Stellar Reddening Based Extinction Maps for Cosmological Applications

Understand

Cosmological surveys must correct their observations for the reddening of extragalactic objects by Galactic dust.

• Existing dust maps, however, have been found to have spatial correlations with the large-scale structure of the Universe.
• Errors in extinction maps can propagate systematic biases into samples of dereddened extragalactic objects and into cosmological measurements such as correlation functions between foreground lenses and background objects and the primordial non-gaussianity parameter $f_{NL}$.
• Emission-based maps are contaminated by the cosmic infrared background, while maps inferred from stellar-reddenings suffer from imperfect removal of quasars and galaxies from stellar catalogs.