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Related papers: Tidally induced spiral arm wraps encoded in phase …

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Our situation as occupants of the Milky Way (MW) Galaxy, bombarded by the Sagittarius dwarf galaxy, provides an intimate view of physical processes that can lead to the dynamical heating of a galactic disc. While this evolution is…

The main goal of this work is to quantify, through a robust methodology, the contribution of invariant manifolds to the formation of spiral arms in a pure N-body simulation, setting up a machinery to perform similar tests in other and more…

Astrophysics of Galaxies · Physics 2026-05-27 Toni Soler-Terricabras , Mercè Romero-Gómez , Santi Roca-Fàbrega

We use numerical simulations to model Gaia DR3 data with the aim of constraining the Milky Way bar and spiral structure parameters. We show that both the morphology and the velocity field in Milky Way-like galactic disc models are strong…

We run N-body smoothed particle hydrodynamics (SPH) simulations of a Milky Way sized galaxy. The code takes into account hydrodynamics, self-gravity, star formation, supernova and stellar wind feedback, radiative cooling and metal…

Astrophysics of Galaxies · Physics 2015-06-04 Robert J. J. Grand , Daisuke Kawata , Mark Cropper

We present first results for Faraday rotation of compact polarized sources (1 to 2 GHz continuum) in The HI/OH/Recombination line (THOR) survey of the inner Galaxy. In the Galactic longitude range 39 degr < l < 52 degr, we find rotation…

Fragmentation of spiral arms can drive the formation of giant clumps and induce intense star formation in disc galaxies. Based on the spiral-arm instability analysis of our Paper I, we present linear perturbation theory of dynamical…

Astrophysics of Galaxies · Physics 2019-03-06 Shigeki Inoue , Naoki Yoshida

Spiral arms greatly affect gas flows and star formation in disk galaxies. We use local three-dimensional simulations of the vertically-stratified, self-gravitating, differentially-rotating, interstellar medium (ISM) subject to a stellar…

Astrophysics of Galaxies · Physics 2020-07-29 Woong-Tae Kim , Chang-Goo Kim , Eve C. Ostriker

We analyze two-armed global spiral density wave modes generated by gravitational instability in razor-thin, non-viscous, self-gravitating protoplanetary disks to understand the dependence of spiral arm morphology (pitch angle $\alpha$ and…

Earth and Planetary Astrophysics · Physics 2021-01-13 Enze Chen , Si-Yue Yu , Luis C. Ho

With the aim of studying the nonlinear stellar and gaseous response to the gravitational potential of a galaxy such as the Milky Way, we have modeled 3D galactic spiral arms as a superposition of inhomogeneous oblate spheroids and added…

Astrophysics · Physics 2009-11-07 Barbara Pichardo , Marco Martos , Edmundo Moreno , Julia Espresate

We have discovered long-lived waves in two sets of numerical models of fast (marginally bound or unbound) flyby galaxy collisions, carried out independently with two different codes. In neither simulation set are the spirals the result of a…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-16 Curtis Struck , Clare L. Dobbs , Jeong-Sun Hwang

Observations and simulations of barred spiral galaxies have shown that, in general, the spiral arms rotate at a different pattern speed to that of the bar. The main conclusion from the bibliography is that the bar rotates faster than the…

Astrophysics of Galaxies · Physics 2022-11-09 M. Harsoula , C. Efthymiopoulos , G. Contopoulos , A. C. Tzemos

Identifying the structure of our Galaxy has always been fraught with difficulties, and while modern surveys continue to make progress building a map of the Milky Way, there is still much to understand. The arm and bar features are important…

Astrophysics of Galaxies · Physics 2020-01-08 Alex R. Pettitt , Sarah E. Ragan , Martin C. Smith

Context. Observations of polarized radio emission show that large-scale (regular) magnetic fields in spiral galaxies are not axisymmetric, but generally stronger in interarm regions. In some nearby galaxies such as NGC 6946 they are…

Astrophysics of Galaxies · Physics 2015-06-16 D. Moss , R. Beck , D. Sokoloff , R. Stepanov , M. Krause , T. G. Arshakian

We present a new N-body model for the tidal disruption of the Sagittarius (Sgr) dwarf that is capable of simultaneously satisfying the majority of angular position, distance, and radial velocity constraints imposed by current wide-field…

Astrophysics of Galaxies · Physics 2015-05-18 David R. Law , Steven R. Majewski

We study the effect of spiral arm passages on the evolution of star clusters on planar and circular orbits around the centres of galaxies. Individual passages with different relative velocity (V_drift) and arm width are studied using N-body…

Astrophysics · Physics 2008-11-26 M. Gieles , E. Athanassoula , S. F. Portegies Zwart

Bars in galaxies may develop through a global instability or due to an interaction with another system. We study bar formation in disky dwarf galaxies orbiting a Milky Way-like galaxy. We employ $N$-body simulations to study the impact of…

Astrophysics of Galaxies · Physics 2017-06-28 Grzegorz Gajda , Ewa L. Lokas , E. Athanassoula

The structure of spiral galaxies is essential to understanding the dynamics and evolution of disk galaxies; however, the precise nature of spiral arms remains uncertain. Two challenges in understanding the mechanisms driving spirals are how…

We generated synthetic observations from the four-arm model presented in Gomez & Cox (2004) for the Galactic ISM in the presence of a spiral gravitational perturbation. We found that velocity crowding and diffusion have a strong effect in…

Astrophysics · Physics 2009-11-10 Gilberto C. Gomez , Donald P. Cox

The dynamical effects on the stellar motion produced by the Galactic central bar and the spiral arms perturbations are investigated separately and compared. The stars from the Gaia DR3 catalog are selected in the region of observable…

Astrophysics of Galaxies · Physics 2026-03-03 Willian Y. Nacafucasaco , Tatiana A. Michtchenko , Douglas Barros , Jacques Lépine

In order to understand the physical mechanisms underlying non-steady stellar spiral arms in disk galaxies, we analyzed the growing and damping phases of their spiral arms using three-dimensional $N$-body simulations. We confirmed that the…

Astrophysics of Galaxies · Physics 2015-06-12 Junichi Baba , Takayuki R. Saitoh , Keiichi Wada