Do Spiral Galaxies have a Variable Disk Thickness?
نویسندگان
چکیده
منابع مشابه
Bars, Spiral Structure, and Secular Evolution in Disk Galaxies
Simulations and observations of galactic bars suggest they do not commonly evolve into bulges, although it is possible that the earliest bars formed bulges long ago, when galaxies were smaller, denser, and had more gas. The most highly evolved of today’s bars may become lenses over a Hubble time. Most galaxies in the early Universe are extremely clumpy, with ∼ 10 −10 M⊙ blue clumps that resembl...
متن کاملUnstable Bar and Spiral Modes of Disk Galaxies
We study bisymmetric modes of angular wavenumber 2 for flat stellar disks in potentials with smooth cores. Stars either all circulate in the same direction or a small fraction may counter-rotate. The bisymmetric modes are unstable unless there is a sufficiently large external halo or bulge. We find two modes for each disk: a more central fundamental mode and a more extensive and more spiral (tr...
متن کاملResonance Excitation and the Spiral-ring Structure of Disk Galaxies
Rings are common in disk galaxies. These rings are either indistinguishable from a pair of tightly wound spirals, or themselves are a part of the spiral structure. Furthermore, their occurrence is seen coincident with a bar in the center. In this paper, we interpret this spiral-ring structure as density waves resonantly excited by a rotating bar potential. The theory gives excellent agreement f...
متن کاملDo Cluster Galaxies Have Extended Dark Halos?
We present the results of the application of the methodology introduced by Natarajan & Kneib (1997) to interpret local perturbations to the cluster shear field resulting from mass associated with individual cluster galaxies. The lensing signal is used to place new constraints on the average mass-to-light ratio and spatial extents of the dark matter halos associated with morphologically-classifi...
متن کاملChemo - spectrophotometric evolution of spiral galaxies : II . Main properties of present day disk galaxies
We study the chemical and spectro-photometric evolution of galactic disks with detailed models calibrated on the Milky Way and using simple scaling relations, based on currently popular semi-analytic models of galaxy formation. We compare our results to a large body of observational data on present day galactic disks, including: disk sizes and central surface brightness, Tully-Fisher relations ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1983
ISSN: 0074-1809
DOI: 10.1017/s0074180900032460