English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We have worked out simple analytical formulae that accurately approximate therelationship between the position of the source with respect to the lens centerand the amplification of the images, hence the lens cross section, forrealistic lens profiles. We find that, for essentially the full range ofparameters either observationally determined or yielded by numericalsimulations, the combination of dark matter and star distribution can be verywell described, for lens radii relevant to strong lensing, by a simplepower-law whose slope is very weakly dependent on the parameters characterizingthe global matter surface density profile and close to isothermal in agreementwith direct estimates for individual lens galaxies. Our simple treatment allowsan easy insight into the role of the different ingredients that determine thelens cross section and the distribution of gravitational amplifications. Theyalso ease the reconstruction of the lens mass distribution from the observedimages and, vice-versa, allow a fast application of ray-tracing techniques tomodel the effect of lensing on a variety of source structures. The maximumamplification depends primarily on the source size. Amplifications larger than~20 are indicative of compact source sizes at high-z, in agreement withexpectations if galaxies formed most of their stars during the dissipativecollapse of cold gas. Our formalism has allowed us to reproduce the counts ofstrongly lensed galaxies found in the H-ATLAS SDP field. While our analysis isfocussed on spherical lenses, we also discuss the effect of ellipticity and thecase of late-type lenses (showing why they are much less common, even thoughlate-type galaxies are more numerous). Furthermore we discuss the effect of acluster halo surrounding the early-type lens and of a supermassive black holeat its center.

Effective Models for Statistical Studies of Galaxy-Scale Gravitational Lensing