RESONANT CLUMPING AND SUBSTRUCTURE IN GALACTIC DISKS

	RESONANT CLUMPING AND SUBSTRUCTURE IN GALACTIC DISKS
	Molloy, Matthew 1; Smith, Martin C.2; Shen, Juntai2 ; Evans, N. Wyn 3
刊名	ASTROPHYSICAL JOURNAL
	2015-05-10
卷号	804 期号:2 页码:1
关键词	galaxies: bulges Galaxy: bulge Galaxy: disk Galaxy: evolution galaxies: kinematics and dynamics Galaxy: kinematics and dynamics
英文摘要	We describe a method to extract resonant orbits from N-body simulations, exploiting the fact that they close in frames rotating with a constant pattern speed. Our method is applied to the N-body simulation of the Milky Way by Shen et al. This simulation hosts a massive bar, which drives strong resonances and persistent angular momentum exchange. Resonant orbits are found throughout the disk, both close to the bar and out to the very edges of the disk. Using Fourier spectrograms, we demonstrate that the bar is driving kinematic substructure even in the very outer parts of the disk. We identify two major orbit families in the outskirts of the disk, one of which makes significant contributions to the kinematic landscape, namely,. the m:l-3:-2 family, resonating with the bar. A mechanism is described that produces bimodal distributions of Galactocentric radial velocities at selected azimuths in the outer disk. It occurs as a result of the temporal coherence of particles on the 3:-2 resonant orbits, which causes them to arrive simultaneously at pericenter. or apocenter. This resonant clumping, due to the in-phase motion of the particles through their epicycle, leads to both inward and outward moving groups that belong to the same orbital family and consequently produce bimodal radial velocity distributions. This is a possible explanation of the bimodal velocity distributions observed toward the Galactic anticenter by Liu et al. Another consequence is that transient overdensities appear and dissipate (in a symmetric fashion), resulting in a periodic pulsing of the disk's surface density.
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	MILKY-WAY BULGE ; RADIAL-VELOCITY ASSAY ; DIGITAL SKY SURVEY ; GAIA-ESO SURVEY ; BARRED GALAXIES ; SPIRAL ARMS ; SPECTROSCOPIC SURVEY ; STELLAR KINEMATICS ; ROTATION CURVES ; DATA RELEASE
收录类别	SCI
语种	英语
WOS记录号	WOS:000354905000002
公开日期	2015-08-18
内容类型	期刊论文
源URL	[http://119.78.226.72/handle/331011/18339]
专题	上海天文台_星系宇宙学重点实验室
作者单位	1.Peking Univ, Kavli Inst Astron & Astrophys, Beijing 100871, Peoples R China 2.Chinese Acad Sci, Shanghai Astron Observ, Key Lab Res Galaxies & Cosmol, Shanghai 200030, Peoples R China 3.Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England
推荐引用方式 GB/T 7714	Molloy, Matthew,Smith, Martin C.,Shen, Juntai,et al. RESONANT CLUMPING AND SUBSTRUCTURE IN GALACTIC DISKS[J]. ASTROPHYSICAL JOURNAL,2015,804(2):1.
APA	Molloy, Matthew,Smith, Martin C.,Shen, Juntai,&Evans, N. Wyn.(2015).RESONANT CLUMPING AND SUBSTRUCTURE IN GALACTIC DISKS.ASTROPHYSICAL JOURNAL,804(2),1.
MLA	Molloy, Matthew,et al."RESONANT CLUMPING AND SUBSTRUCTURE IN GALACTIC DISKS".ASTROPHYSICAL JOURNAL 804.2(2015):1.