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Galaxy–galaxy strong lens perturbations: line-of-sight haloes versus lens subhaloes.
- Source :
- Monthly Notices of the Royal Astronomical Society; Jun2022, Vol. 512 Issue 4, p5862-5873, 12p
- Publication Year :
- 2022
-
Abstract
- We rederive the number density of intervening line-of-sight haloes relative to lens subhaloes in galaxy-galaxy strong lensing observations, where these perturbers can generate detectable image fluctuations. Previous studies have calculated the detection limit of a line-of-sight small-mass dark halo by comparing the lensing deflection angles it would cause, to those caused by a subhalo within the lens. However, this overly simplifies the difference in observational consequences between a subhalo and a line-of-sight halo. Furthermore, it does not take into account degeneracies between an extra subhalo and the uncertain properties of the main lens. More in keeping with analyses of real-world observations, we regard a line-of-sight halo as detectable only if adding it to a smooth model generates a statistically significant improvement in the reconstructed image. We find that the number density of detectable line-of-sight perturbers has been overestimated by as much as a factor of two in the previous literature. For typical lensing geometries and configurations, very deep imaging is sensitive to twice as many line-of-sight perturbers as subhaloes, but moderate depth imaging is sensitive to only slightly more line-of-sight perturbers than subhaloes. [ABSTRACT FROM AUTHOR]
- Subjects :
- CONFIGURATIONS (Geometry)
DETECTION limit
GRAVITATIONAL lenses
DARK matter
Subjects
Details
- Language :
- English
- ISSN :
- 00358711
- Volume :
- 512
- Issue :
- 4
- Database :
- Complementary Index
- Journal :
- Monthly Notices of the Royal Astronomical Society
- Publication Type :
- Academic Journal
- Accession number :
- 156714158
- Full Text :
- https://doi.org/10.1093/mnras/stac759