This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Astronomers using the James Webb Space Telescope (JWST) have confirmed a massive, dust-rich galaxy called Leviathan in the early universe. Seen when the universe was roughly 1.5 billion years old, the galaxy has its stars spread out rather than in a concentrated fashion.
A paper, describing its strange stellar distribution, was posted to the arXiv preprint server on Oct. 19. Submillimeter galaxies are extremely luminous, dust-obscured galaxies, typically at redshifts around 2 to 3, forming stars at hundreds to thousands of solar masses per year. Dust absorbs their shorter-wavelength optical and ultraviolet light and re-emits it, which is detected at submillimeter wavelengths.
They are thought to be possible progenitors of massive quiescent galaxies (MQGs), which are today's massive elliptical galaxies. Studying them can test theories of how galaxies form, how many stars they contain and how efficiently they convert gas into stars. Insights from these galaxies can also explain how heavy their dark matter halos are.
Massive quiescent galaxies, which have stopped forming stars, are very compact when seen 11.5 to 12.5 billion years ago. With half-light radii of only about 0.2 to 1 kiloparsec, they hold tens of billions of the sun's mass in stars. This means their ancestors, which are thought to be submillimeter galaxies, must have built dense stellar cores very quickly.
Their dust emission is compact, with radii of about 1 to 2 kiloparsecs, but it shows only where stars are forming now, not where existing stars are. But now, JWST can detect galaxies' faint glow, which comes from stars. The team led by William M.
Baker of the University of Copenhagen has now investigated where the stars are located in a massive submillimeter galaxy and measured its mass. "Whether these galaxies are on the way to becoming compact MQGs therefore requires measuring where their stellar mass (not just their light) is located," the team writes in the paper. The team measured the mass and redshift of Leviathan, a massive submillimeter galaxy discovered in 2012.
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