Extinction maps toward the Milky Way bulge: Two-dimensional and three-dimensional tests with apogee
- Université de Nice Sophia-Antipolis, CNRS, Observatoire de Côte d'Azur, Laboratoire Lagrange, 06304 Nice Cedex 4 (France)
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States)
- Instituto de Astrofísica de Canarias, Calle Vía Láctea s/n, E-38205 La Laguna, Tenerife (Spain)
- Leibniz-Institut für Astrophysik Potsdam (AIP), D-14482 Potsdam (Germany)
- Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States)
- National Optical Astronomy Observatory, Tucson, AZ 85719 (United States)
- Apache Point Observatory, Sunspot, NM 88349 (United States)
- Department of Physics and Astronomy, Texas Christian University, TCU Box 298840, Fort Worth, TX 76129 (United States)
- Astronomy Department, University of Florida, Gainesville, FL 32611 (United States)
- Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States)
- New Mexico State University, Las Cruces, NM 88003 (United States)
- Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States)
- Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States)
Galactic interstellar extinction maps are powerful and necessary tools for Milky Way structure and stellar population analyses, particularly toward the heavily reddened bulge and in the midplane. However, due to the difficulty of obtaining reliable extinction measures and distances for a large number of stars that are independent of these maps, tests of their accuracy and systematics have been limited. Our goal is to assess a variety of photometric stellar extinction estimates, including both two-dimensional and three-dimensional extinction maps, using independent extinction measures based on a large spectroscopic sample of stars toward the Milky Way bulge. We employ stellar atmospheric parameters derived from high-resolution H-band Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectra, combined with theoretical stellar isochrones, to calculate line-of-sight extinction and distances for a sample of more than 2400 giants toward the Milky Way bulge. We compare these extinction values to those predicted by individual near-IR and near+mid-IR stellar colors, two-dimensional bulge extinction maps, and three-dimensional extinction maps. The long baseline, near+mid-IR stellar colors are, on average, the most accurate predictors of the APOGEE extinction estimates, and the two-dimensional and three-dimensional extinction maps derived from different stellar populations along different sightlines show varying degrees of reliability. We present the results of all of the comparisons and discuss reasons for the observed discrepancies. We also demonstrate how the particular stellar atmospheric models adopted can have a strong impact on this type of analysis, and discuss related caveats.
- OSTI ID:
- 22342294
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 148, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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