Peanut-shaped metallicity distributions in bulges of edge-on galaxies: the case of NGC 4710

Abstract

Bulges of edge-on galaxies are often boxy/peanut-shaped (B/PS), and unsharp masks reveal the presence of an X shape. Simulations show that these shapes can be produced by dynamical processes driven by a bar which vertically thickens the centre. In the Milky Way, which contains such a B/PS bulge, the X-shaped structure is traced by the metal-rich stars but not by the metal-poor ones. Recently Debattista et al. (2016) interpreted this property as a result of the varying effect of the bar on stellar populations with different starting kinematics. This kinematic fractionation model predicts that cooler populations at the time of bar formation go on to trace the X shape, whereas hotter populations are more uniformly distributed. As this prediction is not specific to the Milky Way, we test it with MUSE observations of the B/PS bulge in the nearby galaxy NGC 4710. We show that the metallicity map is more peanut-shaped than the density distribution itself, in good agreement with the prediction. This result indicates that the X-shaped structure in B/PS bulges is formed of relatively metal-rich stars that have been vertically redistributed by the bar, whereas the metal-poor stars have a more uniform, box-shaped distribution.

arXiv commentaccepted for publication in MNRAS Letters, 5 pages, 3 Figures

References in corpus (29)

• Evolutionary tracks and isochrones for low- and intermediate-mass stars: from 0.15 to 7 M_sun, and from Z=0.0004 to 0.03
• Parametric Recovery of Line-of-Sight Velocity Distributions from Absorption-Line Spectra of Galaxies via Penalized Likelihood
• Secular Evolution and the Formation of Pseudobulges in Disk Galaxies
• Adaptive spatial binning of integral-field spectroscopic data using Voronoi tessellations
• The Atlas3D project -- I. A volume-limited sample of 260 nearby early-type galaxies: science goals and selection criteria
• Evolutionary Stellar Population Synthesis with MILES. Part I: The Base Models and a New Line Index System
• The Atlas3D project - XX. Mass-size and mass-sigma distributions of early-type galaxies: bulge fraction drives kinematics, mass-to-light ratio, molecular gas fraction and stellar initial mass function
• The SAURON project. I. The panoramic integral-field spectrograph
• Mergers and Bulge Formation in Lambda-CDM: Which Mergers Matter?
• Mapping the Three-Dimensional Density of the Galactic Bulge with VVV Red Clump Stars
• Our Milky Way as a Pure-Disk Galaxy -- A Challenge for Galaxy Formation
• The Metal Content of Bulge Field Stars from FLAMES-GIRAFFE Spectra. I. Stellar parameters and Iron Abundances
• Empirical calibration of the near-IR Ca II triplet - I. The stellar library and index definition
• A Classical Morphological Analysis of Galaxies in the Spitzer Survey of Stellar Structure in Galaxies (S4G)
• ARGOS III: Stellar Populations in the Galactic Bulge of the Milky Way
• MIUSCAT: extended MILES spectral coverage. I. Stellar populations synthesis models
• 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
• 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
• Reddening and metallicity maps of the Milky Way bulge from VVV and 2MASS III. The first global photometric metallicity map of the Galactic bulge
• The formation of stellar nuclear discs in bar-induced gas inflows
• Exploring the mass assembly of the early-type disc galaxy NGC3115 with MUSE
• A Vertical Resonance Heating Model for X- or Peanut-Shaped Galactic Bulges
• Metallicity Distribution Functions, Radial Velocities, and Alpha Element Abundances in Three Off-Axis Bulge Fields
• Young stars in an old bulge: a natural outcome of internal evolution in the Milky Way
• The 3D structure of the Galactic bulge
• 3D kinematics through the X-shaped Milky Way bulge
• Observed properties of boxy/peanut/barlens bulges
• Comparing the properties of the X-shaped bulges of NGC 4710 and the Milky Way with MUSE

Cited by in corpus (12)

• Chemodynamics of barred galaxies in cosmological simulations: On the Milky Way's quiescent merger history and in-situ bulge
• The Fornax 3D project: unveiling the thick disk origin in FCC 170: signs of accretion?
• The disc origin of the Milky Way bulge: Dissecting the chemo-morphological relations using N-body simulations and APOGEE
• Stars behind bars I: The Milky Way's central stellar populations
• Formation, vertex deviation and age of the Milky Way's bulge: input from a cosmological simulation with a late-forming bar
• The stellar populations of the central region of M31
• Box/peanut-shaped bulges in action space
• Stars behind bars II: A cosmological formation scenario for the Milky Way's central stellar structure
• The disc origin of the Milky Way bulge: On the necessity of the thick disc
• Chemically-dissected rotation curves of the Galactic Bulge from Main Sequence proper motions
• Predicted Trends in Milky Way Bulge Proper Motion Rotation Curves: future Prospects for HST and LSST
• Rediscovering the Milky Way with orbit superposition approach and APOGEE data III. Panoramic view of the bulge