The identification of physical close galaxy pairs

A classification scheme for close pairs of galaxies is proposed. The scheme is motivated by the fact that the majority of apparent close pairs are in fact wide pairs in three-dimensional space. This is demonstrated by means of numerical simulations of random samples of binary galaxies and the scrutiny of the resulting projected and spatial separation distributions. Observational strategies for classifying close pairs according to the scheme are suggested. As a result, physical (i.e., bound and spatially) close pairs are identified.Comment: 16 pages, 5 figures, accepted for publication in The Astronomical Journal, added text corrections on proof

Drop deformation in stokes flow through converging channels

This work presents an application of a direct BEM formulation for drop deformation and interaction in Stokes flows through converging channels. Parametric studies are conducted to investigate the effect, on drop deformation, of the channel’s convergence ratio, the drop-fluid viscosity ratio, the interfacial tension and the initial relative position of the drops

The Mass-to-Light Ratio of Binary Galaxies

We report on the mass-to-light ratio determination based on a newly selected binary galaxy sample, which includes a large number of pairs whose separations exceed a few hundred kpc. The probability distributions of the projected separation and the velocity difference have been calculated considering the contamination of optical pairs, and the mass-to-light ratio has been determined based on the maximum likelihood method. The best estimate of $M/L$ in the B band for 57 pairs is found to be 28 $\sim$ 36 depending on the orbital parameters and the distribution of optical pairs (solar unit, $H_0=50$ km s$^{-1}$ Mpc$^{-1}$). The best estimate of $M/L$ for 30 pure spiral pairs is found to be 12 $\sim$ 16. These results are relatively smaller than those obtained in previous studies, but consistent with each other within the errors. Although the number of pairs with large separation is significantly increased compared to previous samples, $M/L$ does not show any tendency of increase, but found to be almost independent of the separation of pairs beyond 100 kpc. The constancy of $M/L$ beyond 100 kpc may indicate that the typical halo size of spiral galaxies is less than $\sim 100$ kpc.Comment: 18 pages + 8 figures, to appear in ApJ Vol. 516 (May 10

Talking with experts - from research to objects: using academic research as the basis of collaborative and cross disciplinary projects for design students

The role of design is changing and after postmodern design, in which design seemed to be more related to production, business and marketing, we are currently looking at ‘the translation of scientific and technological research into tangible objects that change people's lives’ as one of the most fundamental roles of design [1]. In the majority of Higher Education institutions a significant amount of research takes place and there is considerable potential to develop applications from the results of these activities, many of which are not fully exploited. The primary aim of this project was to investigate how design methods can be used to bridge the gap between the abstraction of research and the tangible requirements of everyday life. A project targeted second year students was developed to explore this concept; it was also an opportunity for students to challenge their familiar working methods by being collaborative and interdisciplinary. First they formed teams and identified examples of scientific and engineering research expertise; they then contacted the research active academic staff working in these fields and carried out a video interview. They analysed their findings and gave a presentation outlining their approach and design development for an appropriate context. Finally the teams presented educational videos that explain and promote their design proposals to expert and non-expert audiences. The paper includes several examples of these design proposals and illustrates the benefits of collaboration for students and to researchers who see how their work can be interpreted and developed into real world tangible applications