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Gravitational lensing

What you are seeing: a point-mass gravitational lens at the origin bends light rays. Choose "lensed image" to see a striped pattern pulled back through the inverse lens map, with yellow dots marking the discrete image positions of a point source. Switch to "extended source" to visualize how a finite-size circular galaxy gets stretched and magnified into arcs or a complete Einstein ring when source and lens align. Drag the canvas to move the source

Figure 1. Image-plane lensed view of a stripe pattern. The yellow points are the two solved point-mass images of the source (red dot). The dashed ring is the Einstein radius. Method: closed-form point-mass lens equation; numerical Jacobian for magnification field.
β_x0.30
β_y0.10
viewlensed
source radius0.08
u_min0.20
shear γ0.25

WHAT TO TRY

  • Vary each control and watch the rail readouts respond.
  • Compare the diagnostic plot against the live scene.