Reionization, as a research area, investigates the cosmic epoch during which the predominantly neutral intergalactic medium (IGM) produced after recombination was ionized by the first luminous sources, such as Population III stars, early galaxies, and possibly accreting black holes. It focuses on constraining the timing, morphology, and sources of ionizing radiation, as well as the feedback processes regulating early structure formation. Key observational probes include CMB optical depth measurements, high-redshift quasar spectra (Gunn–Peterson trough), Lyman-alpha emitters, and 21 cm tomography, while theoretical work employs radiative transfer, cosmological simulations, and semi-analytic models to connect reionization to galaxy formation and large-scale structure.
Astronomers have identified one of the most distant candidate galaxies known to leak ionizing radiation—the same kind of radiation thought to have transformed the early universe during the epoch of reionization.
Astronomers using NASA's Hubble Space Telescope have found something they never expected—ultraviolet light from a galaxy that existed just 1.4 billion years after the Big Bang. That galaxy contains tightly clustered young ...
Astronomy
Jun 23, 2026
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Astronomers have discovered a huge reservoir of cold molecular gas, the direct fuel for star formation, in REBELS-25, a massive, star-forming galaxy. The team, led from Leiden University, focused on REBELS-25, seen when the ...
Astronomy
Jun 11, 2026
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Cornell astronomers are deploying a new instrument that grants them, for the first time, a better view of the universe's earliest galaxies, which can't be observed individually with traditional ground- or space-based telescopes.
Astronomy
May 12, 2026
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The NASA/ESA/CSA James Webb Space Telescope has topped itself once again, delivering on its promise to push the boundaries of the observable universe closer to cosmic dawn with the confirmation of a bright galaxy that existed ...
Astronomy
Jan 28, 2026
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What was the universe like in the first few hundreds of millions of years after it came into existence? How did the first stars and galaxies form? Those are questions that astronomers now have a better chance of answering, ...
Astronomy
Sep 1, 2025
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A new theoretical study by University of Virginia astrophysicist Jonathan Tan, a research professor with the College and Graduate School of Arts & Sciences' Department of Astronomy, proposes a comprehensive framework for ...
Astronomy
Aug 12, 2025
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Our new study of the nearby starburst galaxy Haro 11 has shown that strong X-ray-emitting superwinds may be a key mechanism enabling galaxies to leak ionizing radiation, which is believed to have played a major role in the ...
NASA's SPHEREx (short for Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer) has turned on its detectors for the first time in space. Initial images from the observatory, which launched ...
Astronomy
Apr 1, 2025
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Astronomers have identified a bright hydrogen emission from a galaxy in the very early universe. The surprise finding is challenging researchers to explain how this light could have pierced the thick fog of neutral hydrogen ...
Astronomy
Mar 26, 2025
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