منابع مشابه
Extended Hi Rotation Curve and Mass Distribution of M31
New HI observations of Messier 31 (M31) obtained with the Effelsberg and Green Bank 100-m telescopes make it possible to measure the rotation curve of that galaxy out to ∼ 35 kpc. Between 20 and 35 kpc, the rotation curve is nearly flat at a velocity of ∼ 226 km s−1 . A model of the mass distribution shows that at the last observed velocity point, the minimum dark–to–luminous mass ratio is ∼ 0....
متن کاملExpanding HI shells in NGC 2403 : First results from an automated object recognition packageDavid
We have developed an automated package of object recognition software to detect and accurately characterize expanding HI supershells in nearby spiral galaxies. Our method avoids the ambiguity associated with visually identifying complex, expanding structures in spectral line datacubes. In this pilot study, an analytic expression for the time evolution of a supershell is used to derive the appro...
متن کاملExpanding HI shells in NGC 2403 First results from an automated object recognition package
We have developed an automated package of object recognition software to detect and accurately characterize expanding HI supershells in nearby spiral galaxies. Our method avoids the ambiguity associated with visually identifying complex, expanding structures in spectral line datacubes. In this pilot study, an analytic expression for the time evolution of a supershell is used to derive the appro...
متن کاملOn the properties of HI shells in the Small Magellanic Cloud
There are 509 expanding neutral hydrogen shells catalogued in the Small Magellanic Cloud (SMC), all apparently very young, with dynamical ages of a few Myr. To examine their relationship with young stellar objects we cross-correlated the shell catalogue with various catalogues of OB associations, super giants, Cepheids, WR stars, supernova remnants, and star clusters. The incidence of chance li...
متن کاملA Runaway Red Supergiant in M31
A significant percentage of OB stars are runaways, so we can expect a similar percentage of their evolved descendants to also be runaways. However, recognizing such stars presents its own set of challenges, as these older, more evolved stars will have drifted farther from their birthplace, and thus their velocities might not be obviously peculiar. Several Galactic red supergiants (RSGs) have be...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1983
ISSN: 0074-1809
DOI: 10.1017/s0074180900032654