Scrutinizing Signals from the Universe
October 31, 2013
Poland is set to join an international radio astronomy system launched in the Netherlands in 2010 to study signals from the universe and observe objects that originated billions of years ago.
The system is called LOFAR and was designed and built by Astron, a Dutch agency that brings together a number of astronomy institutes. Another aim behind the project is to gain an insight into phenomena such as magnetic storms on the sun, solar winds and climate change on Earth.
LOFAR is short for Low Frequency Array and is essentially a huge radio telescope that performs observations of the cosmos in low frequencies. This new-generation radio telescope has been created to research the origin of the first galaxies, black holes and gas clouds at the birth of the universe.
Launched in June 2010, LOFAR comprises thousands of small antennas placed in stations in the Netherlands, Germany, Britain, France and Sweden. There are currently 36 stations in the Netherlands, six in Germany and one each in France, Sweden and Britain. Plans are afoot to build more stations in Poland and Italy.
In Poland, three stations will be built: in the Mazurian Lake District in the northeast of the country, near the southern city of Cracow, and not far from the western city of Poznań.
Polish consortium POLFAR will take part in the program, using a zl.26 million grant from Poland’s Science and Higher Education Minister Barbara Kudrycka—one of the highest research and development grants recently handed out by the science ministry and intended for research infrastructure.
Signals from billions of years ago
The light of the Sun takes eight minutes to reach the Earth. Light and other signals from the nearest star take a few years to reach the Earth. Signals from even more distant objects and galaxies take millions and even billions of years before they can be seen. Astronomers now want to observe objects that are so far away that the signals have traveled 13.7 billion years to reach Earth.
This is why Astron developed LOFAR, which consists of about 25,000 antennas. The Dutch government and the European Union as well as universities, research institutes and private businesses have contributed to the 100-million-euro project.
LOFAR consists of two types of antennas: Low Band Antennas, which perform observations between 10 and 90 MHz, and High Band Antennas, performing observations between 110 and 250 MHz.
The aim behind LOFAR is to receive signals from the universe that have never been previously examined, thus opening up a range of potential discoveries. The researchers want to observe objects that originated just after the Big Bang. They also hope to gain unique insights into phenomena closer to Earth: magnetic storms on the sun, solar winds and the way the climate influences the Earth. Moreover, LOFAR is expected to contribute to research in other fields, such as geophysics and agriculture.
All LOFAR stations are connected through fast glass fibers to a supercomputer at the University of Groningen in the Netherlands. This is where the data, received by the antennas, is processed.
The astronomers hope that they will manage to discover many new phenomena. The network can quickly produce maps of very large areas of the sky.
The project is based on a radio interferometer, an astronomical tool for the study of sources of radio radiation, such as active galactic nuclei and quasars. It utilizes the phenomenon of interference of radio waves received by at least two radiotelescopes, from which signals are fed to a common receiver.
The European interferometer is a new, unique instrument. Thanks to the innovative concept, radio astronomers will not only gain a new observation window, but will be able to study and monitor the space environment near the Earth.
Over the next few decades, LOFAR will work in the very low frequency range (10-240 MHz), so far poorly explored by radio astronomers.
The project will make it possible to study objects from the beginnings of the universe, such as radio-emitting clouds of hydrogen and protogalaxies. It will also make it possible to study the evolution of galaxies and their clusters as well as radio galaxies and quasars, in addition to offering the opportunity to study the properties of cosmic rays, solar activity, radio waves emitted by planets and the properties of the plasma around the Earth. Finally, it will make it possible to study a wide range of astronomical objects, including areas around black holes and neutron stars in binary systems.
An important feature of LOFAR will be the possibility of observing populations of low-energy electrons that are important for space plasma physics, but are poorly visible at higher frequencies. In turn, the physics of the Sun and the space around the Earth are important research topics for satellite technology.
Polish scientists could not take advantage of this unique research tool without their own stations. Thanks to funding from the Ministry of Science and Higher Education, the POLFAR consortium plans to build three stations from 2013 to 2015. The construction project at Ba³dy in the northeastern Warmia and Mazuria province is being coordinated by the University of Warmia and Mazuria. The project near Cracow is being coordinated by the Jagiellonian University in Cracow, and the project near Poznań by the Space Research Center of the Polish Academy of Sciences. These stations will be connected by means of an ultra-fast network with the Poznań center, and from there with the LOFAR headquarters in the Netherlands, thus ensuring integration of the Polish subnetwork with other stations in Europe.
The research program proposed by the Polish consortium includes new methods for correcting measurement data due to the influence of the ionosphere and the Earth’s atmosphere. These methods could become a Polish specialty in terms of the LOFAR program as a whole.
Construction of the three Polish stations—the easternmost components of LOFAR—will radically improve the capability of the entire system. The system’s antenna field will be used for experiments in soil physics, geophysics and satellite navigation. The Polish stations will be important to astrophysical studies and applied research.
The work of the POLFAR consortium is being coordinated by Prof. Katarzyna Otmianowska-Mazur from the Jagiellonian University. The Cracow university will deal with studies of galactic magnetic fields and their dynamic impact on rarefied interstellar and intergalactic plasma. Another coordinator of the project is Prof. Andrzej Krankowski from the University of Warmia and Mazuria in Olsztyn. That university will work with other centers on research into pulsars, the distribution of neutral hydrogen in the early universe, and a search for radio emissions from planets. The University of Warmia and Mazuria will also take part in commercial programs involving global navigation and local environment research.
In turn, the Nicolaus Copernicus University in Toruń plans to study the expiration and renewal of the activity of galactic nuclei, which is important for the properties of plasma around black holes. The Toruń branch also proposes research into the magnetosphere of giant planets in our solar system.
Meanwhile, the University of Zielona Góra will conduct research involving plasma physics in the vicinity of neutron stars; it will analyze the behavior of matter under the influence of strong magnetic fields.
The Space Research Center of the Polish Academy of Sciences in Warsaw will focus on plasma physics. The University of Szczecin will explore distant active galaxies and monitor the solar-type activity of cool dwarf stars. Biological life is possible on the planets of such stars.
The University of Environmental and Life Sciences in Wroc³aw is ready to contribute its expertise on global navigation programs and geodynamics research. The Institute of Bioorganic Chemistry of the Polish Academy of Sciences in Poznań will also join the project through the Poznań Supercomputing and Networking Center.