  We present position-velocity strip maps of the Galactic Center region in the
CO J=7-6 and J=4-3 transitions observed with the Antarctic Submillimeter
Telescope and Remote Observatory (AST/RO) located at Amundsen-Scott South Pole
Station. Emission from the two rotational transitions of 12^CO was mapped at
b=0 deg for 3.5 deg > l > -1.5 deg, on a 1' grid with a FWHM beamsize of 58''
at 806 GHz and 105'' at 461 GHz. Previous observations of CO J=4-3 (Martin et
al., in preparation) and CI (Ojha et al. 2001) emission from this region show
that these lines are distributed in a manner similar to CO J=1-0 (Stark et al.
1987); the (CO J=4-3)/(CO J=1-0) line ratio map is almost featureless across
the entire Galactic Center region. In contrast, the CO J=7-6 emission from the
Galactic Center is strongly peaked toward the Sgr A and Sgr B molecular
complexes. A Large Velocity Gradient (LVG) analysis shows that aside from the
two special regions Sgr A and Sgr B, the photon-dominated regions within a few
hundred parsecs of the Galactic Center are remarkably uniform in mean density
and kinetic temperature at n = 2500 to 4000 cm^{-3} and T=30 to 45K. The (CO
J=7-6)/(CO J=4-3) line temperature ratios near Sgr B are a factor of two higher
than those observed in the nuclear region of the starburst galaxy M82 (Mao et
al. 2000), while the CO(J=7-6)/CO(J=4-3) line temperature ratios around Sgr A
are similar to M82. The line ratio on large scales from the Galactic Center
region is an order of magnitude less than that from M82.
