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MNASSA REPORT 2007
Astronomy Department, University of Cape Town
Personnel
Academic Staff: The permanent academic staff consists of the Chair and Head of Department,
Professor Renée C. Kraan-Korteweg, Professor Anthony P. Fairall, Professor Erwin de Blok
(SARChI Chair; since 01 June 2007), Senior Lecturer Dr Patrick A. Woudt, and Senior Lecturer Dr
Thebe Medupe (on a joint SAAO/UCT position). Professor Brian Warner, Emeritus Distinguished
Professor and Professor Michael W. Feast, Honorary Professor and Honorary Research Associate,
both remain active members of the department.
In July 2007, two postdoctoral fellows joined the Department, Dr Sarah Blyth and Dr Kurt van der
Heyden, supported by a SARChI and SKA bursary respectively.
Prof Phil Charles, Director of the SAAO, is an Honorary Professor and Prof Patricia A.Whitelock
(SAAO) is Visiting Professor of the Astronomy Department.
Secretary: Ms Marguerite Armstrong
Graduate Students: PhD students C. Blackman, M. Cluver, E. Elson, A. Getachew, P. Kotze (since
May 2007), N. Mhlahlo (graduated), M. Phorah, I. Riad, B. de Swardt, P. Vermaak (graduated); MSc
students D. Dale, R. Deane, T. Joseph, P. Kotze (graduated), N. Pekeur, N. Shafi, R. Skelton
(graduated), M. Spark, J. Tagg, T. Tshenye (graduated), E. Zietsman and J. Brink.
Visitors: Amongst visitors to the department in 2007 were: Dr Heinz Andernach (Guanajuato,
Mexico), Prof Erwin de Blok (Mt Stromlo, Australia), Dr Noriyuki Matsunaga (Kyoto, Japan), Dr
Takahiro Nagayama (Kyoto, Japan), Prof Ken Wakamatsu (Gifu, Japan), Prof Frank Briggs (ANU,
Australia), Mr Clemens Trachternach (Bochum, Germany), Mr Joshua Rich (Mt Stromlo, Australia),
Mr Nicholas Bonne (Mt Stromlo, Australia), and Mr Se-Heon Oh (Mt Stromlo, Australia).
Teaching
Undergraduate Level: At the undergraduate level Prof Fairall taught the first year course
“Introduction to Astronomy” (AST 1001F) to approximately 60 students, and Senior Lecturer Dr
Woudt the course AST2002S “Introduction to Modern Astrophysics” to 14 students. Dr Medupe
taught the course AST3002F on “Stellar Astrophysics” to 4 students, and Profs Kraan-Korteweg and
Fairall jointly offered the course AST3003S on `Galactic and Extragalactic Astrophysics” to 3
students.
BSc degrees in Astrophysics: The Astronomy Department continues to offer the Astrophysics
Specialisation within the Mathematical, Physical and Statistical Sciences Programme. Various
students who complied with the first and second year prerequisites for a degree in Astrophysics
registered for the third year astrophysics courses, resulting in 3 BSc degrees with a Specialisation in
Astrophysics, two with distinction.
Graduate Level: Within the National Astrophysics and Space Science Programme (NASSP, an
honours and MSc programme; see http://www.star.ac.za/), Prof Fairall presented an intensive version
of his introductory course to students of the SAAO/NASSP summer school. At the NASSP honours
level he taught the module on “Galaxies and Large-Scale Structures”, and Dr Woudt taught the
“General Astrophysics 1” module. At the MSc level, the module on “Extragalactic Astronomy” was
given by Prof Kraan-Korteweg and the module on “Cataclysmic Variables” by Prof Warner. Dr
Medupe taught the NASSP MSc module on “Advance Stellar Structure and Evolution”. Four new
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PhD students (E. Elson, A. Getachew (jointly with SAAO), P.Kotze, I. Riad) started their theses at
the Department.
Graduations
Three MSc students graduated in 2007: Mr Paul Kotze, Ms Ros Skelton (with distinction) and Mr
Thapelo Tshenye, and two PhD students, Mr N. Mhlahlo and Mr P. Vermaak.
Extramural
Prof Kraan-Korteweg gave a talk at NASSP Summerschool that was held at the SAAO in February
titled “What secrets does the Milky Way hide?” She was invited by the Royal Astronomical Society
to give a talk (”What secrets of the universe does the Milky Way hide?”) in November at the Royal
Academy in London, a summary of which will be published in “The Observatory”.
Prof Kraan-Korteweg and Dr Woudt jointly published a popular article on the Great Attractor in the
South African Journal Quest.
Prof De Blok gave a colloquim in the NASSP Series in September on “Dark Matter in Galaxies” and
Prof Feast delivered a talk to the Cape Branch of the ASSA in November.
Prof Fairall continued as Iziko Planetarium Astronomer, where inter alia, he ran a “Starfinder”
course. He also designed and scripted a new planetarium presentation called “The Cape of Stars”,
which opened late in 2007. He has presented numerous lectures to schools, clubs, etc and was called
on for many radio and TV interviews. Together with Prof Warner, a largely web-based version of
his introductory course was developed and run through UCT’s Centre for Extramural Studies.
Dr Medupe gave two lectures at the annual UCT Summer School in January on “African
Astronomers of the past.” He was also invited to give lectures by the friends of Iziko Museum in
May. He submitted two children’s books for publication by the Cambridge University Press. The
titles are “Children of Stars” and “Stars under the African Skies”. He successfully organised the first
NASSP/SAAO Winter School in June, that aims to increase the number of black South African
students in Astronomy. Fifteen students from three historically-black universities attended the
Winter School. He organised this with fellow astronomers from SAAO and UCT.
Prof Warner organized a 5 lecture series for UCT Summer School entitled “Global Catastrophe: Past
& Future” and gave a lecture on Asteroid and Comet Impacts. He also took a group to Sutherland
for a weekend in February as part of the Summer School of Iziko Museum. Other similar trips were
done for the University and for the Friends of the Museum. In addition he gave several popular
lectures to groups and societies.
Dr Sarah Blyth is one of the core team members of an Outreach Programme of the Free High School
Science Textbooks Project whose goal is to write a set of mathematical and physical science
textbooks free of author and publisher royalties and released under an open license for the grades 1012 South African School Syllabus. The project is a collaborative effort by volunteers spread across
the world. The books are approaching final completion and are planned to be distributed during
2009.
Committees
Prof Kraan-Korteweg and Dr Medupe form part of the regularly meeting NASSP Exco and
continued as members of the NASSP Steering Committee.
Profs Fairall and Kraan-Korteweg are both members of the Organising Committee of Commission
28 (Galaxies) of the International Astronomical Union (IAU).
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Prof De Blok is a Member of the MeerKAT Science Advisory Committee since August 2007.
Prof Feast continues as an editor of the Monthly Notices of the Royal Astronomical Society.
Prof Warner is a member of the Organising Committee of Commission 41 (History of Astronomy)
of the IAU and a Vice-President of the IAU.
Dr Kurt van der Heyden was invited as a member of the XMM-Newton Announcement of
Opportunity Cycle 7 Observing Time Allocation Committee. The panel met at the National Institute
for Astrophysics in Milan during November to evaluate the time allocation proposals.
Travel (Conferences, Working visits, Observations)
In January Prof Kraan-Korteweg helped organise the next KAT HI Science Workshop, which was
held at the SAAO in Cape Town, and where she prepared, upon request, a talk on “Who is pulling in
the Zone of Avoidance”. During a 2-day workshop held at UCT and SAAO in March - meant to
pave the way for UCT/Vanderbilt collaborations in Astronomy, Cosmology and Physics, she gave a
presentation on “The UCT Astronomy Department and its Research”. Following this meeting
between the two Universities a memorandum of understanding was developed and signed off later in
the year. Upon invitation by the SA SKA office (and as representative of Astronomy at UCT) Prof
Kraan-Korteweg participated at the “International MeerKAT Conference” in held in Amsterdam
(NL) in April.
In July the Head of Department participated at the international conference on "Galaxies in the Local
Volume" in Sydney (AU) as well as the subsequent Elizabeth and Frederick White conference on the
“Magellanic Clouds”. In the former she gave an invited oral contribution on “Outlining the Local
Void with the Parkes HI ZOA and Galactic Bulge survey”, next to a poster presentation (“Galaxy
transformation in action? - The spiral galaxy WKK6176”, Woudt, Kraan-Korteweg & Fritze-von
Alvensleben). From mid-September to mid-December Prof Kraan-Korteweg spent a sabbatical
period at the University College London UCL (UK) under the auspices of Prof Ofer Lahav, HOD of
Astrophysics. Expenses were supported by the Royal Society, and also by UCL’s Astrophysics
Department, and a NRF Focus Area Research Grant. While in England she participated at the
international meeting on the "The Modern Radio Universe: From Planets to Dark Energy” in
Manchester in October, and presented colloquia in November at UCL and also at the University
Hertfordshire, Centre for Astrophysics Research on “The last secrets of the Great Attractor.” On the
invitation by Prof Donald Lynden-Bell, she visited the IoA in Cambridge.
Prof De Blok participated in IAU Symposium 244 “Dark Galaxies and Lost Baryons” held from 2529 June in Cardiff, (UK). He also attended the SKA Bursary Conference held in November in Cape
Town.
In January 2007, Dr Woudt presented a talk on “Where is the HI in superclusters at intermediate
redshifts?” at the `HI studies with MeerKAT” workshop, held at the SAAO in Cape Town. Dr
Woudt attended the international conference `Galaxies in the Local Volume” held from 8– 13 July in
Sydney (AU) where he presented a poster paper on `Galaxy transformation in action! The spiral
galaxy WKK6176”. In August 2007, Dr Woudt spent three days at the Astronomy Department at
the University of Kyoto (JP) on a working visit to Dr Takahiro Nagayama, as part of a collaborative
South African / Japanese research project on mapping the Great Attractor at near-infrared
wavelengths. Immediately following this visit, Dr Woudt attended the workshop on “Scientific
results from the IRSF” in Atami (JP) from 22 – 24 August. In Atami, Dr Woudt presented a talk on
“IRSF/SIRIUS study of the heart of the Great Attractor, and the NIR evolution of a unique helium
nova”. Dr Woudt furthermore presented a talk (V445 Puppis – a unique helium nova) at the
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international conference on “Hydrogen-deficient stars” held from 17 – 21 September inTübingen
(D).
Dr Medupe visited Bamako and Timbuktu in Mali in January to work with translators on the
Astronomy Manuscripts of Timbuktu. He also spent a month at the Department of Physics and
Astronomy in Aarhus, Denmark in September to work on a research paper titled “Radial nonadiabatic eigenfunctions in A stars.” The paper is at an advanced stage of development. Dr Medupe
spent another month visiting Bamako in October, to work on the manuscripts with translators and
also to further engage with his Malian collaborators with respect to the Timbuktu Science Project.
In late October Dr Medupe attended the Kepler Asteroseismic Science Consortium (KASC) meeting
in Paris, to discuss how to use stars that will be observed by the Kepler Planet mission for asteroseismology.
During November and December Dr Medupe worked with Drs Petra Schmidl and Benno van Dalen
on a survey of the Timbuktu manuscripts at the Institute of History of Islamic Science in Frankfurt,
Germany. As a result of this, two papers are being prepared for publication. One paper on a survey
of the Astronomy Manuscripts of the Ahmed Baba Centre in Timbuktu and another, on the
investigation of zijies from one of the Timbuktu manuscripts. The zijes are data tables. The zij that
forms part of this investigation, is suspected to be a completely new, previously unknown, work of
Ibn Yunus, a 10th century Egyptian Astronomer.
Prof Warner attended the conference “Hot Subdwarf Stars and related Objects” in Bamberg (D) in
July 2007 and gave the conference summary. He was a Visiting Professor in the School of Physics
and Astronomy, Southampton University (UK) from March until October, and returned to Cape
Town in May to help host the Executive Meeting of the International Astronomical Union.
Prof Feast gave a talk on “Cepheids and the Hubble Contant” at the conference “From IRAS to
Herschel/Planck: Cosmology with infrared and submillimetre surveys” held in London (UK) in July.
He also attended an IAU Symposium 245 in July on “Formation and evolution of galaxy bulges”
(Oxford) and “Unsolved problems in stellar physics” (Cambridge). In October he attended the
meeting on “Formation and evolution of galaxy disks” (Rome, I).
Dr Kurt van der Heyden, together with some members of the UCT Cosmology Group, spent 10 days
during November 2007 at the Stockholm University (SE) visiting Prof Ariel Goobar and his group.
The purpose of the visit was to strengthen the basis for long-term research co-operation in the areas
of Supernovae and Dark Energy studies. He also participated in the “Cosmology, Strings, and
Phenomenology Conference” held 11-20 June 2007 at the AlbaNova University Centre, Stockholm.
He participated at the 2nd Annual Postgraduate Bursary Conference with the talk on “Prospects for
HI Surveys with KAT” from 26-30 November.
In August 2007, Ms Cluver attended the Spitzer Data Analysis Workshop held at Caltech (USA). A
six month Visiting Graduate Fellowship, awarded by IPAC (Infrared Processing and Analysis
Center)/Caltech, allowed her to further her PhD research at this institution. In December she
attended the 4th Spitzer Science Centre Conference on “The Evolving ISM in the Milky Way and
Nearby Galaxies” in Pasadena (USA). In April, Mr Elson spent a three week working visit at Mt
Stromlo (AU) to start the data reduction of the ATCA HI observations of three galaxies observatory
under the guidance of Dr De Blok. Mr Riad spent two months at Kyoto University (JP) to work
with Dr Takahiro Nagayama on the reduction and analysis of a deep near-infrared survey of the
Galactic plane. Mr Kotze spent two months at the University of Hertfordshire (UK) to work with
Prof Uta Fritze-von Alvensleben, applying the GALEV galaxy evolution code to Mr Kotze’s multiwavelength data of the intermediate-redshift cluster Abell 1437. The MSc student Ms Shafi worked
for a month (July/August) under the supervision of our collaborator Dr Lister Staveley-Smith at the
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University of Western Australia. Ms Joseph, MSc student, spent three weeks in September at the
Observatoire de Paris-Meudon (F) under the supervision of Dr Wim van Driel.
Research
Extragalactic Research
Local Groups Galaxies and the Distance Scale
During 2007, Prof Feast, Prof Whitelock and Dr Menzies (SAAO) together with their collegues in
the USA and the UK published their work on the revision of Classical Cepheid distance scale based
on trigonometrical parallaxes measured with the HST and in the revised Hipparcos catalogue. This
had led to revisions of the Hubble constant and the distance to the Large Magellanic Cloud. Prof
Feast, Prof Whitelock, Dr Laney (SAAO) together with Dr van Leeuwen (Cambridge, UK) and Dr
Kinman (Tuscon, USA) have continued their work on the luminosities and distance scales of type 11
Cepheids, RR Lyrae stars and Mira variables. Work was also continued (Feast, Whitelock, Menzies)
on the infrared observations of local group galaxies including collaboration with an international
group on the analysis of data from the SPITZER space observatory.
Long-slit spectroscopy of a nearby dwarf galaxy as well as various globular clusters was acquired
during the performance verification phase of SALT. These data will be used in our search for
intermediate mass black holes (IMBH) by the PhD student Ms de Swardt under the supervision of
Prof Kraan-Korteweg. Ms de Swardt has completed the kinematic analysis for the globular clusters
and a single dwarf galaxy. These results have significantly contributed to the testing of the
capabilities of the SALT spectrograph and were presented to the SAAO astronomical community in
March. The kinematic results for the dwarf galaxy will give the first clues of a possible IMBH in its
centre. Ms de Swardt has also developed a data reduction pipeline for complementary near-infrared
observations of the dwarf galaxies.
Large-Scale Structures in the nearby Universe
Prof Kraan-Korteweg and Dr Woudt continued their work in the Zone of Avoidance (ZOA). A
paper on the dynamics of the Norma cluster was accepted for publication and Ms Skelton, who was
working on the near-infrared K-band luminosity function of the Norma cluster for her MSc
dissertation, graduated with distinction in 2007. In collaboration with Dr Anja Schroeder (Leicester,
UK) and Dr Gary Mamon (Institute d”Astrophysique de Paris, F), Kraan-Korteweg and Woudt
completed a study of Galactic extinction at low Galactic latitudes based on near-infrared colours of
galaxies found in the DENIS Survey. Work on the Fundamental Plane of the Norma cluster (in
collaboration with Dr Lucey of the University of Durham, UK) is ongoing.
An example of a galaxy in the nearby Universe undergoing galaxy transformation due to cluster
infall is WKK6176, a jelly-fish spiral galaxy near the centre of the Norma cluster at the Great
Attractor (see below). Dr Woudt presented a poster paper on this galaxy at the “Galaxies in the Local
Universe” meeting held in Sydney (AU). Multi-wavelength observations have been obtained
previously for this galaxy and will be analysed in detail, in combination with the GALEV models
(see galaxy transformation at intermediate redshift below), to determine the star-formation history of
this peculiar galaxy.
To further our understanding of the Great Attractor (GA), Woudt and Kraan-Korteweg have been
involved in a deep near-infrared survey (with the IRSF in Sutherland) of the Norma Wall of
galaxies; a highly obscured large-scale structure central to the Great Attractor, running nearly
parallel to the Galactic plane. This survey commenced in 2006 and the first part is expected to be
completed in 2009. This project involves a large number of international collaborators, namely Dr.
Takahiro Nagayama (Kyoto University, J), Prof Ken Wakamatsu (Gifu University, J), Dr Tom
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Jarrett (IPAC/Caltech, USA) and Dr Baerbel Koribalski (ATNF, Aus). The first results of this survey
were published in the Astronomical Journal in 2007 following the discovery of two highly obscured
galaxy candidates (18 mag in the optical) in GLIMPSE legacy survey. HI observations with ATCA,
the Compact Array in Australia confirmed them to be members of the GA Wall at the highest dust
layer of the ZOA. PhD student Mr Ihab Riad is working on the full analysis of the IRSF data, and
will map the galaxy distribution in this highly obscured region of the Great Attractor. MSc student
Mr James Tagg has worked on part of these data to develop an optimal survey strategy.
Prof Kraan-Korteweg was awarded time on the Spitzer Space Telescope as part of a study of a
massive HI galaxy in the ZOA. This project forms the basis of the PhD thesis of Ms Michelle
Cluver, which aims to uncover the active nature of this galaxy. The analysis of this data is done in
collaboration with Drs Tom Jarrett and Phil Appleton (IPAC, CalTech, USA). The environment is
being explored as well. The data of a NIR survey of 2.24 square degrees have been fully reduced and
over 500 galaxies identified. Reductions of the MIR IRAC and MIPS scans of a smaller survey area
(~ half a square degree) were started.
Prof Fairall’s main interest continues to focus on large-scale structures and voids, particularly those
found in the 6dF Galaxy Survey (mainly based at the AAO, AU), in which he is a collaborator. In
early 2007, he participated in a void finder comparison, in which a number of participants to the
“Cosmic Void” conference, held in Amsterdam (NL) in late 2006, applied their own recipes to void
finding in a common dataset. In spite of some differences, the results are reassuring.
Prof Fairall has continued to employ “Labyrinth” software (developed for him by Carl Hultquist and
Samesham Perumal at UCT), to refine his 6dF atlas of more than 300 slice visualizations for the
purpose of identifying large-scale structures and voids. The atlas has been extended to include
redshift shells in galactic coordinates and cross identifications of features have been carried out.
With assistance from Sebastian Spitzer, (System Administrator), the Atlas was made available over
the web.
In the anticipation of extending this work towards an Atlas for the entire sky (a collaboration with
Brent Tully, Hawaii, USA), a test section, only going to a redshift of 7500 km/s, was prepared.
Similarly the Labyrinth software has been developed further by Richard Baxter and Julian Kenwood
(both students in Computer Science at UCT) and is now more agile in handling multiple data sets,
label sets and grids. It is also able to produce high-resolution visualizations.
The Universe at Intermediate Redshift
Dr Woudt and Prof Kraan-Korteweg, in collaboration with Prof Uta Fritze-von Alvensleben (Univ.
of Hertfordshire, UK) and Drs Vaisanen and Romero-Colemenero (SAAO) are involved in a study
of galaxy transformation and evolution in intermediate-redshift superclusters. The project will use
SALT (photometry and spectroscopy) and the InfraRed Survey Facility (IRSF) in the dense
environment of superclusters at various intermediate redshift. Mr Kotze (who finished his MSc on
this topic in 2007) started his PhD in 2007 at UCT and has spent two months at the University of
Hertfordshire (UK) to work with Prof Fritze-von Alvensleben and her group to master the use of the
GALEV galaxy evolution models. In the initial phase of his PhD, Mr Kotze is analysis a wide range
of pre-existing, multi-wavelength data of the supercluster around the rich equatorial cluster Abell
1437.
Dr van der Heyden, and Prof Bassett (UCT, Cosmology) continued work as external collaborators of
the Sloan Digital Sky Survey-II (SDSS-II) Supernovae Survey. The SDSS-II is a Multi-year project
to identify and measure light curves for intermediate-redshift (0.05<z<0.35) Type Ia supernovae
(SNe Ia) using repeated five-band (ugriz) imaging over an area of 300sq.deg. The survey region is a
stripe 2.5 degrees wide centred on the celestial equator in the Southern Galactic Cap that has been
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imaged numerous times in earlier years, enabling construction of a deep reference image for
discovery of new objects. Supernova imaging observations have been acquired between 1
September and 30 November of 2005-7. Each region was imaged on average every five nights.
Spectroscopic follow-up observations to determine supernova type and redshift are carried out on a
large number of telescopes. We were unfortunately not able to do any follow-up spectroscopic
observations with SALT during the 2007 season as the Robert Stobie Spectrograph was not available
on SALT during this period. In its first two three-month seasons, the survey has discovered and
measured light curves for 327 spectroscopically confirmed SNe Ia, 30 probable SNE Ia,14
confirmed SNE Ib/c, 32 confirmed SNE II, plus a large number of photometrically identified SNe Ia,
94 of which have host-galaxy spectra taken so far. The observational aspect of the project was
concluded in early December 2007, but the collaboration will continue to work on the data reduction
and analysis.
Extragalactic Radio Astronomy
With regard to new HI radio astronomy studies, the MSc student N. Pekeur with Profs KraanKorteweg and De Blok, as well as Dr Baerbel Koribalksi (ATNF, AU) initiated a study of the HI-tooptical diameter relation based on well-resolved ATCA interferomety data obtained for the first 17
LVHIS (Local Volume HI Survey) galaxies. After a visit to the Observatoire de Paris-Meudon (F),
in September, the MSc student T. Joseph with Profs Kraan-Korteweg and De Blok, and Dr Wim van
Driel (Observatoire de Paris-Meudon), started the reduction of the approximately first thousand
SDSS galaxies observed with the Nançay Radio Telescope for a first analysis to the NIBLES project
(Nançay Interstellar Baryon Legacy Extragalactic Survey). The MSc student R. Deane, under the
supervision of Profs Kraan-Korteweg and De Blok, started analysing the very deep and spatially
resolved ATCA HI data of the interacting and possibly giant low –surface brightness galaxy NGC
1512, one of the southern THINGS galaxies (The HI Nearby Galaxy Survey).
Supervised by Profs De Blok and Kraan-Korteweg, PhD student Ed Elson reduced ATCA HI data
for three southern THINGS galaxies and generated total flux maps and velocity fields. The
kinematical analysis of the nearby BCD galaxy NGC 2915 yielded a rotation curve typical of a late
type spiral galaxy. Combined with the deep, high resolution infrared obtained subsequently with the
IRSF, the galaxy seems extremely dark matter dominated, possibly with an anomalous HI
component at inner radii.
The HI data cubes obtained with the Parkes MB receiver in the extension of the Galactic Bulge were
fully analysed by the MSc student Ms Shafi. Close to 150 (mostly unknown) galaxies were detected.
The resulting large-scale structures were investigated, in particular the boundaries of the Local Void
(presented at an international meeting Sydney), a parallel arm to the Great Attractor Wall, and the
possible connection of the Norma cluster to the Ophiuchus supercluster revealed. Follow-up NIR
observations of all HI galaxy candidates were performed with the IRSF at Sutherland.
De Blok continued his involvement in The HI Nearby Galaxy Survey, a high-resolution survey of 34
nearby galaxies with the goal of determining the dark matter distribution as well as the processes that
lead to star formation. This survey is done in collaboration with Dr Fabian Walter (MPIfA,
Heidelberg, Germany), Prof Elias Brinks (Univ of Hertfordshire, UK) and Prof Rob Kennicutt, Jr.
(IoA, Cambridge, UK). De Blok’s students outside UCT are all involved in the THINGS survey and
all of them visited during 2007 for extended working visits (Se-Heon Oh and Joshua Rich from Mt
Stromlo, Canberra, Australia and Clemens Trachternach from the University of Bochum, Germany).
The year was spent working on drafts of papers, which will result in a special issue of the
Astronomical Journal on the THINGS results, currently planned for 2008.
De Blok is also part of the LVHIS team (the Local Volume HI Survey, a Compact Array radio
survey of nearby galaxies lead by Dr Baerbel Koribalski, ATNF, Australia). This led to an extended
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visit by PhD student Nicolas Bonne from Mt Stromlo, Australia.
De Blok is also in collaboration with the engineers at the KAT Office in Pinelands. Regular
discussions and meetings have been held to discuss possible science projects that can be done using
MeerKAT, South Africa’s Square Kilometre Array prototype, and its precursor
KAT-7. This has led to a formal definition of a first-light experiment for KAT-7 when it becomes
operational in 2009/10.
Stellar astrophysics
Cataclysmic Variable Stars
Prof Warner and Dr Woudt continued the work on cataclysmic variable (CV) stars, involving a fair
amount of high-speed photometry from the Southern African Large Telescope, with a particular
emphasis on rapid oscillations (VW Hyi) and pulsations (GW Librae) in accreting white dwarfs. For
his MSc dissertation, Mr Zietsman is analysing SALT spectroscopy and simultaneous photometry
from the SAAO 74-in telescope, of the eclipsing cataclysmic variable star EC21178-5417. This
particular CV has strong dwarf nova oscillations and Mr Zietsman will focus on the analysis of the
spectroscopic signatures of these oscillations.
Stellar Pulsations
Dr Medupe worked with his PhD student, Mr Motee Phorah who submitted his PhD thesis on
“computation of stellar structure equations with convection” in November. The thesis passed with
corrections. He supervised a NASSP honours project on a search for the rapidly oscillation Ap stars
by Mr Rudi Kuhn. Mr Kuhn passed his thesis project.
Interacting Binaries
Mr Santander-Garcia, Dr Corradi (Canary Islands, E), Prof Whitelock (SAAO/UCT), Dr Munari
(Padova, I), Dr Livio (STSci, USA) and others from the same institutions used long slit spectroscopy
form the VLT and multi-epoch images from HST to derive an expansion parallax for the symbiotic
star Hen 2-147. Once it is recognized that what is being observed is a shock front, and not
outflowing material, the derived distance is similar to that found from SAAO data and the Mira P-L
relation.
Mr Gromadzki, Prof Mikolajewska (Copernicus Institute, P) and Prof Whitelock (SAAO)
demonstrated that the cool component of the symbiotic system MWC 560 (V694 Mon) was a semiregular AGB variable with a pulsation period of 340 days.
History of Astronomy
Timbuktu manuscripts
Dr Medupe worked with Drs Holbrook and Urama on the edition of a conference proceedings titled
“African cultural Astronomy” due to be published in 2008. Together with the Timbuktu Research
Team, he wrote a paper contribution to these conference proceedings. Dr Medupe worked with
translators to study a manuscript written by Adul Abbas in 1732 in Timbuktu and they will prepare
this for future publications. Dr Schmidl, of the now defunct Institute of History of Islamic Science
in Frankfurt, Germany, and Dr Medupe worked together to prepare a paper on a survey of the
Astronomical Manuscripts of the Ahmed Baba Centre.
Publications
Books:
Warner, B. & Grogan, T. 2007. Scatological Verse. 64pp. Privately published. Cape Town
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Research Papers:
Bagetakos, I., Brinks, E., Walter, F., de Blok, W.J.G. 2007. Fine-scale structure of the neutral ISM
in M81, in “Triggered star formation in a turbulent ISM”, (eds) B.G. Elmegreen and J. Palous. IAU
Symposium. 237: 394-394
Bagetakos, I., Brinks, E., Walter, F., de Blok, W.J.G. 2007. An inventory of supershells in nearby
galaxies: first results from THINGS, in “Triggered star formation in a turbulent ISM”, (eds) B.G.
Elmegreen and J. Palous. IAU Symposium. 237: 393-393
Benedict, G.F., McArthur, B.E, Feast, M.W., Barnes, T.G., Harrison, T.E., Patterson, R.J., Menzies,
J.W., Bean, J.L., Freedman, W.L. 2007. Hubble Space Telescope Fine Guidance Sensor Parallaxes
of Galactic Cepheid Variable Stars: Period-Luminosity Relations. The Astronomical Journal. 133:
1810-1827
Bigiel, F., Walter, F., de Blok, W.J.G., Brinks, E., Madore, B. 2007. Star formation thresholds
derived From THINGS, in “Triggered star formation in a turbulent ISM”, (eds) B.G. Elmegreen and
J. Palous. IAU Symposium. 237, 397-397
Brinks, E., Bagetakos, I., Walter, F., de Blok, W.J.G. 2007. Observations of supershells in the
interstellar medium of nearby galaxies, in “Triggered star formation in a turbulent ISM”, (eds) B.G.
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dynamics, its Mira variable and its distance. Astronomy & Astrophysics. 465: 481-491
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Doctoral theses
Mhlahlo, N. 2007. The study of the accretion dynamics and behaviour in intermediate polars. 253pp.
Supervised by P.A. Woudt
Vermaak, P. 2007. Fitting binary less gravitational microlensing events with example-based
algorithms. 227pp. Supervised by B. Warner and J. Menzies (SAAO)
Masters degrees (by research)
Kotze, P. 2007. The evolution of galaxies in superclusters at intermediate redshift, supervised by
P.A. Woudt and R.C. Kraan-Korteweg
Skelton, R. 2007. The near infrared luminosity function of the Norma Cluster, supervised by P.A.
Woudt and R.C. Kraan-Korteweg
Tshenye, T.O. 2007. Quality control of astronomical CCD observations. MSc, supervised by L.
Baloni (SAAO) and P.A. Woudt
13