Density wave formation in differentially rotating disk galaxies: Hydrodynamic simulation of the linear regime

Griv, Evgeny; Wang, Hsiang-Hsu

doi:10.1016/j.newast.2014.01.001

Cited by 13 publications

(10 citation statements)

References 92 publications

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“…Griv et al (2002Griv et al ( , 2006 have predicted analytically that Ω p does not depend on m and therefore each Fourier component of a perturbation in a spatially inhomogeneous system will rotate with the same angular velocity. Recently, Griv & Wang (2014) and Mata-Chávez et al (2014) confirmed this result by computer simulations. Since Ω p is a constant, independent of time, radius or m, each component will remain identical with time, spirals do not wind up and any "mixing" of the spirals is absent.…”

Section: Introductionmentioning

confidence: 58%

“…The superposition of selfexcited spiral and circular modes and their linear growth and saturation due to nonlinear effects in dynamically cool collisionless/gas disks have been demonstrated numerically by Laughlin & Różyczka (1996), Griv & Gedalin (2005), Khoperskov et al (2007Khoperskov et al ( , 2012, Michael et al (2012), MataChávez et al (2014) and others. Modern high resolution simulations demonstrate that the self-excited recurrent instabilities can last for a substantial fraction of a Hubble time both in pure stellar and gaseous disks, even in the absence of any cooling (Fujii et al 2011;Baba et al 2013;Griv & Wang 2014).…”

Section: Introductionmentioning

confidence: 99%

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A model for the Lin‐Shu type density‐wave structure of our Galaxy: Line‐of‐sight and transverse‐longitudinal velocities of 242 optically visible open clusters

Griv

Jiang

2015

Astron Nachr

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In this paper, the fourth in a series, we examine again one of the implications of the Lin-Shu density-wave theory, specifically, the noncircular systematic motion of the Galactic objects. Our previous investigation is extended by analyzing simultaneously both the line-of-sight and transversal velocities of a sample of open clusters for which velocities, distances and ages are available. The ordinary equations of the Oort-Lindblad theory of galactic differential rotation are used. The minor effects caused by the two-dimensional tightly-wound density waves are also taken into account. The published data of 242 currently known optically visible clusters having distances r < 3 kpc from the Sun and −200 < z < 200 pc from the Galactic plane, and ages 2×10 8 < t < 2×10 9 yr are collected from Dias et al. (2014), excluding extremely far, high-velocity, young and old objects in our fitting. The most noteworthy result is the fact that the parameters of Lin-Shu type density waves estimated from two independent line-of-sight and transversal along the Galactic longitude velocities are nearly equal. We argue that the resemblance of these Galactic wave structures is so remarkable that no doubt is felt as to the theory's truth with respect to these data. The results obtained allow us to conclude that several low-m trailing density-wave patterns with different number of spiral arms m (say, m = 1, 2, 3, and 4), pitch angles (about 5• , 8• , 11• , and 14 • , respectively) and amplitudes of the perturbed gravitational potential may coexist in the Galaxy. The latter suggests the asymmetric multiarm, not well-organized ("flocculent") spiral structure of the system.

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Section: Introductionmentioning

confidence: 58%

Section: Introductionmentioning

confidence: 99%

A model for the Lin‐Shu type density‐wave structure of our Galaxy: Line‐of‐sight and transverse‐longitudinal velocities of 242 optically visible open clusters

Griv

Jiang

2015

Astron Nachr

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“…We have studied the parallelization efficiency and accuracy of our algorithm by means of simulation of the gravitationally unstable collisionless disk [1,20,21]. The calculations were carried out on GPU Nvidia Tesla computers: K20, K40, K80.…”

Section: Resultsmentioning

confidence: 99%

New Features of Parallel Implementation of N-Body Problems on GPU

Khrapov¹,

Khoperskov²,

Хоперсков³

2018

Bulletin of the SUSU. MMP

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This paper focuses on the parallel implementation of a direct N -body method (particleparticle algorithm) and the application of multiple GPUs for galactic dynamics simulations. Application of a hybrid OpenMP-CUDA technology is considered for models with a number of particles N ∼ 10 5 ÷ 10 7 . By means of N -body simulations of gravitationally unstable stellar galactic we have investigated the algorithms parallelization efficiency for various Nvidia Tesla graphics processors (K20, K40, K80). Particular attention was paid to the parallel performance of simulations and accuracy of the numerical solution by comparing single and double floating-point precisions (SP and DP). We showed that the doubleprecision simulations are slower by a factor of 1.7 than the single-precision runs performed on Nvidia Tesla K-Series processors. We also claim that application of the single-precision operations leads to incorrect result in the evolution of the non-axisymmetric gravitating N -body systems. In particular, it leads to significant quantitative and even qualitative distortions in the galactic disk evolution. For instance, after 10 4 integration time steps for the single-precision numbers the total energy, momentum, and angular momentum of a system with N = 2 20 conserve with accuracy of 10 −3 , 10 −2 and 10 −3 respectively, in comparison to the double-precision simulations these values are 10 −5 , 10 −15 and 10 −13 , respectively. Our estimations evidence in favour of usage of the second-order accuracy schemes with double-precision numbers since it is more efficient than in the fourth-order schemes with single-precision numbers.

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“…On the other hand, several low-m (say, m < 10) density-wave patterns with different number of arms and wavelengths may coexist in the Galaxy (cf. Lin 1971;Bertin et al 1977;Lin & Lau 1979;Griv & Wang 2014;Sellwood 2020). We may consider the multiple-armed spiral structure of the system in terms of several coexisting wave patterns.…”

Section: R E S U Lt S O F C a L C U L At I O Nmentioning

confidence: 99%

“…The wave structure may be excited by real instabilities of small-amplitude gravity perturbations, for instance, those produced by a spontaneous disturbance, i.e. emerged from noise in the initial density and gravitational potential distribution (Lin & Lau 1979;Griv, Gedalin & Yuan 2006;Griv & Wang 2014;Sellwood & Carlberg 2019;Sellwood 2020), a central bar (Feldman & Lin 1973;Korchagin & Marochnik 1975;Romero-Gómez et al 2007;Athanassoula et al 2010;Cheung et al 2013) or a companion system (Goldreich & Tremaine 1979, 1980Bland-Hawthorn et al 2019). The growth rate of the instability which causes initial perturbations to grow to observable amplitudes has a maximum at the radial wavelength λ crit .…”

mentioning

confidence: 99%

Spiral density-wave structure parameters in the solar neighbourhood derived from longitudinal velocities of Gaia EDR3 OB stars: 3D approach

Griv

Gedalin

Mróz

et al. 2021

Monthly Notices of the Royal Astronomical Society

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Distances and transverse along the Galactic longitude velocities vl of 2640 Gaia EDR3 O–B2 stars of Xu et al. within 2.5 kpc from the Sun and 250 pc from the Galactic plane with relative distance and velocity accuracies of <10 and <50 per cent are selected. Under the assumption of spiral density waves, both Galactic differential rotation parameters and parameters of the wave structure in this solar neighborhood are derived from observed vl. In contrast to all preceding studies, we take into account the effect of small but finite thickness of the disk of the Galaxy on even parity (‘sausage’) gravity perturbations of the kind investigated by Lin and Shu. As previously predicted by the modified theory of three-dimensional density waves, two scales of periodic rarefaction–compression irregularity of the vl velocity field with the radial λ0 ≈ 1.5 kpc and vertical ξ0 ≈ 1.0 kpc wavelengths in the form of a spiral wave propagating in the disk are revealed. The Gaia’s DR2 line-of-sight and EDR3 longitudinal velocities analyses performed in the last papers of a series exhibit consistent findings, thus providing a further evidence to support the Lin–Shu density-wave proposal.

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Density wave formation in differentially rotating disk galaxies: Hydrodynamic simulation of the linear regime

Cited by 13 publications

References 92 publications

A model for the Lin‐Shu type density‐wave structure of our Galaxy: Line‐of‐sight and transverse‐longitudinal velocities of 242 optically visible open clusters

A model for the Lin‐Shu type density‐wave structure of our Galaxy: Line‐of‐sight and transverse‐longitudinal velocities of 242 optically visible open clusters

New Features of Parallel Implementation of N-Body Problems on GPU

Spiral density-wave structure parameters in the solar neighbourhood derived from longitudinal velocities of Gaia EDR3 OB stars: 3D approach

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