Related papers: Looking for the first galaxies: Lensing or blank f…
Galaxy-scale strong lenses in galaxy clusters provide a unique tool to investigate their inner mass distribution and the sub-halo density profiles in the low-mass regime, which can be compared with the predictions from cosmological…
Two colour photometry of the cluster A1689 reveals a `relative magnification-bias' between lensed blue and red background galaxies, arising from a dependence of the faint galaxy count-slope on colour. The colour distribution is skewed…
One of the primary goals for the upcoming James Webb Space Telescope (JWST) is to observe the first galaxies. Predictions for planned and proposed surveys have typically focused on average galaxy counts, assuming a random distribution of…
We study the effects of strong lensing on the observed number counts of mm sources using a ray tracing simulation and two number count models of unlensed sources. We employ a quantitative treatment of maximum attainable magnification factor…
We present the first catalogue of strong lensing galaxy clusters identified in the Euclid Quick Release 1 observations (covering $63.1\,\mathrm{deg^2}$). This catalogue is the result of the visual inspection of 1260 cluster fields. Each…
Galaxy clusters are usually detected in blind optical surveys via suitable filtering methods. We present an optimal matched filter which maximizes their signal-to-noise ratio by taking advantage of the knowledge we have of their intrinsic…
We summarize the main results obtained recently by our group on the identification and study of very high-z galaxies (z>7) using lensing clusters as natural gravitational telescopes. A description of our pilot survey with ISAAC/VLT is…
Strong gravitational lensing observations can provide extremely valuable information on the structure of galaxies, but their interpretation is made difficult by selection effects, which, if not accounted for, introduce a bias between the…
We present ALMA 870um and JCMT SCUBA2 850um dust continuum observations of a sample of optically dark and strongly lensed galaxies in the cluster fields. The ALMA and SCUBA2 observations reach a median rms of about 0.11 mJy and 0.44 mJy,…
Lensing probabilities of quasars with image separations greater than \Delta\theta and flux density ratios less than q_{\mathrm{r}} are calculated by foreground dark matter halos in a flat, cosmological constant dominated (\LambdaCDM)…
The high-magnification gravitational lensing cross-section of a galaxy is enhanced significantly if a baryonic disc is embedded in its dark matter halo. We investigate the effects of a population of such disks on the probability of…
We calculate the expected lensing statistics of the galaxy population in large, low-redshift surveys. Galaxies are modeled using realistic, multiple components: a dark matter halo, a bulge component and disc. We use semi-analytic models of…
When gravitational waves pass near massive astrophysical objects, they can be gravitationally lensed. The lensing can split them into multiple wave-fronts, magnify them, or imprint beating patterns on the waves. Here we focus on the…
The gravitational lens effect of galaxy clusters can produce large arcs from source galaxies in their background. Typical source redshifts of ~ 1 require clusters at z ~ 0.3 for arcs to form efficiently. Given the cluster abundance at the…
Gravitational lensing predicts an enhancement of the density of bright, distant QSOs around foreground galaxies. We measure this QSO-galaxy correlation w_qg for two complete samples of radio-loud quasars, the southern 1Jy and Half-Jansky…
Magnification changes the observed number counts of galaxies on the sky. This biases the observed tangential shear profiles around galaxies, the so-called galaxy-galaxy lensing (GGL) signal, and the related excess mass profile.…
High-resolution imaging and strong gravitational lensing of high-redshift galaxies have enabled the detection of compact sources with properties similar to nearby massive star clusters. Often found to be very young, these sources may be…
(abridged) We present the first results of our deep survey of lensing clusters aimed at constraining the abundance of star-forming galaxies at z~6-10. Deep near-IR photometry of two lensing clusters (A1835 and AC114) was obtained with…
We use weak gravitational lensing to measure mean mass profiles around Locally Brightest Galaxies (LBGs). These are selected from the SDSS/DR7 spectroscopic and photometric catalogues to be brighter than any neighbour projected within 1.0…
The Red-Sequence Cluster Survey (RCS) is a 100 deg^2 galaxy cluster survey designed to provide a large sample of optically selected clusters of galaxies with redshifts 0.1<z<1.4. The survey data are also useful for a variety of lensing…