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Cosmic String Interpretation of NANOGrav Pulsar Timing Data

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Original languageEnglish
Article number041304
JournalPhysical Review Letters
Issue number4
Published28 Jan 2021

Bibliographical note

Funding Information: This work was supported by the UK STFC Grant No. ST/P000258/1. J. E. also acknowledges support from the Estonian Research Council Grant No. MOBTT5, and M. L. from the Polish National Science Center Grant No. 2018/31/D/ST2/02048. The project is co-financed by the Polish National Agency for Academic Exchange within Polish Returns Programme under Agreement No. PPN/PPO/2020/1/00013/U/00001. Publisher Copyright: © 2021 authors. Published by the American Physical Society. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

King's Authors


Pulsar timing data used to provide upper limits on a possible stochastic gravitational wave background (SGWB). However, 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-1 km, AEDGE, Einstein Telescope, and Cosmic Explorer.

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