{"id":482252,"date":"2026-05-13T08:19:25","date_gmt":"2026-05-13T08:19:25","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/482252\/"},"modified":"2026-05-13T08:19:25","modified_gmt":"2026-05-13T08:19:25","slug":"astronomers-confirm-a-giant-3-3-million-light-year-radio-halo-in-a-galaxy-cluster-that-was-supposed-to-be-quiet","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/482252\/","title":{"rendered":"Astronomers Confirm a Giant 3.3-Million-Light-Year Radio Halo in a Galaxy Cluster That Was Supposed to Be Quiet"},"content":{"rendered":"

A team of astronomers has confirmed the presence of a giant radio halo extending across more than 3.3 million light-years inside the galaxy cluster RXCJ0232\u20134420<\/strong>. Using observations from the upgraded Giant Metrewave Radio Telescope (uGMRT)<\/strong> and South Africa\u2019s MeerKAT<\/strong> telescope, researchers identified diffuse radio emission on a scale rarely associated with a relatively calm cluster environment.<\/p>\n

The findings, published April 29 on the arXiv<\/strong> preprint server<\/strong>, strengthen the idea that large radio halos can exist even in systems that still preserve a cool core. According to the study led by Pralay Biswas from the National Center for Radio Astrophysics in Pune, the cluster displays characteristics of an intermediate dynamical state.<\/p>\n

RXCJ0232\u20134420<\/strong> was discovered in 2002 and had already drawn attention because earlier radio observations produced conflicting interpretations. Some studies described a compact mini-halo centered on one of the cluster\u2019s brightest galaxies, while others suggested that the diffuse emission stretched across much larger distances.<\/p>\n

Researchers Identify a Huge Structure Across the Full Cluster<\/p>\n

The new observations confirmed that the diffuse radio emission extends beyond 3.3 million light-years<\/strong> at every observed frequency. According to the research paper<\/a>, this establishes the existence of a genuine giant radio halo within RXCJ0232\u20134420<\/strong>. Astronomers also identified an eastern radio relic with an estimated linear size of around 980,000 light-years<\/strong>. The cluster itself contains two brightest cluster galaxies, known as BCG-A<\/strong> and BCG-B<\/strong>, separated by roughly 330,000 light-years.<\/p>\n

\"GiantGiant radio halo revealed in multiwavelength image of RXCJ0232\u20134420. Credit: arXiv\u00a0<\/p>\n

Previous observations had detected diffuse emission primarily around BCG-A, leading researchers to compare the source to a radio mini-halo. The broader structures revealed by uGMRT <\/a>and MeerKAT <\/a>changed that picture substantially.<\/p>\n

Spectral Analysis Points to a Highly Uniform Halo<\/p>\n

The study reports a spectral index of \u22121.17 for the radio halo<\/strong> and \u22120.85 for the eastern relic<\/strong>. These measurements help astronomers examine how radio emission<\/a> changes with frequency across the cluster. Researchers found that the e-folding radius of the halo\u2019s radio profile did not vary significantly with frequency. The study also found no signs of radial spectral steepening at different frequencies<\/p>\n

\"MeerkatuGMRT and MeerKAT observations of RXCJ0232\u20134420 revealing the cluster\u2019s giant radio halo and eastern radio relic. Credit: Researchgate<\/p>\n

The spectral maps showed very little change from one region to another, with most values ranging between about \u22121.0 and \u22121.3<\/strong>. As explained in the paper, these numbers are not especially steep for a radio halo linked to a cool-core cluster. The findings suggest that charged particles <\/strong>are likely being re-energized across much of the cluster, rather than only in a few isolated spots.<\/p>\n

X-Ray Analysis Points to a Gently Disturbed Cluster<\/p>\n

The team also examined how the cluster\u2019s radio and X-ray emissions were connected. Their analysis revealed a strong positive link between the non-thermal radio emission and the hot X-ray-emitting gas spread throughout the cluster<\/a>.<\/p>\n

Further X-ray and thermodynamic measurements suggested that the cluster is in an intermediate dynamical state. Although RXCJ0232\u20134420 still contains a cool core<\/strong>, the observations also uncovered signs of mild structural disturbance. That makes the system somewhat unusual, since giant radio halos are typically associated with clusters undergoing far more violent mergers.<\/p>\n","protected":false},"excerpt":{"rendered":"A team of astronomers has confirmed the presence of a giant radio halo extending across more than 3.3…\n","protected":false},"author":2,"featured_media":482253,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[270],"tags":[18,19,17,133,451],"class_list":{"0":"post-482252","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-space","8":"tag-eire","9":"tag-ie","10":"tag-ireland","11":"tag-science","12":"tag-space"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@ie\/116566292939872663","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/482252","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=482252"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/482252\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/482253"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=482252"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=482252"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=482252"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}