Bleien Radio Observatory is a

radio astronomy Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The first detection of radio waves from an astronomical object was in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation comin ...

observatory located halfway between Zurich and Bern in Switzerland. Its focus is on large

bandwidth Bandwidth commonly refers to: * Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range * Bandwidth (computing), the rate of data transfer, bit rate or thr ...

radio spectroscopy. The observatory is near the village of Bleien, 5 km south of

Gränichen Gränichen is a municipality in the district of Aarau of the canton of Aargau in Switzerland. Geography The river Wyna flows north at first and heads northwest thereafter. The valley has an average width of about . On both sides of the valley ...

in the Canton of Aargau. The place is in a shallow valley that is relatively well protected against terrestrial interference.

History

The observatory was built in 1979 by the Institute for Astronomy at ETH Zurich under the guidance of Prof. Dr.

Arnold O. Benz Arnold O. Benz (born 21 April 1945) is a professor emeritus at the Institute for Particle Physics and Astrophysics in the Physics Department of ETH Zurich. Education and career Benz was educated at ETH Zurich, where he was awarded a diploma in ...

. Since that time it consists of two parabolic antennae of 7 m and 5 m diameter separated by 100 m and a lab building containing the

spectrometer A spectrometer () is a scientific instrument used to separate and measure spectral components of a physical phenomenon. Spectrometer is a broad term often used to describe instruments that measure a continuous variable of a phenomenon where the ...

s and other electronics. For the first time, a fully digitized and remotely controlled receiver was used. Frequency-agile spectrometers were applied initially. Now digital filter banks and FFT ( Fast Fourier transform) spectrometers are in operation. The initial frequency range of 100 - 1000 MHz was enlarged to 10 MHz - 5 GHz. This range is the largest for solar radio observations since 2005. Starting in 2014, the observatory is being converted to observe preferentially non-solar radiation of extragalactic and cosmological origin.

Science

The primary goal was the observation of radio emissions of

solar flare A solar flare is an intense localized eruption of electromagnetic radiation in the Sun's atmosphere. Flares occur in active regions and are often, but not always, accompanied by coronal mass ejections, solar particle events, and other sol ...

s. The most significant contribution was the survey and classification at decimeter wavelength (

ultra high frequency Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter ( ...

). The data are crucial for investigating the acceleration of energetic

electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no ...

s in solar flares. The broad bandwidth was also used to study non-solar radio emissions of

gamma-ray burst In gamma-ray astronomy, gamma-ray bursts (GRBs) are immensely energetic explosions that have been observed in distant galaxies. They are the most energetic and luminous electromagnetic events since the Big Bang. Bursts can last from ten millise ...

s and to search for

fast radio burst In radio astronomy, a fast radio burst (FRB) is a transient radio pulse of length ranging from a fraction of a millisecond to 3 seconds, caused by some high-energy astrophysical process not yet understood. Astronomers estimate the average FRB rel ...

s, transients of possibly extragalactic origin. The solar data since 1979 and the instrument descriptions are stored at the Institute of 4D Technologies at Fachhochschule Nordwestschweiz FHNW in Windisch and are public. The Bleien Radio Observatory was the starting point of the international e-CALLISTO networke-CALLISTO, International Network of Solar Radio Spectrometers, http://www.e-callisto.org/ that surveys

solar activity Solar phenomena are natural phenomena which occur within the atmosphere of the Sun. These phenomena take many forms, including solar wind, radio wave flux, solar flares, coronal mass ejections, coronal heating and sunspots. These phenomena are ...

and

space weather Space weather is a branch of space physics and aeronomy, or heliophysics, concerned with the time varying conditions within the Solar System, including the solar wind, emphasizing the space surrounding the Earth, including conditions in the ...

24 hours per day in radio waves.

References

{{ETH Zurich Radio telescopes Solar observatories ETH Zurich Astronomical observatories in Switzerland