The kinetic Sunyaev-Zel'dovich effect of the milky way halo

Yuval Birnboim*, Abraham Loeb

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


We calculate the expected imprint of the ionized gas in the Milky-Way halo on the Cosmic Microwave Background (CMB) through the kinetic Sunyaev-Zel'dovich (kSZ) effect. Unlike other Galactic foregrounds, the halo kSZ signature covers the full sky, generates anisotropies on large angular scales, is not accompanied by spectral distortions, and could therefore be confused with primordial CMB anisotropies. We construct theoretical models for various halo components, including smooth diffuse gas, filaments of cold inflowing gas and high velocity clouds. We find that the kSZ effect for all components is above the sensitivity of the Planck satellite, over a range of angular scales. However, the typical halo contribution is well below the cosmic variance noise in the primordial CMB power spectrum. High velocity clouds could dominate the halo contribution and better observational data is required to mask them out. We derive expected kSZ maps based on existing data from tracers of the halo gas distribution, such as 21cm maps of neutral hydrogen and H α maps of recombining gas. The cross-correlation of these maps with the WMAP5 data does not yield any statistically significant signal.

Original languageAmerican English
Article number008
JournalJournal of Cosmology and Astroparticle Physics
Issue number6
StatePublished - 2009
Externally publishedYes


Dive into the research topics of 'The kinetic Sunyaev-Zel'dovich effect of the milky way halo'. Together they form a unique fingerprint.

Cite this