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We report the results of a 100 square degree survey of the Taurus Molecular Cloud region in the J = 1 → 0 transition of 12CO and of 13CO. The image of the cloud in each velocity channel includes ≃ 3×106 Nyquist-sampled pixels, sampled on a 20 ′ ′ grid. The high sensitivity and large linear dynamic range of the maps in both isotopologues reveal a very complex, highly structured cloud morphology. There are large scale correlated structures evident in 13CO emission having very fine dimensions, including filaments, cavities, and rings. The 12CO emission shows a quite different structure, with particularly complex interfaces between regions of greater and smaller column density defining the boundaries of the largest–scale cloud structures. The axes of the striations seen in the 12CO emission from relatively diffuse gas are aligned with the direction of the magnetic field. We have developed a statistical method for analyzing the pixels in which 12 13 CO but not CO is detected, which allows us to determine the CO column in the diffuse portion of the cloud as well as in the denser regions in which we detect both isotopologues. Using a column density–dependent model for the CO fractional abundance, we derive the mass of the region mapped to be 2.4×104 M⊙. This is more than a factor of two greater than would be obtained using a canonical fixed fractional abundance of 13CO and a factor three greater than would be obtained using this fractional abundance restricted to the high column density regions. We determine that half the mass of the cloud is in regions having column density below 2.1×10 21 cm −2. The distribution of young stars in the region covered is highly nonuniform, with the probability of finding a star
Goldsmith et al. (2008) studied this question.