相关论文: HI absorption from the epoch of reionization and p…
The implication of primordial magnetic-field-induced structure formation for the HI signal from the epoch of reionization is studied. Using semi-analytic models, we compute both the density and ionization inhomogeneities in this scenario.…
We study the implications of primordial magnetic fields for the thermal and ionization history of the post-recombination era. In particular we compute the effects of dissipation of primordial magnetic fields owing to ambipolar diffusion and…
Primordial magnetic fields (PMF) damp at scales smaller than the photon diffusion and free-streaming scale. This leads to heating of ordinary matter (electrons and baryons), which affects both the thermal and ionization history of our…
Primordial magnetic fields generated in the early universe are subject of considerable investigation, and observational limits on their strength are required to constrain the theory. Due to their impact on the reionization process, the…
We study the absorption along lines of sight toward high-z radio sources caused by the 21 cm transition of neutral hydrogen in the intergalactic medium (IGM) before reionization. Using semi-analytic methods, we compute the number density of…
We explore the ways in which primordial magnetic fields influence the thermal and ionization history of the post-recombination universe. After recombination the universe becomes mostly neutral resulting also in a sharp drop in the radiative…
We recently predicted the existence of random primordial magnetic fields (RPMF) in the form of randomly oriented cells with dipole-like structure with a cell size $L_0$ and an average magnetic field $B_0$. Here we investigate models for…
The fluid forces associated with primordial magnetic fields (PMFs) generate small-scale fluctuations in the primordial density field, which add to the $\mathrm{\Lambda CDM}$ linear matter power spectrum on small scales. These enhanced…
The signs of an expanding atmosphere of HD209458b have been observed with far-ultraviolet transmission spectroscopy and in the measurements of transit absorption by metastable HeI. These observations are interpreted using the hydrodynamic…
We present the first gas dynamical simulations of the photoevaporation of cosmological minihalos overtaken by the ionization fronts which swept through the IGM during reionization in a LCDM universe, including the effects of radiative…
We present the first measurements of inter-subband absorption of microwaves in surface electrons on liquid helium subjected to perpendicular magnetic field B. In quantizing B, the power absorption shows intermittent regions of enhanced and…
The magnetic fields of the solar system planets provide valuable insights into the planets' interiors and can have dramatic consequences for the evolution of their atmospheres and interaction with the solar wind. However, we have little…
We investigate the all-sky signal in redshifted atomic hydrogen (HI) line from the reionization epoch. HI can be observed in both emission and absorption depending on the ratio of Lyman-$\alpha$ to ionizing flux and the spectrum of the…
We present the first gas dynamical simulations of the photoevaporation of cosmological minihalos overtaken by the ionization fronts which swept through the IGM during reionization in a LCDM universe, including the effects of radiative…
The interaction between electromagnetic microwaves (40-200 GHz) and superfluid helium in a stationary electric field has been investigated experimentally. It is found that the narrow line of resonance absorption at the roton frequency is…
We investigate the modification in the optical properties of laser-excited bulk cobalt and nickel using the time-dependent density functional theory at a finite electron temperature. As a result of the first-principles simulation, a complex…
We present a summary of recent studies of HI absorption in radio galaxies. The results show how the absorption can be due to a variety of phenomena and how they can help us in understanding more of what is happening in and around AGNs.
Absorption due to HeII Ly-alpha has been detected at low resolution in the spectra of four quasars between redshifts z = 2.74-3.29. We assess these observations, giving particular attention to the radiative transfer of the ionizing…
We explore some particle physics implications of the growing evidence for a helical primordial magnetic field (PMF). From the interactions of magnetic monopoles and the PMF, we derive an upper bound on the monopole number density, $n(t_0) <…
We use three dimensional radiation magneto-hydrodynamic simulations to study the effects of magnetic fields on the energy transport and structure of radiation pressure dominated main sequence massive star envelopes at the region of the iron…