Four direct measurements of the fine-structure constant 13 billion years ago.
Bosman, Sarah EI
American Association for the Advancement of Science
MetadataShow full item record
Wilczynska, M. R., Webb, J. K., Bainbridge, M., Barrow, J., Bosman, S. E., Carswell, R. F., Dąbrowski, M. P., et al. (2020). Four direct measurements of the fine-structure constant 13 billion years ago.. Science advances, 6 (17), eaay9672. https://doi.org/10.1126/sciadv.aay9672
Observations of the redshift z = 7:085 quasar J1120+0641 have been used to search for variations of the fine structure constant, a, over the redshift range 5:5 to 7:1. Observations at z = 7:1 probe the physics of the universe when it was only 0.8 billion years old. These are the most distant direct measurements of a to date and the first measurements made with a near-IR spectrograph. A new AI analysis method has been employed. Four measurements from the X-SHOOTER spectrograph on the European Southern Observatory’sVery Large Telescope (VLT) directly constrain any changes in a relative to the value measured on Earth (a0). The weighted mean strength of the electromagnetic force over this redshift range in this location in the universe deviates from the present-day terrestrial alue by an amount Da/a = (az--a0)/a0 = (-2:18+/-7:27)x10-5. We thus find no evidence for a temporal change from these 4 new very high redshift measurements. Combining the 4 new measurements with a large sample of existing lower redshift measurements, we derive a new constraint on possible spatial variation; the data suggest thata spatial variation is marginally preferred over a no-variation model at the 3.9 sigma level.
Results are based on observations collected at the European Southern Observatory, Chile, programs 286.A-5025(A), 089.A-0814(A), and 093.A-0707(A). We are grateful for the award of computing time for this research on the gStar and OzStar supercomputing facilities. MRW acknowledges support from an Australian Postgraduate Award. JKW thanks the John Templeton Foundation, the Department of Applied Mathematics and Theoretical Physics and the Institute of Astronomy at Cambridge University for hospitality and support, and Clare Hall for a Visiting Fellowship. The work of ACL and CJM was financed by FEDER—Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020—Operational Programme for Competitiveness and Internationalisation (POCI), and by Portuguese funds through FCT—Fundação para a Ciência e a Tecnologia in the framework of the project POCI-01-0145-FEDER-028987. ACL is supported by an FCT fellowship (SFRH/BD/113746/2015), under the FCT Doctoral Program PhD::SPACE (PD/00040/2012). We thank Julian King for useful discussions. JDB thanks the STFC for support. SB acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 669253). .
External DOI: https://doi.org/10.1126/sciadv.aay9672
This record's URL: https://www.repository.cam.ac.uk/handle/1810/305010
Attribution-NonCommercial 4.0 International
Licence URL: https://creativecommons.org/licenses/by-nc/4.0/