The absence of distortion in the cosmic microwave background spectrum and superconducting cosmic strings

Abstract

From the results of recent measurements we place new constraints on superconducting cosmic strings (SCS) and on their cosmological evolution, independently of numerical simulation results. The absence of distortion in the cosmic microwave background radiation (MBR) spectrum recently reported from the preliminary data of the COBE (cosmic background explorer) satellite, together with the available MBR angular temperature Δ T T measurements and the latest fast pulsar timings, allow us to obtain (i) the electromagnetic-to-gravitational radiation ratio released by SCS loops, ƒ⪅2.3 × 10 −2 , (ii) the chemical potential due to SCS, μ 0 scs⪅0.5 × 10 −3, (iii) constraints on the loop evolution parameters which we confront to those given by numerical simulations, and (iv) limits on the string parameter Gμ: those obtained from COBE's data ( Gμ ⪅ 10 −6 converge to those given by the latest PSR 1937 + 21 timing. Both limits on Gμ are reduced by an order of magnitude when taking into account numerical simulation results.