NOAO >   Observing Info >   Approved Programs >   2012B-0481

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Proposal Information for 2012B-0481


PI: Chris Fassnacht, UC Davis, cdfassnacht@ucdavis.edu
Address: Physics Dept, UC Davis, 1 Shields Ave., Davis, CA, 95616, USA

CoI: Tommaso Treu, UC Santa Barbara
CoI: Sherry Suyu, UC Santa Barbara
CoI: Matt Auger, University of Cambridge
CoI: Leon Koopmans, Kapteyn Institute
CoI: Phil Marshall, Oxford University

Title: Quantifying the line-of-sight mass distributions to time-delay lenses

Abstract: We have recently shown that a single gravitational lens with high-quality data can place constraints on H_0, w, and Omega_k that are comparable to constraints from other cosmological probes. Furthermore, since each lens makes an independent measurement of these quantities, a significant improvement in precision can be obtained by increasing the sample size. This establishes lensing as a powerful and independent tool for determining cosmography, in preparation for the hundreds of time-delay lenses that will be discovered by future surveys. The largest current contributor to the error budget from lensing is uncertainty about the line-of-sight mass distribution. The proposed observations are critical for reducing these uncertainties by providing redshifts and stellar masses for galaxies in the light cones of the target lens systems, and will do so with only a modest investment of observing time.


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NOAO >   Observing Info >   Approved Programs >   2012B-0481

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