VVV catalog of ab-type RR Lyrae in the inner Galactic bulge

Abstract

Context. Observational evidence has accumulated in the past years, showing that the Galactic bulge includes two populations, a metal poor and a metal rich one that, in addition to a different metallicity, show different alpha over iron abundances, spatial distribution, and kinematics. While the metal rich, barred component has been fairly well characterized, the metal poor, spheroidal component has been more elusive and harder to describe. RR Lyrae variables are clean tracers of the old bulge component, and they are, on average, more metal poor than red clump stars. Aims. In the present paper, we provide a new catalog of 16488 ab type RR Lyrae variables in the bulge region within -10<l<10 and -2.8<b<2.8, extracted from multi epoch PSF photometry performed on VISTA Variable in the Via Lactea survey data. We used the catalog to constrain the shape of the old, metal poor, bulge stellar population. Methods. The identification of ab type RR Lyrae among a large sample of candidate variables of different types has been performed via a combination of a Random Forest classifier and visual inspection... [abridged] Results. We use the present catalog to derive the shape of their distribution around the Galactic Center, resulting in an elongated spheroid with projected axis ratio b/a~0.7 and inclination angle ~20 degrees. We discuss how observational biases such as errors on the distances and a non-uniform sampling in longitude, affect both the present measurements and previous ones, especially those based on red clump stars... [abridged] Conclusions. We publish a high purity RRab sample for future studies of the oldest Galactic bulge population, close to the midplane. We explore different choices for the period-luminosity-metallicity relation, highlighting how some of them introduce spurious trends of distances with either period or metallicity, or both... [abridged]

arXiv commentAccepted for publication in Astronomy & Astrophysics

References in corpus (63)

• Secular Evolution and the Formation of Pseudobulges in Disk Galaxies
• VISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way
• Mapping the Three-Dimensional Density of the Galactic Bulge with VVV Red Clump Stars
• Near-Infrared Photometric Variability of Stars Toward the Orion A Molecular Cloud
• On Machine-Learned Classification of Variable Stars with Sparse and Noisy Time-Series Data
• The mass distribution in the Galactic Centre from interferometric astrometry of multiple stellar orbits
• Clumpy Galaxies in CANDELS. I. The Definition of UV Clumps and the Fraction of Clumpy Galaxies at 0.5<z<3
• Improved GRAVITY astrometric accuracy from modeling of optical aberrations
• The origin of the split red clump in the Galactic bulge of the Milky Way
• Separation of Stellar Populations by an Evolving Bar: Implications for the Bulge of the Milky Way
• Deciphering the 3D structure of the old Galactic bulge from the OGLE RR Lyrae stars
• Hubble Space Telescope Proper Motion (HSTPROMO) Catalogs of Galactic Globular Clusters. I. Sample Selection, Data Reduction and NGC 7078 Results
• The GIRAFFE Inner Bulge Survey (GIBS) III. Metallicity distributions and kinematics of 26 Galactic bulge fields
• Chemodynamics of barred galaxies in cosmological simulations: On the Milky Way's quiescent merger history and in-situ bulge
• Ground-Based CCD Astrometry with Wide Field Imagers. I. [Observations just a few years apart allow decontamination of field objects from members in two Globular clusters.]
• The Gaia-ESO Survey: metallicity and kinematic trends in the Milky Way bulge
• RR Lyrae stars as standard candles in the Gaia Data Release 2 Era
• The VISTA ZYJHKs Photometric System: Calibration from 2MASS
• VVV Survey Near-Infrared Photometry of Known Bulge RR Lyrae stars: the Distance to the Galactic Center and Absence of a Barred Distribution of the Metal-Poor Population
• A New Photometric Model of the Galactic Bar using Red Clump Giants
• The Milky Way bar and bulge revealed by APOGEE DR16 and Gaia EDR3
• The nature of giant clumps in distant galaxies probed by the anatomy of the Cosmic Snake
• Clumpy Galaxies in CANDELS. II. Physical Properties of UV-bright Clumps at $0.5\le z<3$
• Before the Bar: Kinematic Detection of A Spheroidal Metal-Poor Bulge Component
• QSO Selection Algorithm Using Time Variability and Machine Learning: Selection of 1,620 QSO Candidates from MACHO LMC Database
• Analysis of RR Lyrae Stars in the Northern Sky Variability Survey
• The disc origin of the Milky Way bulge: Dissecting the chemo-morphological relations using N-body simulations and APOGEE
• The Optical Gravitational Lensing Experiment: Analysis of the bulge RR Lyrae population from the OGLE-III data
• A direct measurement of the distance to the Galactic center using the kinematics of bar stars
• A parametric description of the 3D structure of the Galactic Bar/Bulge using the VVV survey
• On the stellar masses of giant clumps in distant star-forming galaxies
• The disc origin of the Milky Way bulge
• Standard Galactic Field RR Lyrae II: A Gaia DR2 calibration of the period-Wesenheit-metallicity relation
• The Bar and Spiral Arms in the Milky Way: Structure and Kinematics
• Stellar Masses of Giant Clumps in CANDELS and Simulated Galaxies Using Machine Learning
• Mapping the outer bulge with RRab stars from the VVV Survey
• Mapping the stellar age of the Milky Way bulge with the VVV. III. High resolution reddening map
• A machine learned classifier for RR Lyrae in the VVV survey
• The VVV Survey RR Lyrae Population in the Galactic Centre Region
• Proper motions in the VVV Survey: Results for more than 15 million stars across NGC 6544
• The ISLAnds Project III: Variable Stars in Six Andromeda Dwarf Spheroidal Galaxies
• On the optimal calibration of VVV photometry
• Identifying RR Lyrae Variable Stars in Six Years of the Dark Energy Survey
• A New Estimate of the Best Value for the Solar Galactocentric Distance
• A Data-driven Study of RR Lyrae Near-IR Light Curves: Principal Component Analysis, Robust Fits, and Metallicity Estimates
• Using classical Cepheids to study the far side of the Milky Way disk: I. Spectroscopic classification and the metallicity gradient
• New Near-Infrared $JH{K}_s$ light-curve templates for RR Lyrae variables
• Weighing the two stellar components of the Galactic Bulge
• Kinematics of RR Lyrae stars in the Galactic bulge with OGLE-IV and Gaia DR2
• Establishing the Galactic Centre Distance Using VVV Bulge RR Lyrae Variables
• An Updated Census of RR~Lyrae Stars in the Globular Cluster $\omega$~Centauri (NGC\,5139)
• Identification of RR Lyrae stars in multiband, sparsely-sampled data from the Dark Energy Survey using template fitting and Random Forest classification
• The far side of the Galactic bar/bulge revealed through semi-regular variables
• The imprint of clump formation at high redshift. II. The chemistry of the bulge
• Precise Empirical Determination of Metallicity Dependence of Near-infrared Period-Luminosity Relations for RR Lyrae Variables
• An Automated tool to detect variable sources in the Vista Variables in the V\'ıa Láctea Survey. The VVV Variables (V${}^4$) catalog of tiles d001 and d002
• The VVV survey: Long-period variable stars I. Photometric catalog of ten VVV/OGLE tiles
• Blanco DECam Bulge Survey (BDBS) III: A new view of the double red clump in the Milky Way bulge through luminosity and color distribution
• New Near-Infrared Period-Luminosity-Metallicity Relations for Galactic RR Lyrae Stars Based on Gaia EDR3 Parallaxes
• Near-Infrared Search for Fundamental-mode RR Lyrae Stars Toward the Inner Bulge by Deep Learning
• Comparing bulge RR Lyrae stars with bulge giants -- Insight from 3D kinematics
• Automated classification of eclipsing binary systems in the VVV Survey
• Automatic Catalog of RRLyrae from $\sim$ 14 million VVV Light Curves: How far can we go with traditional machine-learning?

Cited by in corpus (3)

• The Galactic Bulge exploration IV.: RR~Lyrae stars as traces of the Galactic bar -- 3D and 5D analysis, extinction variation
• Globular clusters in \textsc{OrbIT}: complete dynamical characterisation of the globular cluster population of the Milky Way through updated orbital reconstruction
• On the Use of Field RR Lyrae as Galactic Probes -- VIII. Early Formation of the Galactic Spheroid