A new theoretical study suggests that Little Red Dots observed by the James Webb Space Telescope (JWST) could be black holes in rare, short-lived \u2013 but extremely volatile \u2013 nuclear bursts.<\/p>\n
A paper<\/a> by Yangyao Chen of Nanjing University and Houjun Mo of the University of Massachusetts reexamined a phenomena that has intrigued scientists since the JWST\u2019s debut<\/a>.<\/p>\n Astronomers have observed nearly 350 faintly-red objects that are particularly unusual for their apparent lack of x-ray, radio and infrared emission. They have a V-shaped spectrum, being bright in ultraviolet and optical light, but dim in between, as well as the broad emission lines associated with black hole activity.<\/p>\n Current theories posed that that the Little Red Dots \u2013 or LRDs \u2013 are primordial galaxies, or non-metallic primordial stars(also known as Population III stars), or even quasi-stars. The majority seem to have been formed 600 million years after the Big Bang, or 13.2 to 12.2 billion years ago.<\/p>\n Chen and Mo created a galaxy formation model built on the \u039bCDM cosmological framework reported in a previous study. Using this model to trace back over 13 billion years ago to what could have created the LDRs, black hole seeds were presented as a possible source.<\/p>\n Frantic feeding during the universe\u2019s infancy<\/p>\n Most of the black hole seeds observed in the model form at redshifts above 20 inside tiny \u201cmini-halos\u201d from the universe\u2019s first generation of stars, less than 200 million years after the Big Bang. However, these seeds are too small to power a LDR on their own.<\/p>\n But growth through super-Eddington accretion- where the seeds are feeding at up to ten times the theoretical maximum rate- during \u201cepisodic nuclear bursts\u201d as the researchers term it, could explain the origin of the LDRs.<\/p>\n \u201cOur model suggests that it is post-seeding growth, mainly through episodic nuclear bursts, that raises BH seeds to supermassive status,\u201d the researchers write in the paper.<\/p>\n These bursts are fast, violent periods of activity triggered by gravitational disturbances such as two galaxies merging. This leads to runaway black hole growth and intense star formation in a compact nuclear star cluster, producing the unique V-shaped spectrum. Younger stars produce blue UV light and super-Eddington black holes produce the red optical glow.<\/p>\n Around a billion years after the Big Bang at redshift 5, the black holes have grown to between 100,000 and 1 million solar masses through repeated nuclear bursts and can be visually identified as Little Red Dots.<\/p>\n There are likely many more LRDs, just out of JWST\u2019s range<\/p>\n Researchers were keen to highlight that the population emerged out of the framework independently: \u201cOur model is among the first to self-consistently include the formation of seeds and the BH-galaxy-halo co-evolution within a cosmological context, allowing the emergence of the LRD population as a natural outcome of the \u039bCDM paradigm, rather than a result of fine-tuning.\u201d<\/p>\n The future of the LRDs was found to be highly variable- some will have been swallowed into cluster galaxies by now. Others that developed in isolation will eventually resemble compact dwarf galaxies, or globular cluster-like objects. The model also predicted that there is a much larger population of less visible black holes in the violent growth phase, simply beyond JWST\u2019s current scope.<\/p>\n \u201cWe will present a detailed analysis of the connection between LRDs and present-day compact dwarf galaxies in a forthcoming paper,\u201d they conclude.<\/p>\n","protected":false},"excerpt":{"rendered":"A new theoretical study suggests that Little Red Dots observed by the James Webb Space Telescope (JWST) could…\n","protected":false},"author":2,"featured_media":490657,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[909,61,60,82,1337,29212],"class_list":["post-490656","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-astrophysics","tag-ie","tag-ireland","tag-science","tag-space-exploration","tag-telescopes"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/490656","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=490656"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/490656\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/490657"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=490656"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=490656"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=490656"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}