A new European search for extraterrestrial radio signals at low, unknown frequencies is underway, with more than 1.6 million galaxies already listened to.
SETI, the search for extraterrestrial intelligence, has traditionally focused on radio frequencies higher than a gigahertz, such as the hydrogen line frequency at 1.42 GHz. SETI astronomers tend to shy away from lower frequencies because the Earth’s atmosphere makes observations noisy.
However, the European Low Frequency Array, LOFAR for short, is specifically designed to perform radio astronomy on these frequencies.
Related: The Search for Extraterrestrial Life (reference)
LOFAR is a series of radio antennas covering hundreds of kilometers across Europe, centered in the Netherlands, but with additional stations in France, Germany, Ireland, Latvia, Poland, Sweden and the United Kingdom. The stations contain two types of antennas: low-band antennas that operate between 10 and 90 MHz, and high-band antennas that listen to the universe between 100 and 250 MHz.
In combination with the Breakthrough Listen SETI project, the LOFAR stations in Ireland and Sweden have been used in combination in the first part of Breakthrough Listen’s first-ever low-frequency search.
This search used the high-band antennas to listen for radio signals on frequencies between 110 and 190 MHz. The primary search is for leakage of powerful transmitters, such as planetary radar or communications with spacecraft. The search included 1,631,198 targets star systems identified by NASA Transiting exoplanet research satellite (TESS) and the European Space Agency‘S Gaia astrometric probe.
By using multiple locations in Ireland and Sweden, astronomers were able to negate the effects of radio frequency interference and quickly rule out any false positives. For example, if an anomalous signal were only noticed by one station and not by the others, there would be local interference. There’s just a signal coming from there room could be detected by all stations.
No narrowband radio signals with a characteristic frequency drift caused by the orbital motion of a exoplanet it hosted a transmitter that radiated signals with a power of at least tens of millions of watts. However, the search for low-frequency signals has only just begun and improvements in the coming years will increase its sensitivity.
“LOFAR will soon undergo a phased series of upgrades to all stations in the array across Europe, allowing for an even broader SETI at a range of 15-240 MHz,” says graduate student Owen Johnson of Trinity College Dublin, lead author of a new paper describing the results. rack.
These upgrades include two new LOFAR stations in Bulgaria and Italy. Computer software and artificial intelligence algorithms will also speed up the analysis of the results.
“We have billions of galaxies to explore and will rely on some of them machine learning techniques to sift through the vast amount of data,” Johnson said. “That in itself is interesting – it would be quite ironic if Humanity has discovered extraterrestrial life using artificial intelligence.”
The first results of the LOFAR SETI search were published on October 24 The astronomical magazine.
