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Cosmic dynamics in the era of Extremely Large Telescopes |
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| Authors: | J Liske A Grazian E Vanzella M Dessauges M Viel L Pasquini M Haehnelt S Cristiani F Pepe G Avila P Bonifacio F Bouchy H Dekker B Delabre S D'Odorico V D'Odorico S Levshakov C Lovis M Mayor P Molaro L Moscardini M T Murphy D Queloz P Shaver S Udry T Wiklind S Zucker |
| Institution: | European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany;INAF –Osservatorio Astronomico di Roma, via di Frascati 33, 00040 Monteporzio Catone, Roma, Italy;INAF –Osservatorio Astronomico di Trieste, Via Tiepolo 11, 34143 Trieste, Italy;Observatoire de Genève, 51 Ch. des Maillettes, 1290 Sauverny, Switzerland;Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA;CIFIST Marie Curie Excellence Team, GEPI, Observatoire de Paris, CNRS, UniversitéParis Diderot, Place Jules Janssen 92190 Meudon, France;Laboratoire d'Astrophysique de Marseille, Traverse du Siphon, 13013 Marseille, France;Observatoire de Haute-Provence, 04870 St Michel l'Observatoire, France;Department of Theoretical Astrophysics, Ioffe Physico-Technical Institute, 194021 St Petersburg, Russia;Dipartimento di Astronomia, Universitàdi Bologna, via Ranzani 1, 40127 Bologna, Italy;INFN –National Institute for Nuclear Physics, Sezione di Bologna, viale Berti Pichat 6/2, 40127 Bologna, Italy;Centre for Astrophysics &Supercomputing, Swinburne University of Technology, Hawthorn, VIC 3122, Australia;Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA;Affiliated with the Space Sciences Department of the European Space Agency;Department of Geophysics and Planetary Sciences, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel |
| Abstract: | The redshifts of all cosmologically distant sources are expected to experience a small, systematic drift as a function of time due to the evolution of the Universe's expansion rate. A measurement of this effect would represent a direct and entirely model-independent determination of the expansion history of the Universe over a redshift range that is inaccessible to other methods. Here we investigate the impact of the next generation of Extremely Large Telescopes on the feasibility of detecting and characterizing the cosmological redshift drift. We consider the Lyα forest in the redshift range 2 < z < 5 and other absorption lines in the spectra of high-redshift QSOs as the most suitable targets for a redshift drift experiment. Assuming photon-noise-limited observations and using extensive Monte Carlo simulations we determine the accuracy to which the redshift drift can be measured from the Lyα forest as a function of signal-to-noise ratio and redshift. Based on this relation and using the brightness and redshift distributions of known QSOs we find that a 42-m telescope is capable of unambiguously detecting the redshift drift over a period of ∼20 yr using 4000 h of observing time. Such an experiment would provide independent evidence for the existence of dark energy without assuming spatial flatness, using any other cosmological constraints or making any other astrophysical assumption. |
| Keywords: | intergalactic medium quasars: absorption lines cosmology: miscellaneous |