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Etherington duality breaking: Gravitational lensing in non-metric space-times versus intrinsic alignments

Giesel, ES and Ghosh, B and Schäfer, BM (2023) Etherington duality breaking: Gravitational lensing in non-metric space-times versus intrinsic alignments. In: Monthly Notices of the Royal Astronomical Society, 518 (4). pp. 5490-5499.

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Official URL: https://doi.org/10.1093/mnras/stac3445


The Etherington distance duality relation is well-established for metric theories of gravity, and confirms the duality between the luminosity distance and the angular diameter distance through the conservation of surface brightness. A violation of the Etherington distance duality due to lensing in a non-metric space-time would lead to fluctuations in surface brightness of galaxies. Likewise, fluctuations of the surface brightness can arise in classical astrophysics as a consequence of intrinsic tidal interaction of galaxies with their environment. Therefore, we study these in two cases in detail: First, for intrinsic size fluctuations and the resulting changes in surface brightness, and secondly, for an area-metric space-time as an example of a non-metric space-time, where the distance duality relation itself acquires modifications. The aim of this work is to quantify whether a surface brightness fluctuation effect due to area-metric gravity would be resolvable compared to the similar effect caused by intrinsic alignment. We thus compare the auto- and cross-correlations of the angular spectra in these two cases and show that the fluctuations in intrinsic brightness can potentially be measured with a cumulative signal-to-noise ratio ς ≥ 3 in a Euclid-like survey. The measurement in area-metric space-times, however, depends on the specific parameter choices, which also determine the shape and amplitude of the spectra. While lensing surveys do have sensitivity to lensing-induced surface brightness fluctuations in area-metric space-times, the measurement does not seem to be possible for natural values of the Etherington-breaking parameters.

Item Type: Journal Article
Publication: Monthly Notices of the Royal Astronomical Society
Publisher: Oxford University Press
Additional Information: The copyright for this article belongs to the Authors.
Keywords: Astrophysics; Gravitation; Luminance; Parameter estimation; Set theory; Signal to noise ratio; Spectrum analysis; Topology, Breakings; Cosmology: theory; Dark energy; Duality relations; Gravitational lensing: weak; Large scale structure of universe; Metric spaces; Non-metric spaces; Spacetime; Surface brightness, Galaxies
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 15 Jun 2023 08:01
Last Modified: 15 Jun 2023 08:01
URI: https://eprints.iisc.ac.in/id/eprint/81967

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