A Spatially Complete [TSUP]13[/TSUP]CO [ITAL]J[/ITAL] = 1–0 Survey of the Orion A Cloud

Abstract

We present the results of new 13CO J \ 1È0 observations of the Orion A molecular cloud made with two 4 m telescopes at Nagoya University. The area observed, corresponding to l D 208¡È215¡ and b D to covers the full extent of this giant molecular cloud at a grid spacing with a [20¡ .5 [18¡ .0, 2@ .0 2@ .7 beam. The present observations provide the Ðrst complete coverage of the cloud in 13CO with a reasonably high angular resolution relative to the cloudÏs size. In addition, the high velocity resolution of 0.1 km s~1 allowed us to resolve velocity components of the 13CO emission. The molecular distribution is highly elongated along the Galactic plane and is Ðlamentary, as is consistent with previous molecular maps. The total molecular mass of the cloud is estimated to be D5.4 ] 104 By using the velocity M _. channel maps every 0.5 km s~1, 39 individual Ðlamentary components have been identiÐed, and their basic physical quantities have been estimated. They typically are 4.8 pc in length, 1.4 pc in width, and 660 in mass. We also Ðnd that these Ðlamentary components are nearly in virial equilibrium. M _