The physics of the intergalactic medium

Meiksin, Avery

doi:10.1103/revmodphys.81.1405

Cited by 343 publications

(369 citation statements)

References 591 publications

(231 reference statements)

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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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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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“…Observational studies of the Epoch of Reionization (EoR) as well as the preceding Dark Ages are thus necessary to understand the formation of the first stars and galaxies as well as the evolution of the diffuse intervening medium to its present state (Venkatesan et al 2001;Ciardi et al 2003;Choudhury & Ferrara 2006;Meiksin 2009). There are various observational probes to study this epoch like the Gunn-Peterson effect, cosmic microwave background, quasars, gamma-ray bursts, etc.…”

Section: Introductionmentioning

confidence: 99%

ON THE DETECTION OF GLOBAL 21-cm SIGNAL FROM REIONIZATION USING INTERFEROMETERS

Singh

Subrahmanyan

Shankar

et al. 2015

ApJ

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Detection of the global redshifted 21-cm signal is an excellent means of deciphering the physical processes during the Dark Ages and subsequent Epoch of Reionization (EoR). However, detection of this faint monopole is challenging due to the high precision required in instrumental calibration and modeling of substantially brighter foregrounds and instrumental systematics. In particular, modeling of receiver noise with mK accuracy and its separation remains a formidable task in experiments aiming to detect the global signal using single-element spectral radiometers. Interferometers do not respond to receiver noise; therefore, here we explore the theory of the response of interferometers to global signals. In other words, we discuss the spatial coherence in the electric field arising from the monopole component of the 21-cm signal and methods for its detection using sensor arrays. We proceed by first deriving the response to uniform sky of two-element interferometers made of unit dipole and resonant loop antennas, then extend the analysis to interferometers made of one-dimensional arrays and also consider two-dimensional aperture antennas. Finally, we describe methods by which the coherence might be enhanced so that the interferometer measurements yield improved sensitivity to the monopole component. We conclude (a) that it is indeed possible to measure the global 21-cm from EoR using interferometers, (b) that a practically useful configuration is with omnidirectional antennas as interferometer elements, and (c) that the spatial coherence may be enhanced using, for example, a space beam splitter between the interferometer elements.

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“…Therefore we chose X e,H = X e,He = 1 at z < 3, which corresponds to f e = 0.875. The values of f IGM are 0.82 and 0.9 at z < 0.4 and z > 1.5, respectively (Meiksin 2009;Shull et al 2012). To describe the slow evolving of f IGM in the range 0.4 < z < 1.5, we assumed that it increases linearly at 0.4 < z < 1.5 (Zhou et al 2014).…”

Section: Main Ideamentioning

confidence: 99%

“…The parameters in F(z) are extensively investigated in previous works (Fan, Carilli, & Keating 2006;McQuinn et al 2009;Meiksin 2009;Becker et al 2011). According to their results, intergalactic hydrogen and helium are fully ionized at z < 3.…”

Section: Main Ideamentioning

confidence: 99%

Measuring the cosmic proper distance from fast radio bursts

Wang

2017

A&A

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The cosmic proper distance d P is a fundamental distance in the Universe. Unlike the luminosity and angular diameter distances, which correspond to the angular size, the proper distance is the length of light path from the source to observer. However, the proper distance has not been measured before. The recent redshift measurement of a repeat fast radio burst (FRB) can shed light on the proper distance. We show that the proper distance-redshift relation can indeed be derived from dispersion measures (DMs) of FRBs with measured redshifts. From Monte Carlo simulations, we find that about 500 FRBs with DM and redshift measurements can tightly constrain the proper distance-redshift relation. We also show that the curvature of our Universe can be constrained with a model-independent method using this derived proper distance-redshift relation and the observed angular diameter distances. Owing to the high event rate of FRBs, hundreds of FRBs can be discovered in the future by upcoming instruments. The proper distance will play an important role in investigating the accelerating expansion and the geometry of the Universe.

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The physics of the intergalactic medium

Cited by 343 publications

References 591 publications

The non-linear power spectrum of the Lyman alpha forest

The non-linear power spectrum of the Lyman alpha forest

ON THE DETECTION OF GLOBAL 21-cm SIGNAL FROM REIONIZATION USING INTERFEROMETERS

Measuring the cosmic proper distance from fast radio bursts

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