Latest News Archive

Please select Category, Year, and then Month to display items
Previous Archive
28 October 2019 | Story Leonie Bolleurs | Photo Anja Aucamp
Dr Brain van Soelen and Prof Pieter Meintjies
UFS scientists, Prof Pieter Meintjes and Dr Brian van Soelen, are part of the prestigious H.E.S.S. collaboration that recently published in Nature Astronomy.

Think of an object with a mass exceeding that of the Sun, squeezed into a volume of a sphere with the radius of a city like Bloemfontein. This very dense, compact object, known as a pulsar, is also a great source of energy. According to Physics Professor, Prof Pieter Meintjes, this pulsar (neutron star produced in supernova explosion) is also a key element of a recently submitted paper in Nature Astronomy.

Prof Meintjes and Dr Brian van Soelen, Senior Lecturer, both from the Department of Physics at the University of the Free State (UFS), were part of the High Energy Stereoscopic System (H.E.S.S.) collaboration of 220-plus scientists worldwide who worked on the paper Resolving the Crab pulsar wind nebula at tera-electronvolt energies, published in the prestige journal Nature Astronomy. 

According to Prof Meintjes, the fact that the paper was accepted for publication in Nature Astronomy testifies of the importance of this finding in the high-energy astrophysics community.

Powerful generators of electricity

He elaborates on the study: “The name pulsar originates from the fact that rotating neutron stars produced in supernova explosions produce beams of radiation, much like a lighthouse. Every time the beam intersects the observer’s line of sight, the observer receives a pulse of radiation.”

“As a result of this enormous mass squeezed into a small volume, these objects have the same density as that of an atomic nucleus. These objects (very dense pulsars) spin very rapidly and have enormous magnetic fields; for example, the pulsar at the centre of the Crab Nebulae spins around its axis once every 33 milliseconds (millisecond: one thousandth of a second) and possesses a magnetic field strength of the order of one tera-Gauss (tera – million x million). For comparison, the average strength of the Earth’s magnetic field is 0.5. Gauss and the magnetic field strength on the Sun ranges between 1 000 and 4 000 Gauss.”

“Because of this very super-strong rapid-spinning magnet, enormous electric fields are induced that can accelerate particles such as electrons and protons to energies in excess of one tera-electronvolt (optical light that are emitted by an ordinary lightbulb has energies of the order of one electronvolt).”

Prof Meintjes continues: “This means that these fast-rotating neutron stars are extraordinary powerful generators of electricity, which fills the surrounding cloud (supernova remnant) with super-high energy-charged particles that can produce, in turn, very high energy gamma rays through various processes such as synchrotron radiation and inverse-Compton radiation, to name a few.”

H.E.S.S. collaboration 

Above one tera-electronvolt, the gamma rays are detected by huge ground-based telescopes such as H.E.S.S., utilising the Earth’s atmosphere.

“When these high-energy gamma rays enter the atmosphere, they produce showers of super-relativistic particles that produce Cherenkov light – detected by the telescope. The technique is called the Atmospheric Cherenkov Technique (ACT).”

HESS
The High Energy Stereoscopic System. (Photo: Supplied)

“The H.E.S.S. gamma-ray collaboration is but one collaboration that has studied this source intensively over the past couple of decades or so.  Being the most powerful gamma-ray telescope facility currently operational, very careful analysis of the data managed to reveal that the gamma-ray emitting region inside the nebula is about 10 times bigger in size than the region where the x-rays are emitted within the nebula.” 

“This has solved a long-standing question as to how big the gamma-ray emitting region within these supernova remnants are, compared to the region where the x-rays, for example, originates,” says Prof Meintjes. 

Both Prof Meintjes and Dr Van Soelen are members of this prestigious H.E.S.S. collaboration. Their participation in this project, together with scientists from universities such as the University of Oxford, the University of Leicester, and the University of Bordeaux, opens up valuable research opportunities for UFS postgraduate students to enter the international stage and interact with the best scientists in the world.

They are also members of the editorial board responsible for the internal review of research papers before being submitted to more prestigious journals, for example, Nature Astronomy. Dr Van Soelen is also a coordinator of multi-wavelength follow-up observations within the H.E.S.S. collaboration. 

This is the second time that Prof Meintjes published in Nature Astronomy. Previously, he was co-author of a paper on emission from a white dwarf pulsar, showing that fast-rotating white dwarf stars could in fact mimic emission from neutron star pulsars. He developed the theoretical model reported in that paper, explaining the multi-wavelength emission from radio to X-ray energies.


News Archive

Launch of the Africa office of the IIDE
2006-05-25

Attending the launch of the Africa office of the IIDE were from the left Prof Sytse Strijbos (Chairperson of IIDE Europe), Rev Kiepie Jaftha (Chairperson of the IIDE in Africa’s Board of Directors and Chief Director: Community Service at the UFS) and Prof Frederick Fourie (Rector and Vice-Chancellor of the UFS).

 

Attending the launch were from the left Prof Lucius Botes (Director: Centre of Development Support at the UFS), Dr Samuel Kareithi (Head: Community Development at the Cornerstone Christian College, Cape Town), Rev Kiepie Jaftha (Chairperson of the IIDE in Africa’s Board of Directors and Chief Director: Community Service at the UFS), Prof Sytse Strijbos (Chairperson of IIDE Europe) and Dr Ezekiel Moraka (Vice-Rector:  Student Affairs at the UFS).

Africa office of IIDE launched on UFS main campus 

The Africa office of the International Institute for Development and Ethics (IIDE) was today (26 May 2006) launched on the Main Campus of the University of the Free State (UFS) in Bloemfontein.

“The IIDE specialises in the studying and research of general questions of developmental theory and practices and provides services and support in education, strategic planning, policy formulation, advocacy and capacity building of development agencies,” said Rev Kiepie Jaftha, Chairperson of the IIDE in Africa’s Board of Directors and Chief Director: Community Service at the UFS.

According to Rev Jaftha the IIDE in Africa will focus on the conceptual and normative aspects of developmental processes in Sub-Saharan Africa.  “We want to foster local and international partnerships with various relevant role-players in civil society, the private sector and public sector in the SACD region and later expand our operations to the rest of Africa,” said Rev Jaftha.

The IIDE in Africa cooperates with a similar foundation in Europe, functioning as the IIDE Europe.  This institute was founded in 2003 and its head office is situated in the Netherlands.  The UFS is a funder of the IIDE in Africa together with the Paul Foundation and private sponsors from the Netherlands.

“We have already started with various projects which are in various stages of implementation,” said Rev Jaftha.  Some of these projects include, among others, the broadening of the master’s degree in Christian Studies of Science and Society (MACSSS) which is currently housed at the Vrije Universiteit in Amsterdam to tertiary institutions in South Africa such as the UFS, the University of Stellenbosch and the Potchefstroom Campus of the Northwest University.

“Another project is an investigation into the possibility of initiating a broad development initiative in the poverty stricken Qwaqwa area.  This initiative will attempt to concentrate on issues like the training and empowerment of prospective entrepreneurs in the region, the identification of prospective entrepreneurs for the rendering of development support and the monitoring of the impact of information and communication technology on local communities during the implementation of sustainable development initiatives,” said Rev Jaftha.

“The establishment of the Africa office of the IIDE on the UFS Main Campus is an indication of one of the aims of the UFS to play a role in South Africa and Africa.  It also signifies our aim to contribute meaningfully to research and development and to establish links between the academe and practice,” said Rev Jaftha. 

 

Media release
Issued by: Lacea Loader
Media Representative
Tel:   (051) 401-2584
Cell:  083 645 2454
E-mail:  loaderl.stg@mail.uovs.ac.za
26 May 2006

We use cookies to make interactions with our websites and services easy and meaningful. To better understand how they are used, read more about the UFS cookie policy. By continuing to use this site you are giving us your consent to do this.

Accept