Using a thermal Sunyaev-Zel ’ dovich ( tSZ ) signal , we search for hot gas in superclusters identified using the Sloan Digital Sky Survey Data Release 7 ( SDSS/DR7 ) galaxies .
We stack a Comptonization y map produced by the Planck Collaboration around the superclusters and detect the tSZ signal at a significance of 6.4 \sigma .
We further search for an intercluster component of gas in the superclusters .
For this , we remove the intracluster gas in the superclusters by masking all galaxy groups/clusters detected by the Planck tSZ , ROSAT X-ray , and SDSS optical surveys down to a total mass of 10 ^ { 13 } { M } _ { \odot } .
We report the first detection of intercluster gas in superclusters with y = ( 3.5 \pm 1.4 ) \times 10 ^ { -8 } at a significance of 2.5 \sigma .
Assuming a simple isothermal and flat density distribution of intercluster gas over superclusters , the estimated baryon density is ( \Omega _ { gas } / \Omega _ { b } ) \times ( T _ { e } / 8 \times 10 ^ { 6 } { K } ) = 0.0 % 67 \pm 0.006 \pm 0.025 .
This quantity is inversely proportional to the temperature , therefore taking values from simulations and observations , we find that the gas density in superclusters may account for 17 - 52 % of missing baryons at low redshifts .
A better understanding of the physical state of gas in the superclusters is required to accurately estimate the contribution of our measurements to missing baryons .