Related papers: Identifying Lenses with Small-Scale Structure. II.…
A source lying near hyperbolic umbilic (HU) leads to a ring-like image formation, constituting four images with high magnification factors and lying in a small region of the lens plane. Since (based on our earlier work) the observed number…
In the strong lensing regime non-parametric lens models struggle to achieve sufficient angular resolution for a meaningful derivation of the central cluster mass distribution. The problem lies mainly with cluster members which perturb…
The amplitude of weak lensing should increase with source distance, rising steeply behind a lens and saturating at high redshift, providing a model-independent means of measuring cosmic geometry. We measure the amplitude of weak lensing…
In this paper it is proved that near a compact, invariant, proper subset of a continuous flow on a compact, connected metric space, at least one, out of twenty eight relevant dynamical phenomena, will necessarily occur. This result shows…
It has been shown that a slab of materials with refractive index = -1 behaves like a perfect lens focussing all light to an exact electromagnetic copy of an object. The original lens is limited to producing images the same size as the…
Lenses are an important tool in applied category theory. While individual lenses have been widely used in applications, many of the mathematical properties of the corresponding categories of lenses have remained unknown. In this paper, we…
We have examined the luminosity-size relationship as a function of environment for 12150 SDSS galaxies with precise visual classifications from the catalog of Nair & Abraham (2010a). Our analysis is subdivided into investigations of…
The {\it two-fold singularity} has played a significant role in our understanding of uniqueness and stability in piecewise smooth dynamical systems. When a vector field is discontinuous at some hypersurface, it can become tangent to that…
We define compactness of a gravitational lens as the scaled closest distance of approach (i.e., $r_0/M$) of the null geodesic giving rise to an image. We model forty supermassive dark objects as Schwarzschild lenses and compute compactness…
The number of lenses found in the JVAS survey of flat-spectrum radio sources for gravitational lenses is consistent with statistical models of optical surveys for lensed quasars. The 90% confidence limit on Omega_0 in flat cosmological…
We study the recently discovered gravitational lens SDSS J1004+4112, the first quasar lensed by a cluster of galaxies. It consists of four images with a maximum separation of 14.62''. The system has been confirmed as a lensed quasar at…
The incidence of sub-galactic level substructures is an important quantity, as it is a generic prediction of high-resolution Cold Dark Matter (CDM) models which is susceptible to observational test. Confrontation of theory with observations…
We present the small-scale (0.2h^{-1} to 7h^{-1} Mpc) cross-correlations between 32,000 luminous early-type galaxies and a reference sample of 16 million normal galaxies from the Sloan Digital Sky Survey. Our method allows us to construct…
We investigate strong lensing by non-singular finite isothermal ellipsoids taking into account the influence of the matter along the line of sight and in the close lens vicinity. We compare three descriptions of light propagation: the full…
We present mid-infrared imaging at 11.7 $\mu$m for the quadruple lens systems, MG0414+0534 and Q2237+030, using the cooled mid-infrared camera and spectrometer (COMICS) attached on the Subaru telescope. MG0414+0534 is characterized by a…
The interpretation of gravitational microlensing events caused by planetary systems or multiple stars is based on the n-point-mass lens model. The first planets detected by microlensing were well described by the two-point-mass model of a…
We investigate the impact of higher-order gravitational lens properties and properties of the background source on our approach to directly infer local lens properties from observables in multiple images of strong gravitationally lensed…
Many recent studies have demonstrated that scaling arguments, such as the so-called hierarchical {\em ansatz}, are extremely useful in understanding the statistical properties of weak gravitational lensing. This is especially true on small…
The cusps of the caustics of any gravitational lens model can be classified into positive and negative ones. This distinction lies on the parity of the images involved in the creation/destruction of pairs occurring when a source crosses a…
Most research on astrophysical lensing has been conducted using the geometric optics framework, where there exists a clear concept of lensing images. However, wave optics effects can be important for coherent sources, e.g. pulsars, fast…