A complete spectroscopic survey of distant X-ray clusters in XXL/VIDEO (North)
PI:
Jon Willis
Co-I(s):
Ben Maughan, Christian Garrel, Ariane Trudeau, Marguerite Pierre, Christophe Adami, Malcolm Bremer
Abstract
We request GMOS spectroscopy of four z=1 candidate galaxy clusters selected from the XXL/VIDEO overlap survey. Target clusters are selected as extended X-ray sources that display a significant redshift spike in optical/NIR photometric redshifts. Although samples of high-redshift clusters have been studied previously, these are either optically- or heterogeneously-selected. We have previously demonstrated that X-ray selected galaxy clusters display a broader range of rest-frame optical properties than red-sequence or richness-based selection. In a separate proposal we request one night of Subaru/MOIRCS observations to confirm two z~1.6 cluster candidates. Should these observations be executed we will have spectroscopically confirmed a complete sample of 13 uniformly selected X-ray galaxy clusters at 1<z<1.8 (when combined with previously confirmed clusters in our target field). Existing deep, multi-wavelength data in our target field will permit us to reveal the rate of stellar mass assembly and star formation quenching in this optically-unbiased sample of clusters.