Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds

We present a full sky 100μm map that is a reprocessed composite of the COBE/DIRBE and IRAS/ISSA maps, with the zodiacal foreground and confirmed point sources removed. Before using the ISSA maps, we remove the remaining artifacts from the IRAS scan pattern. Using the DIRBE 100μm and 240μm data, we have constructed a map of the dust temperature, so that the 100μm map can be converted to a map proportional to dust column density. The dust temperature varies from 17 K to 21 K, which is modest but does modify the estimate of the dust column by a factor of 5. The result of these manipulations is a map with DIRBE-quality calibration and IRAS resolution. A wealth of filamentary detail is apparent on many different scales at all Galactic latitudes. In high latitude regions, the dust map correlates well with maps of H I emission, but deviations are coherent in the sky and are especially conspicuous in regions of saturation of H I emission toward denser clouds or the formation of H2 in molecular clouds. In contrast, high-velocity H I clouds are deficient in dust emission, also as expected. To generate the full sky dust maps, we must first remove zodiacal light contamination as well as a possible cosmic infrared background (CIB). This is done via a regression analysis of the 100μm DIRBE map against the Leiden-Dwingeloo map of H I emission, with corrections for the zodiacal light via a suitable expansion of the DIRBE 25μm flux. This procedure removes virtually all traces of the zodiacal foreground. For the 100μm map no significant CIB is detected, but in the 140μm and 240μm maps, where the zodiacal contamination is weaker, we detect the CIB at surprisingly high flux levels of 32±13 nW/m/sr