%0 Generic %1 degraaff2017missing %A de Graaff, Anna %A Cai, Yan-Chuan %A Heymans, Catherine %A Peacock, John A. %D 2017 %K SZ baryons cosmic missing web %T Missing baryons in the cosmic web revealed by the Sunyaev-Zel'dovich effect %U http://arxiv.org/abs/1709.10378 %X Observations of galaxies and galaxy clusters in the local universe can account for only $10\%$ of the baryon content inferred from measurements of the cosmic microwave background 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 $10^5-10^7$ 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 we report a $5.1 \sigma$ detection of warm-hot baryons in stacked filaments through the thermal Sunyaev-Zel'dovich (SZ) effect, which arises from the distortion in the cosmic microwave background spectrum due to ionised gas. The estimated gas density in these 15 Megaparsec-long filaments is approximately 6 times 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 ionised gas in large-scale filaments, and suggests that the missing baryons problem may be resolved via observations of the cosmic web.

@misc{degraaff2017missing, abstract = {Observations of galaxies and galaxy clusters in the local universe can account for only $10\%$ of the baryon content inferred from measurements of the cosmic microwave background 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 $10^5-10^7$ 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 we report a $5.1 \sigma$ detection of warm-hot baryons in stacked filaments through the thermal Sunyaev-Zel'dovich (SZ) effect, which arises from the distortion in the cosmic microwave background spectrum due to ionised gas. The estimated gas density in these 15 Megaparsec-long filaments is approximately 6 times the mean universal baryon density, and overall this can account for $\sim 30\%$ of the total baryon content of the Universe. This result establishes the presence of ionised gas in large-scale filaments, and suggests that the missing baryons problem may be resolved via observations of the cosmic web.}, added-at = {2017-10-02T10:43:34.000+0200}, author = {de Graaff, Anna and Cai, Yan-Chuan and Heymans, Catherine and Peacock, John A.}, biburl = {https://www.bibsonomy.org/bibtex/25acfdf69c226aa6d9d2f7f3be64fa542/miki}, description = {[1709.10378] Missing baryons in the cosmic web revealed by the Sunyaev-Zel'dovich effect}, interhash = {0529ea5a787f57baab1548ff3d62d935}, intrahash = {5acfdf69c226aa6d9d2f7f3be64fa542}, keywords = {SZ baryons cosmic missing web}, note = {cite arxiv:1709.10378Comment: 19 pages, 6 figures, submitted to Nature}, timestamp = {2017-10-02T10:43:34.000+0200}, title = {Missing baryons in the cosmic web revealed by the Sunyaev-Zel'dovich effect}, url = {http://arxiv.org/abs/1709.10378}, year = 2017 }