APEC Seminar (Astronomy - Particle Physics - Experimental Physics - Cosmology)

Speaker: Yi-Kuan Chiang (ASIAA)
Title: An Improved Galactic Dust Map
Date (JST): Wed, Sep 13, 2023, 16:00 - 17:30
Place: Seminar Room A
Abstract: The widely used Milky Way dust reddening map, the Schlegel, Finkbeiner, & Davis (1998, SFD) map, was found to be contaminated by the extragalactic cosmic infrared background (CIB). When SFD is used for extinction correction, over-correction then occurs in a correlated manner, which could impact precision cosmology using galaxy clustering, lensing, and supernova Ia distances. In this talk, I will present a map-level solution. First, I measure descriptive summary statistics of the CIB in SFD by cross-correlating SFD’s reddening field with spectroscopic galaxies and quasars in SDSS tomographically as functions of redshift and angular scale. To reconstruct the CIB field, however, additional information on the phases is needed. I build a large set of 180 overcomplete, full-sky basis template maps from the density fields of over 450 million galaxies in WISE and find a linear combination that reproduces all the high-dimensional tomographic two-point statistics of the CIB in SFD. After subtracting this reconstructed CIB map, the end product is a nearly full-sky Galactic dust-reddening map that supersedes SFD, carrying all Galactic features therein, with maximally suppressed CIB. I release this new dust map dubbed CSFD—the Corrected SFD—to the community.
Remarks: Seminar Room A + Zoom