[C-II] 158 MICRON AND [O-I] 63 MICRON OBSERVATIONS OF THE GALACTIC-CENTER REGION

Using the balloon-borne infrared telescope (BIRT) incorporated with a liquid-helium-cooled double-channel Fabry-Perot spectrometer, intensities and velocity profiles of [C II] 158 mum and [O I]63 mum fine-structure lines have been observed in the Galactic center region within \l\ less-than-or-equal-to 0.7-degrees. Intense [C II] line emission has been detected ubiquitously in almost all of the observed points. The distribution of the [C II] intensity shows a central peak at Sgr A West together with two prominent peaks at DELTA1 = +/- 0.6-degrees, which correspond to Sgr B1 (not Sgr B2) and Sgr C, respectively. The intensity distribution resembles but is not identical to, that of far-infrared emission. The velocity profiles of the [C II] line are resolved and can be deconvolved into multiple components, many of which can be traced to the features observed by molecular lines. The [O I]63 mum line has been detected at Sgr A West and at some other points. The [O I]63 mum/[C II] 158 mum ratios are always less than 3 in the beam of 3'.7 These observed results can be explained as the emission generated in photodissociation regions formed in the molecular clouds complexes illuminated by intense UV radiation field in the Galactic center regions. However, contribution from ELD region is possibly present and cannot be ruled out.