Program: GS-2013B-Q-28
Title: | Spectroscopic study of the environment of time-delay lenses for accurate cosmology |
PI: | Tommaso Treu |
Co-I(s): | Alessandro Sonnenfeld, Frederic Courbin, Chris Fassnacht, Dominique Sluse, Sherry Suyu |
Abstract
We are conducting a program to achieve compelling and robust cosmographic measurements from five gravitationally lensed quasars with exquisite time-delays and HST images. We aim with this analysis to measure H_0 with an accuracy better than 3.8%, resulting in constraints on cosmological parameters comparable to the one from current BAO and SN work when combined with CMB data. To reach this goal, we need to track any source of errors. The analysis of the first two systems has shown that H_0 can be derived from a single lens with better than 7% accuracy, and that the main source of uncertainty come from the lens environment. In this proposal, we propose to complete multi-object spectroscopy of the galaxies in the field of the time-delays lenses in order to measure their redshift. This will pin down the error from the environment to a few percent, allowing us to deliver state of the art constraints on cosmological parameters.
Publications using this program's data
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[data]
[ADS] H0LiCOW - IV. Lens mass model of HE 0435-1223 and blind measurement of its time-delay distance for cosmology
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[data]
[ADS] H0LiCOW - II. Spectroscopic survey and galaxy-group identification of the strong gravitational lens system HE 0435-1223
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[data]
[ADS] H0LiCOW - I. H0 Lenses in COSMOGRAIL's Wellspring: program overview
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[data]
[ADS] Revealing the effects of galaxy interaction in the main galaxies of the southern group Arp 314