Nearby resolved dwarf galaxies provide excellent opportunities for studying the dust-producing late stages of stellar evolution over a wide range of metallicity ( -2.7 \lesssim [ { Fe / H } ] \lesssim - 1.0 ) .
Here , we describe DUSTiNGS ( DUST in Nearby Galaxies with Spitzer ) : a 3.6 and 4.5 µm post-cryogen Spitzer Space Telescope imaging survey of 50 dwarf galaxies within 1.5 Mpc that is designed to identify dust-producing Asymptotic Giant Branch ( AGB ) stars and massive stars .
The survey includes 37 dwarf spheroidal , 8 dwarf irregular , and 5 transition-type galaxies .
This near-complete sample allows for the building of statistics on these rare phases of stellar evolution over the full metallicity range .
The photometry is > 75 % complete at the tip of the Red Giant Branch for all targeted galaxies , with the exception of the crowded inner regions of IC 10 , NGC 185 , and NGC 147 .
This photometric depth ensures that the majority of the dust-producing stars , including the thermally-pulsing AGB stars , are detected in each galaxy .
The images map each galaxy to at least twice the half-light radius to ensure that the entire evolved star population is included and to facilitate the statistical subtraction of background and foreground contamination , which is severe at these wavelengths .
In this overview , we describe the survey , the data products , and preliminary results .
We show evidence for the presence of dust-producing AGB stars in 8 of the targeted galaxies , with metallicities as low as { [ Fe / H ] } = -1.9 , suggesting that dust production occurs even at low metallicity .