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Title: The Segue K giant survey. II. A catalog of distance determinations for the Segue K giants in the galactic halo

We present an online catalog of distance determinations for 6036 K giants, most of which are members of the Milky Way's stellar halo. Their medium-resolution spectra from the Sloan Digital Sky Survey/Sloan Extension for Galactic Understanding and Exploration are used to derive metallicities and rough gravity estimates, along with radial velocities. Distance moduli are derived from a comparison of each star's apparent magnitude with the absolute magnitude of empirically calibrated color-luminosity fiducials, at the observed (g – r){sub 0} color and spectroscopic [Fe/H]. We employ a probabilistic approach that makes it straightforward to properly propagate the errors in metallicities, magnitudes, and colors into distance uncertainties. We also fold in prior information about the giant-branch luminosity function and the different metallicity distributions of the SEGUE K-giant targeting sub-categories. We show that the metallicity prior plays a small role in the distance estimates, but that neglecting the luminosity prior could lead to a systematic distance modulus bias of up to 0.25 mag, compared to the case of using the luminosity prior. We find a median distance precision of 16%, with distance estimates most precise for the least metal-poor stars near the tip of the red giant branch. The precision and accuracy ofmore » our distance estimates are validated with observations of globular and open clusters. The stars in our catalog are up to 125 kpc from the Galactic center, with 283 stars beyond 50 kpc, forming the largest available spectroscopic sample of distant tracers in the Galactic halo.« less
Authors:
;  [1] ; ; ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ;  [9] ;  [10] ;  [11] ;  [12] ;  [13]
  1. Max-Planck-Institute for Astronomy Königstuhl 17, D-69117 Heidelberg (Germany)
  2. Department of Astronomy, Case Western Reserve University, Cleveland, OH 44106 (United States)
  3. National Optical Astronomy Observatories, Tucson, AZ 85719 (United States)
  4. Department of Physics and Astronomy, The University of Utah, Salt Lake City, UT 84112 (United States)
  5. Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48823 (United States)
  6. Department of Astronomy, 4055 McPherson Laboratory, 140 West 18th Avenue, Columbus, OH 43210 (United States)
  7. Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States)
  8. Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, I-35122 Padua (Italy)
  9. Lick Observatory/University of California, Santa Cruz, CA 95060 (United States)
  10. Laboratoire Lagrange (UMR7293), Universite de Nice Sophia Antipolis, CNRS, Observatoire de la Cote d'Azur, BP 4229, F-06304 Nice Cedex 04 (France)
  11. Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States)
  12. Key Lab of Optical Astronomy, National Astronomical Observatories, CAS, 20A Datun Road, Chaoyang District, 100012 Beijing (China)
  13. Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain)
Publication Date:
OSTI Identifier:
22357237
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 784; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCURACY; CATALOGS; COLOR; DISTANCE; DISTRIBUTION; EXPLORATION; GALAXIES; GIANT STARS; GRAVITATION; INFORMATION; LUMINOSITY; METALLICITY; MILKY WAY; PROBABILISTIC ESTIMATION; RADIAL VELOCITY; RESOLUTION; SPECTRA; STARS