Ellipticity of Outer Regions of Galactic Disks
نویسندگان
چکیده
منابع مشابه
Patterns in the Outer Parts of Galactic Disks
This paper describes test particle simulations of the response of the outer parts of Galactic disks to barring and spiral structure. Simulations are conducted for cold Mestel disks and warm quasi-exponential disks with completely flat rotation curves, subjected to pure quadrupoles and logarithmic spirals. Even though the starting velocity distributions are smooth, the end-points of the bar simu...
متن کاملPerspectives for detecting cold H2 in outer galactic disks
We review here the main direct or indirect ways to detect the possible presence of large amounts of cold molecular hydrogen in the outer parts of disk galaxies, an hypothesis that we have recently developed. Direct ways range from H2 absorption in the UV domain to detection of the radio hyperfine structure: the orthoH2 molecule has an hyperfine, or ultrafine, structure in its fundamental state,...
متن کاملThe Outer Structure of Galactic Disks : Connections Between Bars , Disks , and Environments
Surface-brightness profiles for early-type (S0–Sb) disks exhibit three main classes (Type I, II, and III). Type II profiles are more common in barred galaxies, and most of the time appear to be related to the bar’s Outer Lindblad Resonance. Roughly half of barred galaxies in the field have Type II profiles, but almost none in the Virgo Cluster do. A strong anticorrelation is found between Type ...
متن کاملThe Intrinsic Ellipticity of Spiral Disks
We have measured the distribution of intrinsic ellipticities for a sample of 28 relatively face–on spiral disks. We combine Hα velocity fields and R and I-band images to determine differences between kinematic and photometric inclination and position angles, from which we estimate intrinsic ellipticities of galaxy disks. Our findings suggest disks have a lognormal distribution of ellipticities ...
متن کاملThe Outer Regions of the Galactic Bulge : II { AnalysisRodrigo
Velocity, chemical abundance and spatial distribution data for some 1500 K-and M-giants in the Galactic Bulge, which are presented in an accompanying paper (Ibata & Gilmore 1995), are analysed. We provide three levels of analysis: an almost model-independent determination of basic symmetry properties of the galactic bulge; a more detailed analysis based on conservative assumptions, which invest...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1996
ISSN: 0074-1809
DOI: 10.1017/s0074180900229513