Related papers: Neutrino cooling effect of primordial hot areas in…
We investigate how sterile neutrinos with a range of masses influence cosmology in MeV-scale reheating temperature scenarios. By computing the production of sterile neutrinos through the combination of mixing and scattering in the early…
We study the effect of primordial black holes on the classical rate of nucleation of AdS regions within the standard electroweak vacuum. We find that the energy barrier for transitions to the new vacuum, which characterizes the exponential…
The spectrum of neutrinos produced by the outflow of high temperature matter surrounding microscopic black holes is calculated for neutrino energies between one GeV and the Planck energy. The results may be applicable for the last few hours…
We consider the cosmological effects of sterile neutrinos with the masses of $150- 450$ MeV. The decay of sterile neutrinos changes the thermal history of the Universe and affects the energy density of radiation at the recombination and the…
Dark matter freeze-in at stronger coupling is operative when the Standard Model (SM) bath temperature never exceeds the dark matter mass. An attractive feature of this scenario is that it can be probed by direct detection experiments as…
At times prior to Big Bang Nucleosynthesis, the universe could show a primordial structure formation period if dominated by a fast oscillating inflaton field during reheating. In this context, we have postulated a new mechanism of…
We consider the thermal effects into the evaluation of the dark matter production process. With the assistance of the right handed neutrinos, the freeze-in massive particle dark matter production history can be modified by the two-step…
We sketch the average behaviour of the temperatures and densities of the main components of the $\Lambda$CDM universe after inflation. It is modelled as a perfect fluid with dark energy associated with the macroscopic effect of conformal…
We calculate the structure of accretion disks around Kerr black holes for accretion rates 0.001 - 10 M_sun/s. Such disks are plausible candidates for the central engine of gamma-ray bursts. Our disk model is fully relativistic and treats…
Primordial black holes are a viable dark matter candidate. They decay via Hawking evaporation. Energetic particles from the Hawking radiation interact with interstellar gas, depositing their energy as heat and ionization. For a sufficiently…
Cold dark matter halos form within a smoothly distributed background of relic neutrinos -- at least some of which are massive and non-relativistic at late times. We calculate the accumulation of massive neutrinos around spherically…
We study the cooling of isolated neutron stars. The main cooling regulators are introduced: EoS, thermal transport, heat capacity, neutrino and photon emissivity, superfluid nucleon gaps. Neutrino emissivity includes main processes. A…
We study the dependence of the cooling of isolated neutron stars on the magnitude of the $3P_2$ neutron gap. It is demonstrated that our ``nuclear medium cooling'' scenario is in favor of a suppressed value of the $3P_2$ neutron gap.
Primordial Black Holes (PBH) could dominate in the early universe and, evaporating before Big bang Nucleosynthesis, can provide new freeze in mechanism of dark matter (DM) production. The proposed scenario is considered for two possible…
The expansion history and thermal physical process that happened in the early Universe before big bang nucleosynthesis (BBN) remains relatively unconstrained by observations. Low reheating temperature universes with normalcy temperatures of…
The sum of active neutrino masses is well constrained, $58$ meV $\leq m_\nu \lesssim 0.23$ eV, but the origin of this scale is not well understood. Here we investigate the possibility that it arises by environmental selection in a large…
The Hot Big Bang model predicts the existence of a \emph{cosmic neutrino background}. The number of particles and anti-particles in this primordial bath of neutrinos can be different -- a memory of processes that took place at very early…
The 21 cm signal produced by non-evaporating primordial black holes (PBHs) is investigated. X-ray photons emitted by accretion of matter onto a PBH ionize and heat the intergalactic medium (IGM) gas near the PBH. Using a simple analytic…
Neutrinos are produced in several neutrino nuclear reactions of the proton-proton chain and carbon-nitrogen-oxygen cycle that take place at different radius of the Sun's core. Hence, measurements of solar neutrino fluxes provide a precise…
The Hawking evaporation of ultra-light primordial black holes (PBH) dominating the early Universe before Big Bang Nucleosynthesis can potentially increase the effective number of extra neutrino species $\Delta N_\mathrm{eff}$ through the…