The Absence of the Integrated Sachs-Wolfe Effect: Constraints on a Cosmological Constant

摘要

The hard X-ray background (XRB) provides a tracer of matter out to a redshift of z approx= 4. If the universe is open or has a signih'cant cosmological constant, then the cosmic microwave background (CMB) and XRB should be correlated due to the integrated Sachs-Wolfe (ISW) effect. A comparison of the COBE CMB map with HEAO1 A2 2-10 keV map of the XRB shows no such correlation. If the X-ray bias factor is on the order of 2-3 as implied by the clustering of the XRB, the implied 95% CL upper limit on a cosmological constant is Ω_Λ approx< 0.60.