Galaxy Zoo: A Catalog of Overlapping Galaxy Pairs for Dust Studies

TL;DR

This paper presents a catalog of 1990 overlapping galaxy pairs from SDSS, enabling detailed studies of dust extinction and distribution across various galaxy types, with implications for understanding dust evolution.

Contribution

The creation of a large, diverse catalog of overlapping galaxy pairs specifically designed for dust extinction analysis, leveraging citizen science and SDSS data.

Findings

Catalog includes 1990 galaxy pairs suitable for dust studies

Subsamples useful for measuring UV extinction and disk properties

Potential to study dust distribution variations across galaxy types

Abstract

Analysis of galaxies with overlapping images offers a direct way to probe the distribution of dust extinction and its effects on the background light. We present a catalog of 1990 such galaxy pairs selected from the Sloan Digital Sky Survey (SDSS) by volunteers of the Galaxy Zoo project. We highlight subsamples which are particularly useful for retrieving such properties of the dust distribution as UV extinction, the extent perpendicular to the disk plane, and extinction in the inner parts of disks. The sample spans wide ranges of morphology and surface brightness, opening up the possibility of using this technique to address systematic changes in dust extinction or distribution with galaxy type. This sample will form the basis for forthcoming work on the ranges of dust distributions in local disk galaxies, both for their astrophysical implications and as the low-redshift part of a study of the evolution of dust properties. Separate lists and figures show deep overlaps, where the inner regions of the foreground galaxy are backlit, and the relatively small number of previously-known overlapping pairs outside the SDSS DR7 sky coverage.