Results 31 to 40 of about 164,168 (293)

Spins of Supermassive Black Holes M87* and SgrA* Revealed from the Size of Dark Spots in Event Horizon Telescope Images

open access: yesAstronomy, 2023
We reconstructed dark spots in the images of supermassive black holes SgrA* and M87* provided by the Event Horizon Telescope (EHT) collaboration by using the geometrically thin accretion disk model. In this model, the black hole is highlighted by the hot
Vyacheslav Ivanovich Dokuchaev
doaj   +1 more source

Axions as hot and cold dark matter [PDF]

open access: yesJournal of Cosmology and Astroparticle Physics, 2014
The presence of a hot dark matter component has been hinted at 3 sigma by a combination of the results from different cosmological observations. We examine a possibility that pseudo Nambu-Goldstone bosons account for both hot and cold dark matter components.
Jeong, Kwang Sik   +2 more
openaire   +4 more sources

The Epoch of Reionization in Warm Dark Matter Scenarios [PDF]

open access: yesUniverse, 2021
In this paper we investigate how the Reionization process is affected by early galaxy formation in different cosmological scenarios. We use a semi-analytic model with suppressed initial power spectra to obtain the UV Luminosity Function in thermal Warm ...
M. Romanello, N. Menci, M. Castellano
semanticscholar   +1 more source

Forbidden frozen-in dark matter

open access: yesJournal of High Energy Physics, 2019
We examine and point out the importance of a regime of dark matter pro- duction through the freeze-in mechanism that results from a large thermal correction to a decaying mediator particle mass from hot plasma in the early Universe. We show that mediator
L. Darmé   +3 more
doaj   +1 more source

Hot new early dark energy [PDF]

open access: yesPhysical Review D, 2021
New early dark energy (NEDE) makes the cosmic microwave background consistent with a higher value of the Hubble constant inferred from supernovae observations.
Florian Niedermann, M. Sloth
semanticscholar   +1 more source

Light Dark Matter from Entropy Dilution

open access: yesJournal of High Energy Physics, 2020
We show that a thermal relic which decouples from the standard model (SM) plasma while relativistic can be a viable dark matter (DM) candidate, if the decoupling is followed by a period of entropy dilution that heats up the SM, but not the dark sector ...
Jared A. Evans   +4 more
doaj   +1 more source

The non-singular Trautman–Kopczyński big-bang model and a torsional spinor description of dark matter

open access: yesEuropean Physical Journal C: Particles and Fields, 2023
A view is taken up whereby the non-singular Trautman–Kopczyński big-bang creation of the Universe produced a highly torsional hot state at early stages of the cosmic evolution which particularly brought about the formation of a dark matter cloud.
J. G. Cardoso
doaj   +1 more source

Massive Dark Photons as Hot Dark Matter

open access: yesActa Physica Polonica B, 2022
Motivated by the growing interest in the existence of new massive gauge bosons, we suggest that massive dark photons A0 can be a consequence of a broken new abelian symmetry U(1)'X. Such a dark symmetry U(1)'D is afterwards supposed to be associated with the conservation of the weak number W belonging to the Weakling Interacting Slim Particles U(1)'W ...
openaire   +2 more sources

Cosmological axion and neutrino mass constraints from Planck 2015 temperature and polarization data

open access: yesPhysics Letters B, 2016
Axions currently provide the most compelling solution to the strong CP problem. These particles may be copiously produced in the early universe, including via thermal processes.
Eleonora Di Valentino   +5 more
doaj   +1 more source

Expanding Culturomics from Gut to Extreme Environmental Settings

open access: yesmSystems, 2021
With the advent of metagenomics, a quest began to identify the dynamics of the microbial communities in different ecological niches. Altogether, this has resulted in identification of microorganisms but is limited to only a small number of phylogenetic ...
Utkarsh Sood, Roshan Kumar, Princy Hira
doaj   +1 more source

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