The nearby spiral density-wave structure of the Galaxy: line-of-sight and longitudinal velocities of 223 Cepheids

2016 ◽  
Vol 464 (4) ◽  
pp. 4495-4508 ◽  
Author(s):  
Evgeny Griv ◽  
Li-Gang Hou ◽  
Ing-Guey Jiang ◽  
Chow-Choong Ngeow
Keyword(s):  
Density Wave ◽  
Wave Structure ◽  
Line Of Sight ◽  
Spiral Density Wave ◽  
The Galaxy

The nearby spiral density-wave structure of the Galaxy: Line-of-sight and longitudinal velocities of 61 masers

2017 ◽  
Vol 338 (6) ◽  
pp. 729-739
Author(s):  
E. Griv ◽  
I.-G. Jiang ◽  
L.-G. Hou ◽  
C.-C. Ngeow
Keyword(s):  
Density Wave ◽  
Wave Structure ◽  
Line Of Sight ◽  
Spiral Density Wave ◽  
The Galaxy

The nearby spiral density–wave structure of the Galaxy

2017 ◽  
Vol 468 (3) ◽  
pp. 3361-3367 ◽  
Author(s):  
Evgeny Griv ◽  
Ing-Guey Jiang ◽  
Li-Gang Hou
Keyword(s):  
Density Wave ◽  
Wave Structure ◽  
Spiral Density Wave ◽  
The Galaxy

The Lin–Shu type density–wave structure of the Galaxy: Line-of-sight velocities of selected 37354 RAVE DR5 stars

New Astronomy ◽  
2019 ◽  
Vol 66 ◽  
pp. 1-8 ◽  
Author(s):  
Evgeny Griv ◽  
Ing-Guey Jiang ◽  
Li-Gang Hou ◽  
Chow-Choong Ngeow
Keyword(s):  
Density Wave ◽  
Wave Structure ◽  
Line Of Sight ◽  
The Galaxy

The spiral density-wave structure of our own Galaxy as traced by open clusters: Least-squares analysis of line-of-sight velocities

New Astronomy ◽  
2014 ◽  
Vol 29 ◽  
pp. 9-17 ◽  
Author(s):  
Evgeny Griv ◽  
Chien-Cheng Lin ◽  
Chow-Choong Ngeow ◽  
Ing-Guey Jiang
Keyword(s):  
Least Squares ◽  
Density Wave ◽  
Wave Structure ◽  
Open Clusters ◽  
Line Of Sight ◽  
Spiral Density Wave

The nearby spiral density-wave structure of the Galaxy: line-of-sight velocities of the Gaia DR2 OB stars

2021 ◽  
Vol 503 (1) ◽  
pp. 354-361
Author(s):  
Evgeny Griv ◽  
Michael Gedalin ◽  
Ing-Guey Jiang
Keyword(s):  
Density Wave ◽  
Wave Structure ◽  
Wave Theory ◽  
Solar Neighborhood ◽  
Line Of Sight ◽  
Density Waves ◽  
Ob Stars ◽  
Spiral Density Waves ◽  
The Galaxy ◽  
Gravity Disturbances

ABSTRACT Distances and line-of-sight velocities of 964 Gaia Data Release 2 (DR2) OB stars of Xu et al. within 3 kpc from the Sun and 500 pc from the Galactic mid-plane with accuracies of <50 per cent are selected. The data are used to find small systematic departures of velocities from the mean circular motion for the stars in the solar neighborhood due to the spiral compression-type (Lin–Shu-type) waves, or spiral density waves, e.g. those produced by real instabilities of spontaneous gravity disturbances, a central bar or a companion system. A key point of the study is that our results are consistent with the ones extracted from the asymptotic density-wave theory. Revised parameters of density waves in the solar vicinity of the Galaxy are also provided.

The nearby spiral density-wave structure of the Galaxy: line-of-sight velocities of the Gaia DR2 main-sequence A, F, G, and K stars

2020 ◽  
Vol 493 (2) ◽  
pp. 2111-2126
Author(s):  
Evgeny Griv ◽  
Michael Gedalin ◽  
I-Chun Shih ◽  
Li-Gang Hou ◽  
Ing-Guey Jiang
Keyword(s):  
Main Sequence ◽  
Density Wave ◽  
Wave Structure ◽  
Wave Pattern ◽  
Line Of Sight ◽  
The Sun ◽  
Density Waves ◽  
Spiral Density Waves ◽  
The Galaxy ◽  
Spiral Arm

ABSTRACT Distances and velocities of $\approx \!2400\, 000$ main-sequence A, F, G, and K stars are collected from the second data release of ESA's Gaia astrometric mission. This material is analysed to find evidence of radial and azimuthal systematic non-circular motions of stars in the solar neighbourhood on the assumption that the system is subject to spiral density waves (those produced by a spontaneous disturbance, a central bar, or an external companion), developing in the Galactic disc. Data analysis of line-of-sight velocities of $\approx \!1500\, 000$ stars selected within 2 kpc from the Sun and 500 pc from the Galactic mid-plane with distance accuracies of <10 per cent makes evident that a radial wavelength of the wave pattern is 1.1–1.6 kpc and a phase of the wave at the Sun’s location in the Galaxy is 55°–95°. Respectively, the Sun is situated at the inner edge of the nearest Orion spiral arm segment. Thus, the local Orion arm is a part of a predominant density-wave structure of the system. The spiral structure of the Galaxy has an oscillating nature corresponding to a concept of the Lin–Shu-type moderately growing in amplitude, tightly wound, and rigidly rotating density waves.

scholarly journals Analysis of galaxy kinematics based on Cepheids from the Gaia DR2 Catalogue

2021 ◽  
Vol 502 (3) ◽  
pp. 4377-4391
Author(s):  
V V Bobylev ◽  
A T Bajkova ◽  
A S Rastorguev ◽  
M V Zabolotskikh
Keyword(s):  
Density Wave ◽  
Rotation Velocity ◽  
Proper Motions ◽  
The Past ◽  
Spiral Density Wave ◽  
Classical Cepheids ◽  
The Galaxy ◽  
Galaxy Kinematics ◽  
The One ◽  
Gaia Dr2

ABSTRACT To construct the rotation curve of the Galaxy, classical Cepheids with proper motions, parallaxes and line-of-sight velocities from the Gaia DR2 Catalogue are used in large part. Our working sample formed from literature data contains about 800 Cepheids with estimates of their age. We determined that the linear rotation velocity of the Galaxy at the solar distance is V0 = 240 ± 3 km s−1. In this case, the distance from the Sun to the axis of rotation of the Galaxy is found to be R0 = 8.27 ± 0.10 kpc. A spectral analysis of radial and residual tangential velocities of Cepheids younger than 120 Myr showed close estimates of the parameters of the spiral density wave obtained from data both at the present time and in the past. Therefore, the value of the wavelength λR, θ is in the range [2.4–3.0] kpc, the pitch angle iR, θ is in the range [−13○, −10○] for a four-arm pattern model, and the amplitudes of the radial and tangential perturbations are fR ∼ 12 km s−1 and fθ ∼ 9 km s−1, respectively. Velocities of Cepheids older than 120 Myr currently give a wavelength λR, θ ∼ 5 kpc. This value differs significantly from the one we obtained from samples of young Cepheids. An analysis of the positions and velocities of old Cepheids, calculated by integrating their orbits backward in time, made it possible to determine significantly more reliable values of the parameters of the spiral density wave: wavelength λR, θ = 2.7 kpc and amplitudes of radial and tangential perturbations fR = 7.9 km s−1 and fθ = 5 km s−1, respectively.

Sign in / Sign up

Export Citation Format

Share Document