Constraining isocurvature perturbations with the 21 cm emission from minihaloes

@article{Takeuchi2013ConstrainingIP,
  title={Constraining isocurvature perturbations with the 21 cm emission from minihaloes},
  author={Yoshitaka Takeuchi and Sirichai Chongchitnan},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2013},
  volume={439},
  pages={1125-1135}
}
We investigate the effects of isocurvature perturbations on the 21 cm radiation from minihaloes (MHs) at high redshifts and examine constraints on the isocurvature amplitude and power spectrum using the next generation of radio telescopes such as the Square Kilometre Array. We find that there is a realistic prospect of observing the isocurvature imprints in the 21 cm emission from MHs, but only if the isocurvature spectral index is close to 3 (i.e. the spectrum is blue). When the isocurvature… 

Figures from this paper

Cosmological signatures of tilted isocurvature perturbations: reionization and 21cm fluctuations

We investigate cosmological signatures of uncorrelated isocurvature perturbations whose power spectrum is blue-tilted with spectral index 2≲p≲4. Such an isocurvature power spectrum can promote early

21 cm angular power spectrum from minihalos as a probe of primordial spectral runnings

Measurements of 21 cm line fluctuations from minihalos have been discussed as a powerful probe of a wide range of cosmological models. However, previous studies have taken into account only the pixel

Constraining warm dark matter with 21 cm line fluctuations due to minihalos

Warm dark matter (WDM) with mass mWDM = 𝒪(1) keV has long been discussed as a promising solution for discrepancies between cosmic structures observed at small scales and predications of the

Probing isocurvature perturbations with 21-cm global signal in the light of HERA result

We argue that the 21-cm global signal can be a powerful probe of isocurvature perturbations, particularly for the ones with blue-tilted spectra. Although the 21-cm global signal is much affected by

The 21 cm signal and the interplay between dark matter annihilations and astrophysical processes

Future dedicated radio interferometers, including HERA and SKA, are very promising tools that aim to study the epoch of reionization and beyond via measurements of the 21 cm signal from neutral

Large blue isocurvature spectral index signals time-dependent mass

We show that if a spectator linear isocurvature dark matter field degree of freedom has a constant mass through its entire evolution history, the maximum measurable isocurvature spectral index that

Bump in the blue axion isocurvature spectrum

Blue axion isocurvature perturbations are both theoretically well-motivated and interesting from a detectability perspective. These power spectra generically have a break from the blue region to a

Probing axion dark matter with 21 cm fluctuations from minihalos

If the symmetry breaking inducing the axion occurs after the inflation, the large axion isocurvature perturbations can arise due to a different axion amplitude in each causally disconnected patch.

Elementary theorems regarding blue isocurvature perturbations

Blue CDM-photon isocurvature perturbations are attractive in terms of observability and may be typical from the perspective of generic mass relations in supergravity. We present and apply three

Baryon isocurvature constraints on the primordial hypermagnetic fields

It has been pointed out that hypermagnetic helicity decay at the electroweak symmetry breaking may have produced the observed baryon asymmetry of the Universe through the chiral anomaly in the

References

SHOWING 1-10 OF 64 REFERENCES

On the Direct Detectability of the Cosmic Dark Ages: 21 Centimeter Emission from Minihalos

In the standard cold dark matter (CDM) theory of structure formation, virialized minihalos (with Tvir ≲ 104 K) form in abundance at high redshift (z > 6), during the cosmic "dark ages." The hydrogen

Forecasted 21 cm constraints on compensated isocurvature perturbations

A ``compensated'' isocurvature perturbation consists of an overdensity (or underdensity) in the cold dark matter which is completely cancelled out by a corresponding underdensity (or overdensity) in

Isocurvature, non-gaussianity and the curvaton model

Recent analyses of the statistical distribution of the temperature anisotropies in the cosmic microwave background do not rule out the possibility that there is a large non-Gaussian contribution to

Primordial non-Gaussianity in models with dark matter isocurvature fluctuations

We investigate primordial non-Gaussianity and dark matter isocurvature fluctuations in the modulated reheating and the curvaton scenarios. In these scenarios, a large non-Gaussianity can be

THE IMPACT OF THE SUPERSONIC BARYON–DARK MATTER VELOCITY DIFFERENCE ON THE z ∼ 20 21 cm BACKGROUND

Recently, Tseliakhovich & Hirata showed that during the cosmic Dark Ages the baryons were typically moving supersonically with respect to the dark matter with a spatially variable Mach number. Such

The 21 Centimeter Forest: Radio Absorption Spectra as Probes of Minihalos before Reionization

We study the absorption along lines of sight toward high-z radio sources caused by the 21 cm transition of neutral hydrogen in the intergalactic medium (IGM) before reionization. Using semianalytic

21 cm angular-power spectrum from the dark ages

At redshifts z > or approx. 30 neutral hydrogen gas absorbs cosmic microwave background radiation at the 21 cm spin-flip frequency. In principle this is observable and a high-precision probe of

The shape of the CMB lensing bispectrum

Lensing of the CMB generates a significant bispectrum, which should be detected by the Planck satellite at the 5-sigma level and is potentially a non-negligible source of bias for fNL estimators of

Mass Reconstruction with CMB Polarization

Weak gravitational lensing by the intervening large-scale structure of the Universe induces high-order correlations in the cosmic microwave background (CMB) temperature and polarization fields. We
...