Panchromatic properties of galaxies in wide-field optical spectroscopic and photometric surveys

The past 15 years have seen an explosion in the number of redshifts recovered via wide area spectroscopic surveys. At the current time there are approximately 2million spectroscopic galaxy redshifts known (and rising) which represents an extraordinary growth since the pioneering work of Marc Davis and John Huchra. Similarly there has been a parallel explosion in wavelength coverage with imaging surveys progressing from single band, to multi-band, to truly multiwavelength or pan-chromatic involving the coordination of multiple facilities. With these empirically motivated studies has come a wealth of new discoveries impacting almost all areas of astrophysics. Today individual surveys, as best demonstrated by the Sloan Digital Sky Survey, now rank shoulder-to-shoulder alongside major facilities. In the coming years this trend is set to continue as we being the process of designing and conducting the next generation of spectroscopic surveys supported by multi-facility wavelength coverage.Comment: Invited review article to be published in Proceedings of IAU Symposium 284 on "The Spectral Energy Distribution of Galaxies", (Eds: R.J.Tuffs & C.C.Popescu

Lessons learned from Asian tsunami disaster: Sharing knowledge

Creating an organised common platform to capture, organise and share the knowledge on disaster management strategies is considered vital to enhance the effectiveness of future disaster management efforts. Hence, ensuring the availability and accessibility of accurate and reliable disaster risk information when required entails an efficient system for knowledge sharing. This paper highlights the importance of knowledge and good practice sharing in disaster management strategies, and discusses key lessons learned from 2004 Asian tsunami, particularly relating to the Sri Lankan context. Good practices and lessons learned are discussed on five different themes: social, technical, legal, operational and environmental. Further, the ISLAND website is introduced and developed as part of a research aimed at increasing the effectiveness of disaster management by facilitating the sharing of appropriate knowledge and good practices

Key knowledge management variables for facilities management organisational effectiveness

Although knowledge management concept has grown noticeably during last few years, management of facilities knowledge has been little studies. Facilities knowledge is of crucial importance for organisational effectiveness and makes a proactive contribution to business to achieve competitive advantage. The research addresses the importance of managing facilities knowledge and to reveal the key knowledge variables by examining the current practice and gaps in application of knowledge management techniques in facilities management context. The intellectual capital framework is introduced as a conceptual model with which facilities users can identify and organise facilities knowledge in a purposeful way

Quantifying cosmic variance

We determine an expression for the cosmic variance of any "normal" galaxy survey based on examination of M* +/- 1 mag galaxies in the SDSS DR7 data cube. We find that cosmic variance will depend on a number of factors principally: total survey volume, survey aspect ratio, and whether the area surveyed is contiguous or comprised of independent sight-lines. As a rule of thumb cosmic variance falls below 10% once a volume of 10^7h_0.7^-3Mpc^3 is surveyed for a single contiguous region with a 1:1 aspect ratio. Cosmic variance will be lower for higher aspect ratios and/or non-contiguous surveys. Extrapolating outside our test region we infer that cosmic variance in the entire SDSS DR7 main survey region is ~7% to z < 0.1. The equation obtained from the SDSS DR7 region can be generalised to estimate the cosmic variance for any density measurement determined from normal galaxies (e.g., luminosity densities, stellar mass densities and cosmic star-formation rates) within the volume range 10^3 to 10^7 h^-3_0.7Mpc^3. We apply our equation to show that 2 sightlines are required to ensure cosmic variance is <10% in any ASKAP galaxy survey (divided into dz ~0.1 intervals, i.e., ~1 Gyr intervals for z <0.5). Likewise 10 MeerKAT sightlines will be required to meet the same conditions. GAMA, VVDS, and zCOSMOS all suffer less than 10% cosmic variance (~3%-8%) in dz intervals of 0.1, 0.25, and 0.5 respectively. Finally we show that cosmic variance is potentially at the 50-70% level, or greater, in the HST Ultra Deep Field depending on assumptions as to the evolution of clustering. 100 or 10 independent sightlines will be required to reduce cosmic variance to a manageable level (<10%) for HST ACS or HST WFC3 surveys respectively (in dz ~ 1 intervals). Cosmic variance is therefore a significant factor in the z>6 HST studies currently underway.Comment: Accepted for publication in MNRA

A Tunable Echelle Imager

We describe and evaluate a new instrument design called a Tunable Echelle Imager (TEI). In this instrument, the output from an imaging Fabry-Perot interferometer is cross-dispersed by a grism in one direction and dispersed by an echelle grating in the perpendicular direction. This forms a mosaic of different narrow-band images of the same field on a detector. It offers a distinct wavelength multiplex advantage over a traditional imaging Fabry-Perot device. Potential applications of the TEI include spectrophotometric imaging and OH-suppressed imaging by rejection.Comment: 11 pages, 12 figures, accepted by PAS

The Efficacy of the Tabby Improved Prevention and Intervention Program in Reducing Cyberbullying and Cybervictimization among Students.

Background. This article presents results from the evaluation of the Tabby Improved Prevention and Intervention Program (TIPIP) for cyberbullying and cybervictimization. TIPIP is theoretically designed to address cyberbullying and cybervictimization. It is the first program in this field developed combining the Ecological System Theory and the Threat Assessment Approach. Method. The Tabby Improved program was evaluated using an experimental design with 759 Italian students (aged 10⁻17 years) randomly allocated via their classes to either the Experimental or Control Group. Results. Repeated measures ANOVAs showed a significant decrease both in cyberbullying and cybervictimization among students who received the intervention with a follow-up period of six months. The program was more effective for boys than for girls. Conclusions. Because cyberbullying is a cruel problem negatively affecting those involved, validated interventions that prove their efficacy in reducing the problem using experimental designs should be widely tested and promoted, paying particular attention to implementing a program fully to increase and guarantee its effectiveness

Galaxy bimodality versus stellar mass and environment

We analyse a z<0.1 galaxy sample from the Sloan Digital Sky Survey focusing on the variation of the galaxy colour bimodality with stellar mass and projected neighbour density Sigma, and on measurements of the galaxy stellar mass functions. The characteristic mass increases with environmental density from about 10^10.6 Msun to 10^10.9 Msun (Kroupa IMF, H_0=70) for Sigma in the range 0.1--10 per Mpc^2. The galaxy population naturally divides into a red and blue sequence with the locus of the sequences in colour-mass and colour-concentration index not varying strongly with environment. The fraction of galaxies on the red sequence is determined in bins of 0.2 in log Sigma and log mass (12 x 13 bins). The red fraction f_r generally increases continuously in both Sigma and mass such that there is a unified relation: f_r = F(Sigma,mass). Two simple functions are proposed which provide good fits to the data. These data are compared with analogous quantities in semi-analytical models based on the Millennium N-body simulation: the Bower et al. (2006) and Croton et al. (2006) models that incorporate AGN feedback. Both models predict a strong dependence of the red fraction on stellar mass and environment that is qualitatively similar to the observations. However, a quantitative comparison shows that the Bower et al. model is a significantly better match; this appears to be due to the different treatment of feedback in central galaxies.Comment: 19 pages, 17 figures; accepted by MNRAS, minor change

The Tully-Fisher Relation for 25,000 SDSS Galaxies as Function of Environment

We construct Tully-Fisher relationships (TFRs) in the $u$, $g$, $r$, $i$ and $z$ bands and stellar mass TFRs (smTFRs) for a sample of $25,698$ late spiral type galaxies (with $0.045<z<0.085$) from the Sloan Digital Sky Survey (SDSS) and study the effects of environment on the relation. We use SDSS-measured Balmer emission line widths, $v_{\rm FWHM}$, as a proxy for disc circular velocity, $v_{\rm circ}$. A priori it is not clear whether we can construct accurate TFRs given the small $3"$ diameter of the fibres used for SDSS spectroscopic measurements. However, we show by modelling the H$\alpha$ emission profile as observed through a $3"$ aperture that for galaxies at appropriate redshifts ($z>0.045$) the fibres sample enough of the disc to obtain a linear relationship between $v_{\rm FWHM}$ and $v_{\rm circ}$, allowing us to obtain a TFR and to investigate dependence on other variables. We also develop a methodology for distinguishing between astrophysical and sample bias in the fibre TFR trends. We observe the well-known steepening of the TFR in redder bands in our sample. We divide the sample of galaxies into four equal groups using projected neighbour density ($\Sigma$) quartiles and find no significant dependence on environment, extending previous work to a wider range of environments and a much larger sample. Having demonstrated that we can construct SDSS-based TFRs is very useful for future applications because of the large sample size available.Comment: accepted for publication in MNRAS. 15 pages, 12 figure

Improving dissertation assessment

During the last decade, there have been increasing calls for higher education to improve standards, increase the quality of assessment, and for greater accountability of lecturers. It is recognised that consistency in assessment is even more important where assessment is through one large piece of work, such as a dissertation, and where the assessment outcome will have a significant impact on the final grade of students. Dissertation modules typically pose further problems for assessment consistency due to the large number of students and the resultant need for large numbers of lecturers to participate in its assessment. This paper synthesises the initial literature findings from an on-going research project that aims to identify good practices for dissertation assessment, in an attempt to improve the quality and consistency of assessment