Maps of Dust IR Emission for Use in Estimation of Reddeningand CMBR

We present a full sky 100m map that is a reprocessed composite of the COBE/DIRBE and IRAS/ISSA maps, with the zodiacal foreground and connrmed point sources removed. Before using the ISSA maps, we remove the remaining artifacts from the IRAS scan pattern. Using the DIRBE 100m and 240m data, we have constructed a map of the dust temperature, so that the 100m map may 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 lamentary detail is apparent on many diierent 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 and the formation of H 2 in molecular clouds. In contrast, high-velocity H I clouds are deecient in dust emission, as expected. To generate the full sky dust maps, we must rst remove zodiacal light contamination as well as a possible cosmic infrared background (CIB). This is done via a regression analysis of the 100m DIRBE map against the Leiden-Dwingeloo map of H I emission, with corrections for the zodiacal light via a suitable expansion of the DIRBE 25m ux. This procedure removes virtually all traces of the zodiacal foreground. For the 100m map no signiicant CIB is detected, but at longer wavelengths, where the zodiacal contamination is weaker, we detect the CIB at surprisingly high ux levels of 32 13 nW=m 2 =sr { 2 { at 140m, and 17 4 nW=m 2 =sr at 240m (95% conndence), which is an integrated ux 2 times that extrapolated from optical galaxies in the Hubble Deep Field. The primary use of these maps is likely to be as a new estimator of Galactic extinction. To calibrate our maps, we assume a standard reddening law, and use the colors of elliptical galaxies to measure the reddening per unit ux density of 100m emission. We nd consistent calibration using the (B?R) color distribution of a sample of 106 brightest cluster ellipticals, as well as a sample of 384 ellipticals with (B?V) and Mg line-strength measurements. For …