Halo
نویسندگان
چکیده
منابع مشابه
The halo by halo missing baryon problem
The global missing baryon problem — that the sum of observed baryons falls short of the number expected form BBN — is well known. In addition to this, there is also a local missing baryon problem that applies to individual dark matter halos. This halo by halo missing baryon problem is such that the observed mass fraction of baryons in individual galaxies falls short of the cosmic baryon fractio...
متن کاملHalo Kinematics
I summarize recent observations of the kinematics of hot tracers in elliptical galaxy halos (globular clusters, planetary nebulae, and integrated stellar light), and what these tell us about the dynamics, dark matter content, and formation of ellipticals. A generic result is the ubiquity of dark matter halos in ellipticals. Studies of globular clusters and planetary nebulae are now finding oute...
متن کاملHalo Spacetime
The newtonian potential that describes constant galactic rotation curves, which represent the speed of rotating stars and are independent of their distance from the centre, is φ = −v c ln(r). Substituting into Poisson’s equation gives density 4πGρ = −v c /r. The perfect fluid Einstein equations give the same result to lowest order, to next order terms in v c occur in the pressure and the densit...
متن کاملSun-earth L1 Region Halo-to-halo Orbit and Halo-to-lissajous Orbit Transfers
Practical techniques for designing transfer trajectories between Libration Point Orbits (LPOs) are presented. Motivation for development of these techniques was provided by a hardware contingency experienced by the Solar Heliospheric Observatory (SOHO), a joint mission of the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA) orbiting the L1 point of the Su...
متن کاملBar-halo Friction in Galaxies Iii: Halo Density Changes
The dark matter halos of bright galaxies appear to have densities in their inner parts that are at least an order of magnitude lower than predicted from structure-formation simulations. This well-known difficulty for LCDM would be ameliorated if galaxy evolution could drive down the dark matter density in the inner halo. Here I present a study of the halo density reductions that result from tor...
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: Nature
سال: 1882
ISSN: 0028-0836,1476-4687
DOI: 10.1038/026344a0