Kinematic properties of double-barred galaxies: simulations vs. integral-field observations

Abstract

Using high resolution $N$-body simulations, we recently reported that a dynamically cool inner disk embedded in a hotter outer disk can naturally generate a steady double-barred (S2B) structure. Here we study the kinematics of these S2B simulations, and compare them to integral-field observations from ATLAS${}^{3D}$ and SAURON. We show that S2B galaxies exhibit several distinct kinematic features, namely: (1) significantly distorted isovelocity contours at the transition region between the two bars, (2) peaks in ${\sigma }_{\mathrm{LOS}}$ along the minor axis of inner bars, which we term "$\sigma$-humps", that are often accompanied by ring/spiral-like features of increased ${\sigma }_{\mathrm{LOS}}$, (3) $h_3-\bar{v}$ anti-correlations in the region of the inner bar for certain orientations, and (4) rings of positive $h_4$ when viewed at low inclinations. The most impressive of these features are the $\sigma$-humps, these evolve with the inner bar, oscillating in strength just as the inner bar does as it rotates relative to the outer bar. We show that, in cylindrical coordinates, the inner bar has similar streaming motions and velocity dispersion properties as normal large-scale bars, except for ${\sigma }_z$, which exhibits peaks on the minor axis, i.e., humps. These ${\sigma }_z$ humps are responsible for producing the $\sigma$-humps. For three well-resolved early-type S2Bs (NGC 2859, NGC 2950, and NGC 3941) and a potential S2B candidate (NGC 3384), the S2B model qualitatively matches the integral-field data well, including the "$\sigma$-hollows" previously identified. We also discuss the kinematic effect of a nuclear disk in S2Bs.

arXiv commentaccepted for publication in ApJ, 15 pages, 13 figures

References in corpus (44)

• Parametric Recovery of Line-of-Sight Velocity Distributions from Absorption-Line Spectra of Galaxies via Penalized Likelihood
• 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
• The SAURON project - V. Integral-field emission-line kinematics of 48 elliptical and lenticular galaxies
• The SAURON project -- X. The orbital anisotropy of elliptical and lenticular galaxies: revisiting the (V/sigma,epsilon) diagram with integral-field stellar kinematics
• The SAURON project - III. Integral-field absorption-line kinematics of 48 elliptical and lenticular galaxies
• The ATLAS3D project - II. Morphologies, kinemetric features and alignment between photometric and kinematic axes of early-type galaxies
• Our Milky Way as a Pure-Disk Galaxy -- A Challenge for Galaxy Formation
• Nested and Single Bars in Seyfert and Non-Seyfert Galaxies
• The SAURON project - VII. Integral-field absorption and emission-line kinematics of 24 spiral galaxy bulges
• How Large Are the Bars in Barred Galaxies?
• Bulges Of Nearby Galaxies With Spitzer: Scaling Relations in Pseudobulges and Classical Bulges
• Bar Diagnostics in Edge-On Spiral Galaxies. III. N-Body Simulations of Disks
• Double Bars, Inner Disks, and Nuclear Rings in Early-Type Disk Galaxies
• Dynamics of embedded bars and the connection with AGN. I. ISAAC/VLT stellar kinematics
• Composite Bulges: The Coexistence of Classical Bulges and Disky Pseudobulges in S0 and Spiral Galaxies
• An Imaging Survey of Early-Type Barred Galaxies
• The Kinematic Signature of Face-On Peanut-Shaped Bulges
• When Is a Bulge Not a Bulge? Inner Disks Masquerading as Bulges in NGC 2787 and NGC 3945
• The formation of stellar nuclear discs in bar-induced gas inflows
• Direct Confirmation of Two Pattern Speeds in the Double Barred Galaxy NGC 2950
• Dynamical Decoupling of Nested Bars: Self-Gravitating Gaseous Nuclear Bars
• Orbits Supporting Bars within Bars
• Secular- and merger-built bulges in barred galaxies
• Structure and kinematics of candidate double-barred galaxies
• 2D kinematic signatures of boxy/peanut bulges
• Instabilities of a family of oblate stellar spheroids
• Long-Lived Double-Barred Galaxies From Pseudo-Bulges
• Induced Nested Galactic Bars Inside Assembling Dark Matter Halos
• Nested Bars in Disk Galaxies: No Offset Dust Lanes in Secondary Nuclear Bars
• Constraining the formation of inner bars. Photometry, kinematics and stellar populations in NGC 357
• Regular Orbits and Periodic Loops in Multiply-Barred Galactic Potentials
• Distinct stellar populations in the inner bars of double-barred galaxies
• Observable Properties of Double-Barred Galaxies in N-Body Simulations
• Stellar kinematics in double-barred galaxies: the sigma-hollows
• Forming Double-barred Galaxies From Dynamically Cool Inner Disks
• How can double-barred galaxies be long-lived?
• Kinematics of the X-shaped Milky Way Bulge: Expectations from a Self-consistent N-body Model
• The effect of projection on the observed gas velocity fields in barred galaxies
• Regular motions in double bars. I. Double-frequency orbits and loops
• Regular motions in double bars. II. Survey of trajectories and 23 models
• Spontaneous formation of double bars in dark matter dominated galaxies
• Molecular Gas in Candidate Double Barred Galaxies III. A Lack of Molecular Gas?
• Orbital Support of Fast and Slow Inner Bars in Double Barred Galaxies

Cited by in corpus (8)

• Clocking the assembly of double-barred galaxies with the MUSE TIMER project
• Inner bars also buckle. The MUSE TIMER view of the double-barred galaxy NGC 1291
• A New Channel of Bulge Formation via The Destruction of Short Bars
• Black Hole Growth in Disk Galaxies Mediated by the Secular Evolution of Short Bars
• Time-dependent Pattern Speeds in Barred Galaxies
• Chemical abundances and ages of the bulge stars in APOGEE high-velocity peaks
• Orthogonal vertical velocity dispersion distributions produced by bars
• Local variations of the Stellar Velocity Ellipsoid-II: the effect of the bar in the inner regions of Auriga galaxies