Spectrographs and Spectroscopists for the Sandage Test

Journal
Date Issued
2023
Author(s)
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Boutsia, K.
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Guarneri, F.
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Martins, C.
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Pasquini, L.
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Porru, M.
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DOI
Abstract
The redshift drift is a small, dynamic change in the redshift of objects following the Hubble flow. Its measurement provides a direct, real-time, model-independent mapping of the expansion rate of the Universe. It is fundamentally different from other cosmological probes: instead of mapping our (present-day) past light-cone, it directly compares different past light-cones. Being independent of any assumptions on gravity, geometry or clustering, it directly tests the pillars of the Lambda-CDM paradigm. Recent theoretical studies have uncovered unique synergies with other cosmological probes, including the characterization of the physical properties of dark energy. At the time of the original proposal by Sandage (1962) the expected change in the redshift of objects at cosmological distances appeared to be exceedingly small for reasonable observing times and beyond technological capabilities. In the last decades progress in the spectrographs (e.g. ESPRESSO), in the collecting area of telescopes and in the samples of cosmic beacons, enabled by new datasets and new machine-learning-based selections, have drastically changed the situation, bringing the Redshift Drift Grail within reach. As a consequence, this measurement is a flagship objective of the Extremely Large Telescope (ELT), specifically of its high-resolution spectrograph, ANDES.
Coverage
HACK100
All editors
Bonifacio, P.; Molaro, P.
Volume
94
Start page
251
Conferenece
"Past, Present and Future of Astrophysical Spectroscopy"
Conferenece place
Trieste
Conferenece date
6-10 June, 2022
Uri
Url
Issn Identifier
0037-8720
Ads BibCode
2023MmSAI..94b.251C
Rights
open.access
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