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Related papers: The Milky Way Bar Pattern Speed using Hercules and…

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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

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

Context. Recent studies have suggested that moving groups have a dynamic or "resonant" origin. Under this hypothesis, these kinematic structures become a powerful tool for studying the large-scale structure and dynamics of the Milky Way.…

Astrophysics · Physics 2009-11-13 T. Antoja , F. Figueras , D. Fernandez , J. Torra

We investigate the possibility that the recently discovered Hercules Milky Way satellite is in fact a stellar stream in formation, thereby explaining its very elongated shape with an axis ratio of 3 to 1. Under the assumption that Hercules…

Astrophysics of Galaxies · Physics 2015-05-19 Nicolas F. Martin , Shoko Jin

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

Most late-type stars in the solar neighborhood have velocities similar to the local standard of rest (LSR), but there is a clearly separated secondary component corresponding to a slower rotation and a mean outward motion. Detailed…

Astrophysics · Physics 2009-10-31 Walter Dehnen

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

The origin of the Hercules stream, the most prominent velocity substructure in the Solar neighbour disc stars, is still under debate. Recent accurate measurements of position, velocity, and metallicity provided by Tycho Gaia Astrometric…

Astrophysics of Galaxies · Physics 2019-01-30 Kohei Hattori , Naoteru Gouda , Taihei Yano , Nobuyuki Sakai , Hiromichi Tagawa , Junichi Baba , Jun Kumamoto

Our recent studies of axial-symmetry breaking in the nearby ($d <3 \,{\rm kpc}$) star counts are sensitive to the distortions of stellar orbits perpendicular and parallel to the orientation of the bar just within and beyond the outer…

Astrophysics of Galaxies · Physics 2020-08-20 Austin Hinkel , Susan Gardner , Brian Yanny

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

In this paper we introduce a new method for analysing Milky Way phase-space which allows us to reveal the imprint left by the Milky Way bar and spiral arms on the stars with full phase-space data in Gaia Data Release 2. The unprecedented…

Astrophysics of Galaxies · Physics 2020-02-05 S. Khoperskov , O. Gerhard , P. Di Matteo , M. Haywood , D. Katz , S. Khrapov , A. Khoperskov , M. Arnaboldi

There have been several recent suggestions that the Milky Way has rotating bar-like features based on HI and star count data. In this paper, I show that such features cause distinctive stellar kinematic signatures near OLR and ILR. The…

Astrophysics · Physics 2009-10-22 Martin D. Weinberg

We discuss the results of the first model of the gas dynamics in the Milky Way in the presence of two bars: the large scale primary bar or boxy bulge and a secondary bar in the Galactic center region. We have obtained an accurate potential…

Astrophysics of Galaxies · Physics 2009-01-21 N. J. Rodriguez-Fernandez

Based on a high quality $N$-body simulation of a double bar galaxy model, we investigate the evolution of the bar properties, including their size, strength and instantaneous pattern speed derived by using three distinct methods: the…

Astrophysics of Galaxies · Physics 2018-07-11 Yu-Ting Wu , Daniel Pfenniger , Ronald E. Taam

We investigate the possibility that Hercules, a recently discovered Milky Way (MW) satellite, is a stellar stream in the process of formation. This hypothesis is motivated by Hercules' highly elongated shape as well as the measurement of a…

Astrophysics of Galaxies · Physics 2015-05-20 Shoko Jin , Nicolas F. Martin

We determine the mass of the Milky Way bar and the torque it causes, using Gaia DR2, by applying the orbital arc method. Based on this, we have found that the gravitational acceleration is not directed towards the centre of our Galaxy but a…

Astrophysics of Galaxies · Physics 2020-05-06 Rain Kipper , Peeter Tenjes , Taavi Tuvikene , Punyakoti Ganeshaiah Veena , Elmo Tempel

We present an update to the frequency analysis method for measuring the properties of a galactic bar. The method involves computing the fundamental frequencies of orbits in rotating, N-body-derived potential models, classifying the stars as…

Astrophysics of Galaxies · Physics 2026-05-13 Zachary Langford , Robyn Sanderson , Madeline Lucey , Jason A. S. Hunt

Bars are common galactic structures in the local universe that play an important role in the secular evolution of galaxies, including the Milky Way. In particular, the velocity distribution of individual stars in our galaxy is useful to…

Understanding radial migration is a crucial point to build relevant chemical and dynamical evolution models of the Milky Way disk. In this paper, we analyze a high-resolution N-body simulation of a Milky Way-type galaxy to study the role…

Astrophysics of Galaxies · Physics 2020-07-01 S. Khoperskov , P. Di Matteo , M. Haywood , A. Gomez , O. N. Snaith

The arguments in favor of the unified formation mechanism for both slow (Lynden-Bell's) bars and common fast bars are given. This mechanism consists in a certain instability that is akin to the well-known radial orbit instability; it is…

Astrophysics · Physics 2007-05-23 E. V. Polyachenko , V. L. Polyachenko