Page History
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The concept of Multi-cycle Treasury (MCT) programs was developed as a mechanism to allow the HST community to address high impact science questions that require observations on a scale that cannot be supported by the standard time allocation process. MCT programs were defined as GO programs that required at least 450 orbits. There was no restriction or pre-selection of science topics. Up to 500 GO orbits together with 250 orbits of Director's Discretionary time were made available for these prorgams programs in each of cycle 17, 18 and 19. Following highly successful Servicing Mission 4, the Call for MCT proposals was issued in August 2009. A total of 39 proposals were received and reviewed by a dedicated Telescope Allocation Committee that met in January 2010. Based on the TAC recommendations, the STScI Director, Matt Mountain, approved three programs:
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As the most massive objects in the universe, galaxy clusters represent important signposts in our story of structure evolution, and are the ultimate telescopic lenses, placing gravitationally lensed galaxies from the earliest epochs in comfortable reach for careful study. We take full advantage of the refurbished ACS and WFC3 cameras to deliver deep 14-filter images of 25 carefully chosen clusters. These will enable us to address timely and substantive questions about dark matter, dark energy, and galaxy evolution well beyond z=7. These X-ray clusters are chosen to be free of lensing bias and to span a wide range of redshift and mass. By combining strong and weak lensing, we will obtain the definitive mass profile of relaxed clusters to confront the distinctive prediction of the standard LambdaCDM Lambda-CDM model. Detailed maps of internal structure will be enabled by ~1, 000 new multiply-imaged lensed sources to AB=26, all with precise (2% x (1+z)) photometric redshift measurements, thanks to WFC3's UV and IR coverage. A supernovae search in parallel (with low magnification uncertainties) will extend the Hubble diagram of SN1a to z>1.5, testing the constancy of dark energy with time and probing progenitorevolutionprogenitor evolution. Our homogeneous panchromatic deep imaging of this cluster sample will constitute a vast legacy archive for studies of the formation and evolution of structure.
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