... It is found that the metallisity distribution of disk stars has a gap which subdivide the disk population into two groups. The distribution may be described by the sum of two normal curves which are centered at [Fe/H]=-0.22 and +0.08. The curves can be interpreted as distributions of random errors in metallisity of sample stars. This leads to the conclusion that all stars in each group have actually the same value of [Fe/H]. ... Рассмотрен вопрос о происхождении подсистем Галактики. ...

http://hea-www.harvard.edu/AstroStat/slog/2008/ tests -of- fit -for-the- poisson - distribution / Weaving together Astronomy+ Statistics +Computer Science+Engineering+Intrumentation, far beyond the growing borders Fri, 01 Jun 2012 18:47:52 +0000 hourly 1 http://wordpress.org/?v=3.4 http://hea-www.harvard.edu/AstroStat/slog/2008/ tests -of- fit -for-the- poisson - distribution /comment-page-1/#comment-267 ... Abstract: Improved №З2 statistics are defined for both Poisson and multinomial data sets. ...

Scale-free dynamical models for galaxies: flattened densities in spherical potentials . ... The `case I' distribution functions are anisotropic generalizations of the flattened f(E,L_z) model, which they include as a special case. The `case II' distribution functions generate flattened constant-anisotropy models. Free parameters control the radial power-law slopes of the mass density and potential, the flattening of the mass distribution, and the velocity dispersion anisotropy. ...

Next: Abstract . Mikhail E. Prokhorov and Konstantin A. Postnov . ... Physics of Neutron Stars'' . ... Abstract . ... Initial conditions . Space and velocity distributions . Space position . Initial velocity . ... Mike E. Prokhorov . ...

... ATCA HI and radio continuum observations of the peculiar southern galaxy IC2554 and its surroundings reveal typical signatures of an interacting galaxy group. We detected a large HI cloud between IC2554 and the elliptical galaxy NGC3136B. The gas dynamics in IC2554 itself, which is sometimes described as a colliding pair, are surprisingly regular, whereas NGC3136B was not detected. ... The total HI mass of the IC2554 system is approx. 2 x 10 9 Msun, a third of which resides in the HI cloud. ...

... We demonstrate through numerical simulations that model parameters estimated with our technique are essentially bias-free, even when the average number of counts per bin is 1. ... The IW technique avoids such biases by estimating through successive iterations, where for each iteration, j, , and the best-fit parameters are determined by minimization of . ... In our sample, we find that the minimum values and best-fit parameters converge after about 6 iterations. ...

... 2000; Persi et al. 2000). One of these stars (Cha Halpha1) is a bona-fide brown dwarf, with mass 0.04-0.05 Msun. ... This result provides a first indication that the formation mechanism of T Tauri stars (via core contraction and formation of an accretion disk) extends to objects in the brown dwarf mass range. ...