منابع مشابه
Subsuns, Bottlinger's rings, and elliptical halos.
Subsuns, Bottlinger's rings, and elliptical halos are simulated by the use of a Monte Carlo model; reflection of sunlight from almost horizontal ice crystals is assumed. Subsuns are circular or elliptical spots seen at the specular reflection point when one flies over cirrus or cirrostratus clouds. Bottlinger's rings are rare, almost elliptical rings centered about the subsun. Elliptical halos ...
متن کاملModelling Kinematics and Dark Matter: The Halos of Elliptical Galaxies⋆
This review is focussed on the outer halos of elliptical galaxies. Its emphasis is on (i) planetary nebulae as test particles to trace the stellar kinematics at large radii, (ii) the observed angular momentum in elliptical galaxy halos and its theoretical relevance, (iii) dynamical modelling of stellar-kinematic data, and (iv) a discussion of the evidence for dark matter halos in ellipticals fr...
متن کاملGiant Halos in Dwarf Irregular Galaxies vs. Dwarf Elliptical Galaxies
We present a discovery of a giant stellar halo in NGC 6822, a dwarf irregular galaxy in the Local Group. This halo is mostly made of old red giants, showing striking features: 1) it is several times larger than the main body of the galaxy seen in the optical images, and 2) it is elongated in the direction almost perpendicular to the HI disk of NGC 6822. The structure of this stellar halo looks ...
متن کاملElliptical structure of the lunar South Pole-Aitken basin
The South Pole-Aitken basin (SP-A) is the largest and oldest basin on the Moon. The basin has usually been interpreted to exhibit a degraded circular structure, but here we demonstrate that the topography, iron and thorium signatures of the basin are well described by ellipses with axes measuring 2400 by 2050 km and centered at 53 , 191 E. Topography, abundances of iron, thorium, and the distri...
متن کاملStellar halos and elliptical galaxy formation: Origin of dynamical properties of the planetary nebular systems
Recent spectroscopic observations of planetary nebulae (PNe) in several elliptical galaxies have revealed structural and kinematical properties of the outer stellar halo regions. In order to elucidate the origin of the properties of these planetary nebula systems (PNSs), we consider the merger scenario in which an elliptical galaxy is formed by merging of spiral galaxies. Using numerical simula...
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ژورنال
عنوان ژورنال: Nature
سال: 1913
ISSN: 0028-0836,1476-4687
DOI: 10.1038/091110a0