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ESPRESSO Probes the Fine-structure Constant

M. T. Murphy, P. Molaro, T. M. Schmidt, C. J. A. P. Martins, V. da Fonseca, D. Milaković, G. Cupani, S. Cristiani, V. D'Odorico, T. Barreiro, R. Génova Santos, A. C. O. Leite, C. M. J. Marques, N. J. Nunes, F. Pepe, R. Rebolo López, N. C. Santos, S. G. Sousa, M. R. Zapatero Osorio, M. Amate, V. Zh. Adibekyan, Y. Alibert, C. Allende Prieto, V. Baldini, W. Benz, F. Bouchy, A. Cabral, H. Dekker, P. Di Marcantonio, D. Ehrenreich, P. Figueira, J. I. González Hernández, M. Landoni, C. Lovis, G. Lo Curto, A. Manescau, D. Mégevand, A. Mehner, G. Micela, L. Pasquini, E. Poretti, M. Riva, A. Sozzetti, A. Suárez Mascareño, S. Udry, F. M. Zerbi

The Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations (ESPRESSO) is the new high-resolution spectrograph of ESO’s Very Large Telescope. It was designed for ultra-high radial-velocity precision and extreme spectral fidelity with the aim of performing exoplanet research and fundamental astrophysical experiments with unprecedented precision and accuracy. The first precise ESPRESSO constraint on cosmological variations in the fine-structure constant has been obtained recently by using the laser frequency comb to provide a highly accurate wavelength scale. The target was the famous quasar HE 0515-4414, one of the brightest in the southern sky, with an intervening galaxy at z = 1.15 which imprints metal absorption lines onto the spectrum. The lack of velocity shifts between these lines is consistent with the absence of cosmological variation in the fine-structure constant at the level of about 1 part per million.

The Messenger
Volume 188, Page 15
2022 September

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Faculdade de Ciências da Universidade de Lisboa Universidade do Porto Faculdade de Ciências e Tecnologia da Universidade de Coimbra
Fundação para a Ciência e a Tecnologia COMPETE 2020 PORTUGAL 2020 União Europeia