Variable star classification across the Galactic bulge and disc with the VISTA Variables in the Vía Láctea survey

Thomas A. Molnar, Jason L. Sanders, Leigh C. Smith, Vasily Belokurov, Philip Lucas, Dante Minniti

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

We present VIVACE, the VIrac VAriable Classification Ensemble, a catalogue of variable stars extracted from an automated classification pipeline for the Vista Variables in the Vía Láctea (VVV) infrared survey of the Galactic bar/bulge and southern disc. Our procedure utilizes a two-stage hierarchical classifier to first isolate likely variable sources using simple variability summary statistics and training sets of non-variable sources from the Gaia early third data release, and then classify candidate variables using more detailed light-curve statistics and training labels primarily from OGLE and VSX. The methodology is applied to point-spread-function photometry for 490 million light curves from the VIRAC v2 astrometric and photometric catalogue resulting in a catalogue of 1.4 million likely variable stars, of which 39 000 are high-confidence (classification probability >0.9) RR Lyrae ab stars, 8000 RR Lyrae c/d stars, 187, 000 detached/semi-detached eclipsing binaries, 18, 000 contact eclipsing binaries, 1400 classical Cepheid variables and 2200 Type II Cepheid variables. Comparison with OGLE-4 suggests a completeness of around $90, $ for RRab and $lesssim 60, $ for RRc/d, and a misclassification rate for known RR Lyrae stars of around $1, $ for the high confidence sample. We close with two science demonstrations of our new VIVACE catalogue: first, a brief investigation of the spatial and kinematic properties of the RR Lyrae stars within the disc/bulge, demonstrating the spatial elongation of bar-bulge RR Lyrae stars is in the same sense as the more metal-rich red giant population whilst having a slower rotation rate of $sim !40, {km, s}{-1}{kpc}{-1}$ and secondly, an investigation of the GaiaEDR3 parallax zero-point using contact eclipsing binaries across the Galactic disc plane and bulge.

Original languageEnglish
Pages (from-to)2566-2592
Number of pages27
JournalMonthly Notices of the Royal Astronomical Society
Volume509
Issue number2
DOIs
Publication statusPublished - 1 Jan 2022

Keywords

  • binaries
  • catalogues
  • eclipsing
  • general
  • RR Lyrae
  • stars
  • surveys
  • variables

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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