Portion of the caustic region with the magnification shown as gray scale. Left: small region of 4″ × 4″ showing the caustics for a source at z = 1.0054. The yellow circle marks the predicted position of the Spock galaxy in relation to the caustics. The green square marks the region that is enlarged in the right panel. Right: zoom-in of a small portion in the caustics obtained after interpolating the deflection field to a resolution of 2 milliarcseconds per pixel and applying the inverse ray shooting method. The yellow circle represents the approximate circular shape of the Spock galaxy and its position in relation to the caustic. The length of the caustic that intersects the galaxy is estimated to be ∼530 pc. At a distance d pc from the caustic, the magnification in the interior region of the caustic drops as .