A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä 
Accurate analytic formula for light bending in Schwarzschild metric
Tekijät: Juri Poutanen
Kustantaja: EDP SCIENCES S A
Julkaisuvuosi: 2020
Lehti:Astronomy and Astrophysics
Tietokannassa oleva lehden nimiASTRONOMY & ASTROPHYSICS
Lehden akronyymi: ASTRON ASTROPHYS
Artikkelin numero: ARTN A24
Vuosikerta: 640
Sivujen määrä: 7
ISSN: 0004-6361
DOI: https://doi.org/10.1051/0004-6361/202037471
Verkko-osoite: https://doi.org/10.1051/0004-6361/202037471
Rinnakkaistallenteen osoite: https://arxiv.org/abs/1909.05732
 Tiivistelmä 
We propose new analytic formulae describing light bending in the Schwarzschild metric. For an emission radii above the photon orbit at the 1.5 Schwarzschild radius, the formulae have an accuracy of better than 0.2% for the bending angle and 3% for the lensing factor for any trajectories that turn around a compact object by less than about 160 degrees. In principle, they can be applied to any emission point above the horizon of the black hole. The proposed approximation can be useful for problems involving emission from neutron stars and accretion discs around compact objects when fast accurate calculations of light bending are required. It can also be used to test the codes that compute light bending using exact expressions via elliptical integrals.
We propose new analytic formulae describing light bending in the Schwarzschild metric. For an emission radii above the photon orbit at the 1.5 Schwarzschild radius, the formulae have an accuracy of better than 0.2% for the bending angle and 3% for the lensing factor for any trajectories that turn around a compact object by less than about 160 degrees. In principle, they can be applied to any emission point above the horizon of the black hole. The proposed approximation can be useful for problems involving emission from neutron stars and accretion discs around compact objects when fast accurate calculations of light bending are required. It can also be used to test the codes that compute light bending using exact expressions via elliptical integrals.
| Ladattava julkaisu  This is an electronic reprint of the original article. | 

