification weak-lensing analysis of a sample of 16 X-ray-regular and 4 high-magnification galaxy clusters at 0.19 ≾ z ≾ 0.69 selected from the Cluster Lensing And Supernova survey with Hubble (CLASH). Our analysis uses wide-field multi-color imaging, taken primarily with Suprime-Cam on the Subaru Telescope. From a stacked-shear-only analysis of the X-ray-selected subsample, we detect the ensemble-averaged lensing signal with a total signal-to-noise ratio of ≃ 25 in the radial range of 200-3500 kpc h^(–1), providing integrated constraints on the halo profile shape and concentration-mass relation. The stacked tangential-shear signal is well described by a family of standard density profiles predicted for dark-matter-dominated halos in gravitational equilibrium, namely, the Navarro-Frenk-White (NFW), truncated variants of NFW, and Einasto models. For the NFW model, we measure a mean concentration of c_(200c)=4.01^(+0.35)_(-0.32) at an effective halo mass of M_(200c)=1.34^(+0.10)_(-0.09) x 10^(15)M_☉. We show that this is in excellent agreement with Λ cold dark matter (ΛCDM) predictions when the CLASH X-ray selection function and projection effects are taken into account. The best-fit Einasto shape parameter is ɑ_E=0.191^(+0.071)_(-0.068), which is consistent with the NFW-equivalent Einasto parameter of ~0.18. We reconstruct projected mass density profiles of all CLASH clusters from a joint likelihood analysis of shear-and-magnification data and measure cluster masses at several characteristic radii assuming an NFW density profile. We also derive an ensemble-averaged total projected mass profile of the X-ray-selected subsample by stacking their individual mass profiles. The stacked total mass profile, constrained by the shear+magnification data, is shown to be consistent with our shear-based halo-model predictions, including the effects of surrounding large-scale structure as a two-halo term, establishing further consistency in the context of the ΛCDM model.

Controlling graphene plasmons with resonant metal antennas and spatial conductivity patterns

Abstract: Graphene plasmons promise unique possibilities for controlling light in nanoscale devices and for merging optics with electronics We developed a versatile platform technology based on resonant optical antennas and conductivity patterns for launching and control of propagating graphene plasmons, an essential step for the development of graphene plasmonic circuits We launched and focused infrared graphene plasmons with geometrically tailored antennas and observed how they refracted when passing through a two-dimensional conductivity pattern, here a prism-shaped bilayer To that end, we directly mapped the graphene plasmon wavefronts by means of an imaging method that will be useful in testing future design concepts for nanoscale graphene plasmonic circuits and devices

Hydrophobic Interactions Modulate Self-Assembly of Nanoparticles

Abstract: Hydrophobic interactions constitute one of the most important types of nonspecific interactions in biological systems, which emerge when water molecules rearrange as two hydrophobic species come close to each other. The prediction of hydrophobic interactions at the level of nanoparticles (Brownian objects) remains challenging because of uncontrolled diffusive motion of the particles. We describe here a general methodology for solvent-induced, reversible self-assembly of gold nanoparticles into 3D clusters with well-controlled sizes. A theoretical description of the process confirmed that hydrophobic interactions are the main driving force behind nanoparticle aggregation.