Light bending in f(T) gravity

Abstract

In the framework of [Formula: see text] gravity, we focus on a weak-field and spherically symmetric solution for the Lagrangian [Formula: see text], where [Formula: see text] is a small constant which parametrizes the departure from general relativity (GR). In particular, we study the propagation of light and obtain the correction to the general relativistic bending angle. Moreover, we discuss the impact of this correction on some gravitational lensing observables, and evaluate the possibility of constraining the theory parameter [Formula: see text] by means of observations. In particular, on taking into account the astrometric accuracy in the Solar System, we obtain that [Formula: see text]; this bound is looser than those deriving from the analysis of Solar System dynamics, e.g. [Formula: see text] [L. Iorio, N. Radicella and M. L. Ruggiero, J. Cosmol. Astropart. Phys. 1508 (2015) 021, arXiv:1505.06996 [gr-qc].], [Formula: see text] [L. Iorio and E. N. Saridakis, Mon. Not. R. Astron. Soc. 427 (2012) 1555, arXiv:1203.5781 [gr-qc].] or [Formula: see text] [Y. Xie and X. M. Deng, Mon. Not. R. Astron. Soc. 433 (2013) 3584, arXiv:1312.4103 [gr-qc].]. However, we suggest that, since the effect only depends on the impact parameter, better constraints could be obtained by studying light bending from planetary objects.