Signatures of the Galactic bar in high-order moments of proper motions measured by Gaia

Abstract

Our location in the Milky Way provides an exceptional opportunity to gain insight on the galactic evolution processes, and complement the information inferred from observations of external galaxies. Since the Milky Way is a barred galaxy, the study of motions of individual stars in the bulge and disc is useful to understand the role of the bar. The Gaia mission enables such study by providing the most precise parallaxes and proper motions to date. In this theoretical work, we explore the effects of the bar on the distribution of higher-order moments --the skewness and kurtosis-- of the proper motions by confronting two simulated galaxies, one with a bar and one nearly axisymmetric, with observations from the latest Gaia data release (GaiaDR2). We introduce the code ASGAIA to account for observational errors of Gaia in the kinematical structures predicted by the numerical models. As a result, we find clear imprints of the bar in the skewness distribution of the longitudinal proper motion ${\mu }_{\ell }$ in GaiaDR2, as well as other features predicted for the next Gaia data releases.

arXiv comment11 pages, 9 figures, accepted in A&A

References in corpus (47)

• 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
• On the variation of the Initial Mass Function
• The Gaia mission
• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• Local Kinematics and the Local Standard of Rest
• Estimating distances from parallaxes IV: Distances to 1.33 billion stars in Gaia Data Release 2
• Evolution of asymptotic giant branch stars II. Optical to far-infrared isochrones with improved TP-AGB models
• The Proper Motion of Sgr A*: II. The Mass of Sgr A*
• Gaia Data Release 2: using Gaia parallaxes
• The Frequency of Barred Spiral Galaxies in the Near-IR
• Estimating distances from parallaxes
• The Effect of the Outer Lindblad Resonance of the Galactic Bar on the Local Stellar Velocity Distribution
• Gaia broad band photometry
• Mapping the Three-Dimensional Density of the Galactic Bulge with VVV Red Clump Stars
• Secular Evolution in Disk Galaxies
• Our Milky Way as a Pure-Disk Galaxy -- A Challenge for Galaxy Formation
• Galaxia: a code to generate a synthetic survey of the Milky Way
• COBE's Galactic Bar and Disk
• Characterizing Bars at z~0 in the optical and NIR: Implications for the Evolution of Barred Disks with Redshift
• Science performance of Gaia, ESA's space-astrometry mission
• Modelling the Galactic Bar Using Red Clump Giants
• StarHorse: A Bayesian tool for determining stellar masses, ages, distances, and extinctions for field stars
• The solar chemical composition
• The Long-term Evolution of the Galactic Disk Traced by Dissolving Star Clusters
• Modelling the Galactic bar using OGLE-II Red Clump Giant Stars
• Estimating distances from parallaxes. II. Performance of Bayesian distance estimators on a Gaia-like catalogue
• Kinematic modelling of the Milky Way using the RAVE and GCS stellar surveys
• A New Photometric Model of the Galactic Bar using Red Clump Giants
• Galactic rotation in Gaia DR1
• Revisiting the Tale of Hercules: how stars orbiting the Lagrange points visit the Sun
• Low-Velocity Streams in the Solar Neighborhood Caused by the Galactic Bar
• New Constraints on the Galactic Bar
• A boxy bulge in the Milky Way. Inversion of the stellar statistics equation with 2MASS data
• The Oort Constants Measured from Proper Motions
• Signatures of Bulge Triaxiality from Kinematics in Baade's Window/
• Chemodynamical Modelling of the Galactic Bulge and Bar
• The Apache Point Observatory Galactic Evolution Experiment: First Detection of High Velocity Milky Way Bar Stars
• Proper Motion Dispersions of Red Clump Giants in the Galactic Bulge: Observations and Model Comparisons
• The X-Shaped Milky Way Bulge in OGLE-III Photometry and in N-Body Models
• The Hercules stream as seen by APOGEE-2 South
• Kinematics in the Galactic Bulge with APOGEE: II. High-Order Kinematical Moments and Comparison to Extragalactic Bar Diagnostics
• The stellar kinematics of co-rotating spiral arms in Gaia mock observations
• Orbits of selected globular clusters in the Galactic bulge
• Resonant Orbits and the High Velocity Peaks Towards the Bulge
• Galactic Orbits of Globular Clusters in the Region of the Galactic Bulge
• Signatures of the Galactic bar on stellar kinematics unveiled by APOGEE

Cited by in corpus (2)

• Spiral-like features in the disc revealed by Gaia DR3 radial actions
• 2D chemical evolution models II. Effects of multiple spiral arm patterns on O, Eu, Fe and Ba abundance gradients