Simultaneous Estimation of Large-Scale Structure and Milky Way Dust Extinction from Galaxy Surveys

TL;DR

This paper proposes a novel method to simultaneously estimate Galactic dust extinction and large-scale structure from galaxy surveys, achieving precision comparable to existing dust maps and enabling improved cosmological measurements.

Contribution

The authors develop a Bayesian framework that jointly infers dust extinction and galaxy overdensity from survey data, demonstrating its effectiveness with synthetic simulations.

Findings

Uncertainty in dust extinction measurement is comparable to existing maps.

Galaxy overdensity can be recovered with high precision at various resolutions.

The method integrates prior dust information with survey data for improved estimates.

Abstract

The high cosmological precision offered by the next generation of galaxy surveys hinges on improved corrections for Galactic dust extinction. We explore the possibility of estimating both the dust extinction and large-scale structure from a single photometric galaxy survey, making use of the predictable manner in which Milky Way dust affects the measured brightness and colors of galaxies in a given sky location in several redshift bins. To test our method, we use a synthetic catalog from a cosmological simulation designed to model the Vera C. Rubin Observatory Legacy Survey of Space and Time. At high Galactic latitude ($|b|\gtrsim20^\circ$) and a resolution of $1^\circ$ ($7'$), we predict the uncertainty in the measurement of dust extinction, $E(B-V)$, to be $0.005\ \mathrm{mag}$ ($0.015\ \mathrm{mag}$). This is similar to the uncertainty of existing dust maps, illustrating the feasibility of our method. Simultaneous estimation of large-scale structure is predicted to recover the galaxy overdensity $\delta$ with a precision of $\sim0.01$ ($\sim0.05$) at $1^\circ$ ($7'$) resolution. We also introduce a Bayesian formalism that combines prior information from existing dust maps with the likelihood of Galactic dust extinction determined from the excursion of observed galaxy properties.