Results 31 to 40 of about 26,451 (248)

Cosmological reionization [PDF]

AIP Conference Proceedings, 2001
The universe was reionized by redshift z ~ 6 by a small fraction of the baryons in the universe, which released energy following their condensation out of a cold, dark, and neutral IGM into the earliest galaxies. The theory of this reionization is a critical missing link in the theory of galaxy formation.
openaire   +2 more sources

Reionizing Islands with Inhomogeneous Recombinations

Research in Astronomy and Astrophysics, 2023
Abstract Observations are beginning to constrain the history of the epoch of reionization (EoR). Modeling the reionization process is indispensable to interpret the observations, to infer the properties of ionizing sources, and to probe the various astrophysical processes from the observational data.
Runyu 润玉 Zhu 朱, Yidong 怡冬 Xu 徐, Bin 斌 Yue 岳, Xuelei 学雷 Chen 陈   +3 more
openaire   +2 more sources

Impact of general reionization scenarios on extraction of inflationary parameters [PDF]

, 2010
Determination of whether the Harrison--Zel'dovich spectrum for primordial scalar perturbations is consistent with observations is sensitive to assumptions about the reionization scenario.
Alessandro Melchiorri, Asantha Cooray, Edward W. Kolb, Elena Giusarma, Manuel Peña, Massimiliano Lattanzi, Olga Mena, Paolo Serra, Stefania Pandolfi, Y. B. Zel’dovich   +9 more
core   +4 more sources

Polarity Asymmetries in Rocket‐Triggered Lightning

Geophysical Research Letters, Volume 50, Issue 17, 16 September 2023., 2023
Abstract The dissonant development of positive and negative lightning leaders is a central question in atmospheric electricity. It is also the likely root cause of other reported asymmetries between positive and negative lightning flashes, including the ones regarding: stroke multiplicity, recoil activity, leader velocities, and emission of energetic ...
C. L. da Silva, W. P. Winn, M. C. Taylor, G. D. Aulich, S. J. Hunyady, K. B. Eack, H. E. Edens, R. G. Sonnenfeld, P. R. Krehbiel, E. M. Eastvedt, J. J. Trueblood   +10 more
wiley   +1 more source

Cosmological reionization [PDF]

Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences, 2000
In popular cosmological scenarios, some time beyond a redshift of 10, stars within protogalaxies created the first heavy elements; these systems, together perhaps with an early population of quasars, generated the ultraviolet radiation and mechanical energy that reheated and reionized the cosmos.
openaire   +2 more sources

Statistical Detection of the He ii Transverse Proximity Effect: Evidence for Sustained Quasar Activity for >25 Million Years

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, Tobias M. Schmidt, Gabor Worseck, Joseph F. Hennawi, Joseph F. Hennawi, J. Xavier Prochaska, Neil H. M. Crighton, Zarija Lukić, Jose Oñorbe   +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, Konstantina Boutsia, Emanuele Giallongo, Stefano Cristiani, Fabio Fontanot, Manuela Bischetti, Angela Bongiorno, Giorgio Calderone, Guido Cupani, Valentina D’Odorico, Chiara Feruglio, Fabrizio Fiore, Francesco Guarneri, Matteo Porru, Ivano Saccheo   +14 more
doaj   +1 more source

Cosmological Parameters from Planck Data in SU(2)CMB, Their Local ΛCDM Values, and the Modified Photon Boltzmann Equation

Annalen der Physik, Volume 535, Issue 7, July 2023., 2023
Implications for the cosmological model are explored of the assumption that the cosmic microwave background is subject to an SU(2) Yang– Mills theory of scale 10−4 eV rather than U(1) quantum thermodynamics. This concerns zeroth‐order (changes at high redshifts) and first‐order cosmological perturbations (changes at high and low redshifts).
Ralf Hofmann, Janning Meinert, Shyam Sunder Balaji   +2 more
wiley   +1 more source

CMB Neutrino Mass Bounds and Reionization [PDF]

, 2010
Current cosmic microwave background (CMB) bounds on the sum of the neutrino masses assume a sudden reionization scenario described by a single parameter that determines the onset of reionization.
Alessandro Melchiorri, Asantha Cooray, Maria Archidiacono, Stefania Pandolfi, Y. B. Zel’dovich   +4 more
core   +2 more sources

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, Hy Trac, Suvodip Mukherjee, Renyue Cen   +3 more
doaj   +1 more source