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200 papers

We present distance estimates for eleven peculiar Virgo cluster spiral galaxies based on measurements of the stellar kinematics of their central 2 kpc. Stellar circular velocities were obtained using two-integral dynamical models. Distances…

Astrophysics · Physics 2009-11-13 Juan R. Cortes , Jeffrey D. P. Kenney , Eduardo Hardy

An accurate knowledge of the dark matter distribution in the Milky Way is of crucial importance for galaxy formation studies and current searches for particle dark matter. In this paper we set new dynamical constraints on the Galactic dark…

Astrophysics of Galaxies · Physics 2015-12-03 Miguel Pato , Fabio Iocco , Gianfranco Bertone

The circular rotation speed of the Milky Way at the solar radius, Theta_o, has been estimated to be 220 km/s by fitting the maximum velocity of HI emission as a function of Galactic longitude. This result is in tension with a recent…

Astrophysics of Galaxies · Physics 2016-12-14 M. J. Reid , T. M. Dame

We report on the detection in the combined $Gaia$-DR1/RAVE data of a lack of disk stars in the solar neighbourhood with velocities close to zero angular momentum. We propose that this may be caused by the scattering of stars with very low…

Astrophysics of Galaxies · Physics 2016-12-07 Jason A. S. Hunt , Jo Bovy , Raymond G. Carlberg

We have studied the kinematic properties of the candidates for hot subdwarfs (HSDs) selected by Geier et al. from the Gaia DR2 catalogue. We have used a total of 12 515 stars with relative trigonometric parallax errors less than 30\%. The…

Astrophysics of Galaxies · Physics 2019-10-03 V. V. Bobylev , A. T. Bajkova

When studying massive stars and their life cycles, rotation plays a key role. Hence, understanding the rotation of these stars is crucial when determining their properties, or for constraining evolutionary models. We examine the reliability…

Solar and Stellar Astrophysics · Physics 2026-05-21 L. Delbroek , J. O. Sundqvist , F. Backs , T. Ceulemans , D. Debnath , P. Schillemans

The lensed double QSO 0957+561 has a well-measured time delay and hence is useful for a global determination of H0. Uncertainty in the mass distribution of the lens is the largest source of uncertainty in the derived H0. We investigate the…

Astrophysics · Physics 2009-10-31 Gary Bernstein , Philippe Fischer

We compare distance resolved, absolute proper motions in the Milky Way bar/bulge region to a grid of made-to-measure dynamical models with well defined pattern speeds. The data are obtained by combining the relative VVV Infrared Astrometric…

Astrophysics of Galaxies · Physics 2022-04-29 Jonathan Clarke , Ortwin Gerhard

We report a trigonometric parallax of 12 GHz methanol masers associated with the massive star forming region G9.62+0.20, corresponding to a distance of 5.2+-0.6 kpc. With a local standard of rest velocity of about 2 km/s, the region's…

Astrophysics of Galaxies · Physics 2014-11-20 A. Sanna , M. J. Reid , L. Moscadelli , T. M. Dame , K. M. Menten , A. Brunthaler , X. W. Zheng , Y. Xu

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

The RAVE survey, combined with proper motions and distance estimates, can be used to study in detail stellar kinematics in the extended solar neighbourhood (solar suburb). Using the red clump, we examine the mean velocity components in 3D…

A catalog of more than 43,000 M giant stars has been selected by Li et al. from the ninth data release of LAMOST. Using the data-driven method SLAM, we obtain the stellar parameters (Teff, logg, [M/H], [$\alpha$/M]) for all the M giant…

Solar and Stellar Astrophysics · Physics 2023-05-03 Dan Qiu , Hao Tian , Jing Li , Chao Liu , Lin Long , Jian-Rong Shi , Ming Yang , Bo Zhang

The frequency of Galactic stellar encounters the Solar system experienced depends on the local density and velocity dispersion along the orbit of the Sun in the Milky Way galaxy. We aim at determining the effect of the radial migration of…

Earth and Planetary Astrophysics · Physics 2016-10-12 C. A. Martínez-Barbosa , L. Jílková , S. Portegies Zwart , A. G. A. Brown

With about 12 000 OB type stars selected from the LAMOST and Gaia survey, we study their 3 dimensional velocity distribution over the range of galactocentric radius from 6 to 15 kpc in the Galactic disk plane. A clear ripple pattern in the…

Astrophysics of Galaxies · Physics 2019-03-01 Xinlun Cheng , Chao Liu , Shude Mao , Wenyuan Cui

Based on the first Gaia data release and spectroscopy from the LAMOST Data Release 4, we study the kinematics and chemistry of the local halo stars. The halo stars are identified kinematically with a relative speed of at least 220 km…

Astrophysics of Galaxies · Physics 2018-08-22 Cuihua Du , Hefan Li , Shuai Liu , Thomas Donlon , Heidi Jo Newberg

We measure the proper motion of the pulsar PSR J1745-2900 relative to the Galactic Center massive black hole, Sgr A*, using the Very Long Baseline Array (VLBA). The pulsar has a transverse velocity of 236 +/- 11 km s^-1 at position angle 22…

We apply a simple axisymmetric disc model to 218 Galactic Cepheids whose accurate measurements of the distance and velocities are obtained by cross-matching an existing Cepheids catalogue with the Gaia DR2 data. Our model fit determines the…

Astrophysics of Galaxies · Physics 2018-10-10 Daisuke Kawata , Jo Bovy , Noriyuki Matsunaga , Junichi Baba

Star formation is underway in the W49N molecular cloud (MC) at a high level of efficiency, with almost twenty ultra-compact (UC) HII regions observed thus far, indicating a recent formation of massive stars. Previous works have suggested…

Astrophysics of Galaxies · Physics 2023-09-19 Mendoza-Torres , J. E. , Juárez-Gama , M. , Rodríguez-Esnard , I. T

By correcting the redshift--dependent distances for peculiar motions through a number of peculiar velocity field models, we recover the true distances of a wide, all-sky sample of nearby galaxies (~ 6400 galaxies with velocities cz<5500…

Astrophysics · Physics 2009-10-30 C. Marinoni , P. Monaco , G. Giuricin , B. Costantini

The radial distance to the co-rotation radius Rcoro (where the angular speed of the gas and stars in orbit around the Galactic Centre is equal to the angular speed of the spiral arm pattern) has often been predicted (at various places), but…

Astrophysics of Galaxies · Physics 2018-08-15 Jacques P Vallee