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The emergence of a large-scale stellar bar is one of the most striking features in disc galaxies. By means of state-of-the-art cosmological zoom-in simulations, we study the formation and evolution of bars in Milky Way-like galaxies in a…

Astrophysics of Galaxies · Physics 2018-07-23 Tommaso Zana , Massimo Dotti , Pedro R. Capelo , Silvia Bonoli , Francesco Haardt , Lucio Mayer , Daniele Spinoso

We have done a detailed study on the structural and kinematical properties of lenticular and early- and late-type spiral galaxies with bars, aiming to explore the formation and evolution processes of stellar bars in galaxies, and their…

Astrophysics · Physics 2009-11-10 Dimitri Alexei Gadotti

In this and in a previous paper (Romero-Gomez et al. 2006) we propose a theory to explain the formation of both spirals and rings in barred galaxies using a common dynamical framework. It is based on the orbital motion driven by the…

Astrophysics · Physics 2009-11-13 M. Romero-Gomez , E. Athanassoula , J. J. Masdemont , C. Garcia-Gomez

Almost two-thirds of disk galaxies in the local universe host bars, which serve as important drivers of secular evolutionary processes. While cosmological simulations are powerful tools to study the formation and evolution of galaxies, they…

Astrophysics of Galaxies · Physics 2020-12-09 Dongyao Zhao , Min Du , Luis C. Ho , Victor P. Debattista , Jingjing Shi

Many barred galaxies, possibly including the Milky Way, have cusps in the centres. There is a widespread belief, however, that usual bar instability taking place in bulgeless galaxy models is impossible for the cuspy models, because of the…

Astrophysics of Galaxies · Physics 2017-02-07 E. V. Polyachenko , P. Berczik , A. Just

Stellar bars are a common feature in massive disc galaxies. On a theoretical ground, the response of gas to a bar is generally thought to cause nuclear starbursts and, possibly, AGN activity once the perturbed gas reaches the central…

Astrophysics of Galaxies · Physics 2015-10-28 R. Fanali , M. Dotti , D. Fiacconi , F. Haardt

We report here results of high-resolution hydrodynamical simulations of gas flows in barred galaxies, with a focus on gas dynamics in the central kiloparsec. In a single bar with an Inner Lindblad Resonance, we find either near-circular…

Astrophysics · Physics 2009-11-07 Witold Maciejewski , Peter J. Teuben , Linda S. Sparke , James M. Stone

Recently, both simulations and observations have revealed that flybys - fast, one-time interactions between two galaxy halos - are surprisingly common, nearing/comparable to galaxy mergers. Since these are rapid, transient events with the…

Astrophysics of Galaxies · Physics 2015-06-19 Meagan Lang , Kelly Holley-Bockelmann , Manodeep Sinha

Boxy, peanut- or X-shaped "bulges" are observed in a large fraction of barred galaxies viewed in, or close to, edge-on projection, as well as in the Milky Way. They are the product of dynamical instabilities occurring in stellar bars, which…

Astrophysics of Galaxies · Physics 2020-12-23 Bogdan C. Ciambur , Francesca Fragkoudi , Sergey Khoperskov , Paola Di Matteo , Françoise Combes

Bars are important in the secular evolution of galaxies. This study is aimed at exploring the reasons why some galaxies have bars at redshift $z=0$ while others do not. We use ellipse fitting to measure the properties and evolution of bars…

Astrophysics of Galaxies · Physics 2025-05-28 Shuai Lu , Min Du , P. Victor Debattista

N-body simulations have shown that a bar in a galaxy can be triggered by two processes: (1) by its own instabilities in the disk, or (2) by interactions with other galaxies. Both mechanisms have been widely studied. However, the literature…

Astrophysics of Galaxies · Physics 2019-04-26 D. Valencia-Enríquez , I. Puerari , I. Rodrigues

We propose a theory to explain the formation of both spirals and rings in barred galaxies using a common dynamical framework. It is based on the orbital motion driven by the unstable equilibrium points of the rotating bar potential. Thus,…

Astrophysics · Physics 2016-11-23 M. Romero-Gomez

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

When bars form within galaxy formation simulations in the standard cosmological context, dynamical friction with dark matter (DM) causes them to rotate rather slowly. However, almost all observed galactic bars are fast in terms of the ratio…

Astrophysics of Galaxies · Physics 2021-03-30 Mahmood Roshan , Indranil Banik , Neda Ghafourian , Ingo Thies , Benoit Famaey , Elena Asencio , Pavel Kroupa

We show that non-chaotic multiply-periodic particle orbits can exist in a galaxy-like potential where a small fast-tumbling nuclear bar is nested inside a main bar which has a slower pattern speed. We introduce the concept of a loop: a…

Astrophysics · Physics 2009-10-30 Witold Maciejewski , Linda S. Sparke

Having once thought that we understood how some galaxies were barred and had difficulty accounting for the absence of bars in others, it now seems that we have the opposite problem. Most real galaxies have centres dense enough to inhibit…

Astrophysics · Physics 2007-05-23 J. A. Sellwood

We present results of a high-resolution imaging survey of barred S0--Sa galaxies which demonstrate that the central regions of these galaxies are surprisingly complex. We see many inner bars --- small, secondary bars (typically less than a…

Astrophysics · Physics 2007-05-23 Peter Erwin , Linda S. Sparke , Juan Carlos Vega Beltran , John Beckman

Dark matter (DM) bars that shadow stellar bars have been previously shown to form in idealized simulations of isolated disk galaxies. Here, we show that DM bars commonly occur in barred disk galaxies in the TNG50 cosmological simulation…

Astrophysics of Galaxies · Physics 2024-08-06 Neil Ash , Monica Valluri , Yingtian Chen , Eric F. Bell

We study evolution of galactic bars using suite of very high-resolution zoom-in cosmological simulations of galaxies at z ~ 9-2. Our models were chosen to lie within similar mass DM halos, log(Mvir/Mo) ~ 11.65 +- 0.05, at z=6, 4, and 2, in…

Astrophysics of Galaxies · Physics 2022-08-03 Da Bi , Isaac Shlosman , Emilio Romano-Diaz

While bars are commonly observed in disk galaxies, the precise conditions governing their formation remain incompletely understood. To investigate these conditions, we perform a suite of N-body simulations of bulgeless disk galaxies with…

Astrophysics of Galaxies · Physics 2025-09-10 Dajeong Jang , Woong-Tae Kim , Yun Hee Lee