Volunteer black hole hunters as good as the experts
Trained volunteers are as good as professional astronomers at finding jets shooting from massive black holes and matching them to their host galaxies, according to new research.
Scientists working on citizen science project Radio Galaxy Zoo developed an online tutorial to teach volunteers how to spot black holes and other objects that emit large amounts of energy through radio waves.
The volunteers are given telescope images taken in both the radio and infrared part of the electromagnetic spectrum and asked to compare the pictures and match the “radio source” to the galaxy it lives in. The results from the first year of the Radio Galaxy Zoo project, led by Dr Julie Banfield of the ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO) at the Australian National University (ANU) and Dr Ivy Wong from the International Centre for Radio Astronomy Research (ICRAR), were published today in Monthly Notices of the Royal Astronomical Society.
Before unleashing the eager crowd of online volunteers, the research team tested the same 100 images on both the trained citizen scientists and an expert team of ten professional astronomers.
“With this early study we’ve comfortably shown that anyone, once we’ve trained them through our tutorial, are as good as our expert panel,” said Dr Banfield.
‘The volunteers have already ‘eyeballed’ more than 1.2 million radio images from the Very Large Array in New Mexico, CSIRO’s Australia Telescope Compact Array, and infrared images from NASA’s Spitzer and WISE Space Telescopes."
In one year, the citizen scientists managed to match 60,000 radio sources to their host galaxy – a feat that would have taken a single astronomer working 40 hours a week roughly 50 years to complete.
“In the upcoming all-sky radio surveys, we are expecting 70 million sources – 10% of which will not be classifiable by any of the computer algorithms currently available,” added Dr Wong.
“These 10 per cent will have weird and complex structures that need a human brain to interpret and understand rather than a computer program.”
‘We have asked our volunteers to identify 170,000 radio sources that are most likely to have unusual structures using current datasets, so we are better prepared for what we could find in the upcoming next generation radio surveys.”
At Radio Galaxy Zoo, professional astronomers talk to the participants every day on a dedicated forum and often ask them to look out for objects of interest.
“One member of the Radio Galaxy Zoo science team in Mexico loves looking for ‘giants’—jets longer than a megaparsec, or about 125 times the distance from Earth to the centre of the Milky Way. These are typically very, very old radio jets.” Dr Wong said.
Optical and radio images of Centaurus A reveal the complex morphology of the galaxy. Optical images show the galaxy's centre, filled with the bright light of trillions of stars and the band of dust. Radio images show the true extent of the enormous gas plumes being ejected from the galaxy's black hole.
Movie production by Dr Julie Banfield (CAASTRO, ANU), based on Dr Ilana Feain's idea
Dr Banfield is part of “The Evolving Universe” research theme of the Australian Research Council Centre of Excellence for All-sky Astrophysics (CAASTRO). Follow CAASTRO on Twitter
Dr Ivy Wong is based at the UWA node of the International centre for Radio Astronomy Research (ICRAR), a joint venture between Curtin University and The University of Western Australia with support and funding from the State Government of Western Australia.
The new work appears in ‘Radio Galaxy Zoo: host galaxies and radio morphologies derived from visual inspection’, J. K. Banfield et al, Monthly Notices of the Royal Astronomical Society, Oxford University Press.
Dr Julie Banfield
Dr Ivy Wong
Dr Wiebke Ebeling
Notes for editors
Radio Galaxy Zoo is an online project in which citizen scientists are helping scientists identify galaxies hosting jet-emitting massive black holes.
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