Scientists are asking your help to find the origin of hundreds of thousands of galaxies that have been discovered by the largest radio telescope ever built: LOFAR. Where do these mysterious objects, which extend for thousands of light-years, come from? A new citizen science project called LOFAR Radio Galaxy Zoo gives anyone with a computer the exciting possibility to find out where the black holes at the centre of these galaxies are located.
Tuning the radio
Astronomers use radio telescopes to make images of the radio sky, much like optical telescopes such as the Hubble Space Telescope make maps of stars and galaxies. In the radio sky, stars and galaxies are not directly seen. Instead, an abundance of complex structures is detected that is linked to massive black holes at the centres of galaxies. Most dust and gas surrounding a supermassive black hole gets consumed by the black hole, but part of the material will escape and gets ejected into deep space. This material forms large plumes of extremely hot gas. With radio telescopes, astronomers are able to observe the large structures that are formed by this gas.
Discovering millions of radio sources
The Low Frequency Array (LOFAR) telescope, operated by the Netherlands Institute for Radio Astronomy (ASTRON), scans the radio sky in a huge survey. So far, the mission has resulted in four million newly discovered radio sources. A few hundred thousand of these have very complicated structures. They are so complicated that it is difficult to determine which galaxies belong to which radio source, or in other words, which black hole belongs to which galaxy.
Radio Galaxy Zoo: LOFAR is part of the Zooniverse project, the world's largest and most popular platform for people-powered research. This research is made possible by volunteers - more than a million people around the world who come together to assist professional researchers.
Your help is needed!
While the international LOFAR team consists of more than 200 astronomers from 18 countries, it is simply too small to take on this daunting task of identifying which radio structures belong to which host galaxy. Therefore, LOFAR astronomers are seeking help from the public. In the context of the citizen science project 'LOFAR Radio Galaxy Zoo', you are asked to look at images from LOFAR and compare these with images of known galaxies. Then you need to associate radio sources with galaxies. So far, 2600 volunteers already worked on the project.
How the public can help science
'LOFAR's new survey has revealed millions of previously undetected radio sources. With the help of the public we can investigate the nature of these sources: Where are their black holes? In what kind of galaxies are the black holes located?' says Huub Röttgering, LOFAR Director and Scientific Director of the Leiden Observatory.
Tim Shimwell, astronomer at ASTRON and Leiden University, explains why this is significant: 'Your task is to match the radio sources with the right galaxy,' he says. This newly obtained data can then be used by LOFAR astronomers. 'It will help us understand how radio sources are formed, how black holes evolve, and how vast quantities of material can be ejected into deep space with such unprecedented amounts of energy,' Shimwell concludes.
How it works
If you would like to contribute, visit the website of this citizen science project. Here you can find a tutorial, which explains all the steps from scratch. In addition, there is a tutorial video, which can be seen below.
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Header image: a radio galaxy overlaid on an optical image of the sky. Credits: Cyril Tasse and the LOFAR surveys team
Based on the ASTRON press release
