نتایج جستجو برای: alteration halos

تعداد نتایج: 50314  

2002
D. N. Chen Y. P. Jing

We study the angular momentum profile of dark matter halos for a statistical sample drawn from a set of high-resolution cosmological simulations of 256 3 particles. Two typical Cold Dark Matter (CDM) models have been analyzed, and the halos are selected to have at least 3 × 10 4 particles in order to reliably measure the angular momentum profile. In contrast with the recent claims of Bullock et...

2002
David K. Lynch

Despite the growing scientific awareness of ice-crystal halos, there is surprising lack of quantitative observational data about them. Even the most basic (and often-referenced) angular measurements sometimes consist of casual determinations of the radii of circular-halos with no mention whatever of the intensity distribution. More-complex halos are reported with either freehand drawings or pho...

2008
Ding Ma Ping He

N-body simulations of dark matter halos show that the density profiles of halos behave as ρ(r) ∝ r−α(r), where the density logarithmic slope α ≃ 1 ∼ 1.5 in the center and α ≃ 3 ∼ 4 in the outer parts of halos. However, some observations are not in agreement with simulations in the very central region of halos. The simulations also show that velocity dispersion anisotropy parameter β ≈ 0 in the ...

1998
SNIGDHA DAS

We have tried to understand the recent observations related to metallicity in Ly α forest clouds in the framework of the two component model suggested by Chiba & Nath (1997). The model consists of mini-halos having circular velocities smaller than ∼ 55 km s, with no star formation and galactic halos with higher circular velocities ≤ 250 km s, having clouds, star formation and consequent metal e...

Journal: :Nuclear Physics A 1997

Journal: :Monthly Weather Review 1917

Journal: :Nature 1917

2008
Xiaohu Yang Frank C. van den Bosch

We investigate various galaxy occupation statistics of dark matter halos using a large galaxy group catalogue constructed from the Sloan Digital Sky Survey Data Release 4 (SDSS DR4) with an adaptive halo-based group finder. The conditional luminosity function (CLF), which describes the luminosity distribution of galaxies in halos of a given mass, is measured separately for all, red and blue gal...

2005
Ortwin Gerhard

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...

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