• Featured in Physics
  • Editors' Suggestion
  • Rapid Communication

Shedding light on the small-scale crisis with CMB spectral distortions

Tomohiro Nakama, Jens Chluba, and Marc Kamionkowski
Phys. Rev. D 95, 121302(R) – Published 28 June 2017
Physics logo See Synopsis: Tackling the Small-Scale Crisis

Abstract

The small-scale crisis, discrepancies between observations and N-body simulations, may imply suppressed matter fluctuations on subgalactic distance scales. Such a suppression could be caused by some early-universe mechanism (e.g., broken scale invariance during inflation), leading to a modification of the primordial power spectrum at the onset of the radiation-domination era. Alternatively, it may be due to nontrivial dark-matter properties (e.g., new dark-matter interactions or warm dark matter) that affect the matter power spectrum at late times, during radiation domination, after the perturbations reenter the horizon. We show that early- and late-time suppression mechanisms can be distinguished by measurement of the μ distortion to the frequency spectrum of the cosmic microwave background. This is because the μ distortion is suppressed, if the power suppression is primordial, relative to the value expected from the dissipation of standard nearly scale-invariant fluctuations. We emphasize that the standard prediction of the μ distortion remains unchanged in late-time scenarios even if the dark-matter effects occur before or during the era (redshifts 5×104z2×106) at which μ distortions are generated.

  • Figure
  • Figure
  • Received 31 March 2017

DOI:https://doi.org/10.1103/PhysRevD.95.121302

© 2017 American Physical Society

Physics Subject Headings (PhySH)

Gravitation, Cosmology & Astrophysics

Synopsis

Key Image

Tackling the Small-Scale Crisis

Published 28 June 2017

Precise measurement of the cosmic microwave background could solve a problem of current cosmological models known as the small-scale crisis.

See more in Physics

Authors & Affiliations

Tomohiro Nakama1, Jens Chluba2, and Marc Kamionkowski1

  • 1Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA
  • 2Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 95, Iss. 12 — 15 June 2017

Reuse & Permissions
Access Options
CHORUS

Article Available via CHORUS

Download Accepted Manuscript
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review D

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×