188 results on '"Barmby, P"'
Search Results
2. Left Main Stem Compression by Intrapericardial Paraganglioma Associated With Succinate Dehydrogenase Mutation
- Author
-
Xue Wang, MB BChir, Mohsin Gondal, MBBS, Samer Alabed, MD, Catherine Hill, MB ChB, and David Barmby, MB ChB
- Subjects
cardiac magnetic resonance ,computed tomography ,coronary angiography ,coronary artery bypass ,genetics ,imaging ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Paragangliomas are rare extra-adrenal tumors originating from chromaffin cells. We discovered a large intrapericardial mass confirmed to be a primary cardiac paraganglioma encasing the left main stem coronary artery in a 38-year-old woman who presented with dyspnea and subscapular pain. Genetic predisposition related to succinate dehydrogenase A mutation was identified.
- Published
- 2024
- Full Text
- View/download PDF
3. The Development of a Professional Development Intervention for Mathematical Problem-Solving Pedagogy in a Localised Context
- Author
-
Chirinda, Brantina and Barmby, Patrick
- Abstract
This article reports on the design and findings of the first iteration of a classroom-based design research project which endeavours to design a professional development intervention for teachers' mathematical problem-solving pedagogy. The major outcome of this study is the generation of design principles that can be used by other researchers developing a professional development (PD) intervention for mathematical problem-solving pedagogy. This study contributes to the mathematical problem-solving pedagogy and PD body of knowledge by working with teachers in an under-researched environment (an informal settlement in Gauteng, South Africa). In this iteration, two experienced Grade 9 mathematics teachers and their learners at a public secondary school in Gauteng, South Africa, participated in a 6-month intervention. Findings from the data are discussed in light of their implications for the next cycle and other PD studies.
- Published
- 2017
4. Prospects for Revealing Intermediate-mass Black Holes in NGC 1399 Using SKA
- Author
-
B. Karimi, P. Barmby, and S. Abbassi
- Subjects
Black holes ,Intermediate-mass black holes ,Accretion ,Globular star clusters ,Astrophysics ,QB460-466 - Abstract
This study investigates the detectability of intermediate-mass black holes (IMBHs) within the mass range 10 ^2 M _⊙ ≤ M _BH ≤ 10 ^5 M _⊙ in the globular star clusters of NGC 1399 at a frequency of 300.00 MHz. Employing the theoretical Bondi accretion model and the empirical fundamental plane (FP) of black hole accretion, we estimate IMBH masses based on bolometric luminosity and X-ray/radio luminosities, respectively. By simulating a 3 hr observation of 77 globular cluster (GC) candidates using the Square Kilometre Array, we identify radio detection benchmarks indicative of accretion onto IMBHs. Our results show that IMBHs inside the globular star clusters located in NGC 1399 are indeed detectable, with the Bondi accretion model providing IMBH mass estimates ranging from 2.93 × 10 ^3.0±0.39 M _⊙ to 7.43 × 10 ^4.0±0.39 M _⊙ and the empirical FP relation suggesting IMBH mass estimation with 3.41 × 10 ^5.0±0.96 M _⊙ . These findings highlight the presence and detectability of IMBHs in GCs, offering insights into their role as precursors to supermassive black holes and enriching our understanding of black hole formation and evolution in astrophysical environments.
- Published
- 2024
- Full Text
- View/download PDF
5. Comparing Gaia, NED, and SIMBAD source classifications in nearby galaxies.
- Author
-
Hales, J and Barmby, P
- Subjects
- *
CLASSIFICATION of galaxies , *GALAXY clusters , *MILKY Way , *STARS , *BINARY stars - Abstract
Gaia Data Release 3 (DR3) provides the first classifications for the sources in Gaia 's all-sky database. Most Gaia sources are stars in the Milky Way, but DR3 also contains many sources that belong to nearby galaxies, as well as background galaxies and quasars. In this work, we compare the Gaia classifications from the Discrete Source Classifier (CU8-DSC) module to the more detailed and heterogeneous classifications in NED (NASA Extragalactic Database) and/or SIMBAD (Set of Identifications, Measurements and Bibliography for Astronomical Data) for sources with sky positions within twice the Holmberg radius of nearby galaxies. Matching these catalogues gives approximately |$3.2\times 10^5$| unique Gaia matches for |$4\times 10^5$| sources over 1040 galaxies (excluding some large Local Group galaxies) in the Local Volume Galaxy catalogue. Matched sources contain a lower fraction of Gaia -classified stars and higher fractions of galaxies and quasars (|$\sim 95$| per cent, 2 per cent, and 2 per cent, respectively) than DR3 overall. Considering NED (SIMBAD) classifications as truth values, the balanced accuracy of Gaia classification is 0.80 (0.83): the most common disagreements are literature-classified galaxies Gaia -classified as stars and literature-classified stars Gaia -classified as quasars. Purity (P) and completeness (C) metrics show that agreement between Gaia classification and NED/SIMBAD classification is best for stars (|$P\, \mathrm{ and}\, C\sim 0.9$|), and decreases for quasars (|$P\lt 0.3$| and |$0.7\lt C\lt 0.8$|), galaxies (|$0.7\lt P\lt 0.8$| and |$0.3\lt C\lt 0.6$|), white dwarfs (|$0.04\lt P\lt 0.6$| and |$C\sim 0.6$|), and binary stars (|$P\, \mathrm{ and}\, C\lt 0.1$|). NED or SIMBAD sources classified only by detection wavelength are most often Gaia -classified as stars, while non-stellar components of galaxies appear in all Gaia classes. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. A Comparative Judgement Approach to the Large-Scale Assessment of Primary Writing in England
- Author
-
Wheadon, Christopher, Barmby, Patrick, Christodoulou, Daisy, and Henderson, Brian
- Abstract
Writing assessment is a key feature of most education systems, yet there are limitations with traditional methods of assessing writing involving rubrics. In contrast, comparative judgement appears to overcome the reliability issues that beset the assessment of performance assessment tasks. The approach presented here extends previous work on comparative judgement by directly involving teachers in a large number of schools in the judging of young pupils' writing. To ensure quality control the process incorporated a process of 'anchoring' that ensured that teachers could not artificially inflate their own pupils' scores. The approach was used to assess the writing of 55,599 primary pupils in England in 2017-2018. Overall, the results showed that a comparative judgement approach to writing incorporating anchoring shows promise in providing a fair and robust large-scale method to assess writing.
- Published
- 2020
- Full Text
- View/download PDF
7. A New Approach to Measuring Pre-Service Teachers' Attitudes towards Mathematics
- Author
-
Barmby, Patrick and Bolden, David
- Abstract
Research (for example Ball, 1988; Philippou & Christou, 1998) have linked teachers' attitudes with classroom practice in teaching mathematics. Previous studies have identified and examined the relationships between different components of teachers' attitudes (Nisbet, 1991). However, a particular criticism of these studies is the lack of content validity of the measures used. In the present study, in line with the conference theme for PME 38, we developed an innovative approach to examining the attitudes of pre-service elementary teachers. The study utilised a mixed methods approach, firstly eliciting qualitative statements from teachers, then using these statements in Likert-scale questionnaire items. We argue that this provides a more valid assessment of attitudes, and a method that can be applied across differing contexts for teachers. [For the complete proceedings, see ED597799.]
- Published
- 2014
8. GALFIT-ing AGN Host Galaxies in COSMOS: HST versus Subaru
- Author
-
Callum Dewsnap, Pauline Barmby, Sarah C. Gallagher, C. Megan Urry, Aritra Ghosh, and Meredith C. Powell
- Subjects
AGN host galaxies ,Active galactic nuclei ,Galaxy classification systems ,Surveys ,Astrophysics ,QB460-466 - Abstract
The COSMOS field has been extensively observed by most major telescopes, including Chandra, HST, and Subaru. HST imaging boasts very high spatial resolution and is used extensively in morphological studies of distant galaxies. Subaru provides lower spatial resolution imaging than HST but a substantially wider field of view with greater sensitivity. Both telescopes provide near-infrared imaging of COSMOS. Successful morphological fitting of Subaru data would allow us to measure morphologies of over 10 ^4 known active galactic nucleus (AGN) hosts, accessible through Subaru wide-field surveys, currently not covered by HST. The morphological parameters indicate the types of galaxies that host AGNs. For 4016 AGNs between 0.03 < z < 6.5, we study the morphology of their galaxy hosts using GALFIT, fitting components representing the AGN and host galaxy simultaneously using the i -band imaging from both HST and Subaru. Comparing the fits for the differing telescope spatial resolutions and image signal-to-noise ratios, we identify parameter regimes for which there is strong disagreement between distributions of fitted parameters for HST and Subaru. In particular, the Sérsic index values strongly disagree between the two sets of data, including sources at lower redshifts. In contrast, the measured magnitude and radius parameters show reasonable agreement. Additionally, large variations in the Sérsic index have little effect on the ${\chi }_{\nu }^{2}$ of each fit, whereas variations in other parameters have a more significant effect. These results indicate that the Sérsic index distributions of high-redshift galaxies that host AGNs imaged at ground-based spatial resolution are not reliable indicators of galaxy type and should be interpreted with caution.
- Published
- 2023
- Full Text
- View/download PDF
9. South African Grade 9 Mathematics Teachers' Views on the Teaching of Problem Solving
- Author
-
Chirinda, Brantina and Barmby, Patrick
- Abstract
The South African curriculum emphasizes the teaching of problem solving in mathematics. However, little is known about South African teachers' views on the teaching of mathematical problem solving (MPS). The purpose of this study was to establish Grade 9 South African teachers' views, teaching strategies and the support required in their teaching of MPS. We worked with teachers who teach MPS to large, under-resourced and multilingual classes. Data for the study were collected using an open-ended questionnaire and classroom observations. The questionnaire sample consisted of 31 teachers from 20 schools in a district in Gauteng, South Africa. Data was analysed through grounded theory techniques and the findings indicate that overcrowded classes and learners' problems with English as the language of learning and teaching compel teachers to retain strict ownership of the MPS process. The findings also uncovered that teachers' adoption of the MPS as a step-by-step guided sense-making strategy is a response to learners' perceived lack of mastery of basic algorithms. All participants in the study stated that they required support on the teaching of MPS that included practical demonstration of MPS pedagogy in the context of their classes where discipline is a challenge and learners are under-prepared, lack basic MPS skills and struggle with the language of learning and teaching.
- Published
- 2018
- Full Text
- View/download PDF
10. Understanding Linear Function: A Comparison of Selected Textbooks from England and Shanghai
- Author
-
Wang, Yuqian, Barmby, Patrick, and Bolden, David
- Abstract
This study describes a comparison of how worked examples in selected textbooks from England and Shanghai presented possible learning trajectories towards understanding linear function. Six selected English textbooks and one Shanghai compulsory textbook were analysed with regards to the understanding required for pure mathematics knowledge in linear function. Understanding was defined as being at five levels: Dependent Relationship, Connecting Representations, Local Properties Noticing, Object Analysis and Inventising. These levels were developed by examining the most prominent theories from the existing literature on understanding function. Findings suggested that the English textbooks constrained the structural aspect of understanding linear function due to a point-to-point view of function, while the Shanghai textbook which focussed on a variable view of function overemphasised the algebraic approach. The discussion explored the drawbacks to each approach and what teachers or textbook writers could do to balance these two approaches in order to facilitate students' understanding towards a structural view of linear function.
- Published
- 2017
- Full Text
- View/download PDF
11. In Which Ways and to What Extent Do English and Shanghai Students Understand Linear Function?
- Author
-
Wang, Yuqian, Barmby, Patrick, and Bolden, David
- Abstract
This study investigates how students in England and Shanghai understand linear function. Understanding is defined theoretically in terms of five hierarchical levels: Dependent Relationship; Connecting Representations; Property Noticing; Object Analysis; and Inventising. A pilot study instrument presented a set of problems to both cohorts, showing that the English cohort generally operated at the levels of Property Noticing and Object Analysis, whereas the Shanghai cohort reached the higher level of Inventising. The main study explored understanding levels and students' errors within each cohort in detail, in order to gain insights into reasons for apparent differences. The instrument used in the main study included two overlapping items, which were the same for both cohorts, while others were pitched at levels of understanding revealed in the pilot. Analysis of students' solutions revealed that the English students' errors were manifested in a lack of basic skills including dealing with negative numbers, while the Shanghai students showed weaknesses in their ability to use graphs. The discussion highlights different views of understanding as a possible background reason for the contrasts observed. Errors and apparent difficulties suggest implications for teaching linear function in each context.
- Published
- 2017
- Full Text
- View/download PDF
12. Astronomical observations: a guide for allied researchers
- Author
-
Pauline Barmby
- Subjects
Astronomy ,QB1-991 ,Astrophysics ,QB460-466 - Abstract
Observational astrophysics uses sophisticated technology to collect and measure electromagnetic and other radiation from beyond the Earth. Modern observatories produce large, complex datasets and extracting the maximum possible information from them requires the expertise of specialists in many fields beyond physics and astronomy, from civil engineers to statisticians and software engineers. This article introduces the essentials of professional astronomical observations to colleagues in allied fields, to provide context and relevant background for both facility construction and data analysis. It covers the path of electromagnetic radiation through telescopes, optics, detectors, and instruments, its transformation through processing into measurements and information, and the use of that information to improve our understanding of the physics of the cosmos and its history.
- Published
- 2019
- Full Text
- View/download PDF
13. How Young Children View Mathematical Representations: A Study Using Eye-Tracking Technology
- Author
-
Bolden, David, Barmby, Patrick, Raine, Stephanie, and Gardner, Matthew
- Abstract
Background: It has been shown that mathematical representations can aid children's understanding of mathematical concepts but that children can sometimes have difficulty in interpreting them correctly. New advances in eye-tracking technology can help in this respect because it allows data to be gathered concerning children's focus of attention and so indicate on what aspects of the representations they are focussing. However, recent eye-tracking technology has not been used to any great degree in investigating the way children view and interpret mathematical representations. Purpose: This research explored the use of new advances in eye-tracking technology in investigating how young children view and interpret mathematical representations of multiplication. Sample: Nine Year 5 children (four boys, five girls, aged 9-10 years of age) from a local primary (elementary) school in the North-East of England were asked to complete the test during school time. The children represented a range of attainment levels across the mathematical domain (three higher-, three middle- and three lower-attaining children) and were selected accordingly by their class teacher. We recognise that this study was only based on a small sample of children, however, this number still allowed us to make meaningful comparisons in particular between the different types of representations presented. Design and methods: The study consisted of each child looking at 18 static slides, one after the other, with each slide presenting a symbolic and a picture representation of multiplication problems. The data that was captured by the eye tracker and recorded was then analysed quantitatively (e.g. time on each slide, time on each area of interest specified within the software) and qualitatively (video recordings of each child's gaze trajectory during each representation was carried out, thereby allowing a categorisation of the different approaches adopted). Results: The study showed that (a) the particular form of the number line representation used in this study was less successful than the other picture representations used (equal groups, array) in promoting multiplicative thinking in children, and (b) the success of children to think multiplicatively with the "groups" and the array representation was related to their general mathematics attainment levels. Conclusion: These findings have implications for teacher practice in that teachers need to be clear about the possible drawbacks of particular representations. Even in using more successful representations, for lower-attaining children, the progression in their understanding of the representation needs to be taken into account by the teacher. The study also highlighted that the eye-tracking technology does have some limitations but is useful in investigating young children's focus of attention whilst undertaking a mathematics assessment task.
- Published
- 2015
- Full Text
- View/download PDF
14. Greenhouse Heating Checklist
- Author
-
R. A. Bucklin, P. H. Jones, B. A. Barmby, D. B. McConnell, and R. W. Henley
- Subjects
greenhouses ,Agriculture (General) ,S1-972 ,Plant culture ,SB1-1110 ,Biology (General) ,QH301-705.5 - Abstract
Heating requirements inside greenhouses are affected by outdoor climates, structure characteristics, types of heating systems, and the strategies of operation and management. A properly maintained greenhouse can reduce the energy consumption and thus contribute to energy savings. This article addresses the issues that might lower the system efficiency and provides a checklist to ensure the best performance of the system.
- Published
- 2018
15. Developing the Use of Diagrammatic Representations in Primary Mathematics through Professional Development
- Author
-
Barmby, Patrick, Bolden, David, Raine, Stephanie, and Thompson, Lynn
- Abstract
Background: The research on diagrammatic representations highlights their importance for the teaching and learning of mathematics. However, the empirical evidence to support their use in the classroom is mixed and somewhat lacking. Purpose: The aim of this study was to develop the use of diagrammatic representations of mathematical concepts in primary classrooms, through introducing primary teachers to the research literature in this area, and researching the subsequent impact on children and teachers. A professional development programme was designed, involving three one-day training sessions for mathematics co-ordinators. They were asked to implement the ideas from the training back in their schools. Sample: Mathematics co-ordinators from eight primary schools attended the professional development programme. The study focussed on Year 3 pupils (aged seven- eight) and Year 5 pupils (aged nine-10). Design and methods: In this paper, we report the qualitative findings from the larger project looking at the overall impact of the professional development programme. The paper focuses on semi-structured interviews carried out with the mathematics co-ordinators attending the professional development sessions, and the Year 3 and Year 5 class teachers who subsequently worked with the co-ordinators on their use of diagrammatic representations in their teaching of mathematics. Lesson observations involving the class teachers were also carried out in order to explore further the possible impact of the project on classroom practice. Results: The qualitative results identified the impact of the project on mathematics co-ordinators and class teachers' knowledge and practice. However, the nature of this impact was complex, with a variety of facilitating and hindering factors identified for the transfer of the professional development ideas on the use of diagrammatic representations. In addition, different levels of sophistication of class teachers' use of diagrammatic representations were identified. Conclusions: Implications for the development of professional development programmes to facilitate the transfer of research into practice were identified. Recommendations for the use of diagrammatic representations are also put forward.
- Published
- 2013
- Full Text
- View/download PDF
16. The development of a professional development intervention for mathematical problem-solving pedagogy in a localised context
- Author
-
Brantina Chirinda and Patrick Barmby
- Subjects
design-based research ,mathematical problem solving pedagogy ,professional development intervention ,Mathematics ,QA1-939 ,Theory and practice of education ,LB5-3640 - Abstract
This article reports on the design and findings of the first iteration of a classroom-based design research project which endeavours to design a professional development intervention for teachers’ mathematical problem-solving pedagogy. The major outcome of this study is the generation of design principles that can be used by other researchers developing a professional development (PD) intervention for mathematical problem-solving pedagogy. This study contributes to the mathematical problem-solving pedagogy and PD body of knowledge by working with teachers in an under-researched environment (an informal settlement in Gauteng, South Africa). In this iteration, two experienced Grade 9 mathematics teachers and their learners at a public secondary school in Gauteng, South Africa, participated in a 6-month intervention. Findings from the data are discussed in light of their implications for the next cycle and other PD studies.
- Published
- 2017
- Full Text
- View/download PDF
17. Predicting Success on a Bachelor of Arts Primary Education Degree Course
- Author
-
Barmby, Patrick, Bolden, David, Higgins, Steve, and Tymms, Peter
- Abstract
Background: Successfully selecting students for undergraduate courses and for teaching is notoriously difficult. Traditionally, in England, A level grades and interviews have been used in conjunction with a variety of other approaches. Purpose: This paper examines the predictive validity of students' A level grades and of scores from a structured interview on their subsequent degree classification as well as the ratings from their final teaching placements. Sample: A cohort of 71 students who started studying for a Bachelor of Arts (BA) degree in Primary Education in 2007 and graduated in 2010. Design and methods: The A level grades and the ratings from structured interviews, carried out prior to the start of the course, were linked to the final degree classification and to the teaching placement grades. Results: A-level scores correlated significantly with degree classification but not with the placement grade whereas the interview grades correlated significantly with both outcome measures. Conclusions: These results are discussed in the light of the restricted range available for A-level grades. (Contains 8 tables and 2 notes.)
- Published
- 2012
- Full Text
- View/download PDF
18. The Array Representation and Primary Children's Understanding and Reasoning in Multiplication
- Author
-
Barmby, Patrick, Harries, Tony, and Higgins, Steve
- Abstract
We examine whether the array representation can support children's understanding and reasoning in multiplication. To begin, we define what we mean by understanding and reasoning. We adopt a "representational-reasoning" model of understanding, where understanding is seen as connections being made between mental representations of concepts, with reasoning linking together the different parts of the understanding. We examine in detail the implications of this model, drawing upon the wider literature on assessing understanding, multiple representations, self explanations and key developmental understandings. Having also established theoretically why the array representation might support children's understanding and reasoning, we describe the results of a study which looked at children using the array for multiplication calculations. Children worked in pairs on laptop computers, using Flash Macromedia programs with the array representation to carry out multiplication calculations. In using this approach, we were able to record all the actions carried out by children on the computer, using a recording program called Camtasia. The analysis of the obtained audiovisual data identified ways in which the array representation helped children, and also problems that children had with using the array. Based on these results, implications for using the array in the classroom are considered.
- Published
- 2009
- Full Text
- View/download PDF
19. Examining Changing Attitudes in Secondary School Science
- Author
-
Barmby, Patrick, Kind, Per M., and Jones, Karen
- Abstract
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 particular 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. (Contains 6 tables, 5 figures, and 3 notes.)
- Published
- 2008
- Full Text
- View/download PDF
20. Representing Multiplication
- Author
-
Harries, Tony and Barmby, Patrick
- Abstract
In this study, the authors wish to explore the use of visual representations in facilitating the understanding of multiplication. In doing so, they examine the different aspects of multiplication that they can access through different representations. In addition, they draw on a study that they have been carrying out looking at pupils' actual use of one of the representations--the array. By bringing together their theoretical views and actual experiences in the classroom, the authors put forward suggestions for teaching multiplication and also future directions for research. (Contains 8 figures.)
- Published
- 2008
21. Developing Attitudes towards Science Measures
- Author
-
Kind, Per, Jones, Karen, and Barmby, Partick
- Abstract
In this study, we describe the development of measures used to examine pupils' attitudes towards science. In particular, separate measures for attitudes towards the following areas were developed: learning science in school, practical work in science, science outside of school, importance of science, self-concept in science, and future participation in science. In developing these measures, criticisms of previous attitude studies in science education were noted. In particular, care was taken over the definition of each of the attitude constructs, and also ensuring that each of the constructs was unidimensional. Following an initial piloting process, pupils aged 11-14 from five secondary schools throughout England completed questionnaires containing the attitude measures. These questionnaires were completed twice by pupils in these schools, with a gap of four weeks between the first and second measurements. Altogether, 932 pupils completed the first questionnaire and 668 pupils completed the second one. Factor analysis carried out on the resulting data confirmed the unidimensionality of the separate attitude constructs. Also, it was found that three of the constructs--learning science in school, science outside of school, and future participation in science--loaded on one general attitude towards science factor. Further analysis showed that all the measures showed high internal reliability (Cronbach's alpha greater than 0.7). A particular strength of the approach used in this study was that it allowed for attitude measures to be built up step-by-step, therefore allowing for the future consideration of other relevant constructs. (Contains 5 tables, 4 figures and 3 notes.)
- Published
- 2007
- Full Text
- View/download PDF
22. Secondary School Pupils Perceptions of Physics
- Author
-
Barmby, Patrick and Defty, Neil
- Abstract
This paper describes the analysis of data collected by Durham University's YELLIS project, over the period of 1999 to 2004. Included in this data was the degree to which pupils in England at the end of their secondary education "liked" or "disliked" different subjects, and their expected examination grades in these subjects. The authors' study focused on the perceptions of pupils in the science subjects of biology, chemistry and physics. Using the available data, they were able to analyse the perceptions of a large number of pupils (e.g. 9827 pupils in 2004) who took examinations in the separate sciences. The study found that physics was perceived as the least popular science, particularly by female pupils. We also found that the expected grade in a particular science subject correlated quite strongly (Spearman's rho of around 0.5) with the liking of that subject. These expected grades were found to be the lowest in physics, again particularly for female pupils. The authors therefore concluded that in order to redress the gender imbalance in physics, they need to tackle this problem that physics is perceived as difficult by female pupils. (Contains 5 tables and 13 figures.)
- Published
- 2006
23. Improving Teacher Recruitment and Retention: The Importance of Workload and Pupil Behaviour
- Author
-
Barmby, Patrick
- Abstract
Background: The shortage of teachers in England and Wales continues to be a high profile area of scrutiny. Particular subjects (including mathematics, science and English) are categorized by the Training and Development Agency (TDA) for schools as priority or shortage subjects, and London especially has experienced particular shortages in teacher numbers over recent years. Purpose: This paper reports on the findings from a telephone survey with teachers, examining the issues of teacher recruitment and retention. The paper highlights the important factors, as perceived by teachers, that impact on why teachers enter the profession, and also why they choose to leave. Sample: The survey involved 246 teachers in England and Wales, teaching the shortage subjects of English, maths and science. The sample was chosen such that 25% of the teachers taking part in the study would be working in London. Our intention was to have sample numbers for teachers inside and outside London from which meaningful comparisons could be made regarding their views, and so highlight particular issues that were important for teachers in London. The 75% sample not from London was geographically representative of the rest of England and Wales. Design and methods: Prior to the survey, a provisional examination of recent research findings was carried out, leading us to categorize relevant issues into three areas: (1) reasons for wanting to enter teaching; (2) reasons for not wanting to enter teaching; and (3) reasons for wanting to leave teaching. The telephone survey with teachers therefore looked at these three broad areas. A pilot study was carried out with 22 teachers, trialling the survey questions to be used in the telephone interviews. With the agreement of the teachers, the telephone interviews were recorded to aid the data gathering process. Copies of the interview script were sent out beforehand to the teachers being interviewed, in order to try to reassure teachers that no "unexpected" questions would be asked of them, and also to give teachers the opportunity to provide considered responses during the interviews. Results: The survey found that although more "intrinsic" and "altruistic" reasons were given by teachers for going into teaching, the issues of workload and pupil behaviour were found to be most important in dissuading teachers from entering the profession or possibly causing them to leave teaching. Conclusions: The study concluded that in order to have an impact on teacher numbers, the two issues regarding workload and pupil behaviour should be seen to be tackled from the perspectives of teachers. (Contains 8 tables and 2 notes.)
- Published
- 2006
24. Evaluating the MEI 'Enabling Access to Further Mathematics' Project
- Author
-
Barmby, Patrick and Coe, Robert
- Abstract
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.
- Published
- 2004
25. Ten Simple Rules for Digital Data Storage.
- Author
-
Edmund M Hart, Pauline Barmby, David LeBauer, François Michonneau, Sarah Mount, Patrick Mulrooney, Timothée Poisot, Kara H Woo, Naupaka B Zimmerman, and Jeffrey W Hollister
- Subjects
Biology (General) ,QH301-705.5 - Published
- 2016
- Full Text
- View/download PDF
26. Absolute Calibration of the Infrared Array Camera on the Spitzer Space Telescope
- Author
-
Reach, William T., Megeath, S. T., Cohen, Martin, Hora, J., Carey, Sean, Surace, Jason, Willner, S. P., Barmby, P., Wilson, Gillian, Glaccum, William, Lowrance, Patrick, Marengo, Massimo, and Fazio, Giovanni G.
- Published
- 2005
- Full Text
- View/download PDF
27. Gaia DR3 and nearby galaxies: where do foregrounds matter?
- Author
-
Barmby, P
- Subjects
- *
GALAXIES , *GALAXY clusters , *ASTROMETRY , *MILKY Way , *STELLAR populations , *GLOBULAR clusters - Abstract
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 r 50 = 1.06 a 26, where a 26 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. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
28. Comparing NED and SIMBAD classifications across the contents of nearby galaxies.
- Author
-
Kuhn, L, Shubat, M, and Barmby, P
- Subjects
DATABASE searching ,GALAXIES ,INFORMATION resources ,CLASSIFICATION ,DATABASES - Abstract
Cataloguing and classifying celestial objects is one of the fundamental activities of observational astrophysics. In this work, we compare the contents of two comprehensive data bases, the NASA Extragalactic Database (NED) and Set of Identifications, Measurements and Bibliography for Astronomical Data (SIMBAD) in the vicinity of nearby galaxies. These two data bases employ different classification schemes – one flat and one hierarchical – and our goal was to determine the compatibility of classifications for objects in common. Searching both data bases for objects within the respective isophotal radius of each of the ∼1300 individual galaxies in the Local Volume Galaxy sample, we found that, on average, NED contains about 10 times as many entries as SIMBAD and about two-thirds of SIMBAD objects are matched by position to a NED object, at 5 arcsec tolerance. These quantities do not depend strongly on the properties of the parent galaxies. We developed an algorithm to compare individual object classifications between the two data bases and found that 88 per cent of the classifications agree; we conclude that NED and SIMBAD contain consistent information for sources in common in the vicinity of nearby galaxies. Because many galaxies have numerous sources contained only in one of NED or SIMBAD, researchers seeking the most complete picture of an individual galaxy's contents are best served by using both data bases. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
29. The remnants of galaxy formation from a panoramic survey of the region around M31
- Author
-
McConnachie, Alan W., Irwin, Michael J., Ibata, Rodrigo A., Dubinski, John, Widrow, Lawrence M., Martin, Nicolas F., Côté, Patrick, Dotter, Aaron L., Navarro, Julio F., Ferguson, Annette M. N., Puzia, Thomas H., Lewis, Geraint F., Babul, Arif, Barmby, Pauline, Bienaymé, Olivier, Chapman, Scott C., Cockcroft, Robert, Collins, Michelle L. M., Fardal, Mark A., Harris, William E., Huxor, Avon, Mackey, A. Dougal, Peñarrubia, Jorge, Rich, R. Michael, Richer, Harvey B., Siebert, Arnaud, Tanvir, Nial, Valls-Gabaud, David, and Venn, Kimberly A.
- Published
- 2009
- Full Text
- View/download PDF
30. SEDS: The Spitzer Extended Deep Survey. Survey Design, Photometry, and Deep IRAC Source Counts
- Author
-
Ashby, M. L. N, Willner, S. P, Fazio, G. G, Huang, J.-S, Arendt, A, Barmby, P, Barro, G, Bell, E. F, Bouwens, R, Cattaneo, A, Croton, D, Dave, R, Dunlop, J. S, Egami, E, Faber, S, Finlator, K, Grogin, N. A, Guhathakurta, P, Hernquist, L, Hora, J. L, Illingworth, G, Kashlinsky, A, Koekmoer, A. M, Koo, D. C, and Moseley, H
- Subjects
Astronomy - Abstract
The Spitzer Extended Deep Survey (SEDS) is a very deep infrared survey within five well-known extragalactic science fields: the UKIDSS Ultra-Deep Survey, the Extended Chandra Deep Field South, COSMOS, the Hubble Deep Field North, and the Extended Groth Strip. SEDS covers a total area of 1.46 deg(exp 2) to a depth of 26 AB mag (3sigma) in both of the warm Infrared Array Camera (IRAC) bands at 3.6 and 4.5 micron. Because of its uniform depth of coverage in so many widely-separated fields, SEDS is subject to roughly 25% smaller errors due to cosmic variance than a single-field survey of the same size. SEDS was designed to detect and characterize galaxies from intermediate to high redshifts (z = 2-7) with a built-in means of assessing the impact of cosmic variance on the individual fields. Because the full SEDS depth was accumulated in at least three separate visits to each field, typically with six-month intervals between visits, SEDS also furnishes an opportunity to assess the infrared variability of faint objects. This paper describes the SEDS survey design, processing, and publicly-available data products. Deep IRAC counts for the more than 300,000 galaxies detected by SEDS are consistent with models based on known galaxy populations. Discrete IRAC sources contribute 5.6 +/- 1.0 and 4.4 +/- 0.8 nW / square m/sr at 3.6 and 4.5 micron to the diffuse cosmic infrared background (CIB). IRAC sources cannot contribute more than half of the total CIB flux estimated from DIRBE data. Barring an unexpected error in the DIRBE flux estimates, half the CIB flux must therefore come from a diffuse component.
- Published
- 2013
- Full Text
- View/download PDF
31. An almost head-on collision as the origin of two off-centre rings in the Andromeda galaxy
- Author
-
Block, D. L., Bournaud, F., Combes, F., Groess, R., Barmby, P., Ashby, M. L. N., Fazio, G. G., Pahre, M. A., and Willner, S. P.
- Published
- 2006
32. A sequential probability model of fertility patterns
- Author
-
Barmby, T. and Cigno, A.
- Published
- 1990
- Full Text
- View/download PDF
33. Extremely Red Objects in the Lockman Hole
- Author
-
Wilson, G, Huang, J. -S, Perez-Gonzalez, P. G, Egami, E, Ivison, R. J, Rigby, J. R, Alonso-Herrero, A, Barmby, P, Dole, H, Fazio, G. G, LeFloch, E, Papovich, C, Rigopoulou, D, Bai, L, Engelbracht, C. W, Frayer, D, Gordon, K. D, Hines, D. C, Misselt, K. A, Miyazaki, S, Morrison, J. E, Rieke, G. H, Rieke, M. J, and Surace, J
- Subjects
Astrophysics - Abstract
We investigate extremely red objects (EROs) using near- and mid-infrared observations in five passbands (3.6 to 24 microns) obtained from the Spitzer Space Telescope, and deep ground-based R and K imaging. The great sensitivity of the Infrared Array Camera (IRAC) camera allows us to detect 64 EROs (a surface density of 2.90 +/- 0.36 arcmin(exp -2); [3.6](sub AB) is less than 23.7) in only 12 minutes of IRAC exposure time, by means of an R - [3.6] color cut (analogous to the traditional red R - K cut). A pure infrared K - [3.6] red cut detects a somewhat different population and may be more effective at selecting z greater than 1.3 EROs. We find approximately 17% of all galaxies detected by IRAC at 3.6 or 4.5 microns to be EROs. These percentages rise to about 40% at 5.8 microns, and about 60% at 8.0 microns. We utilize the spectral bump at 1.6 microns to divide the EROs into broad redshift slices using only near-infrared colors (2.2/3.6/4.5 microns). We conclude that two-thirds of all EROs lie at redshift z greater than 1.3. Detections at 24 microns imply that at least 11% of 0.6 less than z and less than 1.3 EROs and at least 22% of z greater than 1.3 EROs are dusty star-forming galaxies.
- Published
- 2004
- Full Text
- View/download PDF
34. Star Formation as Seen by the Infrared Array Camera on Spitzer
- Author
-
Smith, Howard A, Allen, L, Megeath, T, Barmby, P, Calvet, N, Fazio, G, Hartmann, L, Myers, P, Marengo, M, and Gutermuth, R
- Subjects
Astronomy - Abstract
The Infrared Array Camera (IRAC) onboard Spitzer has imaged regions of star formation (SF) in its four IR bands with spatial resolutions of approximately 2"/pixel. IRAC is sensitive enough to detect very faint, embedded young stars at levels of tens of Jy, and IRAC photometry can categorize their stages of development: from young protostars with infalling envelopes (Class 0/1) to stars whose infrared excesses derive from accreting circumstellar disks (Class 11) to evolved stars dominated by photospheric emission. The IRAC images also clearly reveal and help diagnose associated regions of shocked and/or PDR emission in the clouds; we find existing models provide a good start at explaining the continuum of the SF regions IRAC observes.
- Published
- 2004
35. Distances to Galactic X-ray binaries with Gaia DR2.
- Author
-
Arnason, R M, Papei, H, Barmby, P, Bahramian, A, and D. Gorski, M
- Subjects
X-ray binaries ,X-ray bursts ,EDDINGTON mass limit ,DISTANCES ,STAR formation ,SOLAR radio bursts - Abstract
Precise and accurate measurements of distances to Galactic X-ray binaries (XRBs) reduce uncertainties in the determination of XRB physical parameters. We have cross-matched the XRB catalogues of Liu, van Paradijs & van den Heuvel to the results of Gaia Data Release 2. We identify 86 XRBs with a Gaia candidate counterpart, of which 32 are low-mass X-ray binaries (LMXBs) and 54 are high-mass X-ray binaries (HMXBs). Distances to Gaia candidate counterparts are, on average, consistent with those measured by Hipparcos and radio parallaxes. When compared to distances measured by Gaia candidate counterparts, distances measured using Type I X-ray bursts are systematically larger, suggesting that these bursts reach only 50 per cent of the Eddington limit. However, these results are strongly dependent on the prior assumptions used for estimating distance from the Gaia parallax measurements. Comparing positions of Gaia candidate counterparts for XRBs in our sample to positions of spiral arms in the Milky Way, we find that HMXBs exhibit mild preference for being closer to spiral arms; LMXBs exhibit mild preference for being closer to interarm regions. LMXBs do not exhibit any preference for leading or trailing their closest spiral arm. HMXBs exhibit a mild preference for trailing their closest spiral arm. The lack of a strong correlation between HMXBs and spiral arms may be explained by star formation occurring closer to the mid-point of the arms, or a time delay between star formation and HMXB formation manifesting as a spatial separation between HMXBs and the spiral arm where they formed. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
36. Identifying new X-ray binary candidates in M31 using random forest classification.
- Author
-
Arnason, R M, Barmby, P, and Vulic, N
- Subjects
- *
X-ray binaries , *ANDROMEDA Galaxy , *ACTIVE galactic nuclei , *SOLAR flares , *PHOTON flux , *HARD X-rays - Abstract
Identifying X-ray binary (XRB) candidates in nearby galaxies requires distinguishing them from possible contaminants including foreground stars and background active galactic nuclei. This work investigates the use of supervised machine learning algorithms to identify high-probability XRB candidates. Using a catalogue of 943 Chandra X-ray sources in the Andromeda galaxy, we trained and tested several classification algorithms using the X-ray properties of 163 sources with previously known types. Amongst the algorithms tested, we find that random forest classifiers give the best performance and work better in a binary classification (XRB/non-XRB) context compared to the use of multiple classes. Evaluating our method by comparing with classifications from visible-light and hard X-ray observations as part of the Panchromatic Hubble Andromeda Treasury, we find compatibility at the 90 per cent level, although we caution that the number of source in common is rather small. The estimated probability that an object is an XRB agrees well between the random forest binary and multiclass approaches and we find that the classifications with the highest confidence are in the XRB class. The most discriminating X-ray bands for classification are the 1.7–2.8, 0.5–1.0, 2.0–4.0, and 2.0–7.0 keV photon flux ratios. Of the 780 unclassified sources in the Andromeda catalogue, we identify 16 new high-probability XRB candidates and tabulate their properties for follow-up. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
37. SIGNALS: I. Survey description.
- Author
-
Rousseau-Nepton, L, Martin, R P, Robert, C, Drissen, L, Amram, P, Prunet, S, Martin, T, Moumen, I, Adamo, A, Alarie, A, Barmby, P, Boselli, A, Bresolin, F, Bureau, M, Chemin, L, Fernandes, R C, Combes, F, Crowder, C, Della Bruna, L, and Duarte Puertas, S
- Subjects
STAR formation ,SUPERNOVA remnants ,IONIZED gases ,SUPERGIANT stars ,PLANETARY nebulae - Abstract
SIGNALS, the Star formation, Ionized Gas, and Nebular Abundances Legacy Survey, is a large observing programme designed to investigate massive star formation and H ii regions in a sample of local extended galaxies. The programme will use the imaging Fourier transform spectrograph SITELLE at the Canada–France–Hawaii Telescope. Over 355 h (54.7 nights) have been allocated beginning in fall 2018 for eight consecutive semesters. Once completed, SIGNALS will provide a statistically reliable laboratory to investigate massive star formation, including over 50 000 resolved H ii regions: the largest, most complete, and homogeneous data base of spectroscopically and spatially resolved extragalactic H ii regions ever assembled. For each field observed, three datacubes covering the spectral bands of the filters SN1 (363–386 nm), SN2 (482–513 nm), and SN3 (647–685 nm) are gathered. The spectral resolution selected for each spectral band is 1000, 1000, and 5000, respectively. As defined, the project sample will facilitate the study of small-scale nebular physics and many other phenomena linked to star formation at a mean spatial resolution of ∼20 pc. This survey also has considerable legacy value for additional topics, including planetary nebulae, diffuse ionized gas, and supernova remnants. The purpose of this paper is to present a general outlook of the survey, notably the observing strategy, galaxy sample, and science requirements. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
38. Dust properties and star formation of approximately a thousand local galaxies.
- Author
-
Lianou, S., Barmby, P., Mosenkov, A. A., Lehnert, M., and Karczewski, O.
- Subjects
- *
STAR formation , *GALAXIES , *SPECTRAL energy distribution , *DUST , *STELLAR mass , *GALAXY formation , *INTERPLANETARY dust - Abstract
Aims. We derived the dust properties for 753 local galaxies and examine how these relate to some of their physical properties. We present the derived dust emission properties, including model spectral energy distribution (SEDs), star formation rates (SFRs) and stellar masses, as well as their relations. Methods. We modelled the global dust-SEDs for 753 galaxies, treated statistically as an ensemble within a hierarchical Bayesian dust-SED modelling approach, so as to derive their infrared (IR) emission properties. To create the observed dust-SEDs, we used a multi-wavelength set of observations, ranging from near-IR to far-IR-to-submillimeter wavelengths. The model-derived properties are the dust masses (Mdust), the average interstellar radiation field intensities (Uav), the mass fraction of very small dust grains ("QPAH" fraction), as well as their standard deviations. In addition, we used mid-IR observations to derive SFR and stellar masses, quantities independent of the dust-SED modelling. Results. We derive distribution functions of the properties for the galaxy ensemble and as a function of galaxy type. The mean value of Mdust for the early-type galaxies (ETGs) is lower than that for the late-type and irregular galaxies (LTGs and Irs, respectively), despite ETGs and LTGs having stellar masses spanning across the whole range observed. The Uav and "QPAH" fraction show no difference among different galaxy types. When fixing Uav to the Galactic value, the derived "QPAH" fraction varies across the Galactic value (0.071). The specific SFR increases with galaxy type, while this is not the case for the dust-specific SFR (SFR/Mdust), showing an almost constant star formation efficiency per galaxy type. The galaxy sample is characterised by a tight relationship between the dust mass and the stellar mass for the LTGs and Irs, while ETGs scatter around this relation and tend towards smaller dust masses. While the relation indicates that Mdust may fundamentally be linked to M⋆, metallicity and Uav are the second parameter driving the scatter, which we investigate in a forthcoming work. We used the extended Kennicutt–Schmidt (KS) law to estimate the gas mass and the gas-to-dust mass ratio (GDR). The gas mass derived from the extended KS law is on average ∼20% higher than that derived from the KS law, and a large standard deviation indicates the importance of the average star formation present to regulate star formation and gas supply. The average GDR for the LTGs and Irs is 370, and including the ETGs gives an average of 550. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
39. AGB Phase Transition in Globular Clusters: A Tool for Dating Starbursts
- Author
-
Maraston, Claudia, Kissler-Patig, Markus, Brodie, Jean, Barmby, Pauline, and Huchra, John
- Published
- 2002
- Full Text
- View/download PDF
40. Infrared power-law galaxies in the Chandra Deep Field South: AGN and ULIRGs
- Author
-
Alonso-Herrero, A., Perez-Gonzalez, P. G., Alexander, D. M., Rieke, G. H., Rigopoulou, D., Floc'h, E. Le, Barmby, P., Papovich, C., Rigby, J. R., Bauer, F. E., Brandt, W. N., Egami, E., Willner, S. P., Dole, H., and Huang, J. -S.
- Subjects
Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We investigate the nature of a sample of 92 Spitzer/MIPS 24 micron selected galaxies in the CDFS, showing power law-like emission in the Spitzer/IRAC 3.6-8 micron bands. The main goal is to determine whether the galaxies not detected in X-rays (47% of the sample) are part of the hypothetical population of obscured AGN not detected even in deep X-ray surveys. The majority of the IR power-law galaxies are ULIRGs at z>1, and those with LIRG-like IR luminosities are usually detected in X-rays. The optical to IR spectral energy distributions (SEDs) of the X-ray detected galaxies are almost equally divided between a BLAGN SED class (similar to an optically selected QSO) and a NLAGN SED (similar to the BLAGN SED but with an obscured UV/optical continuum). A small fraction of SEDs resemble warm ULIRG galaxies (e.g., Mrk231). Most galaxies not detected in X-rays have SEDs in the NLAGN+ULIRG class as they tend to be optically fainter, and possibly more obscured. Moreover, the IR power-law galaxies have SEDs significantly different from those of high-z (z_sp>1) IR (24 micron) selected and optically bright (VVDS I_AB, 43 pages, 12 figures, accepted for publication in ApJ
- Published
- 2016
41. Multiwavelength survey of X-ray sources in the Sculptor Dwarf Spheroidal Galaxy.
- Author
-
Arnason, R M, Barmby, P, Bahramian, A, Maccarone, T J, and Zepf, S E
- Subjects
- *
X-ray binaries , *DWARF galaxies , *ELLIPTICAL galaxies , *ACTIVE galactic nuclei , *GLOBULAR clusters , *X-rays , *SCULPTORS - Abstract
We present an unprecedented, deep study of the primordial low-mass X-ray binary population in an isolated, lower metallicity environment. We perform follow-up observations of previously identified X-ray binary candidates in the Sculptor Dwarf Galaxy by combining a second Chandra observation with Spitzer and Gemini photometry, as well as Gemini spectroscopy of selected targets. Of the original nine bright X-ray sources identified, we are able to classify all but one as quasars, active galactic nuclei, or background galaxies. We further discover four new X-ray sources in the second-epoch Chandra observation. Three of these new sources are background sources and one is a foreground flaring star. We have found that Sculptor is effectively devoid of X-ray sources above a few 1034 erg s−1. If Sculptor is able to retain primordial binaries at a similar rate to globular clusters, this implies that bright X-ray binaries observed in globular clusters in the present epoch are all formed dynamically. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
42. The Star Formation Reference Survey – III. A multiwavelength view of star formation in nearby galaxies.
- Author
-
Mahajan, Smriti, Ashby, M L N, Willner, S P, Barmby, P, Fazio, G G, Maragkoudakis, A, Raychaudhury, S, and Zezas, A
- Subjects
GALAXIES ,STAR formation ,SCATTERING (Physics) ,FAR infrared lasers ,GALAXY clusters - Abstract
We present multiwavelength global star formation rate (SFR) estimates for 326 galaxies from the Star Formation Reference Survey in order to determine the mutual scatter and range of validity of different indicators. The widely used empirical SFR recipes based on 1.4 GHz continuum, 8.0 |$\mu$| m polycyclic aromatic hydrocarbons (PAHs), and a combination of far-infrared (FIR) plus ultraviolet (UV) emission are mutually consistent with scatter of |$\lesssim$| 0.3 dex. The scatter is even smaller, |$\lesssim$| 0.24 dex, in the intermediate luminosity range |$9.3\lt \log ({L_{60}\, \rm{\mu\,\,m}}/{\mbox{L$_\odot $}})\lt 10.7$|. The data prefer a non-linear relation between 1.4 GHz luminosity and other SFR measures. PAH luminosity underestimates SFR for galaxies with strong UV emission. A bolometric extinction correction to far-UV luminosity yields SFR within 0.2 dex of the total SFR estimate, but extinction corrections based on UV spectral slope or nuclear Balmer decrement give SFRs that may differ from the total SFR by up to 2 dex. However, for the minority of galaxies with UV luminosity >5 × 10
9 L⊙ or with implied far-UV extinction <1 mag, the UV spectral slope gives extinction corrections with 0.22 dex uncertainty. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
43. Deconstructing a galaxy: colour distributions of point sources in Messier 83.
- Author
-
Kiar, A. K., Barmby, P., and Hidalgo, A.
- Subjects
- *
STAR clusters , *GALAXIES , *ASTRONOMICAL photometry , *SPECTRAL lines - Abstract
What do we see when we look at a nearby, well-resolved galaxy? Thousands of individual sources are detected in multiband imaging observations of even a fraction of a nearby galaxy, and characterizing those sources is a complex process. This work analyses a ten-band photometric catalogue of nearly 70 000 point sources in a 7.3 square arcmin region of the nearby spiral galaxy Messier 83, made as part of the Early Release Science programme with the Hubble Space Telescope's Wide Field Camera 3. Colour distributions were measured for both broad-band and broad-and-narrow-band colours; colours made from broad-bands with large wavelength differences generally had broader distributions although B - V was an exception. Two- and three-dimensional colour spaces were generated using various combinations of four bands and clustered with the K-Means and Mean Shift algorithms. Neither algorithm was able to consistently segment the colour distributions: while some distinct features in colour space were apparent in visual examinations, these features were not compact or isolated enough to be recognized as clusters in colour space. K-Means clustering of the UBVI colour space was able to identify a group of objects more likely to be star clusters. Mean Shift was successful in identifying outlying groups at the edges of colour distributions. For identifying objects whose emission is dominated by spectral lines, there was no clear benefit from combining narrow-band photometry in multiple bands compared to a simple continuum subtraction. The clustering analysis results are used to inform recommendations for future surveys of nearby galaxies. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
44. The JCMT Nearby Galaxies Legacy Survey VII: H\alpha{} imaging and massive star formation properties
- Author
-
Sánchez-Gallego, J. R., Knapen, J. H., Wilson, C. D., Barmby, P., Azimlu, M., and Courteau, S.
- Subjects
Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics::Galaxy Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We present H\alpha{} fluxes, star formation rates (SFRs) and equivalent widths (EWs) for a sample of 156 nearby galaxies observed in the 12CO J=3-2 line as part of the James Clerk Maxwell Telescope Nearby Galaxies Legacy Survey. These are derived from images and values in the literature and from new H\alpha{} images for 72 galaxies which we publish here. We describe the sample, observations and procedures to extract the H\alpha{} fluxes and related quantities. We discuss the SFR properties of our sample and confirm the well-known correlation with galaxy luminosity, albeit with high dispersion. Our SFRs range from 0.1 to 11 Msun yr-1 with a median SFR value for the complete sample of 0.2 Msun yr-1. This median values is somewhat lower than similar published measurements, which we attribute, in part, to our sample being HI-selected and, thus, not biased towards high SFRs as has frequently been the case in previous studies. Additionally, we calculate internal absorptions for the H\alpha{} line, A(H\alpha{}), which are lower than many of those used in previous studies. Our derived EWs, which range from 1 to 880\AA{} with a median value of 27\AA{}, show little dependence with luminosity but rise by a factor of five from early- to late-type galaxies. This paper is the first in a series aimed at comparing SFRs obtained from H\alpha{} imaging of galaxies with information derived from other tracers of star formation and atomic and molecular gas., Comment: Accepted for publication in MNRAS. 47 pages, 18 figures
- Published
- 2012
45. Localization of the X-ray Source in the Globular Cluster G1 with Chandra
- Author
-
Kong, A. K. H., Heinke, C. O., Di Stefano, R., Cohn, H. N., Lugger, P. M., Barmby, P., Lewin, W. H. G., and Primini, F. A.
- Subjects
High Energy Astrophysical Phenomena (astro-ph.HE) ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics::Galaxy Astrophysics - Abstract
We report the most accurate X-ray position of the X-ray source in the giant globular cluster G1 in M31 by using the Chandra X-ray Observatory, Hubble Space Telescope (HST), and Canada-France-Hawaii Telescope (CFHT). G1 is clearly detected with Chandra and by cross-registering with HST and CFHT images, we derive a 1-sigma error radius of 0.15 arcsec, significantly smaller than the previous measurement by XMM-Newton. We conclude that the X-ray emission of G1 is likely to come from within the core radius of the cluster. We have considered a number of possibilities for the origin of the X-ray emission but can rule all but two scenarios out: it could be due to either accretion onto a central intermediate-mass black hole (IMBH), or an ordinary low-mass X-ray binary (LMXB). Based on the X-ray luminosity and the Bondi accretion rate, an IMBH accreting from the cluster gas seems unlikely and we suggest that the X-rays are due to accretion from a companion. Alternatively, the probability that a 1.5 solar masses cluster LMXB lies within the 95 per cent X-ray error circle is about 0.7. Therefore we cannot rule out a single LMXB as the origin of the X-ray emission. While we cannot distinguish between different models with current observations, future high-resolution and high-sensitivity radio imaging observations will reveal whether there is an IMBH at the centre of G1., 5 pages, 1 figure, accepted for publication in MNRAS
- Published
- 2009
46. An HST/WFPC2 Survey of Bright Young Clusters in M31 III. Structural Parameters
- Author
-
Barmby, P., Perina, S., Bellazzini, M., Cohen, J. G., Hodge, P. W., Huchra, J. P., Kissler-Patig, M., Puzia, T. H., and Strader, J.
- Subjects
Astrophysics of Galaxies (astro-ph.GA) ,FOS: Physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Astrophysics::Galaxy Astrophysics - Abstract
Surface brightness profiles for 23 M31 star clusters were measured using images from the Wide Field Planetary Camera 2 on the Hubble Space Telescope, and fit to two types of models to determine the clusters' structural properties. The clusters are primarily young (~10^8 yr) and massive (~10^4.5 solar masses), with median half-light radius 7 pc and dissolution times of a few Gyr. The properties of the M31 clusters are comparable to those of clusters of similar age in the Magellanic Clouds. Simulated star clusters are used to derive a conversion from statistical measures of cluster size to half-light radius so that the extragalactic clusters can be compared to young massive clusters in the Milky Way. All three sets of star clusters fall approximately on the same age-size relation. The young M31 clusters are expected to dissolve within a few Gyr and will not survive to become old, globular clusters. However, they do appear to follow the same fundamental plane relations as old clusters; if confirmed with velocity dispersion measurements, this would be a strong indication that the star cluster fundamental plane reflects universal cluster formation conditions., AJ in press; 37 pages, 12 figures
- Published
- 2009
47. An HST/WFPC2 survey of bright young clusters in M31. I. VdB0, a massive star cluster seen at t ≃ 25 Myr
- Author
-
Perina, S., Barmby, P., Beasley, M. A., Bellazzini, M., Brodie, J. P., Burstein, D., Cohen, J. G., Federici, L., Fusi-Pecci, F., Galleti, S., Hodge, P. W., Huchra, J. P., Kissler-Patig, M., Puzia, T. H., and Strader, J.
- Subjects
Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
Aims. We introduce our imaging survey of possible young massive globular clusters in M31 performed with the Wide Field and Planetary Camera 2 (WFPC2) on the Hubble Space Telescope (HST). We obtained shallow (to B ~ 25) photometry of individual stars in 20 candidate clusters. We present here details of the data reduction pipeline that is being applied to all the survey data and describe its application to the brightest among our targets, van den Bergh 0 (VdB0), taken as a test case. Methods. Point spread function fitting photometry of individual stars was obtained for all the WFPC2 images of VdB0 and the completeness of the final samples was estimated using an extensive set of artificial stars experiments. The reddening, the age and the metallicity of the cluster were estimated by comparing the observed color magnitude diagram (CMD) with theoretical isochrones. Structural parameters were obtained from model-fitting to the intensity profiles measured within circular apertures on the WFPC2 images. Results. Under the most conservative assumptions, the stellar mass of VdB0 is M> 2.4 x 10^4 M_☉ , but our best estimates lie in the range ≃4-9 x 10^4 M_☉. The CMD of VdB0 is best reproduced by models having solar metallicity and age ≃25 Myr. Ages less than ≃12 Myr and greater than ≃60 Myr are clearly ruled out by the available data. The cluster has a remarkable number of red super giants (≳18) and a CMD very similar to Large Magellanic Cloud clusters usually classified as young globulars such as NGC 1850, for example. Conclusions. VdB0 is significantly brighter (≳1 mag) than Galactic open clusters of similar age. Its present-day mass and half-light radius ((r_h = 7.4 pc) are more typical of faint globular clusters than of open clusters. However, given its position within the disk of M31, it is expected to be destroyed by dynamical effects, in particular by encounters with giant molecular clouds, within the next ~4 Gyr.
- Published
- 2009
48. A Spatially Resolved Study of the Cold Dust in NGC 205
- Author
-
Marleau, F. R., Noriega-Crespo, A., Misselt, K., Gordon, K., Rieke, G. H., Barmby, P., Willner, S., Engelbracht, C., Chary, Rango-Ram, Teplitz, Harry I., and Sheth, Kartik
- Subjects
Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We present IRAC and MIPS observations of NGC 205, the dwarf elliptical companion of M31, obtained with the Spitzer Space Telescope. The extended dust emission is spatially concentrated in three main emission regions. Based on our mid-to-far infrared flux density measurements alone, we derive a total dust mass estimate of the order of 3.2 × 10^4 M_⊙, at a temperature of ~20K. The gas mass associated with this component matches the predicted mass returned by the dying stars from the last burst of star formation in NGC 205 (~0.5 Gyr ago). Analysis of the Spitzer data combined with previous 1.1mm observations over a small central region or “Core” (18" diameter), suggest the presence of very cold (T ~ 12K) dust and a dust mass 16 times higher than is estimated from the Spitzer measurements alone. Assuming a gas to dust mass ratio of 100, these two datasets, i.e. with and without the millimeter observations, suggest a total gas mass range of 3.2 × 10^6 to 5 × 10^7 M_⊙.
- Published
- 2008
49. The Local Galaxy 8 micron Luminosity Function
- Author
-
Huang, J. -S., Ashby, M. L. N., Barmby, P., Brodwin, M., Brown, M. J. I., Caldwell, N., Cool, R. J., Eisenhardt, P., Eisenstein, D., Fazio, G. G., Floc'h, E. Le, Green, P., Kochanek, C. S., Lu, N. Y., Pahre, M. A., Rigopoulou, D., Rosenberg, J. L., Smith, H. A., Wang, Z., Willmer, C. N. A., and Willner, S. P.
- Subjects
Astrophysics (astro-ph) ,FOS: Physical sciences ,Astrophysics - Abstract
A SST survey in the NOAO Deep-Wide Field in Bo\"otes provides a complete, 8-micron-selected sample of galaxies to a limiting (Vega) magnitude of 13.5. In the 6.88 deg$^2$ field sampled, 79% of the 4867 galaxies have spectroscopic redshifts, allowing an accurate determination of the local (z, Comment: 32 pages, 12 Figures (Fig. 1, Fig. 2, and Fig. 4 are JPEG files), accepted for publication in ApJ
- Published
- 2007
50. A deep Chandra survey of the Groth Strip – II. Optical identification of the X-ray sources
- Author
-
Georgakakis, A., Nandra, K., Laird, E. S., Gwyn, S., Steidel, C. C., Sarajedini, V. L., Barmby, P., Faber, S. M., Coil, A. L., Cooper, M. C., Davis, M., and Newman, J. A.
- Subjects
Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
In this paper, we discuss the optical and X-ray spectral properties of the sources detected in a single 200-ks Chandra pointing in the Groth-Westphal Strip region. A wealth of optical photometric and spectroscopic data are available in this field providing optical identifications and redshift determinations for the X-ray population. The optical photometry and spectroscopy used here are primarily from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) survey with additional redshifts obtained from the literature. These are complemented with the deeper (r ≈ 26 mag) multiwaveband data (ugriz) from the Canada–France–Hawaii Telescope Legacy Survey to estimate photometric redshifts and to optically identify sources fainter than the DEEP2 magnitude limit (R_(AB)≈ 24.5 mag). We focus our study on the 2–10 keV selected sample comprising 97 sources to the limit ≈ 8 × 10^(−1)6 erg s^(−1) cm^(−2), this being the most complete in terms of optical identification rate (86 per cent) and redshift determination fraction (63 per cent; both spectroscopic and photometric). We first construct the redshift distribution of the sample which shows a peak at z≈ 1. This is in broad agreement with models where less luminous active galactic nuclei (AGNs) evolve out to z≈ 1 with powerful quasi-stellar objects (QSOs) peaking at higher redshift, z≈ 2. Evolution similar to that of broad-line QSOs applied to the entire AGN population (both types I and II) does not fit the data. We also explore the observedNH distribution of the sample and estimate a fraction of obscured AGN (N_H > 10^(22) cm^(−2)) of 48 ± 9 per cent. This is found to be consistent with both a luminosity-dependent intrinsic N_H distribution, where less luminous systems comprise a higher fraction of type II AGNs and models with a fixed ratio 2:1 between types I and II AGNs. We further compare our results with those obtained in deeper and shallower surveys. We argue that a luminosity-dependent parametrization of the intrinsic NH distribution is required to account for the fraction of obscured AGN observed in different samples over a wide range of fluxes.
- Published
- 2006
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.