相关论文: Radiation Pressure in Lyman-alpha Forest Clouds
We present a modification of a model of solar cycle evolution of the solar Lyman-alpha line profile, along with a sensitivity study of interstellar neutral H hydrogen to uncertainties in radiation pressure level. The line profile model,…
We examine the statistics of the low-redshift Lyman-alpha forest from smoothed particle hydrodynamic simulations in light of recent improvements in the estimated evolution of the cosmic ultraviolet background (UVB) and recent observations…
We present predictions for the fluorescent Lyman-alpha emission signature arising from photoionized, optically thick structures in Smoothed Particle Hydrodynamic (SPH) cosmological simulations of a Lambda-CDM universe using a Monte Carlo…
Kowalski & Saumon (2006) identified the missing absorption mechanism in the observed spectra of cool white dwarf stars as the Ly-alpha red wing formed by the collisions between atomic and molecular hydrogen and successfully explained entire…
We present a detailed calculation of the propagation of AGN-like ionizing radiation through the intergalactic space. We model the ionization state of absorbing clouds, and show that the universe will be more opaque above $4\,$Ryd than…
Understanding the sources responsible for reionizing the Universe is a key goal of observational cosmology. A discrepancy has existed between the metagalactic hydrogen ionization rate, Gamma_HI, predicted by early hydrodynamical simulations…
Results are presented for one-dimensional numerical hydrodynamics computations of the structure and evolution of Lya forest clouds gravitationally confined by dark matter minihalos. The clouds are developed from linear perturbations at high…
The temperature of the low-density intergalactic medium is set by the balance between adiabatic cooling resulting from the expansion of the universe, and photo-heating by the UV-background. We have analysed the Lyman-alpha forest of eleven…
Motivated by observational and theoretical work which both suggest very small scale ($\lesssim 1\,$pc) structure in the circum-galactic medium of galaxies and in other environments, we study Lyman-$\alpha$ (Ly$\alpha$) radiative transfer in…
We compare cosmological hydrodynamical simulations combined with the homogeneous metagalactic UV background (UVB) of Haardt & Madau (2012) (HM2012) to observations of the Lyman-alpha forest that are sensitive to the thermal and ionization…
We model the $\lya$ forest in a spatially flat, CDM model with $\Omega=0.4$, with an Eulerian hydrodynamic simulation, and find that the intergalactic, photoionized gas collapses into sheet-like and filamentary structures which produce…
Recent studies of interstellar neutral (ISN) hydrogen observed by the Interstellar Boundary Explorer (IBEX) suggested that the present understanding of the radiation pressure acting on hydrogen atoms in the heliosphere should be revised.…
We have analyzed the properties of low column density Lyman alpha forest clouds (12.8 < log N_HI < 16.0) toward 5 QSOs at different redshifts, using high signal-to-noise data from the HIRES spectrograph on the Keck I 10-m telescope. The…
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 epoch of hydrogen reionization is complete by $z=5$, but its progression at higher redshifts is uncertain. Measurements of Ly$\alpha$ forest opacity show large scatter at $z<6$, suggestive of spatial fluctuations in neutral fraction…
We present FUSE observations of the HeII Lyman alpha forest in the redshift range 2.3 < z < 2.7 towards HS1700+6416. Between October 2002 and February 2003, the brightness of the QSO increased by a factor 2. Therefore, with an exposure time…
The transmission of Lyman-{\alpha} (Ly{\alpha}) in the spectra of distant quasars depends on the density, temperature, and ionization state of the intergalactic medium (IGM). Therefore, high-redshift (z > 5) Ly{\alpha} forests could be…
We present models for dusty high-redshift Lyman alpha emitting galaxies by combining the Press-Schechter formalism with a treatment of inhomogeneous dust distribution inside galaxies. These models reproduce the surface density of emitters…
Lyman-alpha (Ly{\alpha}) photons from ionizing sources and cooling radiation undergo a complex resonant scattering process that generates unique spectral signatures in high-redshift galaxies. We present a detailed Ly{\alpha} radiative…
Using a Monte Carlo technique, we have developed a 3D lyman-alpha radiation transfer code allowing for prescribed arbitrary hydrogen density, ionisation, temperature structures, and dust distribution, and arbitrary velocity fields and UV…