SZ effects from annihilating dark matter in the Milky Way: smooth halo, subhalos and intermediate-mass-black-holes

Abstract

We study the Sunyaev-Zel'dovich effect potentially generated by relativistic electrons injected from dark matter annihilation or decay in the Galaxy, and check whether it could be observed by Planck or the Atacama Large Millimeter Array (ALMA), or even imprint the current CMB data as, e.g., the specific fluctuation excess claimed from an recent reanalysis of the WMAP-5 data. We focus on high-latitude regions to avoid contamination of the Galactic astrophysical electron foreground, and consider the annihilation or decay coming from the smooth dark matter halo as well as from subhalos, further extending our analysis to a generic modeling of spikes arising around intermediate-mass black holes. We show that all these dark Galactic components are unlikely to produce any observable Sunyaev-Zel'dovich effect. For a self-annihilating dark matter particle of 10 GeV with canonical properties, the largest optical depth we find is ${\tau }_e\lesssim 10^{-7}$ for massive isolated subhalos hosting intermediate-mass black holes. We conclude that dark matter annihilation or decay on the Galactic scale cannot lead to significant Sunyaev-Zel'dovich distortions of the CMB spectrum.

14 pages, 6 figures. V2: Minor changes to match the published version

References in corpus (10)

• Measurement of the Cosmic Ray e+ plus e- spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope
• A blueprint for detecting supersymmetric dark matter in the Galactic halo
• Constraints on WIMP Dark Matter from the High Energy PAMELA $\bar{p}/p$ data
• Detecting dark matter WIMPs in the Draco dwarf: a multi-wavelength perspective
• Dynamics of galaxy cores and supermassive black holes
• Antiproton and Positron Signal Enhancement in Dark Matter Mini-Spikes Scenarios
• Black Holes as Dark Matter Annihilation Boosters
• Analytical Study on the Sunyaev-Zeldovich Effect for Clusters of Galaxies
• Clarifying the covariant formalism for the SZ effect due to relativistic non-thermal electrons
• Constraints on the SZ Power Spectrum on Degree Angular Scales in WMAP Data

Cited by in corpus (1)

• Diffuse gamma-ray constraints on dark matter revisited. I: the impact of subhalos