Several observational and theoretical arguments suggest that starburst galaxies may rival quasars as sources of metagalactic ionizing radiation at redshifts z > 3. Reionization of the intergalactic medium (IGM) at z > 5 may arise, in part, from the first luminous massive stars. To be an important source of radiative feedback from star formation, a substantial fraction (∼ 1− 10%) of the ionizing...

The observed extragalactic background light (EBL) is affected by light attenuation due to absorption of light by galactic and intergalactic dust in the Universe. Even galactic opacity of 10-20 percent and minute universe intergalactic opacity of 0.01 mag h Gpc ́1 at the local Universe have a significant impact on the EBL because obscuration of galaxies and density of intergalactic dust increase ...

We present templates for the Sunyaev-Zel’dovich (SZ) angular power spectrum based on four models for the nonlinear gas distribution. The frequency-dependent SZ temperature fluctuations, with thermal (TSZ) and kinetic (KSZ) contributions, are calculated by tracing through a dark matter simulation, processed to include gas in dark matter halos and in the filamentary intergalactic medium. Differen...

We present a schematic model for the formation of baryonic galactic halos and hot gas in the Local Group and the intergalactic medium. We follow the dynamics, chemical evolution, heat flow and gas flows of a hierarchy of scales, including: protogalactic clouds, galactic halos, and the Local Group itself. Within this hierarchy, the Galaxy is built via mergers of protogalactic fragments. Hot and ...

We investigate a cross-correlation between the weak gravitational lensing field of the largescale structure, κ, and the secondary temperature fluctuation field, ∆, of cosmic microwave background (CMB) induced by Thomson scattering of CMB photons off the ionized medium in the mildly nonlinear structure. The cross-correlation is expected to observationally unveil the biasing relation between the ...

Early photoionization of the intergalactic medium is discussed in a nearly model-independent way, in order to investigate whether early structures corresponding to rare Gaussian peaks in a CDM model can photoionize the intergalactic medium sufficiently early to appreciably smooth out the microwave background fluctuations. We conclude that this is indeed possible for a broad range of CDM normali...

Hydrodynamic simulations of growth of cosmic structure suggest that 30-50% of the total baryons at z = 0 may be in a warm-hot intergalactic medium (WHIM) with temperatures ∼ 10 − 10K. The O VI λλ1032, 1038 absorption line doublet in the FUV portion of QSO spectra provides an important probe of this gas. Utilizing recent hydrodynamic simulations, it is found that there should be ∼ 5 O VI absorpt...

We present a new constraint on the amount of dust in the intergalactic medium (IGM) at high redshift. We derive the thermal history of the IGM by taking account of the photoelectric heating by dust grains, and compare it with the thermal history suggested by observations of Lyman α forests. As a result, if the IGM grain size is & 100 Å, the dust-gas mass ratio of the IGM at z & 2 is . 1/100 Gal...

We show that spatial correlations in a stochastic large scale velocity field in an otherwise smooth intergalactic medium (homogeneous comoving density) superposed on the general Hubble flow, may cause a ‘line-like’ structure in QSO spectra similar to the population of unsaturated Lyα forest lines which usually are attributed to individual clouds with 10 ∼ NHI ∼ 5× 10 13 cm. Therefore there is n...