ARGOS IV: The Kinematics of the Milky Way Bulge

Abstract

We present the kinematic results from our ARGOS spectroscopic survey of the Galactic bulge of the Milky Way. Our aim is to understand the formation of the Galactic bulge. We examine the kinematics of about 17,400 stars in the bulge located within 3.5 kpc of the Galactic centre, identified from the 28,000 star ARGOS survey. We aim to determine if the formation of the bulge has been internally driven from disk instabilities as suggested by its boxy shape, or if mergers have played a significant role as expected from Lambda CDM simulations. From our velocity measurements across latitudes b = -5 deg, -7.5 deg and -10 deg we find the bulge to be a cylindrically rotating system that transitions smoothly out into the disk. Within the bulge, we find a kinematically distinct metal-poor population ([Fe/H] < -1.0) that is not rotating cylindrically. The 5% of our stars with [Fe/H] < -1.0 are a slowly rotating spheroidal population, which we believe are stars of the metal weak thick disk and halo which presently lie in the inner Galaxy. The kinematics of the two bulge components that we identified in ARGOS paper III (mean [Fe/H] = -0.25 and [Fe/H] = +0.15, respectively) demonstrate that they are likely to share a common formation origin and are distinct from the more metal poor populations of the thick disk and halo which are colocated inside the bulge. We do not exclude an underlying merger generated bulge component but our results favour bulge formation from instabilities in the early thin disk.

arXiv commentAccepted MNRAS 25 March 2013, 12 pages, 11 figures

References in corpus (26)

• What determines the strength and the slowdown rate of bars ?
• Simulations of Galaxy Formation in a Lambda CDM Universe II: The Fine Structure of Simulated Galactic Disks
• New Grids of ATLAS9 Model Atmospheres
• Morphology, photometry and kinematics of N-body bars. I Three models with different halo central concentrations
• The Evolution of Isotope Ratios in the Milky Way Galaxy
• Our Milky Way as a Pure-Disk Galaxy -- A Challenge for Galaxy Formation
• The photometric structure of the inner Galaxy
• Bar formation and evolution in disc galaxies with gas and a triaxial halo: Morphology, bar strength and halo properties
• ARGOS III: Stellar Populations in the Galactic Bulge of the Milky Way
• Galaxia: a code to generate a synthetic survey of the Milky Way
• Bar-Halo Interaction and Bar Growth
• A Hierarchical O(N) Force Calculation Algorithm
• Spiral arms, bar shape and bulge microlensing in the Milky Way
• The SAURON project - VII. Integral-field absorption and emission-line kinematics of 24 spiral galaxy bulges
• The Bulge Radial Velocity Assay (BRAVA): II. Complete Sample and Data Release
• Modelling the Galactic Bar Using Red Clump Giants
• A Very Fast and Momentum-Conserving Tree Code
• The two metallicity groups of the globular cluster M22: a chemical perspective
• Chemical Evolution in Hierarchical Models of Cosmic Structure II: The Formation of the Milky Way Stellar Halo and the Distribution of the Oldest Stars
• The distribution and kinematics of early high-sigma peaks in present-day haloes: implications for rare objects and old stellar populations
• The origin of the split red clump in the Galactic bulge of the Milky Way
• Detection of a 45 Degree Tidal Stream Associated with the Globular Cluster NGC 5466
• ARGOS II: The Galactic Bulge Survey
• Kinematics at the Edge of the Galactic Bulge: Evidence for Cylindrical Rotation
• Where are the First Stars now?
• A bar in the inner halo of barred galaxies I. Structure and kinematics of a representative model

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