Gaia DR3 and nearby galaxies: where do foregrounds matter?

Nearby galaxies provide populations of stellar and non-stellar sources at a common distance and in quantifiable environments. All are observed through the Milky Way foreground, with varying degrees of contamination that depend on observed Galactic latitude and the distance and size of the target galaxy. This work uses Gaia Data Release 3 (DR3) to identify foreground sources via astrometric measurements and thus quantify foreground contamination for a large sample of nearby galaxies. There are approximately half a million Gaia sources in the directions of 1401 galaxies listed in the Local Volume Galaxy catalogue (D<11 Mpc), excluding the largest Local Group galaxies. About two thirds of the Gaia sources have astrometric properties consistent with foreground sources; these sources are brighter, redder, and less centrally-concentrated than non-foreground sources. Averaged over galaxies, foreground sources make up 50 per cent of Gaia sources at projected radius r50=1.06*a26, where a26 is the angular diameter at the B=26.5 isophote. Foreground sources make up 50 per cent of Gaia sources at apparent magnitude m(G,50)=20.50. This limit corresponds to the tip of the red giant branch absolute magnitude at D = 450 kpc, and to the globular cluster luminosity function peak absolute magnitude at 5 Mpc. Gaia data provide a powerful tool for removing foreground contamination in stellar population studies of nearby galaxies, although Gaia foreground removal will be incomplete beyond distances of 5 Mpc.Comment: MNRAS in press; 8 pages, 9 figure

Testing population synthesis models with globular cluster colors

We have measured an extensive set of UBVRIJHK colors for M31 globular clusters [Barmby et al. 2000]. We compare the predicted simple stellar population colors of three population synthesis models to the intrinsic colors of Galactic and M31 globular clusters. The best-fitting models fit the cluster colors very well -- the weighted mean color offsets are all < 0.05 mag. The most significant offsets between model and data are in the U and B passbands; these are not unexpected and are likely due to problems with the spectral libraries used by the models. The metal-rich clusters ([Fe/H] > -0.8) are best fit by young (8 Gyr) models, while the metal-poor clusters are best fit by older (12--16 Gyr) models. If this range of globular cluster ages is correct, it implies that conditions for cluster formation must have existed for a substantial fraction of the galaxies' lifetimes.Comment: To appear in ApJ Letters; 8 pages including 3 figures and 1 tabl

Evaluating the MEI 'Enabling Access to Further Mathematics' Project

Mathematics in Education and Industry (MEI), with funding from Gatsby Technical Education Projects (GTEP), ran the ‘Enabling Access to Further Mathematics’ project from 2000 to 2003. This pilot project was designed to provide AS- and A-level students with additional opportunities to study Further Mathematics, through the use of distance-learning materials. This was in response to the dramatic decline in the numbers of students taking Further Mathematics over the last four decades. An independent evaluation of the project was commissioned by GTEP, and this paper describes the methodology of the evaluation and its findings. In addition to highlighting the benefits of the project for the students and institutions involved, the paper discusses how the project could be developed in the future, based on the issues and difficulties raised in the evaluation

Examining Changing Attitudes in Secondary School Science

This study, carried out in England, examined the variation of attitudes towards science over the first three years of secondary schooling and with gender. The study in question was part of an evaluation of the "Lab in a Lorry" project, and involved 932 pupils completing a pre-measure questionnaire containing items looking at six separate attitude constructs. From these data, two main patterns emerged; pupils' attitudes towards science declined as they progressed through secondary school, and this decline was more pronounced for female pupils. These conclusions are largely in agreement with previous studies in this field. However, in examining separate attitude constructs, we were also able to identify that the sharpest decline occurred specifically for pupils' attitude towards learning science in school. Furthermore, using linear regression, we identified that, as pupils progress through school, this construct becomes a greater influence on attitudes towards future participation in science. Therefore, we also concluded that learning science in school is a partiuclar area that needs to be concentrated upon, if we are to improve children's attitudes towards science. In the final part of the paper, we drew on interview data obtained from 44 pupils involved in the Lab in a Lorry study. Pupils' comments in these interviews provided further insight into why pupils are "switched off" by school science. We drew out the most prevalent themes that emerged in the interviews, in order to provide further insight into why pupils do not enjoy science in school