Isolating Geometry in Weak Lensing Measurements
| dc.creator | Zhang, Jun | |
| dc.creator | Hui, Lam | |
| dc.creator | Stebbins, Albert | |
| dc.date | 2003-12-14 | |
| dc.date.accessioned | 2026-07-07T10:27:09Z | |
| dc.date.available | 2026-07-07T10:27:09Z | |
| dc.description | Given a foreground galaxy-density field or shear field, its cross-correlation with the shear field from a background population of source galaxies scales with the source redshift in a way that is specific to lensing. Such a source-scaling can be exploited to effectively measure geometrical distances as a function of redshift and thereby constrain dark energy properties, free of any assumptions about the galaxy-mass/mass power spectrum (its shape, amplitude or growth). Such a geometrical method can yield a ~ 0.03 - 0.07 f_{sky}^{-1/2} measurement on the dark energy abundance and equation of state, for a photometric redshift accuracy of dz ~ 0.01 - 0.05 and a survey with median redshift of ~ 1. While these constraints are weaker than conventional weak lensing methods, they provide an important consistency check because the geometrical method carries less theoretical baggage: there is no need to assume any structure formation model (e.g. CDM). The geometrical method is at the most conservative end of a whole spectrum of methods which obtain smaller errorbars by making more restrictive assumptions -- we discuss some examples. Our geometrical approach differs from previous investigations along similar lines in three respects. First, the source-scaling we propose to use is less demanding on the photometric redshift accuracy. Second, the scaling works for both galaxy-shear and shear-shear correlations. Third, we find that previous studies underestimate the statistical errors associated with similar geometrical methods, the origin of which is discussed. | |
| dc.description | 13 pages, 4 figures, submitted to ApJ | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0312348 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0312348 | |
| dc.identifier | Astrophys.J.635:806-820,2005 | |
| dc.identifier | doi:10.1086/497676 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/177069 | |
| dc.subject | Astrophysics | |
| dc.title | Isolating Geometry in Weak Lensing Measurements | |
| dc.type | text |