Signals of the cosmological reionization in the radio sky through C and O fine structure lines

Kusakabe, Motohiko; Kawasaki, Masahiro

doi:10.1111/j.1365-2966.2011.19751.x

Cited by 4 publications

(8 citation statements)

References 57 publications

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“…Intensity mapping was originally developed for 21 cm radiation (Hogan & Rees 1979;Scott & Rees 1990;Madau et al 1997), but has been studied for several other lines (in increasing frequency): deuterium (Sigurdson & Furlanetto 2006) (Righi et al 2008;Carilli 2011;Lidz et al 2011;Breysse et al 2014;Li et al 2015), C II (Gong et al 2012;Silva et al 2014;Uzgil et al 2014;Yue et al 2015), Lya Pullen et al 2014), C and O fine-structure (Kusakabe & Kawasaki 2012), and X-ray lines (Hütsi et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Interpreting the Unresolved Intensity of Cosmologically Redshifted Line Radiation

Switzer

Chang

Masui

et al. 2015

ApJ

107

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Intensity mapping experiments survey the spectrum of diffuse line radiation rather than detect individual objects at high signal-to-noise ratio. Spectral maps of unresolved atomic and molecular line radiation contain threedimensional information about the density and environments of emitting gasand efficiently probe cosmological volumes out to high redshift. Intensity mapping survey volumes also contain all other sources of radiation at the frequencies of interest. Continuum foregrounds are typically~10 2 -10 3 times brighter than the cosmological signal. The instrumental response to bright foregrounds will produce new spectral degrees of freedom that are not known in advance, nor necessarily spectrally smooth. The intrinsic spectra of foregrounds may also not be wellknown in advance. We describe a general class of quadratic estimators to analyze data from single-dish intensity mapping experimentsand determine contaminated spectral modes from the data themselves. The key attribute of foregrounds is not that they are spectrally smooth, but instead that they have fewer bright spectral degrees of freedom than the cosmological signal. Spurious correlations between the signal and foregrounds produce additional bias. Compensation for signal attenuation must estimate and correct this bias. A successful intensity mapping experiment will control instrumental systematics that spread variance into new modes, and it must observe a large enough volume that contaminant modes can be determined independently from the signal on scales of interest.

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Section: Introductionmentioning

confidence: 99%

Interpreting the Unresolved Intensity of Cosmologically Redshifted Line Radiation

Switzer

Chang

Masui

et al. 2015

ApJ

107

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show abstract

“…11. Other studies have approached the calculation in different ways, 174 but give generally similar results.…”

Section: Line Emission Perturbationsmentioning

confidence: 60%

“…17. 173,174 The second method 175–177 is simpler and uses an integral over emissive sources assuming no absorption along the line of sight, using the following equation: …”

Section: Line Emission Perturbationsmentioning

confidence: 99%

“…The C ii line intensity, shown as the thick green line, has been estimated by averaging calculations from several published studies. 173–177 The other lines have been scaled from each line frequency, along with ratios of the line luminosity to star-formation rate, according to Eq. 22.…”

Section: Line Emission Perturbationsmentioning

confidence: 99%

“…17. 173,174 The second method [175][176][177] is simpler and uses an integral over emissive sources assuming no absorption along the line of sight, using the following equation: Here, the line element dl=dz ¼ c= 1 þ z ð ÞH z ð Þ contains the cosmology and CII is the proper volume emissivity of CII radiation at rest frequency n CII . If all CII emission comes from gas in galaxies located in dark matter halos, we can write the proper volume emissivity as…”

Section: The CII Linementioning

confidence: 99%

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The Spectrum of the Universe

2018

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Cosmic background (CB) radiation, encompassing the sum of emission from all sources outside our own Milky Way galaxy across the entire electromagnetic spectrum, is a fundamental phenomenon in observational cosmology. Many experiments have been conceived to measure it (or its constituents) since the extragalactic Universe was first discovered; in addition to estimating the bulk (cosmic monopole) spectrum, directional variations have also been detected over a wide range of wavelengths. Here we gather the most recent of these measurements and discuss the current status of our understanding of the CB from radio to γ-ray energies. Using available data in the literature, we piece together the sky-averaged intensity spectrum and discuss the emission processes responsible for what is observed. We examine the effect of perturbations to the continuum spectrum from atomic and molecular line processes and comment on the detectability of these signals. We also discuss how one could, in principle, obtain a complete census of the CB by measuring the full spectrum of each spherical harmonic expansion coefficient. This set of spectra of multipole moments effectively encodes the entire statistical history of nuclear, atomic, and molecular processes in the Universe.

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Initial Li Abundances in the Proto-Galaxy and Globular Clusters Based upon the Chemical Separation and Hierarchical Structure Formation

Kusakabe

Kawasaki

2019

ApJL

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The chemical separation of Li + ions induced by a magnetic field during the hierarchical structure formation can reduce initial Li abundances in cosmic structures. It is shown that cosmological reionization of neutral Li atoms quickly completes as soon as the first star is formed. Since almost all Li is singly ionized during the main course of structure formation, it can efficiently separate from gravitationally collapsing neutral gas. The separation is more efficient in smaller structures which formed earlier. In the framework of the hierarchical structure formation, extremely metal-poor stars can have smaller Li abundances because of their earlier formations. It is found that the chemical separation by a magnetic field thus provides a reason that Li abundances in extremely metal-poor stars are lower than the Spite plateau and have a large dispersion as well as an explanation of the Spite plateau itself. In addition, the chemical separation scenario can explain Li abundances in NGC 6397 which are higher than the Spite plateau. Thus, Li abundances in metal-poor stars possibly keep information on the primordial magnetic field and the structure formation history.

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Signals of the cosmological reionization in the radio sky through C and O fine structure lines

Cited by 4 publications

References 57 publications

Interpreting the Unresolved Intensity of Cosmologically Redshifted Line Radiation

Interpreting the Unresolved Intensity of Cosmologically Redshifted Line Radiation

The Spectrum of the Universe

Initial Li Abundances in the Proto-Galaxy and Globular Clusters Based upon the Chemical Separation and Hierarchical Structure Formation

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