Abstract
We have established a pipeline that can generate various extinction maps. With the point source catalog from the 2MASS and GLIMPSE360 projects, we applied various methods such as star count, color excess, and SED fitting method for our extinction mapping. In particular observation in Spitzer mid-infrared bands could trace visual extinction up to AV∼100 mag (∼column densities of 9 × 10^22 cm^−2). Thus, the data allow the identification of dense molecular clouds, such as infrared dark clouds, in the absence of bright diffuse Galactic background emission. The high-spatial resolution achieved by the GLIMPSE360 project data allow us to investigate the mass distribution from Galactic size-scales (spiral structures) down to individual clouds for the entire Galactic plane. To verify our approaches and pipeline, particularly the new SED fitting method, we compared extinction maps of our two test fields towards both the inner and outer Galaxy. For the field toward outer Galaxy, our extinction map derived from the H−K near-infrared color excess method resembles the map derived from the SED-fitting method. Both of these two methods trace diffuse parts of clouds with the AV ranging from 0 mag to 40 mag (∼3.6 × 10^22 cm^−2). In contrast, Spitzer [3.6]−[4.5] extinction map probes denser (AV up to ∼ 100 mag) clumps in the central region of the cloud. For the field toward the Galactic center, both our extinction maps generated by the H−K color excess method and that generated by the SED fitting method suffer from the contamination of foreground stars in high extinction regions. The comparison of the [3.6]−[4.5] extinction map to the Spitzer 8μm image infers that [3.6]−[4.5] color excess method is capable to outline high extinction features corresponding to infrared dark clouds in the Galactic plane. Comparing stellar density maps to our extinction maps is feasible to identify high extinction regions contain purely foreground stars.