Like its name, Latin for \u201cpoint\u201d or \u201cdot,\u201d Punctum is a compact, bright splotch of light in space\u2014but it\u2019s only visible at millimeter wavelengths and harbors an unusually organized magnetic field. A paper on Punctum has been accepted for publication in Astronomy & Astrophysics and is currently available on arXiv<\/a>.<\/p>\n The team wanted to show that Punctum is simply an unusual example of a known phenomenon, such as a magnetar or a supernova remnant. NGC 4945<\/a>, where Punctum lives, is a nearby galaxy known for hosting an active population of baby stars\u2014so it made sense to assume Punctum was one of them. After all, NGC 4945 resides so close to the Milky Way that astrophysicists thought they had a solid grasp of the galaxy. We couldn\u2019t have missed something \u201chiding in plain sight,\u201d as Shablovinskaia put it\u2026could we?\u00a0<\/p>\n But the more they tried to force Punctum into established astrophysical wisdom, the more it seemed to defy it. For example, Punctum disappeared when the team checked the same region using X-ray or radio telescopes, appearing only in the millimeter spectrum with the Atacama Large Millimeter\/submillimeter Array<\/a> (ALMA). ALMA\u2019s ability to capture polarized light also revealed Punctum\u2019s weird magnetic field to the scientists, adding to its mystery.<\/p>\n<\/p>\n \u201cSo we compared its brightness, polarization, and spectrum to every extreme object we could think of\u2014magnetars, pulsars, star-forming regions, and black hole jets,\u201d Shablovinskaia recalled. \u201cNothing matched.\u201d<\/p>\n But accepting that they\u2019d struck something entirely new only raised more questions. What exactly is it? Where does Punctum\u201410,000 to 100,000 times brighter than magnetars and 10 to 100 times brighter than most supernovas\u2014get its light? Could it be connected to a black hole or a neutron star?\u00a0<\/p>\n \u201cPunctum shows us the universe can still surprise us in places we thought we understood well.\u201d <\/p>\n For Shablovinskaia, the best shot at finding the answer might be to investigate Punctum\u2019s strange polarization, \u201cbasically a fingerprint of the magnetic environment,\u201d she said. After all, the disturbingly neat alignment of the light waves around Punctum was what alerted the team to the object\u2019s weirdness.<\/p>\n \u201cUsually, when light is produced in cosmic environments, it comes out mixed and disordered because the magnetic fields are tangled,\u201d she explained. \u201cIf we can measure [Punctum\u2019s magnetic field] at more wavelengths or watch how it changes over time, we can start to figure out what powers Punctum and whether it links to known astrophysical objects.\u201d<\/p>\n \u201cPunctum shows us the universe can still surprise us in places we thought we understood well,\u201d Shablovinskaia said. \u201cFor me, it\u2019s a reminder that astronomy is far from finished; we\u2019re still just beginning to discover the full variety of cosmic objects out there.\u201d<\/p>\n The new research marks another strong example of multi-messenger astronomy<\/a>, in which astronomers use different kinds of signals to investigate a single source. Recently, astronomers found an ultramassive black hole<\/a> using gravitational lensing. In this case, the scientists studied a specific behavior of light\u2014polarization\u2014alongside more conventional methods to double-check their results.\u00a0<\/p>\n","protected":false},"excerpt":{"rendered":"At first, the dot looked like any other star. Then the astrophysicists switched to polarized light and found…\n","protected":false},"author":2,"featured_media":354702,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3845],"tags":[5632,74,70,16,15],"class_list":{"0":"post-354701","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-physics","8":"tag-astrophysics","9":"tag-physics","10":"tag-science","11":"tag-uk","12":"tag-united-kingdom"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@uk\/115051002936410197","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts\/354701","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/comments?post=354701"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts\/354701\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/media\/354702"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/media?parent=354701"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/categories?post=354701"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/tags?post=354701"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"Punctum](\"https:\/\/www.europesays.com\/uk\/wp-content\/uploads\/2025\/08\/punctum-map-ngc-4945-e1755535549304.jpg\")
ALMA imaging of the galaxy NGC 4945. Punctum is the small dot inside the box. Credit: Elena Shablovinskaia et al., 2025 <\/p>\n