Corrected SFD: A More Accurate Galactic Dust Map with Minimal Extragalactic Contamination

Understand

The widely used Milky Way dust reddening map, the Schlegel, Finkbeiner, & Davis (1998; SFD) map, was found to contain extragalactic large-scale structure (LSS) imprints (Chiang & M\'enard 2019).

• Such contamination is inherent in maps based on infrared emission, which pick up not only Galactic dust but also the cosmic infrared background (CIB).
• When SFD is used for extinction correction, over-correction occurs in a spatially correlated and redshift-dependent manner, which could impact precision cosmology using galaxy clustering, lensing, and supernova Ia distances.
• Similarly, LSS imprints in other Galactic templates can affect intensity mapping and cosmic microwave background experiments.