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The absorption by neutral hydrogen in the intergalactic medium (IGM) produces the Ly$\alpha$ forest in the spectra of quasars. The Ly$\alpha$ forest absorbers have a broad distribution of neutral hydrogen column density $N_{\rm HI}$ and…

Astrophysics of Galaxies · Physics 2023-04-05 Li Yang , Zheng Zheng , T. -S. Kim

The hardness of the ionizing continuum from the first sources of UV radiation plays a crucial role in the reionization of the intergalactic medium (IGM). While usual stellar populations have soft spectra, mini-quasars or metal-free stars…

Astrophysics · Physics 2009-10-31 S. Peng Oh , Zoltan Haiman , Martin J. Rees

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…

We present self-consistent radiation hydrodynamic simulations of hydrogen reionization performed with Arepo-RT complemented by a state-of-the-art galaxy formation model. We examine how photoheating feedback, due to reionization, shapes the…

Astrophysics of Galaxies · Physics 2019-06-25 Xiaohan Wu , Rahul Kannan , Federico Marinacci , Mark Vogelsberger , Lars Hernquist

The preheating of intergalactic medium(IGM) by structure collapsing and ultraviolet background(UVB) are investigated in cosmological hydrodynamical simulations. When gravitational collapsing is the sole heating mechanism, we find that (1)…

Astrophysics of Galaxies · Physics 2017-09-27 Weishan Zhu , Long-Long Feng

This Letter investigates the amount of dust in the intergalactic medium (IGM). The dust photoelectric heating can be the most efficient heating mechanism in the IGM where the density is very small and there are a lot of hard ultraviolet…

Astrophysics · Physics 2009-11-07 Akio K. Inoue , Hideyuki Kamaya

A simple analytical model is used to calculate the X-ray heating of the IGM for a range of black hole masses. This process is efficient enough to decouple the spin temperature of the intergalactic medium from the cosmic microwave background…

Astrophysics · Physics 2008-11-26 Saleem Zaroubi , Rajat M. Thomas , Naoshi Sugiyama , Joe Silk

The ionizing background determines the ionization balance and the thermodynamics of the cosmic gas. It is therefore a fundamental ingredient to theoretical and empirical studies of both the IGM and galaxy formation. We present here a new…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-28 C. -A. Faucher-Giguere , A. Lidz , M. Zaldarriaga , L. Hernquist

In this paper we examine the effect of X-ray and Lyalpha photons on the intergalactic medium temperature. We calculate the photon production from a population of stars and micro-quasars in a set of cosmological hydrodynamic simulations…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Benedetta Ciardi , Ruben Salvaterra , Tiziana Di Matteo

We show that the process of photoionizing a gas of atomic hydrogen and helium by line radiation whose energy is slightly above the helium single-ionization threshold is unstable if the helium fraction by number is less than approximately…

Astrophysics · Physics 2009-10-28 Ethan Bradford , Craig Hogan

The reionization of the intergalactic medium (IGM) was likely inhomogeneous and extended. By heating the IGM and photo-evaporating gas from the outskirts of galaxies, this process can have a dramatic impact on the growth of structures.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Emanuele Sobacchi , Andrei Mesinger

In this paper we investigate the overcooling problem and propose some possible solutions. We show that the overcooling problem is generic to the hierarchical picture of structure formation, as long as the cooling is actually possible in…

Astrophysics · Physics 2007-05-23 S. Prunet , A. Blanchard

The reionization history of the intergalactic medium (IGM) at high redshift (z > 6) was likely strongly shaped by several global feedback processes. Because the earliest ionizing sources formed at the locations of the rare density peaks,…

Astrophysics · Physics 2008-11-26 Roban Hultman Kramer , Zoltan Haiman , S. Peng Oh

When the neutral interstellar medium is exposed to EUV and soft X ray radiation, the argon atoms in it are far more susceptible to being ionized than the hydrogen atoms. We make use of this fact to determine the level of ionization in the…

Astrophysics of Galaxies · Physics 2013-01-29 Edward B. Jenkins

We show that radiative feedback due to reionization has a pronounced effect on the extent of mechanical feedback due to galactic outflows. The photoionization of the Intergalactic Medium (IGM) suppresses low-mass galaxy formation by…

Astrophysics · Physics 2008-11-26 Matthew M. Pieri , Hugo Martel

Spatial variations of the [S II]/H-Alpha and [N II]/H-Alpha line intensity ratios observed in the gaseous halo of the Milky Way and other galaxies are inconsistent with pure photoionization models. They appear to require a supplemental…

Astrophysics · Physics 2009-10-31 R. J. Reynolds , L. M. Haffner , S. L. Tufte

Intergalactic medium temperature is a powerful probe of the epoch of reionisation, as information is retained long after reionisation itself. However, mean temperatures are highly degenerate with the timing of reionisation, with the amount…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-25 James E. Davies , Simon J. Mutch , Yuxiang Qin , Andrei Mesinger , Gregory B. Poole , J. Stuart B. Wyithe

We develop an efficient method to study the effects of reionization history on the temperature-density relation of the intergalactic medium in the low density limit (overdensity less than 5). It is applied to the study of photo-reionization…

Astrophysics · Physics 2015-06-24 Lam Hui , Nickolay Y. Gnedin

We present new measurements of the thermal state of the intergalactic medium (IGM) at $z\sim2.4$ derived from absorption line profiles in the Ly$\alpha$ forest. We use a large set of high-resolution hydrodynamical simulations to calibrate…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 James S. Bolton , George D. Becker , Martin G. Haehnelt , Matteo Viel

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…

Astrophysics · Physics 2007-05-23 Michael Fisher
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