1709.10378
Missing baryons in the cosmic web revealed by the Sunyaev-Zel'dovich effect
de Graaff, Cai, Haymans, Peacock
Observations of galaxies and galaxy clusters the local universe can account for only 10% of the baryon content inferred from galaxy measurements of the CMB and from nuclear reactions in the early Universe. Locating the remaining 90% of baryons has been one of the major challenges in modern cosmology. Cosmological simulations predict that the 'missing baryons' are spread throughout filamentary structures in the cosmic web, forming a low density gas with temperatures of 1e5-1e7 K. Previous attempts to observe this warm-hot filamentary gas via X-ray emission or absorption in quasar spectra have proven difficult due to its diffuse and low-temperature nature. Here, report a 5.1 sigma detection of warm-hot baryons in stacked filaments through the tSZ effect, which arises from the distortion in the CMB spectrum due to ionized gas. The estimated gas density in these 15 Mph-long filaments is approximately 6x the mean universal baryon density, and overall this can account for ~30% of the total baryon content of the Universe. This result establishes the presence of ionized gas in LS filaments, and suggests that the missing baryons problem may be resolved via observations of the cosmic web.
No comments:
Post a Comment