The effects of the small-scale behaviour of dark matter power spectrum on CMB spectral distortion

Abstract

After numerous astronomical and experimental searches, the precise particle nature of dark matter is still unknown. The standard Weakly Interacting Massive Particle(WIMP) dark matter, despite successfully explaining the large-scale features of the universe, has long-standing small-scale issues. The spectral distortion in the Cosmic Microwave Background(CMB) caused by Silk damping in the pre-recombination era allows one to access information on a range of small scales $0.3\mathrm{Mpc}<k<10^4\mathrm{Mp}{\mathrm{c}}^{-1}$, whose dynamics can be precisely described using linear theory. In this paper, we investigate the possibility of using the Silk damping induced CMB spectral distortion as a probe of the small-scale power. We consider four suggested alternative dark matter candidates---Warm Dark Matter (WDM), Late Forming Dark Matter, Ultra Light Axion dark matter and Charged Decaying Dark Matter; the matter power in all these models deviate significantly from the $\Lambda$CDM model at small scales. We compute the spectral distortion of CMB for these alternative models and compare our results with the $\Lambda$CDM model. We show that the main impact of alternative models is to alter the sub-horizon evolution of the Newtonian potential which affects the late-time behaviour of spectral distortion of CMB. The $y$-parameter diminishes by a few percent as compared to the $\Lambda$CDM model for a range of parameters of these models: LFDM for formation redshift $z_f=10^5$ (7\%); WDM for mass $m_{\mathrm{wdm}}=1\mathrm{keV}$ (2\%); CHDM for decay redshift $z_{\mathrm{decay}}=10^5$ (5\%); ULA for mass $m_a=10^{-24}\mathrm{eV}$ (3\%). We also briefly discuss the detectability of this deviation in light of the upcoming CMB experiment PIXIE, which might have the sensitivity to detect this signal from the pre-recombination phase.

21 Pages, 7 figures. Accepted in JCAP

References in corpus (20)

• A direct empirical proof of the existence of dark matter
• Ultralight scalars as cosmological dark matter
• Cosmological Constraints from the SDSS Luminous Red Galaxies
• Too big to fail? The puzzling darkness of massive Milky Way subhaloes
• Cosmic Structure as the Quantum Interference of a Coherent Dark Wave
• Results from a Low-Energy Analysis of the CDMS II Germanium Data
• A search for ultra-light axions using precision cosmological data
• First Dark Matter Results from the XENON100 Experiment
• Cosmic-ray positron fraction measurement from 1 to 30 GeV with AMS-01
• Axion dark matter, solitons, and the cusp-core problem
• The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations in Fourier-space
• Too Big to Fail in the Local Group
• Constraints on the Dark Matter Particle Mass from the Number of Milky Way Satellites
• Ultra-Light Scalar Fields and the Growth of Structure in the Universe
• Beyond y and μ: the shape of the CMB spectral distortions in the intermediate epoch, 1.5x10^4 < z < 2x10^5
• Lines in the Cosmic Microwave Background Spectrum from the Epoch of Cosmological Hydrogen Recombination
• Mixing of blackbodies: entropy production and dissipation of sound waves in the early Universe
• Creation of the CMB spectrum: precise analytic solutions for the blackbody photosphere
• How Late can the Dark Matter form in our universe?
• Evolution of CMB spectral distortion anisotropies and tests of primordial non-Gaussianity

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• Impact of kinetic and potential self-interactions on scalar dark matter
• Ballistic Dark Matter oscillates above $\Lambda$CDM
• Using the redshift evolution of the Lyman-$\alpha$ effective opacity as a probe of dark matter models
• Dark matter kinetic decoupling with a light particle
• Modified initial power spectrum and too big to fail problem
• Smallest Halos in Thermal Wino Dark Matter
• Cosmological constraints on mass-varying dark matter
• More power on large scales