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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

Context: One of the ways to determine the contribution of the dark halo to the gravitational potential of a galaxy is the study of non-circular (streaming) motions and the associated gas shocks in the bar region. These motions, determined…

Astrophysics · Physics 2009-11-13 I. Perez

Bars drive gas inflow. As the gas flows inwards, shocks and shear occur along the bar dust lanes. Such shocks and shear can affect the star formation and change the gas properties. For four barred galaxies, we present H{\alpha} velocity…

We present new gas flow models for the Milky Way inside the solar circle. To this end we use SPH simulations in gravitational potentials determined from the NIR luminosity distribution (including spiral arms) which are based on the…

Astrophysics · Physics 2009-11-07 Nicolai Bissantz , Peter Englmaier , Ortwin Gerhard

Co-moving groups of stars (streams) are well known in the velocity space of the disc near the Sun. Many are thought to arise from resonances with the Galactic bar or spiral arms. In this work, we search for similar moving groups in the…

Astrophysics of Galaxies · Physics 2025-07-16 Adam M. Dillamore , Jason L. Sanders , Vasily Belokurov , Hanyuan Zhang

Self-consistent hybrid N-body and SPH simulations are used to give a new and coherent interpretation of the main features standing out from the HI and CO longitude-velocity observations within the Galactic bar. In particular, the traces of…

Astrophysics · Physics 2009-10-31 R. Fux

Galactic bars are prominent dynamical structures within disk galaxies whose size, formation time, strength, and pattern speed influence the dynamical evolution of their hosts galaxies. Yet, their formation and evolution in a cosmological…

We have derived absolute proper motions of the entire Galactic bulge region from VIRAC and Gaia. We present these as both integrated on-sky maps and, after isolating standard candle red clump (RC) stars, as a function of distance using RC…

Astrophysics of Galaxies · Physics 2019-12-06 Jonathan P. Clarke , Christopher Wegg , Ortwin Gerhard , Leigh C. Smith , Phil W. Lucas , Shola M. Wylie

Mass inflow in barred galaxies has been invoked to account for a wide variety of phenomena, but until now direct evidence for inflow has been lacking. We present Fabry-Perot H-alpha observations of the barred spiral galaxy NGC 1530 from…

Astrophysics · Physics 2009-10-30 Michael W. Regan , Stuart N. Vogel , Peter J. Teuben

The dynamics of a barred galaxy depends on the angular velocity or pattern speed of its bar. Indeed, it is related to the location of corotation where gravitational and centrifugal forces cancel out in the rest frame of the bar. The only…

Astrophysics of Galaxies · Physics 2010-02-08 E. M. Corsini

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

We construct a large set of dynamical models of the galactic bulge, bar and inner disk using the Made-to-Measure method. Our models are constrained to match the red clump giant density from a combination of the VVV, UKIDSS and 2MASS…

Astrophysics of Galaxies · Physics 2016-12-21 Matthieu Portail , Ortwin Gerhard , Christopher Wegg , Melissa Ness

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 use Schwarzschild's orbit-superposition technique to construct self-consistent models of the Galactic bar. Using $\chi^2$ minimisation, we find that the best-fit Galactic bar model has a pattern speed $\Omega_{\rm p}=60 \rm{km s^{-1}…

Astrophysics of Galaxies · Physics 2015-06-11 Yougang Wang , Hongsheng Zhao , Shude Mao , R. M. Rich

We present new observations of the strongly-barred galaxy NGC 1365, including new photometric images and Fabry-Perot spectroscopy, as well as a detailed re-analysis of the neutral hydrogen observations from the VLA archive. We find the…

Astrophysics · Physics 2009-11-13 R. Zanmar Sanchez , J. A. Sellwood , B. J. Weiner , T. B. Williams

Simulations predict that bars in galaxies should slow down over time. This is often attributed to the exchange of angular momentum between the bar and other regions of the galaxy, such as the outer disc and dark matter halo, which implies…

Astrophysics of Galaxies · Physics 2026-04-07 Tobias Géron , Kai Zhu , Steph Campbell , Chris Lintott , R. J. Smethurst , Behzad Tahmasebzadeh

Gas morphology and kinematics in the Milky Way contain key information for understanding the formation and evolution of our Galaxy. We present a high resolution hydrodynamical simulation based on a realistic barred Milky Way potential…

Astrophysics of Galaxies · Physics 2022-02-02 Zhi Li , Juntai Shen , Ortwin Gerhard , Jonathan P. Clarke

We measure and compare the pattern speeds of vertical breathing, vertical bending, and spiral density waves in two isolated N-body+SPH simulations, using windowed Fourier transforms over 1 Gyr time intervals. We show that the pattern speeds…

In the density wave theory of spiral structure, the grand-design two-armed spiral pattern is taken to rotate rigidly in a galactic disc with a constant, definite pattern speed. The observational measurement of the pattern speed of the…

Astrophysics of Galaxies · Physics 2016-06-01 Soumavo Ghosh , Chanda J Jog

Longitude-velocity (l-V) diagrams of H I and CO gas in the inner Milky Way have long been known to be inconsistent with circular motion in an axisymmetric potential. Several lines of evidence suggest that the Galaxy is barred, and gas flow…

Astrophysics · Physics 2008-11-26 Benjamin J. Weiner , J. A. Sellwood