---
title: "Radio Galaxy Zoo"
chunk: 2/3
source: "https://en.wikipedia.org/wiki/Radio_Galaxy_Zoo"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T04:15:44.023207+00:00"
instance: "kb-cron"
---

ii) Radio Galaxy Zoo: discovery of a poor cluster through a giant wide-angle tail radio galaxy. (May 2016)
The abstract begins: "We have discovered a previously unreported poor cluster of galaxies (RGZ-CL J0823.2+0333) through an unusual giant wide-angle tail radio galaxy found in the Radio Galaxy Zoo project." It continues to explain that the analysis of 2MASX J08231289+0333016's surrounding environment indicates that it is within a poor cluster. Radio morphology suggests that, firstly, "the host galaxy is moving at a significant velocity with respect to an ambient medium like that of at least a poor cluster" and secondly that "the source may have had two ignition events of the active galactic nucleus with 10^7yrs in between." These suggestions reinforce the idea that there is an association between RGZ J082312.9+033301 and the newly discovered poor cluster.
On The Conversation website in an article "How citizen scientists discovered a giant cluster of galaxies", Ray Norris writes about the above study. He explains that two Russian citizen scientists (CSs), Ivan Terentev and Tim Matorny, were participating in RGZ when they noticed something odd with one of the radio sources. It became clear that the radio source the two CSs had found "was just one of a line of radio blobs that delineate a C-shaped “wide angle tail galaxy” (WATG)." Lead scientist Julie Banfield explained that this was "something that none of us had even thought would be possible."
WATGs are rare objects that are formed when jets of electrons from black holes, usually seen to be straight, are bent into a C shape by intergalactic gas. This characteristic shape is "a sure sign that there is intergalactic gas, signifying a cluster of galaxies, the largest known objects in the universe." The WATG discovered by Terentev and Matorny is one of the largest known and has led to the cluster being named after them. "This cluster, more than a billion light years away, contains at least 40 galaxies, marking an intersection of the sheets and filaments of the cosmic web that make up our universe." Clusters, despite their importance, are hard to find but the use of WATGs might be a way of finding more: However WATGs are rare.
On the National Radio Astronomy Observatory website, Matorny and Terentev commented on their discovery. “I am still amazed and feel more motivated to look for stunning new radio galaxies,” Matorny said. Terentev added, “I got a chance to see the whole process of science … and I have been a part of it!”
iii) Radio Galaxy Zoo: A Search for Hybrid Morphology Radio Galaxies. (December 2017)
The abstract begins: "Hybrid morphology radio sources are a rare type of radio galaxy that display different Fanaroff-Riley classes on opposite sides of their nuclei." The authors explain that RGZ has enabled them to discover 25 new candidate hybrid morphology radio galaxies (HyMoRS). These HyMoRS are at distances between redshifts z=0.14 and 1.0. Nine of the host galaxies have previous spectra and include quasars and  a rare Green bean galaxy. It states: "Although the origin of the hybrid morphology radio galaxies is still unclear, this type of radio source starts depicting itself as a rather diverse class." The abstract ends:"While high angular resolution follow-up observations are still necessary to confirm our candidates, we demonstrate the efficacy of the Radio Galaxy Zoo in the pre-selection of these sources from all-sky radio surveys, and report the reliability of citizen scientists in identifying and classifying complex radio sources."
In an article on the ARC Centre of Excellence for All-Sky Astrophysics CAASTRO website named "Citizen scientists bag a bunch of 'two-faced' galaxies", the author explains the findings of the above study. The lead scientist is Anna Kapinska with CS Ivan Terentev named second. Kapinska's team have been looking for rare types of galaxies named Hybrid Morphology Radio Galaxies (HyMoRS). These show galaxy characteristics that are combined, rather than distinct. The article states: "Finding more HyMoRS helps us understand what kind of galaxy can turn out this way, and what gives them their unusual properties. Knowing that, in turn, helps us better understand how all galaxies evolve."
The first recognised HyMoRS was discovered in 2002 and since then 30 more. RGZ near doubled the discoveries by adding 25 more. Galaxies with black holes that produce jets are often "divided into two classes, Fanaroff-Riley I and Fanaroff-Riley II (or FR I and II). FR I galaxies have jets that fade away as they extend outwards, while FR II galaxies have jets that end in a bright, strongly-emitting region (a ‘hotspot’)." Explanations include the behaviour of the central black hole, different densities of matter in the surrounding environment or simply illusions because of different distances.
iv) Radio Galaxy Zoo: Cosmological Alignment of Radio Sources (November 2017)