Results 61 to 70 of about 36,124 (299)
Frontiers in Astronomy and Space Sciences, 2017 The reionization of helium at z ~ 3 is the final phase transition of the intergalactic medium and supposed to be driven purely by quasars. The He ii transverse proximity effect—enhanced He ii transmission in a background sightline caused by the ionizing ...
Tobias M. Schmidt +8 more
doaj +1 more source
Crossing the Rubicon of Reionization with z ∼ 5 QSOs
The Astrophysical Journal, 2023 One of the key open questions in cosmology is the nature of sources that completed cosmological hydrogen reionization at z ∼ 5.2. High- z primeval galaxies have been long considered the main drivers of reionization, with a minor role played by high- z ...
Andrea Grazian +14 more
doaj +1 more source
Early Reionization by Miniquasars [PDF]
The Astrophysical Journal, 2004 Motivated by the recent detection by WMAP of a large optical depth to Thomson scattering -- implying a very early reionization epoch -- we assess a scenario where the universe was reionized by `miniquasars' powered by intermediate-mass black holes (IMBHs), the remnants of the first generation of massive stars.
S. P. Oh +5 more
openaire +6 more sources
Reionization after JWST: A photon budget crisis? [PDF]
Monthly Notices of the Royal Astronomical Society: LettersNew James Webb Space Telescope (JWST) observations are revealing the first galaxies to be prolific producers of ionizing photons, which we argue gives rise to a tension between different probes of reionization. Over the last two decades a consensus has
Julian B. Muñoz +4 more
semanticscholar +1 more source
RELICS: Reionization Lensing Cluster Survey [PDF]
Astrophysical Journal, 2019 Large surveys of galaxy clusters with the Hubble Space Telescope (HST) and Spitzer, including the Cluster Lensing And Supernova survey with Hubble and the Frontier Fields, have demonstrated the power of strong gravitational lensing to efficiently deliver
D. Coe +56 more
semanticscholar +1 more source
Simulating Reionization: Character and Observability [PDF]
, 2007 In recent years there has been considerable progress in our understanding of the nature and properties of the reionization process. In particular, the numerical simulations of this epoch have made a qualitative leap forward, reaching sufficiently large ...
Bond, J. Richard +5 more
core +6 more sources
Simulating the Cosmic Dawn With Enzo
Frontiers in Astronomy and Space Sciences, 2018 We review two decades of progress using the Enzo hydrodynamic cosmology code to simulate the Cosmic Dawn, a period of roughly 1 billion years beginning with the formation of the first stars in the universe, and ending with cosmic reionization.
Michael L. Norman +5 more
doaj +1 more source
Patchy Kinetic Sunyaev–Zel’dovich Effect with Controlled Reionization History and Morphology
The Astrophysical Journal, 2023 Using the novel semi-numerical code for reionization AMBER, we model the patchy kinetic Sunyaev–Zel’dovich (kSZ) effect by directly specifying the reionization history with the redshift midpoint z _mid , duration Δ _z , and asymmetry A _z .
Nianyi Chen +3 more
doaj +1 more source
Cosmic Reionization on Computers: Properties of the Post-reionization IGM [PDF]
The Astrophysical Journal, 2017 Abstract We present a comparison between several observational tests of the post-reionization intergalactic medium and the numerical simulations of reionization completed under the Cosmic Reionization On Computers (CROC) project. The CROC simulations match the gap distribution reasonably well, and also provide a good match for the ...
George D. Becker +3 more
openaire +4 more sources
Onset of Cosmic Reionization: Evidence of an Ionized Bubble Merely 680 Myr after the Big Bang [PDF]
Astrophysical Journal, 2020 While most of the intergalactic medium (IGM) today is permeated by ionized hydrogen, it was largely filled with neutral hydrogen for the first 700 million years after the big bang.
V. Tilvi +16 more
semanticscholar +1 more source