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Annual Review 2008 1
UCL DEPARTMENT OF PHYSICS AND ASTRONOMY PHYSICS AND ASTRONOMY ANNUAL REVIEW 2008 Contents Introduction 1 Students 2 Careers 5 Highlights and News 8 Astrophysics 17 High Energy Physics 19 Atomic, Molecular, Optical and Position Physics 21 Condensed Matter and Material Physics 25 Grants and Contracts 27 Publications 31 Staff 40 Cover image: Threaded molecular wire This image was produced by Dr Sergio Brovelli and refers to recent results obtained by the group of Professor Franco Cacialli. The molecular wire consists of a semiconducting conjugated polymer supramolecularly encapsulated (i.e. with no covalent bonds) into cyclodextrin macrocycles (in green). This class of organic functional materials gives highly controllable optical properties and higher luminescence efficiency when employed as the active layer in light-emitting diodes. The supramolecular shield prevents potentially detrimental intermolecular interactions and preserves single-molecule photophysics even at high concentration. PHYSICS AND ASTRONOMY ANNUAL REVIEW 2008 1 Introduction in trying to help pilot STFC through maintaining a flourishing Department. very choppy waters and as major It is therefore with particular pleasure recipients of their funding support. Our that I note the award of no less than six Astrophysics group were particularly long-term Fellowships to young scientists unfortunate in the timing of the crisis, wishing to start their independent as it arrived just as the majority of the academic careers at UCL, see page 8. groups funding was due to be renewed. These Fellowships are deeply UCL has moved to ensure that years competitive as they attract world wide of research excellence in fundamental attention resulting in success rates of physics are not destroyed by what I hope 5% or less. -
Multi-Periodic Photospheric Pulsations and Connected Wind Structures in HD 64760
A&A 447, 325–341 (2006) Astronomy DOI: 10.1051/0004-6361:20053847 & c ESO 2006 Astrophysics Multi-periodic photospheric pulsations and connected wind structures in HD 64760 A. Kaufer1,O.Stahl2,R.K.Prinja3, and D. Witherick3, 1 European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Santiago 19, Chile e-mail: [email protected] 2 Landessternwarte Heidelberg, Königstuhl 12, 69117 Heidelberg, Germany 3 Department of Physics & Astronomy, University College London, Gower Street, London, WC1E 6BT, UK Received 18 July 2005 / Accepted 17 October 2005 ABSTRACT We report on the results of an extended optical spectroscopic monitoring campaign on the early-type B supergiant HD 64760 (B0.5 Ib) designed to probe the deep-seated origin of spatial wind structure in massive stars. This new study is based on high-resolution echelle spectra obtained with the Feros instrument at ESO La Silla. 279 spectra were collected over 10 nights between February 14 and 24, 2003. From the period analysis of the line-profile variability of the photospheric lines we identify three closely spaced periods around 4.810 h and a splitting of ±3%. The velocity – phase diagrams of the line-profile variations for the distinct periods reveal characteristic prograde non-radial pulsation patterns of high order corresponding to pulsation modes with l and m in the range 6−10. A detailed modeling of the multi-periodic non-radial pulsations with the Bruce and Kylie pulsation-model codes (Townsend 1997b, MNRAS, 284, 839) favors either three modes with l = −m and l = 8, 6, 8 or m = −6andl = 8, 6, 10 with the second case maintaining the closely spaced periods in the co-rotating frame. -
POSTERS SESSION I: Atmospheres of Massive Stars
Abstracts of Posters 25 POSTERS (Grouped by sessions in alphabetical order by first author) SESSION I: Atmospheres of Massive Stars I-1. Pulsational Seeding of Structure in a Line-Driven Stellar Wind Nurdan Anilmis & Stan Owocki, University of Delaware Massive stars often exhibit signatures of radial or non-radial pulsation, and in principal these can play a key role in seeding structure in their radiatively driven stellar wind. We have been carrying out time-dependent hydrodynamical simulations of such winds with time-variable surface brightness and lower boundary condi- tions that are intended to mimic the forms expected from stellar pulsation. We present sample results for a strong radial pulsation, using also an SEI (Sobolev with Exact Integration) line-transfer code to derive characteristic line-profile signatures of the resulting wind structure. Future work will compare these with observed signatures in a variety of specific stars known to be radial and non-radial pulsators. I-2. Wind and Photospheric Variability in Late-B Supergiants Matt Austin, University College London (UCL); Nevyana Markova, National Astronomical Observatory, Bulgaria; Raman Prinja, UCL There is currently a growing realisation that the time-variable properties of massive stars can have a funda- mental influence in the determination of key parameters. Specifically, the fact that the winds may be highly clumped and structured can lead to significant downward revision in the mass-loss rates of OB stars. While wind clumping is generally well studied in O-type stars, it is by contrast poorly understood in B stars. In this study we present the analysis of optical data of the B8 Iae star HD 199478. -
Annual Report 2008
Koninklijke Sterrenwacht van België Observatoire royal de Belgique Royal Observatory of Belgium Mensen voor Aarde en Ruimte , Aarde en Ruimte voor Mensen Des hommes et des femmes pour la Terre et l'Espace, La Terre et l'Espace pour l'Homme Jaarverslag 2008 Rapport Annuel 2008 Annual Report 2008 De activiteiten beschreven in dit verslag werden ondersteund door Les activités décrites dans ce rapport ont été soutenues par The activities described in this report were supported by De POD Wetenschapsbeleid / Le SPP Politique Scientifique De Nationale Loterij La Loterie Nationale De Europese Gemeenschap Het Europees Ruimtevaartagentschap La Communauté Européenne L’Agence Spatiale Européenne Het Fond voor Wetenschappelijk Onderzoek Le Fonds de la Recherche Scientifique – Vlaanderen Le Fonds pour la formation à la Recherche dans l’Industrie et dans l’Agriculture (FRIA) Instituut voor de aanmoediging van innovatie door Wetenschap & Technologie in Vlaanderen Privé-sponsoring door Mr. G. Berthault / Sponsoring privé par M. G. Berthault 2 Deel 1: Wetenschappelijke activiteiten Partie 1: Activités Scientifiques Part 1: Scientific Activities 3 4 Summary Abbreviations.................................................................................................................................. 7 A. GNSS Positioning and Time............................................................................................. 14 A.1. Time and Time transfer .............................................................................................................15 -
Geometric Algebra and Covariant Methods in Physics and Cosmology
GEOMETRIC ALGEBRA AND COVARIANT METHODS IN PHYSICS AND COSMOLOGY Antony M Lewis Queens' College and Astrophysics Group, Cavendish Laboratory A dissertation submitted for the degree of Doctor of Philosophy in the University of Cambridge. September 2000 Updated 2005 with typo corrections Preface This dissertation is the result of work carried out in the Astrophysics Group of the Cavendish Laboratory, Cambridge, between October 1997 and September 2000. Except where explicit reference is made to the work of others, the work contained in this dissertation is my own, and is not the outcome of work done in collaboration. No part of this dissertation has been submitted for a degree, diploma or other quali¯cation at this or any other university. The total length of this dissertation does not exceed sixty thousand words. Antony Lewis September, 2000 iii Acknowledgements It is a pleasure to thank all those people who have helped me out during the last three years. I owe a great debt to Anthony Challinor and Chris Doran who provided a great deal of help and advice on both general and technical aspects of my work. I thank my supervisor Anthony Lasenby who provided much inspiration, guidance and encouragement without which most of this work would never have happened. I thank Sarah Bridle for organizing the useful lunchtime CMB discussion group from which I learnt a great deal, and the other members of the Cavendish Astrophysics Group for interesting discussions, in particular Pia Mukherjee, Carl Dolby, Will Grainger and Mike Hobson. I gratefully acknowledge ¯nancial support from PPARC. v Contents Preface iii Acknowledgements v 1 Introduction 1 2 Geometric Algebra 5 2.1 De¯nitions and basic properties . -
PRAJNA - Journal of Pure and Applied Sciences ISSN 0975 2595 Volume 19 December 2011 CONTENTS
PRAJNA - Journal of Pure and Applied Sciences ISSN 0975 2595 Volume 19 December 2011 CONTENTS BIOSCIENCES Altered energy transfer in Phycobilisomes of the Cyanobacterium, Spirulina Platensis under 1 - 3 the influence of Chromium (III) Ayya Raju, M. and Murthy, S. D. S. PRAJNA Volume 19, 2011 Biotransformation of 11β , 17 α -dihydroxy-4-pregnene-3, 20-dione-21-o-succinate to a 4 - 7 17-ketosteroid by Pseudomonas Putida MTCC 1259 in absence of 9α -hydroxylase inhibitors Rahul Patel and Kirti Pawar Influence of nicking in combination with various plant growth substances on seed 8 - 10 germination and seedling growth of Noni (Morinda Citrifolia L.) Karnam Jaya Chandra and Dasari Daniel Gnana Sagar Quantitative analysis of aquatic Macrophytes in certain wetlands of Kachchh District, 11 - 13 Journal of Pure and Applied Sciences Gujarat J.P. Shah, Y.B. Dabgar and B.K. Jain Screening of crude root extracts of some Indian plants for their antibacterial activity 14 - 18 Purvesh B. Bharvad, Ashish R. Nayak, Naynika K. Patel and J. S. S. Mohan ________ Short Communication Heterosis for biometric characters and seed yield in parents and hybrids of rice 19 - 20 (Oryza Sativa L.) M. Prakash and B. Sunil Kumar CHEMISTRY Adsorption behavior and thermodynamics investigation of Aniline-n- 21 - 24 (p-Methoxybenzylidene) as corrosion inhibitor for Al-Mg alloy in hydrochloric acid V.A. Panchal, A.S. Patel and N.K. Shah Grafting of Butyl Acrylate onto Sodium Salt of partially Carboxymethylated Guar Gum 25 - 31 using Ceric Ions J.H. Trivedi, T.A. Bhatt and H.C. Trivedi Simultaneous equation and absorbance ratio methods for estimation of Fluoxetine 32 - 36 Hydrochloride and Olanzapine in tablet dosage form Vijaykumar K. -
Optimising Cosmic Shear Surveys to Measure Modifications to Gravity on Cosmic Scales
Mon. Not. R. Astron. Soc. 000, 1–13 (2009) Printed 11 November 2019 (MN LATEX style file v2.2) Optimising cosmic shear surveys to measure modifications to gravity on cosmic scales Donnacha Kirk1,Istvan Laszlo2, Sarah Bridle1, Rachel Bean2 1Department of Physics & Astronomy, University College London, Gower Street, London, WC1E 6BT, UK 2Department of Astronomy, Cornell University, Ithaca, NY 14853, USA 11 November 2019 ABSTRACT We consider how upcoming photometric large scale structure surveys can be opti- mized to measure the properties of dark energy and possible cosmic scale modifications to General Relativity in light of realistic astrophysical and instrumental systematic uncertainities. In particular we include flexible descriptions of intrinsic alignments, galaxy bias and photometric redshift uncertainties in a Fisher Matrix analysis of shear, position and position-shear correlations, including complementary cosmolog- ical constraints from the CMB. We study the impact of survey tradeoffs in depth versus breadth, and redshift quality. We parameterise the results in terms of the Dark Energy Task Force figure of merit, and deviations from General Relativity through an analagous Modified Gravity figure of merit. We find that intrinsic alignments weaken the dependence of figure of merit on area and that, for a fixed observing time, halving the area of a Stage IV reduces the figure of merit by 20% when IAs are not included and by only 10% when IAs are included. While reducing photometric redshift scatter improves constraining power, the dependence is shallow. The variation in constrain- ing power is stronger once IAs are included and is slightly more pronounced for MG constraints than for DE. -
EPSRC Service Level Agreement with STFC for Computational Science Support
CoSeC Computational Science Centre for Research Communities EPSRC Service Level Agreement with STFC for Computational Science Support FY 2016/17 Report and Update on FY 2017/18 Work Plans This document contains the 2016/17 plans, 2016/17 summary reports, and 2017/18 plans for the programme in support of CCP and HEC communities delivered by STFC and funded by EPSRC through a Service Level Agreement. Notes in blue are in-year updates on progress to the tasks included in the 2016/17 plans. Text highlighted in yellow shows changes to the draft 2017/18 plans that we submitted in January 2017. Contents CCP5 – Computer Simulation of Condensed Phases .......................................................................... 4 CCP5 – 2016 / 17 Plans (1 April 2016 – 31 March 2017) ...................................................... 4 CCP5 – Summary Report (1 April 2016 – 31 March 2017) .................................................... 7 CCP5 –2017 / 18 Plans (1 April 2017 – 31 March 2018) ....................................................... 8 CCP9 – Electronic Structure of Solids .................................................................................................. 9 CCP9 – 2016 / 17 Plans (1 April 2016 – 31 March 2017) ...................................................... 9 CCP9 – Summary Report (1 April 2016 – 31 March 2017) .................................................. 11 CCP9 – 2017 / 18 Plans (1 April 2017 – 31 March 2018) .................................................... 12 CCP-mag – Computational Multiscale -
Statistical Properties of a Sample of Periodically Variable B-Type
Astronomy & Astrophysics manuscript no. Lefever © ESO 2018 August 21, 2018 Statistical properties of a sample of periodically variable B-type supergiants ⋆ Evidence for opacity-driven gravity-mode oscillations K. Lefever1, J. Puls2, and C. Aerts1,3 1 Instituut voor Sterrenkunde, K.U.Leuven, Celestijnenlaan 200B, B–3001 Leuven, Belgium 2 Universit¨atssternwarte M¨unchen, Scheinerstr. 1, D-81679 M¨unchen, Germany 3 Departement Astrofysica, Radboud Universiteit van Nijmegen, PO Box 9010, 6500 GL Nijmegen, the Netherlands Received 14 July 2006 / Accepted 3 November 2006 ABSTRACT Aims. We have studied a sample of 28 periodically variable B-type supergiants selected from the HIPPARCOS mission and 12 comparison stars covering the whole B-type spectral range. Our goal is to test if their variability is compatible with opacity-driven non-radial oscillations. Methods. We have used the NLTE atmosphere code FASTWIND to derive the atmospheric and wind parameters of the complete sample through line profile fitting. We applied the method to selected H, He and Si line profiles, measured with the high resolution CES spectrograph attached to the ESO CAT telescope in La Silla, Chile. Results. From the location of the stars in the (log Teff , log g) diagram, we suggest that variability of our sample supergiants is indeed due to the gravity modes resulting from the opacity mechanism. We find nine of the comparison stars to be periodically variable as well, and suggest them to be new α Cyg variables. We find marginal evidence of a correlation between the amplitude of the photometric variability and the wind density. We investigate the Wind Momentum Luminosity Relation for the whole range of B spectral type supergiants, and find that the later types (> B5) perfectly follow the relation for A supergiants. -
Keiichi Umetsu — CURRICULUM VITAE (Updated on July 8, 2021)
Keiichi Umetsu —CURRICULUM VITAE (Updated on September 8, 2021) Contact and Personal Information Work Address: Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA), 11F of Astronomy-Mathematics Building, National Taiwan University (NTU), No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan Email: [email protected] Web: http://idv.sinica.edu.tw/keiichi/index.php ORCID: 0000-0002-7196-4822 WOS ResearcherID: AAZ-7589-2020 Academic Appointments Full Research Fellow [rank equivalent to Full Professor], ASIAA (01/2014 – present) Kavli Visiting Scholar, Kavli Institute for Astronomy and Astrophysics, Peking University, China (2016) Associate Research Fellow [tenured], ASIAA (01/2010 – 12/2013) Adjunct Research Fellow, Leung Center for Cosmology and Particle Astrophysics, NTU (01/2008 – 12/2012) Assistant Research Fellow [tenure track], ASIAA (06/2006 – 12/2009) Science Lead for the Yuan Tseh Lee Array: AMiBA, Mauna Loa, Hawaii, USA (08/2005 – 07/2011) Faculty Staff Scientist, ASIAA (07/2005 – 05/2006) Postdoctoral Research Fellow, ASIAA (06/2001 – 06/2005) Education Ph.D. in Astronomy, Tohoku University, Japan (04/1998 – 03/2001) M.Sc. in Astronomy, Tohoku University, Japan (04/1996 – 03/1998) B.Sc. in Physics, Tohoku University, Japan (04/1992 – 03/1996) Publication Summary According to the NASA Astrophysics Data System, I have • 181 research papers published or in press in peer-reviewed journals, with a total h-index of 53 • 21 lead (first or corresponding*) author publications with a total of over 1400 citations • Lead author publications: 1 paper cited at least 200 times (Umetsu* et al. 2014), 6 cited at least 100 times and +1 cited 99 times (Umetsu* et al. -
Annual Review 2011/12
UCL DEPARTMENT OF PHYSICS AND ASTRONOMY PHYSICS AND ASTRONOMY 2011–12 ANNUAL REVIEW PHYSICS AND ASTRONOMY ANNUAL REVIEW 2011–12 Contents Welcome It is an honour to write this WELCOME 1 introduction standing, to misquote Newton, on the shoulders of giants. COMMUNITY FOCUS 3 Jonathan Tennyson finished his Teaching Lowdown 4 tenure as Head of Department in September 2011 and so the majority Student Accolades 4 of the material contained in this Outstanding PhD Theses Published 5 Review records achievements under his leadership. In addition, Tony Career Profiles 6 Harker is currently acting as Head of Science in Action 8 Department in many matters and will continue to do so until October 2012. Alumni Matters 9 This is due to my on-going commitments with the ATLAS experiment on the ACADEMIC SHOWCASE 11 Large Hadron Collider (LHC) at CERN. Staff Accolades 12 I currently spend a large amount of my time in Geneva and I am very grateful Academic Appointments 14 to both Tony and Jonathan, as well as to other members of staff for helping Doctor of Philosophy (PhD) 15 to make this transition a success. In Portrait of Dr Phil Jones 16 particular I would also like to thank Hilary Wigmore as Departmental Manager and Raman Prinja as the new Director of RESEARCH SPOTLIGHT 17 Teaching for their continued support. Atomic, Molecular, Optical and Position Physics (AMOPP) 19 High Energy Physics (HEP) 21 “Success in such long- Condensed Matter and term, high-impact projects Materials Physics (CMMP) 25 requires sustained vision Astrophysics (Astro) 29 and dedicated work by Biological Physics (BioP) 33 excellent scientists over Research Statistics 35 many years.” Staff Snapshot 38 Underpinning this success is the outstanding quality of scientific research and education within the Department. -
Efeitos Da Modelagem Da PSF Em Estimativas Cosmológicas Usando
Universidade Estadual de Campinas Instituto de F´ısica \Gleb Wataghin" Andres Alejandro Navarro Alsina Efeitos da modelagem da PSF em estimativas cosmologicas´ usando lentes gravitacionais fracas Effects of PSF modeling in cosmological estimates using weak gravitational lensing Campinas 2020 Andres Alejandro Navarro Alsina Effects of PSF modeling in cosmological estimates using weak gravitational lensing Efeitos da modelagem da PSF em estimativas cosmologicas´ usando lentes gravitacionais fracas Dissertation presented to the \Gleb Wataghin" Physics Institute of the University of Campinas in partial ful- fillment of the requirements for the degree of Master in Physics, in the area of physics. Disserta¸c~aoapresentada ao Instituto de F´ısica \Gleb Wataghin"da Universidade Estadual de Campinas como parte dos requisitos exigidos para a obten¸c~ao do t´ıtulo de Mestre em F´ısica, na ´area de F´ısica. Supervisor/Orientadora: Prof. Dr. Fl´avia Sobreira Este exemplar corresponde a` versao~ final da disserta¸cao~ defendida pelo aluno Andres Alejandro Navarro Alsina, e orientado pela Prof. Dra. Flavia´ Sobreira. Campinas 2019 Ficha catalográfica Universidade Estadual de Campinas Biblioteca do Instituto de Física Gleb Wataghin Lucimeire de Oliveira Silva da Rocha - CRB 8/9174 Navarro Alsina, Andres Alejandro, 1993- N228e NavEffects of PSF modeling in cosmological estimates using weak gravitational lensing / Andres Alejandro Navarro Alsina. – Campinas, SP : [s.n.], 2019. NavOrientador: Flávia Sobreira. NavDissertação (mestrado) – Universidade Estadual