Imprints of cosmological tensions in reconstructed gravity. (arXiv:2107.12992v1 [astro-ph.CO])

Imprints of cosmological tensions in reconstructed gravity. (arXiv:2107.12992v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Pogosian_L/0/1/0/all/0/1">Levon Pogosian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Raveri_M/0/1/0/all/0/1">Marco Raveri</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Koyama_K/0/1/0/all/0/1">Kazuya Koyama</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Martinelli_M/0/1/0/all/0/1">Matteo Martinelli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Silvestri_A/0/1/0/all/0/1">Alessandra Silvestri</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhao_G/0/1/0/all/0/1">Gong-Bo Zhao</a>

The late-time modifications of the standard $Lambda$ Cold Dark Matter
($Lambda$CDM) cosmological model can be parameterized by three time-dependent
functions describing the expansion history of the Universe and gravitational
effects on light and matter in the Large Scale Structure. In this Letter, we
present the first joint reconstruction of these three functions performed in a
non-parametric way from a combination of recent cosmological observations. The
reconstruction is performed with a theory-informed prior, built on the general
Horndeski class of scalar-tensor theories. We find that current data can
constrain 15 combined modes of these three functions with respect to the prior.
Our methodology enables us to identify the phenomenological features that
alternative theories would need to have in order to ease some of the tensions
between datasets within $Lambda$CDM, and deduce important constraints on broad
classes of modified gravity models.

The late-time modifications of the standard $Lambda$ Cold Dark Matter
($Lambda$CDM) cosmological model can be parameterized by three time-dependent
functions describing the expansion history of the Universe and gravitational
effects on light and matter in the Large Scale Structure. In this Letter, we
present the first joint reconstruction of these three functions performed in a
non-parametric way from a combination of recent cosmological observations. The
reconstruction is performed with a theory-informed prior, built on the general
Horndeski class of scalar-tensor theories. We find that current data can
constrain 15 combined modes of these three functions with respect to the prior.
Our methodology enables us to identify the phenomenological features that
alternative theories would need to have in order to ease some of the tensions
between datasets within $Lambda$CDM, and deduce important constraints on broad
classes of modified gravity models.

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