Redshift-space distortion of the 21-cm background from the epoch of reionization - I. Methodology re-examined

Mao, Yi; Shapiro, Paul R.; Mellema, Garrelt; Iliev, Ilian T.; Koda, Jun; Ahn, Kyungjin

doi:10.1111/j.1365-2966.2012.20471.x

Cited by 140 publications

(209 citation statements)

References 55 publications

Supporting

Mentioning

202

Contrasting

Order By: Relevance

“…To derive high quality estimates of the cosmological parameters from observations with the SKA, however, it will be necessary to go beyond the simple linear treatment (e.g. Mao et al 2012). …”

Section: Fluctuations From Peculiar Velocitymentioning

confidence: 99%

Reionization and the Cosmic Dawn with the Square Kilometre Array

et al. 2013

Self Cite

View full text Add to dashboard Cite

The Square Kilometre Array (SKA) will have a low frequency component (SKA-low) which has as one of its main science goals the study of the redshifted 21cm line from the earliest phases of star and galaxy formation in the Universe. This 21cm signal provides a new and unique window both on the time of the formation of the first stars and accreting black holes and the subsequent period of substantial ionization of the intergalactic medium. The signal will teach us fundamental new things about the earliest phases of structure formation, cosmology and even has the potential to lead to the discovery of new physical phenomena. Here we present a white paper with an Executive SummaryThe Square Kilometre Array (SKA) will have a low frequency component (AA-low/SKA-low 1 ) which has as one of its main science goals the study of the redshifted 21cm line from the earliest phases of star and galaxy formation in the Universe (see SKA Memo 125). It is during this phase that the first building blocks of the galaxies that we see around us today, including our own Milky Way, were formed. It is a crucial period for understanding the history of the Universe and one for which we have currently very little observational data.We divide the period into two different phases based on the physical processes which affect the Intergalactic Medium. The first period, which we call the Cosmic Dawn, saw the formation of the first stars and accreting black holes, which changed the quantum state of the still neutral Intergalactic Medium. The second period, known as the Epoch of Reionization, is the one during which large areas between the galaxies were photo-ionized by the radiation produced in galaxies and which ended when the Intergalactic Medium had become completely ionized.Observations of the redshifted 21-cm line with SKA will provide a new and unique window on the entire period of Cosmic Dawn and Reionization. The signal is sensitive to the emergence of the first stellar populations, radiation from growing massive black holes and the formation of larger groups of galaxies and bright quasars. At the same time it maps the distribution of most of the baryonic matter in the Universe. The study of the redshifted 21cm line will teach us fundamental new things about the earliest phases of structure formation and cosmology. It even has the potential to lead to the discovery of new physical phenomena. Here we present an overview of the science questions that SKA-low can address, how we plan to tackle these questions and what this implies for the basic design of the telescope.The redshifted 21cm signal will be analyzed with different techniques, which each come with their own requirements for the SKA: (i) Tomography, (ii) power-spectra and higher-order statistics, (iii) hydrogen absorption, (iv) global/total-intensity signal. Whereas all precursors/pathfinders aim to study the signal statistically through its power spectrum, SKA will be able to image the neutral hydrogen distribution directly and its focus will therefore be more on tomograph...

show abstract

Section: Fluctuations From Peculiar Velocitymentioning

confidence: 99%

Reionization and the Cosmic Dawn with the Square Kilometre Array

et al. 2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…Other, more recent approaches are instead based on a particleby-particle method where the HI is assigned to gas particles according to more refined physical prescriptions which take into account self-shielding effects and the conversion to molecular hydrogen (e.g. Davé et al 2013;Popping et al 2009;Rahmati et al 2013;Duffy et al 2012;Mao et al 2012). A comprehensive comparison of several different methods in terms of 21 cm power spectrum is redshift space, performed in the post-reionisation era at z 2−4, has been recently presented by Villaescusa-Navarro et al (2014), who used high resolution cosmological hydrodynamic simulations.…”

Section: Intensity Mapping After the Epoch Of Reionisationmentioning

confidence: 99%

Cosmology on the Largest Scales with the SKA

Camera¹,

Raccanelli²,

Bull³

et al. 2015

Proceedings of Advancing Astrophysics With the Square Kilometre Array — PoS(AASKA14)

Self Cite

View full text Add to dashboard Cite

The study of the Universe on ultra-large scales is one of the major science cases for the Square Kilometre Array (SKA). The SKA will be able to probe a vast volume of the cosmos, thus representing a unique instrument, amongst next-generation cosmological experiments, for scrutinising the Universe's properties on the largest cosmic scales. Probing cosmic structures on extremely large scales will have many advantages. For instance, the growth of perturbations is well understood for those modes, since it falls fully within the linear régime. Also, such scales are unaffected by the poorly understood feedback of baryonic physics. On ultra-large cosmic scales, two key effects become significant: primordial non-Gaussianity and relativistic corrections to cosmological observables. Moreover, if late-time acceleration is driven not by dark energy but by modifications to general relativity, then such modifications should become apparent near and above the horizon scale. As a result, the SKA is forecast to deliver transformational constraints on non-Gaussianity and to probe gravity on super-horizon scales for the first time.Advancing Astrophysics with the Square Kilometre Array

show abstract

“…In particular, since the velocity gradient is directly related to density through the continuity equation, P µ 4 is proportional to the primordial density power spectrum P δ , P µ 0 is the sum of all the isotropic 21-cm fluctuation sources (i.e., those other than the velocity gradient), and P µ 2 is proportional to the correlation of density with the isotropic 21-cm fluctuation sources. However, 21-cm fluctuations are non-linear, and recent numerical investigations during cosmic reionization [17][18][19][20] suggest that it will be difficult to make this separation of terms and recover cosmological information from the 21-cm power spectrum.…”

Section: Introductionmentioning

confidence: 99%

Reconstructing the Nature of the First Cosmic Sources from the Anisotropic 21-cm Signal

2015

View full text Add to dashboard Cite

The redshifted 21-cm background is expected to be a powerful probe of the early Universe, carrying both cosmological and astrophysical information from a wide range of redshifts. In particular, the power spectrum of fluctuations in the 21-cm brightness temperature is anisotropic due to the lineof-sight velocity gradient, which in principle allows for a simple extraction of this information in the limit of linear fluctuations. However, recent numerical studies suggest that the 21-cm signal is actually rather complex, and its analysis likely depends on detailed model fitting. We present the first realistic simulation of the anisotropic 21-cm power spectrum over a wide period of early cosmic history. We show that on observable scales, the anisotropy is large and thus measurable at most redshifts, and its form tracks the evolution of 21-cm fluctuations as they are produced early on by Lyman-α radiation from stars, then switch to X-ray radiation from early heating sources, and finally to ionizing radiation from stars. In particular, we predict a redshift window during cosmic heating (at z ∼ 15), when the anisotropy is small, during which the shape of the 21-cm power spectrum on large scales is determined directly by the average radial distribution of the flux from X-ray sources. This makes possible a model-independent reconstruction of the X-ray spectrum of the earliest sources of cosmic heating.

show abstract

Redshift-space distortion of the 21-cm background from the epoch of reionization - I. Methodology re-examined

Cited by 140 publications

References 55 publications

Reionization and the Cosmic Dawn with the Square Kilometre Array

Reionization and the Cosmic Dawn with the Square Kilometre Array

Cosmology on the Largest Scales with the SKA

Reconstructing the Nature of the First Cosmic Sources from the Anisotropic 21-cm Signal

Contact Info

Product

Resources

About