Using cosmological N -body simulations we study the radial velocity distribution in dark matter haloes focusing on the lowest-order even moments, dispersion and kurtosis. We determine the properties of ten massive haloes in the simulation box approximating their density distribution by the NFW formula characterized by the virial mass and concentration. We also calculate the velocity anisotropy ...

BV CCD frames have been used to derive surface brightness pro les for NGC 3201 which extend out to approximately 180. A total of 857 radial velocities with median precision ' 1 km s 1 for 399 member giants have been used to trace the velocity dispersion pro le out to 32.10 (the approximate tidal radius determined from ts of single-mass, isotropic King-Michie models to the cluster surface bright...

We present a detailed study of two luminous super star clusters in the starburst galaxy M82. Spectra, covering 3250–8790 Å at a resolution of 1.6 Å, were obtained at the 4.2m William Herschel Telescope (WHT) for cluster F and the highly reddened cluster L. We compare the strengths of the observed Balmer absorption lines and the Balmer jump in the blue spectrum of F with theoretical model cluste...

Combining HST/WFPC2 mosaics with extensive ground-based spectroscopy, we study the nature of E+A galaxies in three intermediate redshift clusters (z = 0.33, 0.58, & 0.83). From a sample of ∼ 500 confirmed cluster members, we isolate 46 E+A candidates to determine the E+A fraction and study their physical properties. Spectral types are assigned using Balmer (Hδ, Hγ, Hβ) and [OII] λ3727 equivalen...

these are notes from introductory survey lectures given at the institute for studies in theoretical physics and mathematics (ipm), teheran, in 2008 and 2010. we present the definition and the fundamental properties of fomin-zelevinsky’s cluster algebras. then, we introduce quiver representations and show how they can be used to construct cluster variables, which are the canonical generators of ...