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

Giesel, E. S. and Ghosh, B. (2022) Etherington duality breaking: gravitational lensing in non-metric space – times versus intrinsic alignments. [Publications (Pre-joining)]

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Abstract

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(ℓ) ≥ 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:	Publications (Pre-joining)
Authors:	Giesel, E. S. and Ghosh, B.
Document Language:	Language English
Uncontrolled Keywords:	gravitation, gravitational lensing: weak, dark energy, large-scale structure of Universe, cosmology: theory
Subjects:	Natural Sciences > Astronomy & allied sciences Natural Sciences > Physics
Divisions:	Azim Premji University - Bengaluru > School of Arts and Sciences
Full Text Status:	Public
URI:	http://publications.azimpremjiuniversity.edu.in/id/eprint/6452
Publisher URL:	https://academic.oup.com/mnras

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