The 21cm radiation from minihalos as a probe of small primordial non-Gaussianity

Abstract

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 background from minihalos containing HI at redshift \sim 6-20, and find a significant enhancement due to small non-Gaussianity with amplitude f_NL \leq 1. This enhancement can be attributed to the nonlinear bias which is strongly increased in the presence of non-Gaussianity. We show that our results are robust against changes in the assumed mass function and some physical aspects of minihalo formation, but are nevertheless sensitive to the presence of strong radiation sources within or around the minihalos. Our findings are relevant for constraining and searching for small primordial non-Gaussianity with upcoming radio telescopes such as LOFAR and SKA.

5 pages. Much improved version. Accepted by MNRAS-Letters

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Cited by in corpus (18)

• Constraining the primordial black hole abundance with 21cm cosmology
• The 21 cm signal and the interplay between dark matter annihilations and astrophysical processes
• Probing small-scale cosmological fluctuations with the 21 cm forest: effects of neutrino mass, running spectral index and warm dark matter
• The Hunt for Primordial Interactions in the Large Scale Structures of the Universe
• Small-scale structure and 21cm fluctuations by primordial black holes
• Constraining warm dark matter with 21 cm line fluctuations due to minihalos
• Cosmological signatures of tilted isocurvature perturbations: reionization and 21cm fluctuations
• Can the 21 cm signal probe Population III and II star formation?
• 21 cm Angular Power Spectrum from Minihalos as a Probe of Primordial Spectral Runnings
• The scale-dependent signature of primordial non-Gaussianity in the large-scale structure of cosmic reionization
• Constraining isocurvature perturbations with the 21cm emission from minihaloes
• The 21-cm signals from ultracompact minihalos as a probe of primordial small-scale fluctuations
• Distribution of primordial black holes and 21cm signature
• Probing primordial non-Gaussianity with 21 cm fluctuations from minihalos
• Probing the primordial Universe with 21-cm line from cosmic dawn/epoch of reionization
• Probing axion dark matter with 21cm fluctuations from minihalos
• Thermal Effects and Sudden Decay Approximation in the Curvaton Scenario
• High redshift signatures in the 21 cm forest due to cosmic string wakes