Astronomy Department, University of Cape Town
Annual report for 2003
The permanent staff are Professors B.Warner (Head of Department), and A.P. Fairall. The vacant lectureship remained unfilled. Professor M. Feast continued as Honorary Professor, Dr P. Woudt continued as Research Officer, Dr S. Vrielmann completed her tenure as a Claude Harris Leon Foundation Postdoctoral Fellow.
Professor Fairall took 2003 as sabbatical leave, although he chose to remain based in the Department at UCT.
With the introduction of the National Astrophysics and Space Science program, contributed to by several universities and institutions in South Africa but based at the University of Cape Town, there were some changes in the lectures given by the Astronomy Department. Professor Warner gave half of the course on General Astrophysics at Honours level, and a course on cataclysmic variable stars at Masters level. In spite of Professor Fairall being on sabbatical leave he nevertheless taught the NASSP module on "Galaxies and large-scale structures".
At undergraduate level, Michelle Wiehahn gave a second-year introductory course on Astronomy.
Professor Warner was engaged in the following overseas visits during the year:
In January, at Santa Barbara, California, attending the conference "Globular Clusters: Formation, Evolution and the Role of Compact Objects" and the subsequent Workshop on "The Physics of Ultracompact Stellar Binaries". In May at Warsaw, Poland, as a Senior Fellow, giving a series of lectures and a colloquium at the Pedagogical University in Cracow and at the Copernicus University in Torun. During 26 June to 25 August, he was first in Auckland, New Zealand, where a lecture was given to the Astronomical Society and a colloquium at the University, then in Wellington, attending the Annual Meeting of the Royal Astronomical Society of New Zealand where an invited review was given. Continuing in Wellington, attended IAU Colloquium No 193: "Variable Stars in the Local Group" and gave a paper on rapid oscillations in cataclysmic variables.
The attendance at the IAU General Assembly in Sydney, with involvement in various business and scientific sessions, followed by a month of research as a visiting Fellow in the Mathematics Institute at the Australian National University in Canberra, where a colloquium was given, and a similar talk during a brief visit to Swinburne University in Melbourne.
In November, jointly with David Levy, a group of about 80 persons was accompanied on a flight to Antarctica in a successful viewing of the total solar eclipse.
At the General Assembly of the IAU in Sydney, Professor Warner was re-elected to the Organising Committee of Commission 41 (History of Astronomy) and was elected as one of the three new Vice Presidents of the IAU itself.
In July, Professor Fairall traveled to Sydney to attend the General Assembly of the International Astronomical Union. Aside from attending the symposium and a great diversity of sessions available he presented one oral paper, two poster papers and participated in various business meetings. He also visited Parkes Observatory, the Anglo-Australian Observatory and the Australia Telescope.
Dr Woudt also attended the General Assembly of the International Astronomical Union (IAU) in Sydney. There he gave an oral presentation at the Joint Discussion 5 (White dwarfs: Galactic and Cosmological Probes), a poster presentation at the IAU Symposium 216 (Maps of the Cosmos), and attended a day-long discussion on Virtual Observatories (VO) as representative of the South African VO workgroup.
In 2003 November, Dr Woudt travelled to Mexico for a two week-work visit to Professor Kraan-Korteweg (University of Guanajuato) followed by attending the international conference (IAU Colloquium 194) on "Compact binaries in the galaxy and beyond" where he gave an oral presentation. In addition, Dr Woudt spent two weeks at the University of Nagoya in December 2003, at the invitation of Professor Nagata and Mr Nagayama of the University of Nagoya.
In April, Professor Feast gave the opening address at a meeting in Leiden, The Netherlands, on AGB star research, held in honour of Professor Harm Habing on his retirement. In July, he attended IAU Colloquium 193, "Variable Stars in the local Group" held in Christchurch, New Zealand and gave an invited review on "AGB Stars as Distance Indicators". At the second "Science with SALT" workshop held in Cape Town in October he gave a talk on "SALT and RR Lyrae variables: Our Galaxy, The Magellanic Clouds and the local Group".
There were no long-term Visitors
Professor Fairall began his sabbatical in completing a review of the 2dF and Sloan Digital Sky Surveys, which was subsequently submitted and published. After that he put time and effort into two major projects. The first was the completion of his catalogue of galaxies partially observed behind the Scorpius region of the southern Milky Way. Aside from the task of establishing accurate positions for close on two thousand objects, numerous problem cases had to be sorted out and overlaps with a neighbouring survey addressed. Problems arose in determining magnitudes of the galaxies, but that has been largely sorted out. A paper has been drafted and only last details are now required before it is submitted for publication.
Fairall also spent time completing all reductions of spectra made in years past with the 1.9-m telescope at Sutherland. This led to a data paper, which was submitted for publication.
In collaboration with various students, past and present, Fairall investigated the percolation properties of nearby large-scale structures. Based on the environment of our Galaxy, it appears that galaxies within the same large-scale structure are never separated by more than 100 km/s (of redshift space). Even large-scale structure percolates into a labyrinth at 700 km/s. A preliminary report on this work was presented in Sydney; a detailed paper will soon be released.
Fairall also continued his long-standing collaboration with the Department of Computer Science by co-supervising the Honours project of Carl Hultiquist and Sameshan Perumel, which allows visualizations of large-scale structures, if necessary turning them into three-dimentional bodies which can be viewed by stereoscopic vision. This work also involved collaboration with Brian Abbott of Hayden Planetarium, New York, and is done in close association with Brent Tully (Hawaii).
Fairall and T. Matomela also investigated Xhosa indigenous astronomical knowledge. A field trip by the latter produced data that confirmed previous findings and also revealed some new aspects regarding Jupiter, and the sighting of Venus in the daytime.
Fairall and Woudt also undertook the organization of a conference on "Nearby large-scale structures and the Zone of Avoidance" to be held March – April 2004.
Dr Woudt has continued to use the Japanese Infrared Survey Facility (IRSF), a 1.4-m telescope equipped with a simultaneous J, H, and Ks camera (SIRIUS), this time for an initial study of distant large scale structures; this is the MSc project of Ms Michelle McIntyre (UCT). The project is co-supervised by Professor Fairall and Dr Woudt both at UCT. With the IRSF we will perform a deep survey at selected fields of southern declinations, and this will be a basis for further spectroscopic follow-ups with the Southern African Large Telescope (SALT).
In a separate project, Dr Woudt in collaboration with Dr J. Lucey (University of Durham), Dr M. McCall (York University), Professor R. Kraan Korteweg (University of Guanajuato), Professor D. Burnstein (Arizona State University) and Professor Fairall (UCT) is analyzing R, J, H and Ks photometry of ~70 elliptical galaxies in the nearby, rich Norma cluster at the heart of the Great Attractor in order to determine its distance through the Fundamental Plane. Due to the low Galactic latitude of this cluster, specific care must be given to the star crowding effects and the correction for the Galactic foreground extinction. Various simulations are used to quantify the effects of star crowding on surface photometry of galaxies at low Galactic latitude.
Professor Warner and Dr Woudt continued their high speed photometric survey of faint southern Cataclysmic Variable (CV) stars, with special attention to old novae. For this survey they used the 1.9-m and 1.0-m telescopes at the Sutherland site of the South African Astronomical Observatory together with the University of Cape Town CCD photometer during 2003. This survey can be regarded as an input survey for the Southern African large Telescope to identify the more interesting specimens from more detailed structural studies with SALT. A distinct highlight in 2003 was the discovery of three new dwarf novae with non-radially pulsating primaries (a pulsating ZZ Ceti white dwarf in a close interacting binary system). Prior to this discovery, there was only one such hybrid known, namely GW Lib. Studies of these CV/ZZ stars will hopefully lead to a detailed understanding of the impact of accretion on the internal structure of white dwarfs. Denise Dale (NASSP Honours student in 2003) worked on the photometric analysis of the three new pulsating CV/ZZ stars.
Professor Warner and Dr Woudt have also been involved in the study of dwarf nova oscillations (DNOs) and quasi-periodic oscillations (QPOs) in Cataclysmic Variable stars. Ms Retha Pretorius worked on her MSc thesis on this topic in 2003 at the Department. One of the outcomes of this study is the recognition that ~27 CVs follow a tight relation in which the ratio of the QPO period is roughly 15 times the DNO period. The CVs therefore extend the two-QPO diagram of X-Ray binaries (neutron stars and black holes) by about three orders of magnitude and this relation now covers a range of six orders magnitude for a wide range of astronomical objects. In addition a new kind of DNO was discovered, the longer-period dwarf nova oscillation (lpDNO).
P.A. Whitelock (SAAO), Feast (UCT), J. van Loon and A.A. Zijlstra completed the analysis of an eight year program of infrared photometry of large amplitude AGB variables in the Large Magellanic Cloud. The emphasis was on those variables obscured by circumstellar dust and the observations were combined with mid-infrared data from IRAS and ISO. It was found that most of the very long period stars followed an extrapolation of the Mira period-luminosity (PL) relation to longer periods. However, three stars more luminous than expected from the PL relation were identified as undergoing the process known as hot-bottom-burning. Another large observing project was completed by Feast, Whitelock and Marang (SAAO). This dealt with 18 years of infrared observations of the mass-losing carbon Mira II Lup. During this time the star underwent an extended dust obscuration event. An analysis showed that this event was due to the ejection of a dust cloud of limited extent in the line-of-sight rather than a complete dust shell. This model is similar to that thought to operate in the case of the R Coronae Borealis variables though the Miras and the RCB stars are otherwise very different.
Feast continued observing with the Infrared Survey Facility in collaboration with J.W. Menzies, P.A. Whitelock (SAAO) and Japanese collaborators. The work concentrated on the study of red variables in Local Group galaxies and galactic globular clusters (the latter in collaboration with N Matsunaga (Tokyo)).
Professor Fairall continued as Head of the Planetarium (part time) at Iziko Museums of Cape Town. As part of his planetarium duties, he ran numerous public presentations and two "Starfinder" courses. He gave a number of invited lectures (to schools, clubs etc) and many radio interviews (up to three a day during the close approach to Mars).
Professor Feast continued as an editor of the Monthly Notices of the Royal Astronomical Society.
Crause, L.A., Lawson, W.A., Kilkenny, D. van Wyl, F., Marang, F. & Jones, A.F. 2003. The Post outburst photometric ehaviour of V838 Mon. Monthly Notices of the Royal Astronomical Society. 341:785-791
Lyo, A.R., Lawson, W.A., Mamajek, E.E., Feigelson, E.D., Sung, E. & Crause, L.A. 2003. Infrared study of the eta Chamaeleontis cluster and the longevity of circumstellar discs. Monthly Notices of the Royal Astronomical Society. 338:616-622
Romero-Colmenero, E., Potter, S.B., Buckley, D.A.H., Barret,. P.E. & Vrielmann, S. 2003. Multi-epoch spectroscopy, polarimetry and photometry of the polar UW Pic. Monthly Notices of the Royal Astronomical Society. 339:685-694
Schuh, S.L., Handler, G., Drechel, H., Hauschildt, P., Driezler, S., Medupe, R., & others. 2003. 2MASS J0516288+260738: Discovery of the first eclipsing late K + Brown dwarf binary system. Astronomy & Astrophysics. 410:649-661
Vermaak, P. 2003. Rapid analysis of binary lens gravitational microlensing light curves. Monthly Notices of the Royal Astronomical Society. 344: 651-656
Vrielmann, S. & Warren, O. 2003. The disc evolution of V2051 Oph on decline from superoutburst. Monthly Notices of the Royal Astronomical Society. 338:165-175
Warner, B. 2003. Magnetic Cataclysmic Variables. Publications of the Astronomical Society of the Pacific. 115:410-411
Warner, B. 2003. Whence the Constellations? Bulletin du Bibliophile. Part 1:85-104
Warner, B., Woudt, P.A. & Pretorius, M.L. 2003. Dwarf Nova Oscillations and Quasi-Periodic Oscillations in Cataclysmic Variables: A new kind of Dwarf Nova Oscillation, and further examples of the similarities to X-Ray Binaries. Monthly Notices of the Royal Astronomical Society. 344:1193-1209
Warner, B. 2003. Stellar Apoplexy, Convalescence and Recovery: The life cycles of cataclysmic variable stars. Monthly Notices of the Astronomical Society of Southern Africa. 62:74-84
Whitelock, P.A., Feast, M.W., van Loon, J.T. & Zijlstra, A.A. 2003. Obscured Asympototic Giant Branch variables in the Large Magellanic Cloud and the Period-Luminosity Relation. Monthly Notices of the Royal Astronomical Society. 342:86-104
Woudt, P.A. & Warner, B. 2003. High-Speed Photometry of the Recurrent Nova IM Normae. Monthly Notes of the Royal Astronomical Society. 343: 313-314
Woudt, P.A. & Warner, B. 2003. High-Speed Photometry of the Faint Cataclysmic Variables: III. V842 Cen, By Cir, TV Crv, V655 CrA, CP Cru, V794 Oph, V992 Sco, EU Sct and V373 Sct. Monthly Notices of the Royal Astronomical Society. 340:1011-1019
Woudt, P.A. & Warner, B. 2003. The new AM CVn Star in Hydra. Monthly Notices of the Royal Astronomical Society. 345:1266-1270
Woudt, P.A. & Warner, B. 2003. RX J1039.7-0507: A new Intermediate Polar and Probable Recent Novae, possessing a large Reflection Effect. Monthly Notices of the Royal Astronomical Society. 339: 731-734
Woudt, P.A. & Warner, B. 2003. RX J0944.5+0357: A Probable Intermediate Polar. Astrophysics and Space Science. 288:573-580
Fairall, A.P. 2003. Maps and Characteristics of Nearby Large-Scale Structures (Abstract), in Maps of the Cosmos, I.A.U. Symposium 216, Sydney.
Fairall, A.P. 2003. On the Role of Planetariums, in Effective Teaching and Learning of Astronomy, I.A.U. Special Session 4, Sydney.
Feast, M.W. 2003. The Galactic Kinematics of Mira Variables in Mass-losing Pulsating Stars and their Circumstellar Matter. Ed. Nakada,Y & Honma,M. Kluwer. Dordrecht 83-89
Feast, M.W. 2003. Miras and Other Cool variables with GAIA in GAIA Spectroscopy, Science and Technology. Ed. Munari, U. ASP Conference Series. 298: 257-266
Warner, B. 2003. Symbiosis Canarias – Concluding Remarks. Astronomical Society of the Pacific, Conference Series. 303: 549 –556
Woudt, P.A. & Warner, B. 2003. Quiescent Properties of Classical Novae. Astronomical Society of the Pacific, Conference Series. 303, 317 –320.
Fairall, A.P. 2003. Large-Scale Structures in the Distribution of Galaxies: The 2dF and Sloan Surveys, in Astrophysics Update, Ed. Mason, J.W., Praxis-Springer, Chichester. 211-230
Feast, M.W. 2003. Current Uncertainties in the use of Cepheids as Distance Indicators, in Stellar Candles for the Extragalctic Distance Scale. Eds. Gieren, W. & Alloin, D. Springer.Berlin. 635:45-70
Woudt, P.A., Charles, P. & Shih, I.C. 2003. XTE J1550-564. IAU Circular 8102,2
Woudt, P.A. & Warner, B. 2003. 2003aw. IAU Circular 8085,3