相关论文: The Dark Ages' 21-cm Trispectrum
A measurement of primordial non-gaussianity will be of paramount importance to distinguish between different models of inflation. Cosmic microwave background (CMB) anisotropy observations have set unprecedented bounds on the non-gaussianity…
The brightness temperature fluctuations in the 21 cm background related to neutral Hydrogen distribution provide a probe of physics related to the era of reionization when the intergalactic medium changed from a completely neutral to a…
Brightness-temperature fluctuations in the redshifted 21-cm background from the cosmic dark ages are generated by irregularities in the gas-density distribution and can then be used to determine the statistical properties of density…
We study the signature of primordial non-Gaussianity imprinted on the power spectrum of the 21-cm line differential brightness temperature during dark ages. Employing the perturbative treatment of gravitational clustering, we quantitatively…
The 21-cm brightness temperature fluctuation from the Dark Ages ($z \simeq 30-100$) will allow us to probe the inflationary epoch on very small scales ($>0.1 \, \mbox{Mpc}^{-1}$), inaccessible to cosmic microwave background experiments.…
The 21-cm anisotropies from the neutral hydrogen distribution prior to the era of reionization is a sensitive probe of primordial non-Gaussianity. Unlike the case with cosmic microwave background, 21-cm anisotropies provide multi-redshift…
We study the constraints on primordial magnetic fields (PMFs) in light of the global 21-cm signal observed during the dark ages. Primordial magnetic fields can heat the intergalactic medium (IGM) via magnetohydrodynamic effects. We…
Fluctuations of the 21 cm brightness temperature before the formation of the first stars hold the promise of becoming a high-precision cosmological probe in the future. The growth of over densities is very well described by perturbation…
The non-Gaussianity of initial perturbations provides information on the mechanism that generated primordial density fluctuations. The expected non-Gaussianity for slow-roll inflationary models is well below the ultimate detection level…
We present a new probe of primordial non-Gaussianity via the 21cm radiation from minihalos at high redshifts. We calculate the fluctuations in the brightness temperature (measured against the cosmic microwave background) of the 21cm…
Measurements of the temperature of the baryons at the end of the cosmic dark ages can potentially set very precise constraints on energy injection from exotic sources, such as annihilation or decay of the dark matter. However, additional…
The Dark Ages, probed by the redshifted 21-cm signal, is the ideal epoch for a new rigorous test of the standard LCDM cosmological model. Divergences from that model would indicate new physics, such as dark matter decay (heating) or…
Measurements of 21cm intensity mapping (IM) during the dark ages can potentially provide us with an unprecedented window on high redshifts and small scales. One of the main advantages this can bring involves the possibility to probe the…
Measurements from the Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission 2 (ARCADE-2) reveal a strong radio background in the GHz frequency range. Since the cosmological 21-cm signal is measured relative to the background…
We approximately compute the bispectrum induced on the CMB temperature by fluctuations in the standard recombination epoch. Of all the second order sources that can induce non-Gaussianity during recombination, we concentrate on those…
The radiations from the first luminous sources drive the fluctuations in the 21-cm signal at Cosmic Dawn (CD) via two dominant astrophysical processes i.e. the Ly$\alpha$ coupling and X-ray heating, making this signal highly non-Gaussian.…
The epoch of reionization (EoR) 21-cm signal is expected to be highly non-Gaussian in nature and this non-Gaussianity is also expected to evolve with the progressing state of reionization. Therefore the signal will be correlated between…
Detecting a deviation from a featureless primordial power spectrum of fluctuations would give profound insight into the physics of the primordial Universe. Depending on their nature, primordial features can either provide direct evidence…
During cosmic reionization, the 21-cm brightness fluctuations were highly non-Gaussian, and complementary statistics can be extracted from the distribution of pixel brightness temperatures that are not derivable from the 21-cm power…
Redshifted 21cm signal is a promising tool to investigate the state of intergalactic medium (IGM) in the Cosmic Dawn (CD) and Epoch of Reionization(EoR). In our previous work (Shimabukuro et al 2015), we studied the variance and skewness to…