A NEW GALACTIC EXTINCTION MAP OF THE CYGNUS REGION

We have made a Galactic extinction map of the Cygnus region with 5' spatial resolution. The selected area is 80 degrees to 90 degrees in the Galactic longitude and -4 degrees to 8 degrees in the Galactic latitude. The intensity at 140 mu m is derived from the intensities at 60 and 100 mu m of the IRAS data using the tight correlation between 60, 100, and 140 mu m found in the Galactic plane. The dust temperature and optical depth are calculated with 5' resolution from the 140 and 100 mu m intensity, and A(V) is calculated from the optical depth. In the selected area, the mean dust temperature is 17 K, the minimum is 16 K, and the maximum is 30 K. The mean A(V) is 6.5 mag, the minimum is 0.5 mag, and the maximum is 11 mag. The dust temperature distribution shows significant spatial variation on smaller scales down to 5'. Because the present study can trace the 5'-scale spatial variation of the extinction, it has an advantage over the previous studies, such as the one by Schlegel, Finkbeiner, and Davis, who used the COBE/DIRBE data to derive the dust temperature distribution with a spatial resolution of 1 degrees. The difference of A(V) between our map and Schlegel et al.'s is +/- 3 mag. A new extinction map of the entire sky can be produced by applying the present method.