The Lyman Alpha Forest in the Spectra of Quasistellar Objects

Rauch, Michael

doi:10.1146/annurev.astro.36.1.267

Cited by 456 publications

(339 citation statements)

References 236 publications

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“…A tighter upper limit of 5% for the volume of voids (with sizes ∼ 50 h −1 Mpc comoving) at z ∼ 3.2 has been discussed in a review of Lyα forest in QSO spectra (Rauch 1998, and references therein). Our enriched volume fraction result of < 5% at z ∼ 3, for most of the runs, are well within these upper limits.…”

Section: Discussionmentioning

confidence: 99%

Anisotropic Active Galactic Nucleus Outflows and Enrichment of the Intergalactic Medium. I. Metal Distribution

Germain

Barai

Martel

2009

ApJ

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We investigate the cosmological-scale influence of outflows driven by active galactic nuclei (AGNs) on metal enrichment of the intergalactic medium (IGM). AGNs are located in dense cosmological structures which tend to be anisotropic. We designed a semianalytical model for anisotropic AGN outflows which expand away along the direction of least resistance. This model was implemented into a cosmological numerical simulation algorithm for simulating the growth of large-scale structure in the universe. Using this modified algorithm, we perform a series of nine simulations inside cosmological volumes of size (128 h −1 Mpc) 3 , in a concordance ΛCDM universe, varying the opening angle of the outflows, the lifetimes of the AGNs, their kinetic fractions, and their level of clustering. For each simulation, we compute the volume fraction of the IGM enriched in metals by the outflows. The resulting enriched volume fractions are relatively small at z 2.5, and then grow rapidly afterward up to z = 0. We find that AGN outflows enrich from 65% to 100% of the entire universe at the present epoch, for different values of the model parameters. The enriched volume fraction depends weakly on the opening angle of the outflows. However, increasingly anisotropic outflows preferentially enrich underdense regions, a trend found more prominent at higher redshifts and decreasing at lower redshifts. The enriched volume fraction increases with increasing kinetic fraction and decreasing AGN lifetime, and level of clustering.

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Section: Discussionmentioning

confidence: 99%

Anisotropic Active Galactic Nucleus Outflows and Enrichment of the Intergalactic Medium. I. Metal Distribution

Germain

Barai

Martel

2009

ApJ

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“…The transmitted Lyα flux observed in the spectrum of a distant source (typically a quasar) provides us with a one-dimensional map of absorption along the line of sight (LOS), with the observed wavelength corresponding to the redshift of the intervening neutral hydrogen causing the Lyα scattering (e.g. [43,49]). …”

Section: Introductionmentioning

confidence: 99%

The non-linear power spectrum of the Lyman alpha forest

Arinyo-i-Prats

Miralda-Escudé

Viel

et al. 2015

J. Cosmol. Astropart. Phys.

133

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Abstract. The Lyman alpha forest power spectrum has been measured on large scales by the BOSS survey in SDSS-III at z ∼ 2.3, has been shown to agree well with linear theory predictions, and has provided the first measurement of Baryon Acoustic Oscillations at this redshift. However, the power at small scales, affected by non-linearities, has not been well examined so far. We present results from a variety of hydrodynamic simulations to predict the redshift space non-linear power spectrum of the Lyα transmission for several models, testing the dependence on resolution and box size. A new fitting formula is introduced to facilitate the comparison of our simulation results with observations and other simulations. The non-linear power spectrum has a generic shape determined by a transition scale from linear to non-linear anisotropy, and a Jeans scale below which the power drops rapidly. In addition, we predict the two linear bias factors of the Lyα forest and provide a better physical interpretation of their values and redshift evolution. The dependence of these bias factors and the non-linear power on the amplitude and slope of the primordial fluctuations power spectrum, the temperature-density relation of the intergalactic medium, and the mean Lyα transmission, as well as the redshift evolution, is investigated and discussed in detail. A preliminary comparison to the observations shows that the predicted redshift distortion parameter is in good agreement with the recent determination of Blomqvist et al., but the density bias factor is lower than observed. We make all our results publicly available in the form of tables of the non-linear power spectrum that is directly obtained from all our simulations, and parameters of our fitting formula.

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“…2 N/dz/dN (H i), is close to a powerlaw ∝ N (H i) β with β < 0, as function of column-density, and evolves strongly with redshift as fewer lines are produced as the mean density decreases due to the expansion of the Universe, see Rauch (1998) for a review.…”

Section: Introductionmentioning

confidence: 95%

ELT requirements for future observations of the Intergalactic Medium

Theuns

Srianand

2005

Proc. IAU

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Abstract. We summarise the science cases for an ELT that were presented in the parallel session on the intergalactic medium, and the open discussion that followed the formal presentations. Observations of the IGM with an ELT provides tremendous potential for dramatic improvements in current programmes in a very wide variety of subjects. These range from fundamental physics (expansion of the Universe, nature of the dark matter, variation of physical constants), cosmology (geometry of the Universe, large-scale structure), reionisation (ionisation state of the IGM at high z 6), to more traditional astronomy, such as the interactions between galaxies and the IGM (metal enrichment, galactic winds and other forms of feedback), and the study of the interstellar medium in high z galaxies through molecules. The requirements on ELTs and their instruments for fulfilling this potential are discussed.

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The Lyman Alpha Forest in the Spectra of Quasistellar Objects

Cited by 456 publications

References 236 publications

Anisotropic Active Galactic Nucleus Outflows and Enrichment of the Intergalactic Medium. I. Metal Distribution

Anisotropic Active Galactic Nucleus Outflows and Enrichment of the Intergalactic Medium. I. Metal Distribution

The non-linear power spectrum of the Lyman alpha forest

ELT requirements for future observations of the Intergalactic Medium

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