Context. Inhomogeneities along the road of sight in sturdy gravitational lensing distort the images produced, in an effect referred to as shear. If measurable, this shear may present independent constraints on cosmological parameters, complementary to conventional cosmic shear. Aims. We mannequin 50 robust gravitational lenses from the Sloan Lens ACS (SLACS) catalogue with the intention of measuring the road-of-sight (LOS) shear for the primary time. We use the ‘minimal model’ for the LOS shear, which has been shown to be theoretically safe from degeneracies with lens model parameters, Wood Ranger Tools a finding which has been confirmed using mock knowledge. Methods. We use the dolphin automated modelling pipeline, which makes use of the lenstronomy software program as a modelling engine, to model our selected lenses. We model the main deflector Wood Ranger Tools with an elliptical energy legislation profile, Wood Ranger Tools the lens gentle with elliptical Sérsic profiles and the source with a foundation set of shapelets and an elliptical Sérsic profile. Results. We efficiently obtain a line-of-sight shear measurement from 18 of the 50 lenses.

We find that these LOS shear measurements are consistent with external power shears measured in recent works utilizing a simpler shear mannequin, which are bigger than those expected from weak lensing. Neglecting the publish-Born correction to the potential of the main deflector resulting from foreground shear results in a propagation of degeneracies to the LOS shear measurement, and Wood Ranger Tools the identical impact is seen if a prior is used to attach the lens mass and light ellipticities. The inclusion of an octupole second in the lens mass profile doesn't lead to shear measurements which might be in higher settlement with the expectations from weak lensing. Gravitational lensing provides a novel window into the cosmology of our Universe on a wide range of scales. Refsdal, 1964

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Pub: 14 Oct 2025 02:01 UTC

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