SAAO report: 2004-2009.
The last decade has seen perhaps the most dramatic developments and advances in the astronomical facilities of SAAO since it was formed almost 40 years ago. Construction was beginning on SALT, the Southern African Large Telescope, and anticipation was running high as to the science potential of what would be the largest single optical telescope in the southern hemisphere. SALT was driven as a South African project by my predecessor, Bob Stobie, whose untimely passing in 2002 meant that he was sadly not to see the completion of what was then the largest scientific research project in South Africa. But even before its completion, the perceived success of SALT as a high-level scientific collaboration on a global scale had contributed to South Africa proposing to host the SKA and beginning the construction of a technology demonstrator and SKA-precursor, MeerKAT.
Consequently, there has been much interest in the activities and output of South African astronomy in recent years. And while SAAO contributes to the (published) annual report of the NRF, under whose auspices SAAO is administered, there has been no separate annual report of the Observatory since 2003/4. However, the NRF and its research facilities are independently reviewed every five years, and part of this process requires SAAO to generate a "Self-Assessment Report" covering that five-year period. This happened most recently in mid-2010 when the NRF's Astro-Geosciences facilities (including SAAO) were reviewed for the interval 2004-2009, and SAAO produced its self-assessment report (SAR). I decided that this SAR, whilst containing a large amount of management information, also included scientific material which would be of wider interest to the astronomical community, both locally and internationally. Consequently, the SAR has been edited into an astronomical report of that period, for which I am very grateful to our Librarian (Shireen Davis) and Ian Glass for their efforts in compiling this document.
SAAO has evolved significantly during this interval, as it prepares to host a truly world-class facility (SALT), and offer it as part of a full suite of research telescopes and instruments at Sutherland to the South African astronomical community. In parallel with these activities, which form the core of SAAO, it was recognised that South Africa had to generate the homegrown human capital capable of exploiting this new facility. This meant an expansion of the number of South African research astronomers, and required a re-think of the system to produce them. SAAO has played a leading role in the creation of NASSP, the National Astrophysics and Space Science Program, hosted at UCT, but utilising the resources of SAAO in both Cape Town and Sutherland. NASSP brings together scientists from all SA universities and national research facilities which have involvement in astronomy to provide international-standard courses that take students to Honours and Masters level in Astronomy, thereby preparing them to undertake PhDs. The number of PhD students in Astronomy in SA has expanded considerably over the last 5 years, and while there is a concomitant demand for increased supervisory capacity, to which SAAO has been contributing, it has the added benefit of increasing the overall breadth and scope of research undertaken at the SAAO. NASSP continues to grow and is held up by DST as an example of how such fields should be developed given the limited national resources available.
Furthermore, the SALT Collateral Benefits Programme, which was established at the start of the SALT construction project, has expanded considerably the SAAO's efforts in education and outreach. Special attention has focused on the needs and aspirations of young people in the Northern Cape, particularly in and around Sutherland. The success of this division was demonstrated recently with the decision by the IAU to host its global office of astronomy for development at SAAO in Cape Town.
In spite of all these efforts, which have occupied a significant fraction of the time of SAAO's research-active staff, the scientific output of SAAO and its research collaborations during this interval has been considerable. These play to its world-class strengths in time-domain astronomy and the late stages of stellar evolution, now enhanced by new researchers in planetary and extragalactic astronomy. Since 2005, SAAO has held the contract to operate SALT on behalf of the SALT consortium, which has led to a substantial increase in its staffing level and annual budget. And with SA as the majority shareholder (%) in SALT, SAAO is the steward of this share on behalf of the South African community. While SALT's entry into normal operations has been delayed by the problems described here, some significant science has nevertheless been undertaken as part of the commissioning and performance verification process. These provide a hint of the scientific potential of this outstanding, African facility.
Phil Charles, March 2011
Outline of Activities and Responsibilities: The SAAO provides observational facilities for optical and near-infrared astronomy and the necessary engineering and technical support. Its research facilities are made available to South African and international astronomers. SAAO also operates the Southern African Large Telescope (SALT) under contract to the international SALT consortium in which South Africa has a major share (1/3) SAAO staff also contribute to the teaching and training of the next generation of South African research astronomers.
Scientific output: In the period under review, 696 scientific papers were published using SAAO facilities, of which 494 were written or co-authored by SAAO staff.
Human Capital Development: SAAO is contributing to the training and development of the next generation of astronomers through the National Astrophysics & Space Science Programme (NASSP), which began only in 2003, and has grown and evolved substantially during the period under review. This is one of the biggest challenges facing SAAO. Only a tiny fraction of those students who enter university as undergraduates, end up graduating with a PhD: almost ten times less than in developed countries. Yet it is essential that SALT (and other SA facilities) be utilized fully by the South African astronomical community in future.
Since the required numbers of postgraduate students do not currently exist, the astronomical community decided to "grow its own timber." NASSP was established in 2003 as a collaborative venture by the astronomical community to produce the next generation of astronomers. SAAO is one of the founding members and a committed supporter of this programme, both financially and academically through the provision of lecture courses on observational astronomy, spectroscopy and computational methods at Honours level and on stellar structure and evolution, observational cosmology and space technology at Masters level.
SAAO staff members supervise Honours and Masters students' projects, and also organise the summer and winter schools associated with NASSP (more details below). NASSP takes advantage of the combined skills and expertise of the wider South African astronomical community to present a powerful and broad-based postgraduate training programme at a single university. The NASSP consortium as of 2009 is comprised of ten SA universities and three national facilities.
In most respects NASSP has been highly successful (DST holds NASSP as an example to be emulated in other fields) and the demand for places growing so that by 2010 there were over two applicants for each Honours place and four applicants for each Masters' place. The fraction of women was around 30% which although less than ideal is better than for most mathematical or physical science programmes in South Africa. However, the number of black South African graduates has remained a major challenge.
To meet this challenge, in 2008 an Extended Honours Programme (EHP) was created. This is only open to students from previously disadvantaged backgrounds and it is aimed at preparing those students so that once they enter NASSP they don't just scrape through, they do well. Recruitment is via a Winter School held at SAAO and run for the first time in 2007. Staff members with HBU experience visit these institutions and invite students to come to Cape Town for the 2-week school. The Winter School is run by staff from SAAO, UCT and UWC, with a growing contribution from "graduates" of the EHP itself. It gives students from HBUs a flavour of astronomy and Cape Town as well as giving us an opportunity to see where their learning gaps are. The Winter School is financed from SAAO, SKA and NASSP--as it was not part of the programme originally envisaged when DST funding began.
Perhaps the single largest change in the scientific practices of SAAO during the period under review was that, by 2009, SAAO staff were supervising or co-supervising 23 MSc and PhD students.
SAAO also provides training to students in various other supporting disciplines, such as mechanical and electronic engineering, optics and IT.
Conservation: The SAAO is at the forefront of South Africa's efforts to preserve its dark sites for astronomy. SAAO is the primary institute responsible for maintaining Sutherland as an "Astronomy Advantage Area" within the AGA Act, passed in 2007 and now signed into law. This act aims to preserve and protect the geographical advantages of South Africa's best astronomical sites. The protection of the Act has already been invoked in order to influence proposed mining and wind-farm developments in the Northern Cape. (This also includes of course the radio astronomy development of MeerKAT, which is underway near Carnarvon, and under the control of SA's SKA Project Team.)
Space: The SAAO hosts the Space Secretariat, which has played a leading role in the development of the space arena in South Africa, and in particular its National Space Policy, which was adopted by the Minister of Trade and Industry in March 2009. This led to the establishment of the new South African Space Agency in 2011. SAAO is the chief local organiser of the International Astronautical Congress 2011, which is being held in Cape Town, the first time it has ever been in Africa.
Awareness and Outreach: The SAAO plays a leading role in the promotion of science awareness and community development through a variety of science outreach programmes delivered by the SALT Collateral Benefits Division (SCBD) of SAAO. These activities are regarded as part of the core functions of the SAAO.
The overarching goal of SCBD is to ensure that the maximum collateral benefits are derived from the SALT project to advance the economy, technology, and society of Africa. In January 2006 the SCBD came under new leadership (Kevin Govender) at about the same time that SALT moved from the construction to operational phase. Although the main focus of activities has been in the immediate vicinity of the SAAO sites (Sutherland and Cape Town areas), the programme has made an impact across the continent.
The SCBD has focussed on three areas:
* education in mathematics, science, engineering and technology in order to supply the country and the continent with well-trained and motivated professionals in substantially increased numbers;
* science communication and awareness to effectively engage with the public in order to disseminate relevant information in the fields of astronomy and space science;
* and socio-economic development in order to contribute to a better quality of life for all people, especially the disadvantaged.
The biggest impact that SALT and astronomy has had on the people in South Africa has probably been in education. SALT is now an icon that is known by virtually every school learner in the country--it is even a part of the school curriculum at various levels. What it means to a young South African is that there are great opportunities in their own country in the fields of science, engineering and technology. The SCBD uses this icon to inspire learners towards careers in these fields. Astronomy and SALT are also used as a tool for teaching concepts in mathematics, science and technology at school level.
The IYA 2009 allowed these activities to be taken to an even higher level, achieving record visitor numbers in both Cape Town and Sutherland, combined with the SCBD reaching into the African continent as a result of international funding support. This led directly to SAAO winning the competition to host the IAU's Global Office of Astronomy for Development (GOAD), which opened in 2011 and is based at SAAO.
Hosting international telescope projects: SAAO hosts a number of specialised telescopes on behalf of international organisations. Some are manned, most are robotic:
* BiSON: Birmingham Solar Oscillation Network of stations, University of Birmingham, UK (198X). Part of an international network to monitor the spectrum of vibration frequencies observed on the surface of the Sun.
* IRSF: Infrared Survey Facility. 1.3 m survey telescope. Developed and constructed by Nagoya University, Japan in collaboration with SAAO (2000). Equipped with a simultaneous 3-channel infrared camera which has mapped the Galactic Bulge region and both Magellanic Clouds, providing the most sensitive surveys yet undertaken.
* YSTAR: 0.5-m telescope. Yonsei University, Korea (2000?). To monitor large areas of the sky for variability and moving objects.
* SuperWASP: The Wide-Area Search for Planets. UK University Consortium (2005). Daily surveys of transient and variable phenomena, especially planetary transits. In just 5 years SuperWASP has become the principal source of bright, transiting exoplanet systems in the southern hemisphere.
* KELT-South: The Kilodegree Extremely Little Telescope. Vanderbilt University, USA (2009). The KELT project is a survey of planetary transits of very bright stars using a wide-field small-aperture telescope.
* MONET: Network of two remotely-operable, fast-slewing 1.2m telescopes, the other being at the University of Texas. Goettingen Univ, Germany (2009). Associated with SALT.
* GFZ: Field measurement instrumentation for GeoForschungsZentrum, Potsdam, Germany (199X). Geo-dynamic observation of the Earth.
Public and School Visitors: Typically ten thousand each of visitors and school pupils pass through the facilities each year. This number was greatly exceeded during 2009, as a result of activities associated with the International Year of Astronomy, but the momentum of this increase has been maintained.
Staff numbers and Affirmative Action: In the period 2004 (pre-SALT) to 2009 the number of staff increased from 73 to 113. The Observatory is striving to achieve the following targets by 2015:
* To have a workforce of over 70% black employees. As at 30 March 2009, our black staff accounted for 63% of our total workforce.
* Females to reach a representation level of 45%. As at 30 March 2009 the figure was 35%.
* People with disabilities to account for at least 2% of the total staff complement.
Budget: The core annual budget of SAAO increased from R21M to R24M over the period under review. However, separate contracts, principally for the operation of SALT, increased the total from R28M to R52M over this time.
Telescope usage: About half of the available time on the 1m and 1.9m telescopes was suitable for observing; the remainder was downtime due to adverse weather. Demand typically exceeds the available time on these two telescopes by about 20%, although this has increased very recently, as a result of the increased demand for student research projects. The 0.5m and 0.75m telescopes are about 2/3 subscribed. A few percent of the time is lost to routine or unscheduled maintenance.
The SALT Telescope: SALT Science productivity has not yet reached its anticipated level due to various incomplete subsystems, plus the discovery of serious problems during the initial commissioning year (2006), which are detailed below. Nonetheless some astronomical projects have been undertaken since August 2005 using the two First Generation instruments,
SALTICAM (a CCD camera for high-speed photometry plus general field acquisition) and RSS, the Robert Stobie Spectrograph (a multimode imaging and low/medium resolution general-purpose spectrograph).
Data has been obtained for astronomers within the SALT consortium, both as part of commissioning and the initial Performance Verification (PV) phase. While in many cases these observations were severely compromised by poor image quality and other telescope/instrument issues, some have resulted in science publications. Somewhat more than half the available observing time has been devoted to engineering work during most of the review period.
More recently, considerable engineering work was devoted to diagnosis of the image quality and other problems. On-sky image quality testing took precedence over scientific observations. The scientific programs during this time were on an ad hoc basis, with feasible proposals accepted at any time from users. They mostly exploited the high-time resolution capability of SALTICAM, and included rapidly varying astronomical phenomena (CVs and X-ray binaries, flare stars, asteroids, planetary transits and occultations). In addition, some full-field imaging programs were attempted (e.g. stellar population and extinction law studies in nearby galaxies).
SALT Image Quality problems: It was only in late 2005 that imaging over the full 8 arcmin field of view became possible, leading to the realization that there was an image quality (IQ) problem. This manifested itself as a focus gradient with time-dependent effects that appeared to be associated with the instrument rotator angle and temperature. A detailed IQ study through much of 2006 and 2007 revealed that the source of this problem lay not with the auxiliary instruments or the primary mirror array, but with the Spherical Aberration Corrector (SAC). This unit is of a design unique to SALT, and allows for a much wider field-of-view and larger back-focal distance than that of the HET original.
From this study it was concluded that:
* the last pair of mirrors in the SAC are mis-aligned with respect to the optical axis of the telescope, and
* there are significant mechanical stresses transmitted into the SAC via the Tracker interface due to thermal effects and instrument rotation.
The SALT SAC is substantially different from that of HET (the Hobby-Eberly Telescope in Texas, which acted as a prototype for SALT) and most importantly has a much higher optical specification. It therefore requires a much more sophisticated mechanical support system, which was missing from the original design.
Since high quality (0.85 arcsec) images were obtained early on with SALT, there was no reason to doubt the optical quality of the individual SAC mirrors, or the overall SAC optical design. A redesign of the SAC-Tracker mechanical interface took place in 2008/09 and the process of installing the new interface and realigning the SAC mirrors began in April 2009. It was successfully completed in mid-2010.
SALT Spectrograph blue-throughput problem: The RSS spectrograph was installed on SALT in late 2005, and most of its observing modes were exercised during its initial commissioning year. The poor image quality of the telescope itself precluded comprehensive testing of its wide field capabilities, but a significant and completely separate problem was found: poor UV/blue throughput. This was traced to the fact that some lens-coupling fluid within the collimator and camera lens multiplets was degraded as a result of a previously unrecognised chemical reaction between the fluid and its surrounding polyurethane bladder. The spectrograph was removed from the telescope in 2006, and the key optical components returned to the US for repair. It has since been fully reassembled, and tests show that the blue-throughput problem is solved. During the SALT IQ repair, RSS has been undergoing exhaustive additional improvements and testing of all its electronic, mechanical and software components, building on the experience gained during initial commissioning.
These are the two main problem areas that have been the principal focus of SALT activities during the period of this review. With the SALT construction team having left in mid-2006, the operations team, together with key personnel from SAAO, has had to undertake the task of resolving these problems. This is without doubt the most radical surgery and intervention that SALT has undergone since its completion. That it took place entirely in SAAO's facilities in Sutherland is a dramatic event worthy of note in its own right, as it takes SALT technical operations to a potentially new level. Ten years ago the SAC repair project would only have been possible in high-tech facilities in either Europe or the US. However, advances in modern optics (such as the computer generated hologram) and the acquisition of some specialised, though affordable, equipment (such as an alignment telescope, wavefront camera and portable coordinate measuring machine) meant that all this work could be undertaken at Sutherland by SAAO staff. Thus the adjustment, maintenance and repair of SALT's opto-mechanics are now within the capability of the SALT team. This is a far better situation than that envisaged at the beginning of the SALT project, and bodes well for future developments and new instrumentation projects.
Virtual Observatory: The Virtual Observatory initiative at SAAO will be a major effort to utilize the most recent advances in computer hardware and software technology to develop a new generation of data analysis, visualization and mining tools. These tools will be able to address multi-terabyte data sets generated by SALT and SKA. It will be possible to apply the developments to a variety of disciplines within astronomy, from the optical to the radio regime as well as outside astronomy, e.g. in remote sensing, biological and social sciences.
Research Highlights: Selected items of research worthy of note: Extragalactic Astronomy: Understanding how the elemental abundances of galaxies have changed over time is an essential issue for understanding galaxy evolution. Abundance measurements constrain theoretical models, providing important clues on modes and rates of star formation in galaxies and on the importance of infall and outflows. HII regions indicate the present-day gas-phase element abundances, while planetary nebulae (PNe) reveal the chemical composition of a galaxy at 'intermediate' ages of a few 100 Myr to a few Gyr. Spectrophotometric results were obtained with SALT during its performance-verification phase on two PNe in the Sagittarius dwarf, the closest known dwarf spheroidal galaxy that is strongly disrupted by its interaction with the Milky Way. One of these is the most metal-rich PN known in any dwarf spheroidal galaxy. This result supports the idea that the Sagittarius dwarf contains a younger stellar population, in good agreement with spectroscopic abundance measurements in these stars.
The 1.4m infrared survey facility (IRSF) at Sutherland is a jointly run Japanese-South African telescope that has proved very productive for both partners. The first papers were published in 2002, since when there have been about 70 publications and two South African (UCT) PhDs awarded.
A study of asymptotic giant branch (AGB) stars in Local Group galaxies has involved scientists from SAAO, UCT and various institutes in Japan. Observations of the Leo I, Fornax and Phoenix dwarf galaxies have been published to date. For each of these galaxies extreme mass-losing AGB stars have been identified and characterized. They provide an independent method of estimating the distances to these galaxies that, together with other work by the same South African scientists, provides the foundation of a distance calibration method that will be useful with the next generation of extremely large telescopes. This is based on the period- luminosity relation for large amplitude AGB variables. Several of these newly discovered AGB stars have been studied with the Spitzer Space Telescope in a collaboration involving astronomers from the UK, Australia, USA, Japan and South Africa. Their spectra show strong [C.sub.2][H.sub.2] bands and relatively high mass-loss rates have been deduced. Mass-loss from AGB stars remains a poorly understood aspect of stellar astrophysics, despite its importance to the enrichment of the interstellar medium and thus for star and planet formation.
High-speed photometry of polars: The first extensive SALT science observations, which were subsequently published as the first SALT scientific paper (O'Donoghue et al. 2006), were eclipse light curves of the polar, SDSS J015543.40+002807.20, observed in August and September 2005 with SALTICAM. These high-speed "slot mode" photometric data were taken with time resolutions of between 112 and 285 milliseconds, and with minimal dead-time losses (<9 msec). The eclipse light-curves were of unprecedented quality and completely resolved the eclipses of the two accretion spots on the white dwarf surface. Model-fitting to the data enabled determinations of the likely masses of the component stars, the orbital inclination of the system and co-latitudes of the accretion spots.
Extrasolar Planets: The PLANET collaboration has used the 1.0-m telescope at Sutherland to monitor micro-lensing events in the Galactic Bulge, being allocated typically 10 contiguous weeks per year. The aim has been to detect deviations from "ideal" micro-lensing light curves that might reveal the presence of an additional object of planetary mass that is associated with the lensing star. For this it is important to have full (24 hour) coverage of the complete micro-lensing event, since a planetary deviation would last typically only 1 day compared with a lensing timescale of 40 days. SAAO is advantageously positioned between Australia and South America where the other PLANET telescopes operate.
Instrumentation : The Instrumentation Division comprises 14 staff responsible for the conception, design and construction of new instrumentation for the SAAO/SALT telescopes. During the review period the Electronics Dept completed extensive work on constructing and optimising the instrumentation for SALT. This included extensive work on modifying the SALTICAM camera, participating in the testing and commissioning of the RSS detectors, and a CCD test facility to allow for the testing of any CCD chip.
This has meant that SAAO telescope instrumentation work has largely been restricted to repair and maintenance, with staff limitations meaning that significantly less new development has been possible than in the past. One pleasing exception to this has been the development of a new polarimeter (HIPPO) that was completed and commissioned in 2008/9, and is now fully operational. Other projects that have started include the upgrading of the Unit Spectrograph on the 1.9m, the 1.0-m and 1.9-m telescope control systems were changed to PLC based, the ACT (Alan Cousins Telescope) was upgraded to PLC control, 1.0-m and 1.9-m X-Y slides were built and installed, and the 0.75-m was upgraded for remote control (encoders, software). This last upgrade formed the basis of a PhD project for a UCT student.
The Mechanical Department has been involved in various projects: manufacture of RSS cryostat and various additional components, manufacture of many parts for SALTICAM, manufacture of the new SAAO polarimeter and many parts for the extensive SALT Image Quality investigations described above.
Analysis of Publications: As already mentioned, a total of 696 publications were reported for the period, April 2004 to March 2009. A study using NASA-ADS reveals that 450 of the papers produced were cited 6722 times. 92 papers (13%) were written by SAAO staff, 402 papers (58%) were co-authored with researchers from elsewhere and 202 papers (29%) were written by visiting researchers using SAAO facilities. SAAO staff members were first authors of 95 collaborative papers. Further analysis indicates that 398 papers (57%) were published in ISI-rated journals, 178 were published in conference proceedings, 56 were published in other international journals and 39 were published in local journals. The cumulative figure also includes 17 papers authored by SAAO staff, published as individual chapters in various books and 8 books authored or edited by SAAO staff.
Challenges facing SAAO: it is important to be aware of some of the challenges to be addressed over the next five years:
* Full commissioning of SALT and its first generation instrumentation, with the aim of reaching normal operations as soon as possible (goal: mid 2011).
* Establishing a development program for SALT that identifies future scientific goals and the instrumentation to address them.
* The funding of SALT future instrumentation development.
* Replacement of ageing SAAO laboratory infrastructure (ongoing) with the aim of participating in future SALT and other Sutherland instrumentation projects (very recently, late 2010, substantial additional funding has been made available for this purpose by DST).
* Addressing the increasing demand from other African countries for participation in, and support in terms of astronomy/ education development.
* Educationally and socio-economically, the town of Sutherland relies heavily on astro-tourism and related activities for its development.
* Liaison, collaboration and cooperation with MeerKAT operations and scientists in the CT area.
* Continuing to grow NASSP with the aim of achieving, a) demographic representation of
* participants and b) wider SA institutional involvement.
* Maintaining and enhancing the small telescopes so as to support SALT, and thus improve
* the overall efficiency of operation as well as extending its scientific capabilities.
* Make the success of the SAAO-UCT collaboration a success of the wider SA community through the implementation of a long-term (10-year) SA Strategy for Astronomy.
Compiled by Prof. Phil Charles and Dr. Ian Glass
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|Title Annotation:||news notes|
|Author:||Charles, Phil; Glass, Ian|
|Publication:||Monthly Notes of the Astronomical Society of Southern Africa|
|Date:||Jun 1, 2011|
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