The Next Generation Virgo Cluster Survey (NGVS ; Ferrarese et al. 2012, Raichoor, Mei et al. 2014 ; http://astrowww.phys.uvic.ca/~lff/NGVS.html) is Canada France Hawaii Telescope large program. It is a survey of the region inside the virial radius of the Virgo cluster, our nearest cluster of galaxies at a distance of 16.5Mpc (Mei et al. 2007), for a total area of 104 deg2, in four bandpasses (u, g, i, z) (and 34deg2 in five bandpasses u,g,r,i,z) to depths of g 25.9 AB mag (10σ detection limit for point-sources) and μg 29 AB mag arcsec-2 (2σ detection for extended sources) in all filters. The total exposure time was distributed over 5 semesters from Spring 2009 to Spring 2013, with a French contribution of half of the time. Because of its depth and area, NGVS supersedes all previous optical studies of this benchmark galaxy cluster, and it is a reference survey for all local studies of the densest environments.
The goal of the NGVS survey is the in depth study of the Virgo cluster to understand how galaxies evolved in its dense environment. Within the collaborations we have working groups to measure and analyze Virgo galaxy luminosity and mass functions ; the color-magnitude relation ; galaxy scaling relations ; compact stellar systems ; galactic nuclei ; the extragalactic distance scale ; the large-scale environment of the cluster and its relationship to the Local Supercluster ; diffuse light and the intracluster medium ; galaxy interactions and evolutionary processes ; and extragalactic star clusters. Beside the Virgo cluster, we study both foreground and background objects : trans-Neptunian objects ; the structure of the Galactic halo in the direction of the Virgo Overdensity and Sagittarius Stream ; the measurement of cosmic shear, galaxy-galaxy, and cluster lensing ; and the identification of distant galaxy clusters, and strong-lensing events.
All NGVS observations have been reduced with the new reduction pipeline Elixir LSB developed by Jean-Charles Cuillandre. At GEPI, in collaboration with Thomas Erben and Hendrik Hildebrandt at the University of Bonn, we have produced a PSF matched photometry catalog and photometric redshift catalog of all background sources (Raichoor, Mei et al. 2014), available to all the NGVS collaboration. Mei is the coordinator of both the Photometric redshift and the Background galaxy cluster science working group.
The collaboration meets every year since 2009. This year we have decided to meet in Paris. We are 52 collaborators, mainly from Canada, The United States, China, Chile, Germany, of which 20 in France, counting the students and the postdoctoral fellows.