Imprint of f(R) gravity in the cosmic magnification. (arXiv:2210.09303v2 [astro-ph.CO] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Duniya_D/0/1/0/all/0/1">Didam Duniya</a> (BIUST), <a href="http://arxiv.org/find/astro-ph/1/au:+Abebe_A/0/1/0/all/0/1">Amare Abebe</a> (NWU, NITheCS), <a href="http://arxiv.org/find/astro-ph/1/au:+Cruz_Dombriz_A/0/1/0/all/0/1">Alvaro de la Cruz-Dombriz</a> (de Salamanca, Cape Town), <a href="http://arxiv.org/find/astro-ph/1/au:+Dunsby_P/0/1/0/all/0/1">Peter Dunsby</a> (Cape Town)
f(R) gravity is one of the simplest viable modifications to General
Relativity: it passes local astrophysical tests, predicts both the early-time
cosmic inflation and the late-time cosmic acceleration, and also describes dark
matter. In this paper, we probe cosmic magnification on large scales in f(R)
gravity, using the well-known Hu-Sawicki model as an example. Our results
indicate that at redshifts z < 3, values of the model exponent n > 1 lead to
inconsistent behaviour in the evolution of scalar perturbations. Moreover, when
relativistic effects are taken into account in the large scale analysis, our
results show that as z increases, large-scale changes in the cosmic
magnification angular power spectrum owing to integral values of n tend to
share a similar pattern, while those of decimal values tend to share another.
This feature could be searched for in the experimental data, as a potential
“smoking gun” for the given class of gravity models. Furthermore, we found that
at z = 1 and lower, relativistic effects lead to a suppression of the cosmic
magnification on large scales in f(R) gravity, relative to the concordance
model; whereas, at z > 1, relativistic effects lead to a relative boost of the
cosmic magnification. In general, relativistic effects enhance the potential of
the cosmic magnification as a cosmological probe.
f(R) gravity is one of the simplest viable modifications to General
Relativity: it passes local astrophysical tests, predicts both the early-time
cosmic inflation and the late-time cosmic acceleration, and also describes dark
matter. In this paper, we probe cosmic magnification on large scales in f(R)
gravity, using the well-known Hu-Sawicki model as an example. Our results
indicate that at redshifts z < 3, values of the model exponent n > 1 lead to
inconsistent behaviour in the evolution of scalar perturbations. Moreover, when
relativistic effects are taken into account in the large scale analysis, our
results show that as z increases, large-scale changes in the cosmic
magnification angular power spectrum owing to integral values of n tend to
share a similar pattern, while those of decimal values tend to share another.
This feature could be searched for in the experimental data, as a potential
“smoking gun” for the given class of gravity models. Furthermore, we found that
at z = 1 and lower, relativistic effects lead to a suppression of the cosmic
magnification on large scales in f(R) gravity, relative to the concordance
model; whereas, at z > 1, relativistic effects lead to a relative boost of the
cosmic magnification. In general, relativistic effects enhance the potential of
the cosmic magnification as a cosmological probe.
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