2025/12/04 by Natalie B Hogg, Daniel Ezra Johnson, Hogg, Natalie B. +5 · 1 voice
Physics and Astronomy · #Galaxies: Formation, Evolution, Phenomena #Astrophysical Phenomena and Observations #Pulsars and Gravitational Waves Research
paper · doi:10.33232/001c.165032
openalex created_date 2025/12/06 · openalex publication_date 2026/07/14 · openalex updated_date 2026/07/28
Strong gravitational lensing images are subject to shape distortions due to inhomogeneities along the line of sight. The leading order shape distortion is shear, which, if measurable, will be a complementary cosmological probe to traditional cosmic shear. In Hogg et al. (2025a), we modelled 23 of the SLACS strong lenses, studying the line-of-sight (LOS) shear under a variety of shear and mass model parametrisations. In this work, we model 27 additional lenses, extending our sample of LOS shear constraints to 45 in total. We find a mean shear magnitude of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mn>0.11</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.024</mml:mn> </mml:mrow> </mml:math> , showing that a significant fraction of the lenses modelled in this work possess LOS shears with unexpectedly large magnitudes, , even when an octupolar distortion is included in the lens mass. We further investigate if factors such as lens and source redshift, filter and PSF, or flux and signal-to-noise ratio in the lensed arcs correlate with shear. We find that none of these features play a statistically significant role in the production of unusually large shear magnitudes.