LOFAR seeks citizen scientists to hunt for black holes

Scientists are asking for the public’s help to locate the black holes at the centre of hundreds of thousands of galaxies discovered by the Low Frequency Array (LOFAR) radio telescope. The citizen science project, LOFAR Radio Galaxy Zoo, gives anyone with a computer the chance to get involved, and so far more than 4,000 volunteers have taken part.

Radio images show a sky that is very different from that seen by optical telescopes. In the radio sky, stars and galaxies are not directly visible. Instead, an abundance of complex structures linked to the supermassive black holes at the centres of galaxies are detected. For instance, most dust and gas surrounding a supermassive black hole gets consumed by the black hole, but some material will escape, forming large plumes of extremely hot gas. These large gas structures are observed by radio telescopes.

LOFAR, operated by the Netherlands Institute for Radio Astronomy (ASTRON) and celebrating its 10-year anniversary this month, has so far discovered four million radio sources in its ongoing sky survey. A few hundred thousand of these are such complicated structures that it is difficult to determine which galaxies they’re coming from – in other words, which black hole belongs to which galaxy?

From top: radio, optical and an overlay of the two images. Combining the data in this way enables the human eye to link radio sources with their host galaxies.

Credit: Aleksandar Shulevski, Erik Osinga & The LOFAR surveys team.

While a lot of radio data analysis can be automated using algorithms, so far no algorithm can identify shapes better than the human eye. The international LOFAR team consists of more than 200 astronomers from 18 countries, but that’s still not enough given the volume of images. That’s where the citizen scientists come in! By looking at images where optical and radio observations have been overlaid, they can help to work out which radio sources and galaxies go together.

“This will help researchers 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”, says Dr Tim Shimwell of ASTRON and Leiden University.

Radio Galaxy Zoo: LOFAR is part of the Zooniverse project, the world’s largest and most popular platform for people-powered research.

By ASTRON