We have performed a detailed statistical study of the evolution of structure in a photoionized intergalactic medium (IGM) using analytical simulations to extend the calculation into the mildly non-linear density regime found to prevail at z = 3. Our work is based on a simple fundamental conjecture: that the probability distribution function of the density of baryonic diffuse matter in the unive...

We investigate the effect of accreting primordial black holes (PBHs) on thermal history intergalactic medium (IGM), including accretion baryonic matter and dark particles. The variations IGM caused by PBHs will result in changes global 21-cm signal cosmic dawn. Based detection EDGES, requiring differential brightness temperature, e.g., $\delta T_{21} \lesssim -100~(-50)~\rm mK$, we obtain upper...

Abstract Dark matter energy injection in the early universe modifies both ionization history and temperature of intergalactic medium. In this work, we improve CMB bounds on sub-keV dark extend previous from Lyman-α observations to same mass range, resulting new competitive constraints axion-like particles (ALPs) decaying into two photons. The limits depend underlying reionization history, here ...

This article reviews the life and death of a scientific theory 1. The MACHO Ideology 1.1. The Dawn of Dark Matter The hypothesis of dark matter is often ascribed to Fritz Zwicky. Certainly, Zwicky 1 in his book " Morphological Astronomy " noted the discrepancy between masses of clusters inferred from the virial theorem and masses inferred from the visible constituent galaxies. He suggests five ...

The galaxy-IGM part of the Lyman-break survey currently consists of measured redshifts for more than 1000 galaxies with redshift 1.5 < ∼ z < ∼ 3.5 along the sightlines to 25 background QSOs. One of the goals of the survey was to measure the influence on the intergalactic medium of energetic feedback from star and black-hole formation. This talk begins with a description of the observed correlat...

Intergalactic type-Ia supernovae (SNe) have been discovered recently in rich galaxy clusters. These SNe are likely the descendants of an intergalactic stellar population, which has been discovered in recent years through a variety of tracers. We estimate the observational signatures of the associated SN remnants (SNRs) in the unusual intracluster medium (ICM) environment. We find that, if type-...

A soft ultraviolet radiation field, 10.2 eV< hν < 13.6 eV, that permeates neutral intergalactic gas during the Epoch of Reionization (EoR) excites the 2p (directly) and 2s (indirectly) states of atomic hydrogen. Because the 2s state is metastable, the lifetime of atoms in this level is relatively long, which may cause the 2s state to be overpopulated relative to the 2p state. It has recently be...

We compute the properties of dark matter halos with mass 10 − 10M⊙ at redshift z = 6 − 11 in the standard cold dark matter cosmological model, utilizing a very high resolution N-body simulation. We find that dark matter halos in these mass and redshift ranges are significantly biased over matter with a bias factor in the range 2− 6. The dark matter halo mass function displays a slope of 2.05±0....

It appears that the Lyman α forest is becoming thick at a redshift of about 5.5, cutting off the higher redshift intergalactic medium from view in neutral hydrogen. However, the effects of star formation at higher redshift are still readable in the intergalactic metal lines. In this paper I use observations of 32 quasars with emission redshifts in the range 2.31 to 5.86 to study the evolution o...