Age and metallicity of the bulges in lenticular galaxies

Panoramic spectroscopic data of the sample of 80 nearby lenticular galaxies obtained with the Multi-Pupil Fiber Spectrograph of the 6-m telescope are presented. The SSP-equivalent ages, [Z/H], and [Mg/Fe] are determined through the Lick indices H-beta, Mgb, and separately for the nuclei and for the bulges. About a half of the sample contain chemically distinct nuclei, more metal-rich and younger than the bulges. The correlations of the stellar population properties for the nearby S0s are discussed.Comment: 5 pages, 2 figures. To appear in the Proceedings of the IAU Symposium 245, "Formation and Evolution of Galaxy Bulges", held at Oxford, U.K., July 2007, Eds. M. Bureau, E. Athanassoula, B. Barbu

Thin film dynamics on a vertically rotating disk partially immersed in a liquid bath

The axisymmetric flow of a thin liquid film is considered for the problem of a vertically rotating disk that is partially immersed in a liquid bath. A model for the fully three-dimensional free-boundary problem of the rotating disk, that drags a thin film out of the bath is set up. From this, a dimension-reduced extended lubrication approximation that includes the meniscus region is derived. This problem constitutes a generalization of the classic drag-out and drag-in problem to the case of axisymmetric flow. The resulting nonlinear fourth-order partial differential equation for the film profile is solved numerically using a finite element scheme. For a range of parameters steady states are found and compared to asymptotic solutions. Patterns of the film profile, as a function of immersion depth and angular velocity are discussed.Comment: 31 pages, 19 figures accepted: Applied Mathematical Modellin

Two more disk galaxies with global gas counterrotation

We report a discovery of extended counterrotating gaseous disks in early-type disk galaxies NGC 2551 and NGC 5631. To find them, we have undertaken complex spectral observations including integral-field spectroscopy for the central parts of the galaxies and long-slit deep spectroscopy to probe the external parts. The line-of-sight velocity fields have been constructed and compared to the photometric structure of the galaxies. As a result, we have revealed full-size counterrotating gaseous disks, the one coplanar to the stellar disk in NGC 2551 and the other inclined to the main stellar disk in NGC 5631. We suggest that we observe the early stages of minor-merger events which may be two different stages of the process of lenticular galaxy formation in rather sparse environments.Comment: 8 pages, 8 EPS figures, accepted for publication in Ap

Numerical simulation of three-dimensional cavitation bubble oscillations by boundary element method

This work is devoted to a numerical investigation of threedimensional cavitation bubble. Bubble oscillations in ambient unbounded fluid are investigated numerically. The fluid is assumed inviscid, incompressible and unbounded and the flow is irrotational. The boundary integral method is used as an instrument of numerical investigation. Much attention is paid to the description of a numerical algorithm.http://deepblue.lib.umich.edu/bitstream/2027.42/84303/1/CAV2009-final127.pd

A new method for reconstructing the density distribution of matter in the disks of spiral galaxies from the rotation velocity curve in it

In this paper we propose a new method for reconstructing the surface density of matter in flat disks of spiral galaxies. The surface density is expressed through observational rotation velocity curves of visible matter in the disks of spiral galaxies. The new method is not based on quadrature of special functions. The found solution is used for processing and analysis of observational data from several spiral galaxies. The new method can be used to more accurately estimate the amount of dark matter in spiral galaxies.Comment: 18 pages, 6 figure