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Résumé |
The NANOGrav Collaboration has recently reported strong evidence for a stochastic
common-spectrum process, which we interpret as a SGWB in the framework of cosmic
strings. The possible NANOGrav signal would correspond to a string tension
Gμ∈(4×10^{−11},10^{−10}) at the 68% confidence level, with a different frequency
dependence from supermassive black hole mergers. The SGWB produced by cosmic
strings with such values of Gμ would be beyond the reach of LIGO, but could be
measured by other planned and proposed detectors such as SKA, LISA, TianQin, AION-
1km, AEDGE, Einstein Telescope and Cosmic Explorer. If this interpretation is
confirmed future GW measurements would also allow us to probe the expansion
history of the Universe to times much before what we can infer from the currently
known data. |
