The development of astrophysics in South Africa

A brief overview is given of the history of astrophysics in South Africa up to the beginning of the modern era.     

Cosmology in South Africa

This paper reviews research in theoretical cosmology in South Africa, providing an overview of the work that has been done and the groups involved in that work.     

Astronomy education in South Africa

At a time when major reforms are shaping the education system of the new South Africa, Astronomy could play a crucial role in the teaching and appreciation of science. There is as yet very little Astronomy in formal school curricula, so extra-mural approaches are necessary. In this regard, initiatives have been made by the astronomical national facilities, while many school pupils visit the two major planetariums. At an advanced level, various universities offer courses and professional training.     

Amateur astronomy in South Africa

A review is given of the achievements of amateur astronomers in South Africa.     

Future goals for imaging

The demands imposed on the imaging system of an astronomical gamma-ray telescope are numerous; it must identify and resolve individual point sources, often in crowded regions of the sky; extended emission structures must be measured on angular dimensions which can extend up to the size scale of the Galactic plane; it must achieve these goals with high sensitivity for both the wide band continuum radiation as well a for discrete spectral line emissions, and ideally have as large a field of view as possible to enhance the probability of registering the unpredictable transient events which pervade the high energy sky. True imaging systems are currently under development for operation for energies up to about 100 keV, however the most practical tool for higher energies, for the time being, remains the coded mask. Some options are briefly reviewed.     

LAMOST远程无线监控系统研究

国家重大科学工程项目“大天区面积多目标光纤光谱天文望远镜”LAMOST（Large sky Area Multi-Object fiber Spectroscopic Telescope）目前已经进入了安装调试阶段,在2007年即将逐步投入使用．LAMOST总控系统是一个复杂的软件工程,需要对望远镜实时监控并给维护者提供多种控制手段．随着手机成为大众日常通讯工具,利用基于GSM（GlobalSystemforMobilecommunication）网络的手机短信对LAMOST望远镜进行远程无线监控,已经成为总控系统的一种辅助监控手段．文章着重描述该系统的软硬件原理、接口、控制流以及安全性的考虑．该项研究的使用在国内望远镜控制系统中尚属首次,目前已获得国家发明专利申请号．     

Integral Field Spectroscopy with Gemini: Support for IFU data in the Gemini IRAF package

We present a brief overview of facilities for Integral Field Spectroscopy at the Gemini Observatory. These include four optical and near-infrared IFUs suitable for high spatial resolution work and a suite of tasks for handling IFU data in the Gemini IRAF package. We describe the tools for data reduction that are available now or planned in the near future, helping investigators make productive use of these ground-breaking instruments. Further details on the individual IFUs, specific science applications and reduction examples are given in associated presentations by Beck et al., Carrasco et al., Trancho et al. and Winge et al.     

Instrumentation plans for 1024×1024 HgCdTe detector arrays at the University of Hawaii

The U.S. Air Force Phillips Laboratory will build the 3.63 m Advanced Electro Optical System (AEOS) telescope on Haleakala, Maui. The Institute for Astronomy will participate in this project and will develop astronomical instruments optimized for using the AEOS telescope in survey projects. As part of this instrument development program 1024×1024 HgCdTe near-infrared detector arrays will be developed at the Rockwell International Science Center.     

Observations of pulsating Ap stars in South Africa

The rapidly oscillating Ap (roAp) stars currently represent the only main sequence stars other than the Sun which exhibit non-radial acoustic pulsations of high overtone. This makes them excellent subjects for asteroseismology, an approach which promises to yield accurate knowledge of the interior structures of stars. Of the 27 known roAp stars, 24 were discovered in Sutherland despite extensive searches conducted elsewhere. This paper reviews the discovery of the roAp phenomenon and describes the factors that contribute to the high discovery rate for these stars at Sutherland. Two long-term observational projects in progress at Sutherland are discussed,viz. the Cape roAp Star Survey and long-term monitoring of frequency variations in roAp stars.     

Detrending time series for astronomical variability surveys

We present a detrending algorithm for the removal of trends in time series. Trends in time series could be caused by various systematic and random noise sources such as cloud passages, changes of airmass, telescope vibration, CCD noise or defects of photometry. Those trends undermine the intrinsic signals of stars and should be removed. We determine the trends from subsets of stars that are highly correlated among themselves. These subsets are selected based on a hierarchical tree clustering algorithm. A bottom-up merging algorithm based on the departure from normal distribution in the correlation is developed to identify subsets, which we call clusters. After identification of clusters, we determine a trend per cluster by weighted sum of normalized light curves. We then use quadratic programming to detrend all individual light curves based on these determined trends. Experimental results with synthetic light curves containing artificial trends and events are presented. Results from other detrending methods are also compared. The developed algorithm can be applied to time series for trend removal in both narrow and wide field astronomy.     

Automatic guide for the Raduga astronomical spectrograph

An automatic mirror guide has been designed and made for the Raduga fiber-optic echelle spectrograph. The new device was built into one of the parts of the spectrograph and allows the work of observers to be facilitated significantly. The automatic guide efficiently removes stellar image oscillations at frequencies of 0–2 Hz, which compensates almost completely for errors in setting the polar axis of a telescope and in its clockwork drive. The guide can be used on any telescope with a focal length of more than 5 m and has operated on two different telescopes. Over two observing seasons, several hundred stellar spectra were taken with the Raduga spectrograph using the automatic guide.     

均值漂移算法在LAMOST动态选星中的应用

将均值漂移算法运用于LAMOST动态选星过程,用以寻找局部天区内观测目标密度最高的区域进行观测.通过模拟试验分析了在不同的天区覆盖方法对均值漂移算法观测效率的影响,并与使用最大密度算法得到的结果进行了比较,证实了均值漂移算法的优越性.     

Horizon synthesis for archaeo‐astronomical purposes

In this paper I describe a simple numerical procedure to compute synthetic horizon altitude profiles for any given site. The method makes use of a simplified model of local Earth's curvature, and it is based on the availability of digital elevation models describing the topography of the area surrounding the site under study. Examples constructed using the Shuttle Radar Topographic Mission (SRTM) data (with 90 m horizontal resolution) are illustrated, and compared to direct theodolite measurements. The proposed method appears to be reliable and applicable in all cases when the distance to the local horizon is larger than ∼10 km, yielding a rms accuracy of ∼0.1 degrees (both in azimuth and elevation). Higher accuracies can be achieved with higher resolution digital elevation models, like those produced by many modern national geodetic surveys (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

New aspects for new generation telescopes

A selection of future observing facilities relevant to galaxy evolution science covering the wavelength range from X-rays to the radio regime are summarized. Scientific aspects that can be investigated with these next generation telescopes are briefly discussed. While prospects look bright for highly advanced and innovative future facilities, it will be important to ensure that human resources in observational astronomy and theory – both in terms of expertise, funding, and available positions – are keeping pace with the technological developments. This revised version was published online in August 2006 with corrections to the Cover Date.     

Arome,a balloon-borne instrument for astronomical near-infrared spectrophotometry

We present here the French balloon-borne experiment named AROME. This astronomical instrument is specifically designed for the detection of near infrared emission bands (=3–12m) from extended sources of low surface brightness with an angular resolution of 0.5°. The rms sensitivity achieved is of the order of 10^-8 Wm^-2sr^-1, in terms of the power radiated in the 3.3m band. We recall that this program led to the first detection of the 3.3m feature in the spectrum of the diffuse galactic emission. The scientific results were presented and interpreted in Paper I, Giard et al., 1989. Future work will include both the observation of fainter objects at 3.3m and the detection of other emission bands at 6.2 and 11.3m.     

An active fiber sensor for mirror vibration metrology in astronomical interferometers

We present a fiber sensor based on an active integrated component which could be effectively used to measure the longitudinal vibration modes of telescope mirrors in an interferometric array. We demonstrate the possibility to measure vibrations with frequencies up to ⋍100 Hz with a precision better than 10 nm (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Periodicity in the crater formation rate and implications for astronomical modeling

Claim for periodicity in the crater formation rate is reinvestigated using a criterion proposed by Broadbent, and data sets of Rampino and Stothers and of Grieve are shown to satisfy the periodicity criterion (P 30 Myr).On the other hand, currently observed impactors are mainly asteroids, while long and short periodic comets whose fluxes may vary by external disturbances occupy only a small fraction. Using a Monte Carlo simulation, constraints are obtained for the dispersion Q(Myr) from an exact periodicity and for the periodic components (F _tp) in the signals for their periodicity to be detected. It is found that for = 5, 6 and 7 Myr, F _tp, would have to be 40% or greater, 60% or greater and 80% or greater, respectively. These constraints are used to discuss whether the giant molecular cloud perturbations can give rise to the periodicity in the impact events. The amplitude of the solar Z-motion need to be some 100pc for = 6 Myr, which requires the periodic component (SP and LP comets, if the former originate from the latter) to be 60%, while for = 7 Myr, the periodic component need to be 80%. The GMC perturbation model consistent with the periodicity appears to be the one where the amplitude is 100pc and the periodic component - 60% of the impactors. If SP comets mainly originate from a source such as the hypothetical Kuiper belt, the GMC perturbation would not be consistent with the periodicity.     

The IPS work in Beijing astronomical observatory

This article describes the IPS work in the Beijing astronomical observatory including the hardware and software of the instrument and some theoretical research.The project is supported by the China National Nature Science Fundation under the program 49391400     

Distributed intelligence in an astronomical Distributed Sensor Network

The Telescope Alert Operations Network System (TALONS) was designed and developed in the year 2000, around the architectural principles of a distributed sensor network. This network supported the original Rapid Telescopes for Optical Response (RAPTOR) project goals; however, only with further development could TALONS meet the goals of the larger Thinking Telescope Project. The complex objectives of the Thinking Telescope project required a paradigm shift in the software architecture – the centralised intelligence merged into the TALONS network operations could no longer meet all of the new requirements. The intelligence needed to be divorced from the network operations and developed as a series of peripheral intelligent agents, distributing the decision making and analytical processes based on the temporal volatility of the data. This paper is presented as only one part of the poster from the workshop and in it we will explore the details of this architecture and how that merges with the current Thinking Telescope system to meet our project goals. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)