Grey Milky Way Extinction from SDSS Stellar Photometry

TL;DR

This paper investigates high-latitude galactic extinction using SDSS stellar data, identifying three grey extinction clouds with specific properties, and discusses implications for astrophysics.

Contribution

It introduces a method to map and analyze high-latitude galactic extinction and reports the discovery of grey extinction clouds with detailed characteristics.

Findings

Identified three extinction clouds at 1-2 kpc distance

Clouds cause 0.2-0.4 mag extinction in g'-band

Extinction is nearly wavelength-independent (grey)

Abstract

We report results concerning the distribution and properties of galactic extinction at high galactic latitudes derived from stellar statistics using the Sloan Digital Sky Survey (SDSS). We use the classical Wolf diagram method to identify regions with extinction, and derive the extinction and the extinction law of the dust using all five SDSS spectral bands. We estimate the distance to the extinguishing medium using simple assumptions about the stellar populations in the line of sight. We report the identification of three extinguishing clouds, each a few tens of pc wide, producing 0.2-0.4 mag of g'-band extinction, located 1-2 kpc away or 0.5-1 kpc above the galactic plane. All clouds exhibit grey extinction, i.e., almost wavelength-independent in the limited spectral range of the SDSS. We discuss the implication of this finding on general astrophysical questions.