Related papers: Intergalactic medium heating by dark matter
The intergalactic medium is expected to be at its coldest point before the formation of the first stars in the universe. Motivated by recent results from the EDGES experiment, we revisit the standard calculation of the kinetic temperature…
A numerical calculation of properties of finite absorbers and of intergalactic medium based on photoionization equilibrium is performed to confront alternative UV sources in addition to quasars. It is seen that a spectrum including a large…
We propose the radiative decay of sterile neutrinos which fill a fraction of the halo dark matter with a mass of 27.4 eV and lifetime of $\sim 10^{22}$ sec. as a way to explain the observed diffuse ionization in the Milky Way galaxy. Since…
In the early universe, neutrinos decouple from equilibrium with the electromagnetic plasma at a temperature which is only slightly higher than the temperature where electrons and positrons annihilate. Therefore neutrinos to some extent…
The physical characteristics of the Lyman-alpha forest cloud systems are combined with observations on the baryonic mass density of the Universe and constraints from primordial nucleosynthesis to set boundary conditions on the Intergalactic…
We examine the hypothesis of decaying heavy dark matter (HDM) in the context of the IceCube highest energy neutrino events and recent limits on the diffuse flux of high-energy photons. We consider dark matter (DM) particles $X$ of mass…
The simplest model that can accomodate a viable nonbaryonic dark matter candidate is the standard electroweak theory with the addition of right-handed or sterile neutrinos. We reexamine this model and find that the sterile neutrinos can be…
Dark Matter in Earth intersecting orbits can scatter off the electrons and lose energy, and finally be gravitationally bound to Earth. Eventually they lose enough energy and accumulate at the core. It is assumed that DM annihilates/decays…
We propose a simple mechanism of light dark matter (DM) production from the decay of the oscillating inflaton condensation. If the reheating temperature after inflation is higher than the inflaton mass, which is of the same order of the…
It has been suggested that a sterile neutrino \nu_s which mixes with standard neutrinos can form nonthermal ``cool'' Dark Matter if its mass and mixing angle fall in the ranges 0.1 keV \lsim m_s \lsim 10 keV and 10^{-10} \lsim \sin^2 \theta…
We investigate the particle production from thermal gravitational annihilation in the very early universe, which is an important contribution for particles that might not be in thermal equilibrium or/and only have gravitational interaction,…
We consider the Standard Model (SM) extended by a secluded $U(1)_D$ gauge sector encompassing a Dirac fermion ($\chi$) dark matter (DM), an abelian gauge boson $Z^\prime$ and a SM-singlet complex-scalar field $\Phi$, whose radial component…
Joint analysis of the results of the Neutrino-4 experiment and the data of the GALLEX, SAGE and BEST experiments confirms the parameters of neutrino oscillations declared by the Neutrino-4 experiment $(\Delta m_{14}^2= 7.3 \text{eV}^2$ and…
Primordial black holes (PBHs) have been explored as potential dark matter candidates, with various astrophysical observations placing upper limits on the fraction $f_\mathrm{PBH}$ of dark matter in the form of PBHs. However, a largely…
A possible explanation of the present discrepancy between the abundance of galactic subhaloes predicted by N-Body simulations with those observed in the Local Group is presented. We study the impact of an early reionization on the baryonic…
Interstellar chemistry is important for galaxy formation, as it determines the rate at which gas can cool, and enables us to make predictions for observable spectroscopic lines from ions and molecules. We explore two central aspects of…
We revisit the phenomenon of elements diffusion in the intergalactic medium (IGM) in clusters of galaxies. The diffusion is driven by gravity, concentration and temperature gradients. The latter cause thermal diffusion, which has been so…
The interstellar medium (ISM) of galaxies very often contains a gas component that reaches the temperature of several million degrees, whose physical and chemical properties can be investigated through imaging and spectroscopy in the…
The cold dark matter may be in a meta-stable state and decays to other particles with a very long lifetime. If the decaying products of the dark matter are weakly interacting, e.g. neutrinos, then it would have little impact on…
We present measurements of the intergalactic medium (IGM) temperature within ~5 proper Mpc of seven luminous quasars at z~6. The constraints are obtained from the Doppler widths of Lyman-alpha absorption lines in the quasar near-zones and…