We present results studying the distribution and properties of the diffuse dust in the Milky Way Galaxy using large optical surveys—specifically, the Sloan Digital Sky Survey (SDSS) and the Panoramic Survey Telescope and Rapid Response System 1 (Pan-STARRS1). This work has resulted in accurate measurements of dust reddening in regions of low extinction over large regions of sky. We present maps of reddening from dust covering the footprint of the SDSS, which covers one quarter of the sky. We present preliminary maps of dust covering the Pan-STARRS1 footprint, which covers three-quarters of the sky, including most of the plane of our Galaxy. We use these maps of dust to decisively exclude some simple parameterizations of dust extinction (Cardelli et al., 1989) in favor of others (Fitzpatrick, 1999). We show that the extinction predicted by the widely-used far-infrared dust map of Schlegel et al. (1998) is overestimated by 18%, and recalibrate that map using our extinction measurements. We further map variation in the properties of the dust, as indicated by variation in the amount of extinction relative to the amout of far-infrared dust extinction, and by variation in the ratio of dust extinction at different frequencies. We confirm these results by measuring reddening using two independent techniques and data sets, the SDSS photometry and spectroscopy. We further present the photometric calibration of the Pan-STARRS1 data—a necessary step to studying the dust with that ongoing survey. We achieve photometric precision unprecedented in a large optical survey, accurate to better than 1%. We additionally show the suitability of the calibrated photometry for studying the distribution of dust. Finally, we present preliminary three-dimensional maps of the dust in the Galaxy using our calibrated data from Pan-STARRS1. These maps will provide by far the most extensive information yet achieved about the three-dimensional distribution of extinction in the Galaxy. / Physics
| Identifer | oai:union.ndltd.org:harvard.edu/oai:dash.harvard.edu:1/9366601 |
| Date | 03 August 2012 |
| Creators | Schlafly, Edward Ford |
| Contributors | Finkbeiner, Douglas |
| Publisher | Harvard University |
| Source Sets | Harvard University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis or Dissertation |
| Rights | open |
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