Dwarfs or Giants? Stellar Metallicities and Distances from ugrizG Multiband Photometry

Guillaume F. Thomas*, Nicholaas Annau, Alan McConnachie, Sebastien Fabbro, Hossen Teimoorinia, Patrick Côté, Jean-Charles Cuillandre, Stephen Gwyn, Rodrigo A. Ibata, Else Starkenburg, Raymond Carlberg, Benoit Famaey, Nicholas Fantin, Laura Ferrarese, Vincent Hénault-Brunet, Jaclyn Jensen, Ariane Lançon, Geraint F. Lewis, Nicolas F. Martin, Julio F. NavarroCéline Reylé, Rubén Sánchez-Janssen

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

14 Citations (Scopus)

Abstract

We present a new fully data-driven algorithm that uses photometric data from the Canada-France Imaging Survey (CFIS; u), Pan-STARRS 1(PS1; griz), and Gaia (G) to discriminate between dwarf and giant stars and to estimate their distances and metallicities. The algorithm is trained and tested using the Sloan Digital Sky Survey (SDSS)/SEGUE spectroscopic data set and Gaia photometric/astrometric data set. At[Fe/H] < -1.2, the algorithm succeeds in identifying more than70% of the giants in the training/test set, with a dwarf contamination fraction below 30% (with respect to the SDSS/SEGUE data set). The photometric metallicity estimates have uncertainties better than 0.2 dex when compared with the spectroscopic measurements. The distances estimated by the algorithm are valid out to a distance of at least∼80 kpc without requiring any prior on the stellar distribution and have fully independent uncertainties that take into account both random and systematic errors. These advances allow us to estimate these stellarparameters for approximately 12 million stars in the photometric dataset. This will enable studies involving the chemical mapping of the distant outer disk and the stellar halo, including their kinematics using the Gaia proper motions. This type of algorithm can be applied in the southern hemisphere to the first release of LSST data, thus providing an almost complete view of the external components of ourGalaxy out to at least ∼80 kpc. Critical to the success of these efforts will be ensuring well-defined spectroscopic training sets that sample a broad range of stellar parameters with minimal biases. A catalog containing the training/test set and all relevant parameters within the public footprint of CFIS is available online.
Original languageEnglish
Article number10
Number of pages23
JournalThe Astrophysical Journal
Volume886
Issue number1
DOIs
Publication statusPublished - 1-Nov-2019
Externally publishedYes

Keywords

  • Distance measure
  • Metallicity
  • Milky Way Galaxy
  • Milky Way stellar halo
  • Red giant stars
  • Stellar photometry
  • 395
  • 1031
  • 1054
  • 1060
  • 1372
  • 1620

Fingerprint

Dive into the research topics of 'Dwarfs or Giants? Stellar Metallicities and Distances from ugrizG Multiband Photometry'. Together they form a unique fingerprint.

Cite this