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P.J. Marshall (KIPAC), C. Baltay (Yale), R.D. Blandford, M. Sako (KIPAC), SNAP Collaboration
The potent combination of high angular resolution imaging over a wide survey field in many colours offered by SNAP satisfies the principal requirements of an optical strong gravitational lensing survey. The majority of multiple-imaging events occur on arcsecond angular scales, requiring sub-arcsecond resolution for their detection, and good SED modelling for their confirmation as lenses. From a 1000 square degree survey we anticipate a catalogue containing upwards of 104 strong lenses, the majority of which will be faint blue galaxies lensed by massive ellipticals at redshifts of less than or around one, but that will contain a few hundred lensed quasars and a comparable number of cluster-scale multiple image systems.
Both the statistics of galaxy-scale lenses, and measurements of image separations, can be used as cosmological probes, providing an important additional test of the dark energy world model. In the SNAP era it is likely that the problem will be turned around in order to infer the properties of galaxy and cluster mass distributions, the evolution of the lens galaxy populations, and the redshift distribution of the faintest galaxies. In the many cases where the source galaxy is optically variable, combining the SNAP lens model with ground-based time delay measurements should allow the Hubble constant, and its scatter, to be measured.
The author(s) of this abstract have provided an email address for comments about the abstract: pjm@stanford.edu
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.