Calibrating Milky Way dust extinction using cosmological sources

TL;DR

This study constrains the Milky Way dust extinction properties by analyzing the correlation between infrared-inferred dust column density and the observed colors of distant cosmological objects, finding consistent proportionality and reddening parameters.

Contribution

It provides new empirical constraints on the dust extinction law in the Milky Way using cosmological sources, with consistent results across different galaxy types.

Findings

Proportionality constant p=0.02 between E(B-V) and dust column density D^T.

Reddening parameter R_V=3 with about 10% uncertainty.

No significant spatial variation in dust properties detected.

Abstract

We constrain the light extinction properties of Milky Way dust. We investigated the correlations between dust column density as inferred from infrared data and the observed colours of celestial objects at cosmological distances with low levels of colour dispersion. Results derived using colours of quasars, brightest central galaxies, and luminous red galaxies are broadly consistent, indicating a proportionality constant between the reddening E(B-V)=A_B-A_V and the dust column density D^T (given in units of MJy/sr) of p=E(B-V)/D^T=0.02 and a reddening parameter R_V=A_V/E(B-V)=3 with fractional uncertainties of approximately 10%. The data do not provide any evidence for spatial variations in the dust properties, except for a possible hint of scatter in the dust extinction properties at the longest optical wavelengths.