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Dark matter (DM) halos in $\Lambda$ Cold DM cosmological simulations are triaxial. Most exhibit figure rotation. We study 40 isolated halos with stellar disks from the TNG50 simulation suite across $\sim 4$~Gyr to understand whether and how…

Astrophysics of Galaxies · Physics 2026-02-03 Saarthak Johri , Neil Ash , Monica Valluri

This paper explores resonance-driven secular evolution between a bar and dark-matter halo using N-body simulations. We make direct comparisons to our analytic theory (Weinberg & Katz 2005) to demonstrate the great difficulty that an N-body…

Astrophysics · Physics 2008-11-26 Martin D. Weinberg , Neal Katz

We describe a new phenomenon of `bar damping' that may have played an important role in shaping the Milky Way bar and bulge as well as its spiral structure. We use a collisionless N-body simulation of a Milky Way-like galaxy initially…

Astrophysics of Galaxies · Physics 2016-11-07 Ewa L. Lokas

Magnetic braking can drive angular momentum loss in star formation and influence disk evolution. A previous study of HH 111 VLA1 suggested a decrease in rotation velocity in a region between the infalling envelope and rotating disk. Using…

Astrophysics of Galaxies · Physics 2025-12-09 Jyun-Heng Lin , Chin-Fei Lee , Zhi-Yun Li , Yueh-Ning Lee , Ya-Lin Wu , J. A. López-Vázquez

In the $\Lambda$-CDM paradigm, the dark halo governs the gravitational potential within which a galaxy can form and evolve. In this Letter we show that the present-day inner ($r<50\text{ kpc}$) dark halo can be significantly misaligned with…

Astrophysics of Galaxies · Physics 2023-09-18 Jiwon Jesse Han , Vadim Semenov , Charlie Conroy , Lars Hernquist

We study bisymmetric modes of angular wavenumber 2 for flat stellar disks in potentials with smooth cores. Stars either all circulate in the same direction or a small fraction may counter-rotate. The bisymmetric modes are unstable unless…

Astrophysics · Physics 2009-11-10 M. A. Jalali , C. Hunter

Although more than two-thirds of star-forming disk galaxies in the local universe are barred, some galaxies remain un-barred, occupying the upper half of the Hubble tuning fork diagram. Numerical simulations almost always produce bars…

Astrophysics of Galaxies · Physics 2018-05-16 Kanak Saha , Bruce Elmegreen

Aims: To study the imprints of a rotating bar on the kinematics of stars in the thin and thick disks throughout the Galaxy. Methods: We perform test particle numerical simulations of the thin and thick disks in a 3D Galactic potential that…

Astrophysics of Galaxies · Physics 2013-11-25 Giacomo Monari , Teresa Antoja , Amina Helmi

Galaxy angular momenta (spins) contain valuable cosmological information, complementing their positions and velocities. The baryonic spin direction of galaxies has been probed as a reliable tracer of their host halos and the primordial spin…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-04 Ming-Jie Sheng , Lin Zhu , Hao-Ran Yu , Hongchuan Ma , Haikun Li , Peng Wang , Xi Kang

We have used Spitzer images of a sample of 68 barred spiral galaxies in the local universe to make systematic measurements of bar length and bar strength. We combine these with precise determinations of the corotation radii associated with…

Stars in galaxies form from the cold rotationally supported gaseous disks that settle at the center of dark matter halos. In the simplest models, such angular momentum is acquired early on at the time of collapse of the halo and preserved…

We investigate dynamical self-friction, the process by which material that is stripped from a subhalo torques its remaining bound remnant, which causes it to lose orbital angular momentum. By running idealized simulations of a subhalo…

Astrophysics of Galaxies · Physics 2020-06-29 Tim B. Miller , Frank C. van den Bosch , Sheridan B. Green , Go Ogiya

The surface brightness distribution in the majority of stellar galactic discs falls off exponentially. Often what lies beyond such a stellar disc is the neutral hydrogen gas whose distribution also follows a nearly exponential profile at…

Astrophysics of Galaxies · Physics 2015-06-22 Kanak Saha , Chanda J. Jog

We study the stability of trajectories near the disk plane of galaxy models with a triaxial dark matter halo component. We also examine the effect of weak discreteness noise, rapidly rotating bar perturbations and weak dissipation on these…

Astrophysics · Physics 2009-10-30 Amr El-Zant , Bjoern Hassler

Observations of lopsided spiral galaxies motivated us to explore whether the rapid passage of a companion galaxy could cause them. We examine whether the center of mass of the visible matter becomes displaced from the center of mass of the…

Astrophysics · Physics 2009-10-31 Thomas Zeltwanger , Neil F. Comins , Richard V. E. Lovelace

Secular evolution is one of the key routes through which galaxies evolve along the Hubble sequence. Not only the disk undergoes morphological and kinematic changes, but also a preexisting classical bulge may be dynamically changed by the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Kanak Saha , Inma Martinez-Valpuesta , Ortwin Gerhard

Low surface brightness galaxies are an excellent laboratory where stars and baryonic matter act as tracers of the gravitational potential of the dark matter halo. If dark matter is modeled as a perfect fluid, then spherically symmetric and…

Astrophysics of Galaxies · Physics 2024-08-29 Andrés Aceña , Juan Barranco , Argelia Bernal , Ericson López , Mario Llerena

The disks of galaxies are primarily stellar systems, and fundamentally dynamical entities. Thus, to fully understand galactic disks, we must study their stellar kinematics as well as their morphologies. Observational techniques have now…

Astrophysics · Physics 2007-05-23 Michael R. Merrifield , Konrad Kuijken

A significant fraction of local galaxies exhibit stellar bars, non-axisymmetric structures composed of stars, gas, and dust. Identifying key differences between the properties of barred and unbarred galaxies can uncover clues about the…

Astrophysics of Galaxies · Physics 2025-05-23 Paula D. López , Cecilia Scannapieco , Sofía A. Cora , Ignacio D. Gargiulo

Cosmological simulations show that dark matter halos surrounding baryonic disks have a wide range of angular momenta, measured by the spin parameter ($\lambda$). In this study, we bring out the importance of inner angular momentum($<$30…

Astrophysics of Galaxies · Physics 2022-12-14 Sandeep Kumar Kataria , Juntai Shen