The Chandra COSMOS Legacy Survey A New Window to the Obscured and Distant Universe

The equatorial 2 deg2 COSMOS area is the only large field for which a complete, deep, pan-chromatic data set exists, from an outstanding survey effort, and that all large telescopes can observe. Now, this pioneering and ambitious COSMOS survey is undergoing major extension, pushing its frontiers via the newly approved Chandra COSMOS Legacy Survey, the second largest Chandra proposal ever approved.'COSMOS-Legacy' will uniformly cover the 1.7 deg2 COSMOS/HST field with 2.8 Ms of Chandra ACIS-I imaging at ~160 ksec depth. This project expands the current deep C-COSMOS area by a factor of ~3 at ~3e-16 (1.45 vs 0.44 deg2). This will be achieved with 56x50 ks tiles covering a total area of 2.2 deg2, which will be observed during Chandra Cycle 14. The area and depth of COSMOS Legacy are designed to detect ~40 z>4, and ~4 z>5 Large Scale Structures on >15 arcmin scales. These structures have proven to connect luminous AGN (over 200 at z>3 will be detected) and sub-mm galaxies. COSMOS Legacy will also probe mini-quasars at z>7, using anistotropies of the unresolved X-ray Background, and the masses of the Dark Matter halos hosting X-ray AGN up to 3, via autocorrelation functions on ~30arcmin scales. To fully achieve these goals, COSMOS Legacy is complemented by spectroscopic follow-up with DEIMOS and MOSFIRE at Keck and KMOS at the VLT and FMOS at Subaru, just approved observations with Spitzer and JVLA, and with harder (5-80 keV) X-ray imaging with NuSTAR. In the near future, observations with Subaru HyperSuprimeCam (grizY) to r(AB)=28.2 are planned.