A fresh look at the RR Lyrae population in the Draco dwarf spheroidal galaxy with Gaia

Abstract

We present a catalogue of 285 RR Lyrae stars (RRLs) in the Draco dwarf spheroidal galaxy (dSph), obtained by combining data from a number of different surveys including the second data release (DR2) of the European Space Agency (ESA) cornerstone mission Gaia. We have determined individual distances to the RRLs in our sample using for the first time a Gaia G-band luminosity-metallicity relation (MG - [Fe/H]) and study the structure of the Draco dSph as traced by its RRL population. We find that the RRLs located in the western/south-western region of Draco appear to be closer to us, which may be a clue of interaction between Draco and the Milky Way (MW). The average distance modulus of Draco measured with the RRLs is 19.53 +/- 0.07 mag, corresponding to a distance of 80.5 +/- 2.6 kpc, in good agreement with previous determinations in the literature. Based on the pulsation properties of the RRLs we confirm the Oosterhoff-intermediate nature of Draco. We present an additional sample of 41 candidate RRLs in Draco, which we selected from the Gaia DR2 catalogue based on the uncertainty of their G-band magnitudes. Additional epoch data that will become available in the Gaia third data release (DR3) will help to confirm whether these candidates are bona-fide Draco RRLs.

arXiv comment15 pages, 14 figures, 5 tables. Accepted for publication in MNRAS

References in corpus (57)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• Gaia Data Release 2. Summary of the contents and survey properties
• The Gaia mission
• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• Gaia Data Release 2: The astrometric solution
• The observed properties of dwarf galaxies in and around the Local Group
• The Palomar Transient Factory: System Overview, Performance and First Results
• The Universal Stellar Mass-Stellar Metallicity Relation for Dwarf Galaxies
• Gaia Data Release 2: Photometric content and validation
• Gaia Data Release 2: Kinematics of globular clusters and dwarf galaxies around the Milky Way
• Gaia Data Release 2: Catalogue validation
• Numerical Methods of Star Formation History Measurement and Applications to Seven Dwarf Spheroidals
• The Star Formation Histories of Local Group Dwarf Galaxies I. Hubble Space Telescope / Wide Field Planetary Camera 2 Observations
• The Catalina Surveys Periodic Variable Star Catalog
• Gaia Data Release 1: Catalogue validation
• Magellanic Cloud Structure from Near-IR Surveys I: The Viewing Angles of the LMC
• The RR Lyrae Period-Luminosity Relation. I. Theoretical Calibration
• Probing the Outer Galactic halo with RR Lyrae from the Catalina Surveys
• Machine-Learned Identification of RR Lyrae Stars from Sparse, Multi-band Data: the PS1 Sample
• A pulsational approach to near infrared and visual magnitudes of RR Lyrae stars
• The Draco and Ursa Minor dwarf spheroidals. A comparative study
• RR Lyrae stars as standard candles in the Gaia Data Release 2 Era
• Exploring the Variable Sky with LINEAR. III. Classification of Periodic Light Curves
• The Star Formation History and the Morphological Evolution of the Draco Dwarf Spheroidal Galaxy
• Exploring the Variable Sky with LINEAR. II. Halo Structure and Substructure Traced by RR Lyrae Stars to 30 kpc
• Evidence for a Milky Way Tidal Stream Reaching Beyond 100 kpc
• The RR Lyrae Period - K Luminosity relation for Globular Clusters: an observational approach
• Globular Cluster Distances from RR Lyrae Stars
• Gaia Data Release 1. Testing the parallaxes with local Cepheids and RR Lyrae stars
• Bayesian analysis of resolved stellar spectra: application to MMT/Hectochelle Observations of the Draco dwarf spheroidal
• RR Lyrae variables: visual and infrared luminosities, intrinsic colours, and kinematics
• Comparison of Distances from RR Lyrae Stars, the Tip of the Red-Giant Branch and Classical Cepheids
• Gaia Data Release 1 - The Cepheid & RR Lyrae star pipeline and its application to the south ecliptic pole region
• The RR Lyrae Distance to the Draco Dwarf Spheroidal Galaxy
• The Variable Stars of the Draco Dwarf Spheroidal Galaxy - Revisited
• Hubble Space Telescope Observations of the Draco Dwarf Spheroidal
• The Globular Cluster Omega Centauri and the Oosterhoff Dichotomy
• CU Comae: a new field double-mode RR Lyrae, the most metal poor discovered to date
• New near-infrared period-luminosity-metallicity relations for RR Lyrae stars and the outlook for Gaia
• Gaia Data Release 2: Summary of the variability processing & analysis results
• On a new theoretical framework for RR Lyrae stars II: Mid--Infrared Period--Luminosity--Metallicity Relations
• The infrared JHK light curves of RR Lyr
• A Probabilistic Approach to Fitting Period-Luminosity Relations and Validating Gaia Parallaxes
• A Preliminary Calibration of the RR Lyrae Period-Luminosity Relation at Mid-Infrared Wavelengths: WISE Data
• Gaia Data Release 2: All-sky classification of high-amplitude pulsating stars
• On the distance of the globular cluster M4 (NGC 6121) using RR Lyrae stars: II. Mid-infrared period-luminosity relations
• On a new method to estimate distance, reddening and metallicity of RR Lyrae stars using optical/near-infrared ($B$,$V$,$I$,$J$,$H$,$K$) mean magnitudes: $\omega$ Centauri as a first test case
• Mid-infrared PL relations for Globular Cluster RR Lyrae
• Newly Discovered RR Lyrae Stars in the SDSSXPanXSTARRS1XCatalina Footprint
• Mid-Infrared Period--Luminosity Relations of RR Lyrae Stars Derived from the AllWISE Data Release
• The All Sky Automated Survey. A Catalog of almost 3900 variable stars
• Predicted properties of RR Lyrae stars in the SDSS photometric system
• Precision distances to dwarf galaxies and globular clusters from Pan-STARRS1 3$\pi$ RR Lyrae
• The Carnegie RR Lyrae Program: Mid-infrared Period-Luminosity relations of RR Lyrae stars in Reticulum
• The Draco dwarf galaxy in the near-infrared
• A hierarchical Bayesian model to infer PL(Z) relations using Gaia parallaxes
• Pulsating variable stars in the Magellanic Clouds

Cited by in corpus (10)

• Gaia early DR3 systemic motions of Local Group dwarf galaxies and orbital properties with a massive Large Magellanic Cloud
• RR Lyrae From Binary Evolution: Abundant, Young and Metal-Rich
• Timing the r-Process Enrichment of the Ultra-Faint Dwarf Galaxy Reticulum II
• HSTPROMO Internal Proper Motion Kinematics of Dwarf Spheroidal Galaxies: I. Velocity Anisotropy and Dark Matter Cusp Slope of Draco
• Stellar proper motions in the outskirts of classical dwarf spheroidal galaxies with Gaia EDR3
• On the Use of Field RR Lyrae as Galactic Probes. VI. Mixed mode RR Lyrae variables in Fornax and in nearby dwarf galaxies
• The VMC Survey -- LIV. Anomalous Cepheids in the Magellanic Clouds Period-Luminosity relations in the near-infrared bands
• The mass-metallicity relation at z>3 down to M_*= 10^4 M_Sun. A local perspective using the metallicity distribution of RR Lyrae stars
• Constraining the shape of Milky Way satellites with distance gradients
• rrlfe: Software for Generating and Applying Metallicity Calibrations for RR Lyrae Variable Stars Across a Wide Range of Phases and Temperatures