Stellar-reddening-based Extinction Maps for Cosmological Applications

Abstract

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. Thus, stellar-reddening-based maps using catalogs without extragalactic objects offer a promising path to making dust maps with minimal correlations with large-scale structure. We present two high-latitude integrated extinction maps based on stellar reddenings, with a point-spread functions of FWHMs 6.′1 and 15′. We employ a strict selection of catalog objects to filter out galaxies and quasars and measure the spatial correlation of our extinction maps with extragalactic structure. Our galactic extinction maps have reduced spatial correlation with large-scale structure relative to most existing stellar-reddening-based and emission-based extinction maps.

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

“…First, compared to most Planck-based FIR emission dust maps (e.g., Meisner & Finkbeiner 2015;Planck Collaboration et al 2016), SFD has less CIB contamination as shown in CM19. Compared to stellar reddening maps from Pan-STARRS and Gaia (e.g., Green et al 2019;Mudur et al 2023), SFD is of far higher S/N, which leads to less noise in extinction corrections. Compared to full-sky H I-based reddening maps (e.g., Lenz et al 2017), SFD has a higher angular resolution and traces dust column more directly.…”