相关论文: Heating the intergalactic medium by radiative deca…
Recent Chandra and Newton observations indicate that there are two-temperature components ($T \sim$ 8 keV, 0.8 keV) of the diffuse x-rays emitted from deep inside the center of Milky Way. We show that this can be explained by the existence…
We derive the evolution of the energy deposition in the intergalactic medium (IGM) by dark matter (DM) decays/annihilations for both sterile neutrinos and light dark matter (LDM) particles. At z > 200 sterile neutrinos transfer a fraction…
Based on the assumptions that a fraction of cluster dark matter is composed of degenerate neutrinos and they are in hydrostatic equilibrium with other matter, we predict a relation between the density profile and temperature of the cluster…
I point out that the sterile neutrinos suggested as candidates of "cool" Dark Matter will decay through their mixing with light neutrinos. This leads to an upper bound of about 200 keV on the mass of the sterile neutrinos, but might…
Measurements of the evolution with redshift of the number density of massive galaxy clusters are used to constrain the energy density of massive neutrinos and so the sum of neutrino masses $\sum m_\nu$. We consider a spatially-flat…
We calculate the thermochemical equilibrium of the diffuse interstellar medium, including ionization by a photon flux F_{nu} from neutrino decay. The main heating mechanism considered is photoelectrons from grains and PAHs. For the studied…
Solar, atmospheric and reactor neutrino experiments established that neutrinos are massive. It is quite natural then to consider neutrinos as candidate particles for explaining the dark matter in halos around galaxies. We study the…
We derived constraints on parameters of a radiatively decaying warm dark matter particle, e.g., the mass and mixing angle for a sterile neutrino, using Chandra X-ray spectra of a galaxy cluster 1E0657-56 (the ``bullet'' cluster). The…
We show that the existence of a degenerate halo of sterile neutrinos with rest mass of 17.4 keV near the Galactic Center can account for both the excess 8.7 keV emission observed by the $Suzaku$ mission and the power needed ($10^{40}$ erg…
Galaxy clusters have the potential to accelerate cosmic rays (CRs) to ultra-high energies via accretion shocks or embedded CR acceleration sites. CRs with energies below the Hillas condition will be confined within the cluster and will…
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 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 calculate the incoherent resonant and non-resonant scattering production of sterile neutrinos in the early universe. We find ranges of sterile neutrino masses, vacuum mixing angles, and initial lepton numbers which allow these species to…
Two lines of evidence indicate that active galaxies, principally radio galaxies, have heated the diffuse hot gas in clusters. The first is the general need for additional heating to explain the steepness of the X-ray luminosity--temperature…
A sterile neutrino with mass of several keV can account for cosmological dark matter, as well as explain the observed velocities of pulsars. We show that X-rays produced by the decays of these relic sterile neutrinos can boost the…
We derive analytic approximations for the neutrino luminosities and the heat capacities of neutron stars with isothernal nucleon cores as functions of the mass and radius of stars. The neutrino luminosities are approximated for the three…
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…
If sterile neutrinos exist and form halos in galactic centers, they can give rise to observational consequences. In particular, the sterile neutrinos decay radiatively and heat up the gas in the protogalaxy to achieve hydrostatic…
The dynamical mass of clusters of galaxies, calculated in terms of modified Newtonian dynamics, is a factor of two or three times smaller than the Newtonian dynamical mass but remains significantly larger than the observed baryonic mass in…
In this work, we compute the contribution from clusters of galaxies to the diffuse neutrino background. Clusters of galaxies can potentially produce cosmic rays (CRs) up to very-high energies via large-scale shocks and turbulent…