Spectrophotometric Parallaxes with Linear Models: Accurate Distances for Luminous Red-giant Stars
Year: 2019
Type: article
Abstract: With contemporary infrared spectroscopic surveys like APO Galactic Evolution Experiment ( APOGEE ), red-giant stars can be observed to distances and extinctions at which Gaia parallaxes are not highly informative. Yet the combination of effective temperature, surface gravity, composition, and age—all accessible through spectroscopy—determines a giant’s luminosity. Therefore spectroscopy plus photometry should enable precise spectrophotometric distance estimates. Here we use the overlap of APOGEE, Gaia , the Two Micron All Sky Survey (2MASS), the and Wide-field Infrared Survey Explorer ( WISE ) to train a data-driven model to predict parallaxes for red-giant branch stars with (more luminous than the red clump). We employ (the exponentiation of) a linear function of APOGEE spectral pixel intensities and multiband photometry to predict parallax spectrophotometrically. The model training involves no logarithms or inverses of the Gaia parallaxes, and needs no cut on the Gaia parallax signal-to-noise ratio. It includes an L1 regularization to zero out the contributions of uninformative pixels. The training is performed with leave-out subsamples such that no star’s astrometry is used even indirectly in its spectrophotometric parallax estimate. The model implicitly performs a reddening and extinction correction in its parallax prediction, without any explicit dust model. We assign to each star in the sample a new spectrophotometric parallax estimate; these parallaxes have uncertainties of less than 15%, depending on data quality, which is more precise than the Gaia parallax for the vast majority of targets, and certainly any stars more than a few kiloparsec distance. We obtain 10% distance estimates out to heliocentric distances of 20 kpc, and make global maps of the Milky Way’s disk.
Source: The Astronomical Journal
Authors: David W. Hogg, Anna-Christina Eilers, Hans-Walter Rix
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funders: National Science Foundation, Smithsonian Institution, U.S. Department of Energy, National Aeronautics and Space Administration, Alfred P. Sloan Foundation, Yale University, Carnegie Institution of Washington, Vanderbilt University, Ohio State University, California Institute of Technology, University of Washington, Johns Hopkins University, Carnegie Mellon University, University of Notre Dame, University of Portsmouth, New Mexico State University, European Space Agency, Flatiron Health, York University, University of Oxford, Ministério da Ciência, Tecnologia e Inovação, Universidad Nacional Autónoma de México, Max-Planck-Institut für Astrophysik, Max-Planck-Institut für Astronomie, Instituto de Astrofísica de Canarias, Office of Science, Jet Propulsion Laboratory, University of California, Los Angeles, University of Colorado Boulder, Smithsonian Astrophysical Observatory, Leibniz-Gemeinschaft, Lawrence Berkeley National Laboratory
OpenAlex ID: W2896289061