POLFAR and LOFAR-ERIC

For more than a decade, radio observation techniques have been entering an entirely new area of instrumentation, in which enormous telescope dishes are replaced by large numbers of small, simple antennas coupled together. Digital information technologies and high-speed Internet connections play a key role in this approach.

One example of this type of instrument is LOFAR (LOw Frequency ARray), currently the world’s largest system of radio telescopes located in different parts of Europe, including the Netherlands, Germany, Poland and Sweden. The system uses radio wave interference to observe radio sources and study the physical phenomena occurring within them. Observations are conducted at low frequencies (10–240 MHz), covering a previously unexplored part of the radio spectrum. The system currently comprises 53 stations connected by a very high-speed Internet link. Each LOFAR station consists of two antenna fields: Low-Band Antennas (LBA), which record radio signals in the 30–90 MHz range, and High-Band Antennas (HBA), operating in the 110–240 MHz range.

LOFAR was conceived and initiated by the radio astronomy community associated with the Dutch institute ASTRON, and the project dates back to the 1990s. Of the 53 stations operating in the LOFAR system, 38 are in the Netherlands, while the remaining 15 are located in Germany (6), Poland (3), Sweden (1), the United Kingdom (1), France (1), Ireland (1), Bulgaria (1) and Latvia (1). A station will be built in Italy in 2027, in Medicina, near Bologna. In 2028–2029, a second Italian station, in Noto in Sicily, and a station in Czechia will be built. Spain, Greece, Belgium and Ukraine have also expressed an interest in building stations.

The distribution of LOFAR stations across the continent is essential because it allows astronomical objects to be observed with very high angular resolution. In total, more than 100 thousand dipole antennas with receiving systems have been installed at the stations. By appropriately controlling signal delays (phases), they can operate as a single directional telescope or simultaneously observe multiple objects visible in different parts of the sky above the horizon.

LOFAR is often called a digital telescope, in which IT infrastructure and software play a key role in processing astrophysical information.

The collected data help make groundbreaking discoveries. In 2021–2026, several years of work by scientists from all stations made it possible to produce the most detailed and largest radio map of the Universe, containing more than 4.4 million objects, including approximately one million newly discovered objects. The observations enabled the detection of tens of thousands of galaxies similar to our Milky Way, even at the far reaches of the Universe.

National cooperation to support Poland’s participation in LOFAR formally began in 2007 with the establishment of the POLFAR consortium, which currently comprises 12 institutions.

All three Polish LOFAR stations, in Borówiec, Łazy and Bałdy, were built in 2013–2015 through the project ‘Construction of the Polish stations of the European LOFAR radio interferometer’, funded by the Ministry of Science and Higher Education (decision No. 6339/IA/158/2013.1).

Since 2015, Poland, with its three LOFAR stations in Borówiec, Łazy and Bałdy, has been part of the International LOFAR Telescope (ILT), now the Low Frequency Array European Research Infrastructure Consortium (LOFAR ERIC). In 2016–2026, Poland’s participation in the consortium was funded by the Ministry of Science and Higher Education through the project ‘Participation of the POLFAR consortium and the POLFARO working group in the European ILT structure’ (decision No. DIR/WK/2016/05 and agreement No. 2021/WK/02).

In 2023–2026, the first mandatory modernization of all European LOFAR stations (LOFAR 2.0), including the three Polish stations, was carried out within LOFAR ERIC. In Poland, the modernization was undertaken through the project ‘Participation of the POLFAR consortium and the POLFARO working group in the European ILT structure for 2021–2026’, funded by the Ministry of Science and Higher Education (agreement No. 2021/WK/02).