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In an effort to better understand the formation and evolution of barred galaxies, we have examined the properties of equatorial orbits in the effective potential of one model of a rapidly rotating, steady-state gas-dynamical bar that has…

Astrophysics · Physics 2009-11-06 Eric Barnes , Joel E. Tohline

We present an analysis of major-axis surface-brightness profiles of bars in a volume-limited sample of 182 barred spiral galaxies, using Spitzer 3.6 micron images. Unlike most previous studies, we use the entire bar profile, and we classify…

Astrophysics of Galaxies · Physics 2023-07-12 Peter Erwin , Victor P. Debattista , Stuart Robert Anderson

We study a sample of bar-like galaxies in the Illustris TNG100 simulation, in which almost the whole stellar component is in the form of a prolate spheroid. The sample is different from the late-type barred galaxies studied before. In…

Astrophysics of Galaxies · Physics 2021-03-24 Ewa L. Lokas

We analyze the role of bars in the build-up of central mass concentrations in massive, disk galaxies. Our parent sample consists of 3757 face-on disk galaxies with redshifts between 0.01 and 0.05, selected from the seventh Data Release of…

Does the environment of a galaxy directly influence the kinematics of its bar? We present observational evidence that bars in high-density environments exhibit significantly slower rotation rates than bars in low-density environments.…

Astrophysics of Galaxies · Physics 2026-03-18 Natalia Puczek , Tobias Géron , Rebecca J. Smethurst , Chris J. Lintott

This paper presents bar strength measurements for a sample of 180 galaxies, based on the H-band images of the Ohio State University Bright Galaxy Survey (Eskridge et al. 2002, ApJS, 143, 73). We use a gravitational bar torque method, where…

Astrophysics · Physics 2009-11-10 E. Laurikainen , H. Salo , R. Buta , S. Vasylyev

Most of the observed and simulated galactic bars are symmetric in the face-on view. However, there are indeed cases of bars that are off-center with respect to the disk or have an asymmetric shape. The only well-known example showing both…

Astrophysics of Galaxies · Physics 2021-12-01 Ewa L. Lokas

The regular or chaotic dynamics of an analytical realistic three dimensional model composed of a spherically symmetric central nucleus, a bar and a flat disk is investigated. For describing the properties of the bar we introduce a new…

Astrophysics of Galaxies · Physics 2015-11-18 Christof Jung , Euaggelos E. Zotos

We propose a new, more realistic, description of the perturbed gravitational potential of spiral galaxies, with spiral arms having Gaussian-shaped groove profiles. We investigate the stable stellar orbits in galactic disks, using the new…

Astrophysics of Galaxies · Physics 2015-06-12 T. C. Junqueira , J. R. D. Lépine , C. A. S. Braga , D. A. Barros

We define a physically-motivated measure for galactic bar length, called the dynamical length. The dynamical length of the bar corresponds to the radial extent of the orbits that are the backbone supporting the bar feature. We propose a…

Astrophysics of Galaxies · Physics 2023-05-24 Michael S. Petersen , Martin D. Weinberg , Neal Katz

We re-analyse photometric near-infrared data in order to investigate why it is so hard to get a consensus for the shape and density law of the bulge, as seen from the literature. To solve the problem we use the Besancon Galaxy Model to…

Astrophysics of Galaxies · Physics 2015-06-03 Annie C. Robin , Douglas J. Marshall , Mathias Schultheis , Celine Reyle

We construct numerical models of mildly triaxial elliptical galaxies with central density cusps. Using a technique we call ``adiabatic squeezing'', we begin with a spherical gamma=1 Hernquist model and apply a drag to the velocities of the…

We present an automated method for the detection of bar structure in optical images of galaxies using a deep convolutional neural network which is easy to use and provides good accuracy. In our study we use a sample of 9346 galaxies in the…

Instrumentation and Methods for Astrophysics · Physics 2018-08-13 Sheelu Abraham , Arun Aniyan , Ajit K. Kembhavi , N. S. Philip , Kaustubh Vaghmare

Using $N$-body simulations we study the buckling instability in a galactic bar forming in a Milky Way-like galaxy. The galaxy is initially composed of an axisymmetric, exponential stellar disk embedded in a spherical dark matter halo. The…

Astrophysics of Galaxies · Physics 2019-09-04 Ewa L. Lokas

We demonstrate an efficient method to compute the strong-gravitational-lensing deflection angle and magnification for any elliptical surface-density profile. This method solves a numerical hurdle in lens modelling that has lacked a general…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-10 Anowar J. Shajib

The gas dynamics in the Galactic disc is modeled by releasing an initially axisymmetric SPH component in a completely self-consistent and symmetry-free 3D N-body simulation of the Milky Way in which the stellar components display a…

Astrophysics · Physics 2007-05-23 R. Fux

In a series of papers we study the stellar dynamics of the grand design barred-spiral galaxy NGC~1300. In the first paper of this series we estimate the gravitational potential and we give it in a form suitable to be used in dynamical…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 C. Kalapotharakos , P. A. Patsis , P. Grosbol

Many observed disc galaxies harbour a central bar. In the standard cosmological paradigm, galactic bars should be slowed down by dynamical friction from the dark matter halo. This friction depends on the galaxy's physical properties in a…

We present direct observational constraints on the orbital distribution of the stars in the giant elliptical NGC 2320. Long-slit spectra along multiple position angles are used to derive the stellar line-of-sight velocity distribution…

Astrophysics · Physics 2009-10-31 Nicolas Cretton , Hans-Walter Rix , Tim de Zeeuw

Spiral arms that emerge from the ends of a galactic bar are important in interpreting observations of our and external galaxies. It is therefore important to understand the physical mechanism that causes them. We find that these spiral arms…

Astrophysics of Galaxies · Physics 2015-05-19 Mattia C. Sormani , James Binney , John Magorrian