Sunyaev-Zel'dovich distortion from early galactic winds

Abstract

We consider the distortion in the cosmic microwave background (CMB) resulting from galactic winds at high redshift. Winds outflowing from galaxies have been hypothesized to be possible sources of metals in the intergalactic medium, which is known to have been enriched to 10-2.5Z⊙ at z ∼ 3. We model these winds as functions of mass of the parent galaxy and redshift, assuming that they activate at a common initial redshift, zin, and calculate the mean y-distortion and the angular power spectrum of the distortion in the CMB. We find that the thermal Sunyaev-Zel'dovich (SZ) effect resulting from the winds is consistent with previous estimates. The distortion arising from the kinetic SZ (kSZ) effect is, however, found to be more important than the thermal SZ (tSZ) effect. We find that the distortion resulting from galactic winds is an important contribution to the power spectrum of distortion at very small angular scales (l ∼ 104). We also find that the power spectrum resulting from clustering dominates the Poisson power spectrum for l ≤ (4-5) × 105. We show explicitly how the combined power spectrum from wind dominates over that of clusters at 217 GHz, relevant for PLANCK. We also show how these constraints change when the efficiency of the winds is varied.