Missing matter found in the cosmic web

Synopsis

Approximately 95% of the energy density of the universe is due to Dark Energy and Dark Matter with only 5% being due to regular baryonic matter (protons and neutrons). While the mystery of the origin and composition of Dark Energy and Dark Matter are very compelling, this presentation will be concerning the lesser known mystery of missing baryonic matter. Baryonic matter observed in stars and galaxy clusters only accounts for 50% of the expected baryonic matter, the remainder, until recently has yet to be identified. It has been proposed that the remainder of the baryonic matter is contained in web-like filaments that connect clusters of galaxies. Two recent papers independently report 5 sigma detection of warm/hot gas filaments between pairs of galaxies [1] [2]. In this presentation I will discuss the data sets, analysis techniques employed, and underlying physics for these new results.

[1] H. Tanimura, G. Hinshaw, I. G. McCarthy, L. Van Waerbeke, Y.-Z. Ma, A. Mead, A. Hojjati, and T. Troster. A Search for Warm/Hot Gas Filaments Between Pairs of SDSS Luminous Red Galaxies. ArXiv e-prints, September 2017.

[2] A. de Graa_, Y.-C. Cai, C. Heymans, and J. A. Peacock. Missing baryons in the cosmic web revealed by the Sunyaev-Zel'dovich e_ect. ArXiv e-prints, September 2017.