Related papers: Intergalactic heating by Lyman-alpha photons inclu…
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…
Allowing for enhanced Ly$\alpha$ photon line emission from Population III dominated stellar systems in the first forming galaxies, we show the 21-cm cosmic dawn signal at $10<z<30$ may substantially differ from standard scenarios. Energy…
The intergalactic medium (IGM) prior to the epoch of reionization consists mostly of neutral hydrogen gas. Ly-alpha photons produced by early stars resonantly scatter off hydrogen atoms, causing energy exchange between the radiation field…
During the epoch of reionization a large number of photons were produced with frequencies below the hydrogen Lyman limit. After redshifting into the closest resonance, these photons underwent multiple scatterings with atoms. We examine the…
The Lyman-$\alpha$ photons couple the spin temperature of neutral hydrogen (HI) to the kinetic temperature during the era of cosmic dawn. During this process, they also exchange energy with the medium, heating and cooling the HI. In…
The scattering of Ly$\alpha$ photons from the first radiating sources in the Universe plays a pivotal role in 21-cm radio detections of Cosmic Dawn and the Epoch of Reionization through the Wouthuysen-Field effect. New data from JWST show…
The 21-cm signal from the cosmic reionization epoch can shed light on the history of heating of the primordial intergalactic medium (IGM) at z~30-10. It has been suggested that X-rays from the first accreting black holes could significantly…
The global 21-cm signal from the cosmic dawn is affected by a variety of heating and cooling processes. We investigate the impact of heating due to Lyman-$\alpha$ (Ly~$\alpha$) photons on the global 21-cm signal at cosmic dawn using an…
High-resolution hydrodynamics simulations of the Ly-alpha forest in cold dark matter dominated cosmologies appear to predict line widths that are substantially narrower than those observed. Here we point out that Compton heating of the…
Models and simulations of the epoch of reionization predict that spectra of the 21-cm transition of atomic hydrogen will show a clear fluctuation peak, at a redshift and scale, respectively, that mark the central stage of reionization and…
The filamentary network of intergalactic medium (IGM) gas that gives origin to the Lyman-alpha forest in the spectra of distant quasars encodes information on the physics of structure formation and the early thermodynamics of diffuse…
We investigate the interaction of Lyman alpha photons produced by the first stars in the universe with the intergalactic medium (IGM) prior to reionization. The background Lyman alpha spectral profile is obtained by solving a Fokker-Planck…
The temperature of the diffuse, photo-heated intergalactic medium (IGM) depends on its reionization history because the thermal time scales are long. The widths of the hydrogen Lyman-alpha absorption lines seen in the spectra of distant…
The resonance scattering of Ly$\alpha$ photons with neutral hydrogen atoms in the intergalactic medium not only couples the spin temperature to the kinetic temperature but also leads to a heating of the gas. We investigate the impact of…
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…
The 21-cm signal from the epoch of cosmic dawn ($z \sim 10-30$) offers a powerful probe of new physics. One standard mechanism for constraining decaying dark matter from 21-cm observations relies on heating of the intergalactic medium by…
It is extremely important to understand the processes through which the thermal state of the inter-galactic medium (IGM) evolved in the early universe in order to study the evolution of HI 21-cm signal during cosmic dawn. Here, we consider…
The sky-averaged (global) 21-cm signal is a powerful probe of the intergalactic medium (IGM) prior to the completion of reionization. However, it has so far been unclear that even in the best case scenario, in which the signal is accurately…
Cosmic rays generated by supernovae carry away a significant portion of the lifetime energy emission of their parent star, making them a plausible mechanism for heating the early universe intergalactic medium (IGM). Following a review of…
We re-examine scattering of photons near the Lyman-alpha resonance in the intergalactic medium (IGM). We first derive a general integral solution for the radiation field around resonance when spin diffusivity is ignored. Our solution shows…