The VST-ISW Survey

We propose a southern 5000 deg2 deep survey of galaxies in the r band to detect the Integrated Sachs-Wolfe Effect with a signal to noise ratio 40 % higher than any other survey so far (e.g. SDSS DR4). The aim is to determine the equation of state of the universe by cross-correlating this galaxy map with high resolution CMB anisotropy maps from existing WMAP and future Planck observations. We show that we can reach a near-maximum S/N value of the ISW effect using a single broad-band (r) spatially-contiguous galaxy catalogue with a mean redshift 〈z 〉 = 1.2 at a particular scale of the sky (0.5 deg2). Morever, galaxy binning it is not required and therefore redshift information is not needed for all galaxies to compute the ISW effect. To cover the desired field, 64 nights in 4 years (rAB. 23.8, 16 dark-grey 1.0 arcsec seeing nights per year) are required with VST. To maximize the output and open this survey to further science goals (ACT clusters, SZ effect, Red sequence galaxy clusters, LSBs, UCDs, Dwarf Galaxies, lenses) we will observe the same area as the approved VST ATLAS survey, which will provide de deep g band observations. The ISW results from this survey will surpass the results from SDSS, because of its depth, and be comparable to the results of the Dark Energy Survey, but 3 years earlier. This survey will b