1. SPIRE-FTS spectrum of Arp 220, Mrk 231 and NGC 1068. Bright CO (J = 4-3 to J = 13-12), water, and atomic fine-structure line transitions are labeled. The excitation of high-J CO lines is caused by an AGN in NGC 1068 (Spinoglio +2012) and Mrk 231 (Van der Werf +2010). In Arp 220, the high-J CO lines are excited by intense star-formation and are tracing very warm molecular gas with T K ≈1500 K (Rangwala +2011). The CO J=4-3, 3-2, and 2-1 lines, together with [CI] will be accessible at z=0, and the CO J=5-4, 6-5 and 7-6 lines will be visible to X-Spec at z=0.1, 0.3 and 0.5, respectively. The CO (4-3) transition in N1068 could be detected in under 5sec with X-Spec, making fast, unbiased surveys of hundreds of local starbursts and AGN feasible. Introduction to CCAT CCAT will be a 25m telescope for sub-millimeter astronomy located at an altitude of 5600 meters on Cerro Chajnator in northern Chile. CCAT will combine high sensitivity, a wide field of view, and a broad wavelength range to provide an unprecedented capability for deep, large-area multicolor sub-millimeter surveys. Instrumentation for CCAT will include bolometer cameras, direct detection spectrometers, and heterodyne receiver arrays. A primary science objective for CCAT is the study of galaxy formation and evolution throughout a significant fraction of the age of the Universe. Since it will be sensitive to low surface brightness emission from dust, as well as the key far-infrared and mm cooling lines of the ISM, CCAT will also be a superb telescope for studying nearby galaxies in exquisite detail, and these observations will be invaluable for informing our understanding of the physics that regulates the formation of stars and the build up of black holes in galaxies at all epochs. CCAT Performance Specifications Aperture25m diameter Wavelength coverage200 – 2200 μm Field of view1o1o Angular resolution3.5” (λ/350 μm) Pointing accuracy0.35” Mapping speed1 o /sec Herschel SPIRE 350 μm (left) and IRAC 8μm (right) images of M83 (Foyle +2012). Although IRAC-8 traces PAH and warm dust emission, the beam size (here smoothed to a FWHM ~ 3.5”) is comparable to what CCAT will deliver at 350μm, where the resolution in M83 will be about 60 pc, allowing the study of individual giant molecular clouds, and an unbiased survey of dusty structures of ≤ 1000 M , and, when combined with CO and HI maps, the derivation of X(CO) in active and quiescent regions throughout the disk. The Dusty Disk of M83 CCAT Proposed 1 st Light Instruments InstrumentbandsdetectorsFoV SWCam (200), 350, 450, (620) μm >55K pxls12’ LWCam (750), 850, 1100, 1300, 2100 μm 37K pxls20’ X-Spec 195-320, 320-500 GHz at R≈500 100 spectra 1o1o RGB composite of HERITAGE Herschel 100 micron, SMC-SAGE Spitzer 24 micron, and MCELS H-alpha showing the distribution of dust and star formation throughout the SMC. The full image is 2x3 o. Green boxes show the existing Herschel spectroscopy. The insets are the star-forming regions N83 and N22. SEST 12CO maps are shown as white contours (covering 1-15 km s -1 at 43” FWHM). With its large aperture and high-frequency performance, CCAT will reveal the structure of the dust and dense gas on extremely small scales. CCAT could map 50 ☐ o at 1pc resolution down to 1-3 M  of dust (3.6 mJy at 350 μm) in about 350 hrs, providing a complete census of YSOs in the SMC and LMC. Star Formation in the SMC Observing Nearby Galaxies with CCAT L. Armus 1, G. Stacey 2, C. Wilson 3, A. Bollatto 4, N. Rangwala 5, J. Kauffmann 6, F. Bertoldi 7, J. Glenn 5 1 Caltech, 2 Cornell University, 3 McMaster University, 4 University of Maryland, 5 University Colorado, 6 JPL, 7 University of Bonn Starbursts and AGN Canadian Consortium CCAT Engineering Design Phase is partially supported by funding by the National Science Foundation’s Division of Astronomical Sciences www.CCATObservatory.org