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Related papers: Determining the Galactic Bar Parameters based on t…

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We analyzed the velocity space of the thin and thick-disk Gaia white dwarf population within 100 pc looking for signatures of the Hercules stellar stream. We aimed to identify those objects belonging to the Hercules stream and, by taking…

We have modelled 38 barred galaxies by using near-IR and optical data from the Ohio State University Bright Spiral Galaxy Survey. We constructed the gravitational potentials of the galaxies from $H$-band photometry, assuming constant…

Astrophysics · Physics 2009-11-13 P. Rautiainen , H. Salo , E. Laurikainen

We use about 15,000 F/G nearby dwarf stars selected from the LAMOST pilot survey to map the U-V velocity distribution in the solar neighbourhood. An extreme deconvolution algorithm is applied to reconstruct an empirical multi-Gaussian…

Astrophysics of Galaxies · Physics 2014-12-17 Qiran Xia , Chao Liu , Yan Xu , Shude Mao , Shuang Gao , Yonghui Hou , Ge Jin , Yong Zhang

Using high-resolution spectra of nearby F and G dwarf stars, we have investigated the detailed abundance and age structure of the Hercules stream. We find that the stars in the stream have a wide range of stellar ages, metallicities, and…

Astrophysics · Physics 2009-11-11 T. Bensby , M. S. Oey , S. Feltzing , B. Gustafsson

Previous work has related the Galactic Bar to structure in the local stellar velocity distribution. Here we show that the Bar also influences the spatial gradients of the velocity vector via the Oort constants. By numerical integration of…

Astrophysics · Physics 2009-11-13 I. Minchev , J. Nordhaus , A. C. Quillen

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

There are multiple groups of comoving stars in the Solar neighbourhood, which can potentially be explained as the signatures of one of the fundamental resonances of non-axisymmetric structure such as the Galactic bar or spiral arms. One…

Astrophysics of Galaxies · Physics 2018-05-02 Jason A. S. Hunt , Jo Bovy

We present the physical and evolutionary properties of prestellar and protostellar clumps in the Herschel Infrared GALactic plane survey (Hi-GAL) in two large areas centered in the Galactic plane and covering the tips of the long Galactic…

We report Very Large Array B-configuration observations of the atomic hydrogen 21 cm line emission from the barred disk galaxy NGC 5597 at an angular resolution of 7.1" x 4.2". Using the resonance method, and assuming the ratio of the…

Astrophysics of Galaxies · Physics 2022-06-14 J. Antonio Garcia-Barreto , Emmanuel Momjian

A model of the Galaxy with the outer ring R1R2 can explain the observed distribution of the radial, VR, and azimuthal, VT, velocity components along the Galactocentric distance, R, derived from the Gaia EDR3 data. We selected stars from the…

Astrophysics of Galaxies · Physics 2021-09-16 A. M. Melnik , A. K. Dambis , E. N. Podzolkova , L. N. Berdnikov

The effects in the local U-V velocity field due to orbital trapping by bar resonances have been studied computing fifteen resonant families in a non-axisymmetric Galactic potential, considering the bar's angular velocity between 35 and 57.5…

From the tangential velocities of stars all over the sky, one can, in a statistical way, infer their 3D velocity distribution. An application to Hipparcos data reveals rich structure in the planar stellar motions: there are several moving…

Astrophysics · Physics 2007-05-23 Walter Dehnen

We show by numerical simulations that a purely stellar dynamical model composed of an exponential disc, a cuspy bulge, and an NFW halo with parameters relevant to the Milky Way Galaxy is subject to bar formation. Taking into account the…

Astrophysics of Galaxies · Physics 2016-08-17 Evgeny Polyachenko , Peter Berczik , Andreas Just

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

Using available kinematical data for a subsample of NLTT stars from the HIPPARCOS mission we confirm the existence of a previously reported local anomaly in the (u,v) plane: the mean motion u for old disc stars, with v < -30 km/s, is…

Astrophysics · Physics 2007-05-23 D. Raboud , M. Grenon , L. Martinet , R. Fux , S. Udry

The second data release of the Gaia mission has revealed a very rich structure in local velocity space. In terms of in-plane motions, this rich structure is also seen as multiple ridges in the actions of the axisymmetric background…

Astrophysics of Galaxies · Physics 2019-06-19 Giacomo Monari , Benoit Famaey , Arnaud Siebert , Christopher Wegg , Ortwin Gerhard

We consider three samples of O- and B-type stars from the solar neighborhood 0.6--4 kpc for which we have taken the distances, line-of-sight velocities, and proper motions from published sources. The first sample contains 120 massive…

Astrophysics of Galaxies · Physics 2015-07-30 V. V. Bobylev , A. T. Bajkova

We examine the idea that dynamical parameters can be estimated by identifying locations in the solar neighbourhood where simulated velocity distributions match the observed local distribution. Here, the dynamical influence of both the…

Astrophysics · Physics 2009-11-13 Dalia Chakrabarty

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

Using a numerical simulation of an isolated barred disc galaxy, we first demonstrate that the resonances of the inner bar structure induce more prominent features in the action space distribution for the kinematically hotter stars, which…