The phenomenon of so-called gravitational lensing produced by massive cosmic entities, including galaxies, their clusters, and also massive black holes, has been exploited by astronomers for several decades now. Using gravitational lenses, scientists are able to explore greater depths of the Universe, find new distant objects or determine various cosmological parameters, since these lenses act like a magnifying glass allowing to observe and detect light propagating from sources which could not be observed otherwise.
Until now it was considered that the mass of object which causes the effect of gravitational lens is the main factor determining the magnitude of lens-related spacetime distortion. But now scientists from Hunan University of Humanities, Science and Technology in China have presented their research (at arXiv.org), which postulates the impact of dark energy on the strength of gravitational lens effect.
Apparently, such idea was quite logical, since many scientific teams agree that the dark energy and dark matter exists, and, in fact, constitutes a large part of all matter in our Universe. Therefore, it was necessary to verify the manifestations of dark energy in ‘lesser’ scale compared to galaxies or entire Universe: black holes.
Black holes are relatively ‘compact’ sources of strong gravitational fields. There have been at least several studies already in which astronomers had discussed the fact that the dark energy participates in the accretion of black holes. Naturally, dark energy, when present in the vicinity of such strong gravitation, could provide additional source of space-time distortion.
The team performed numerical calculations which indicate, that gravitational lensing is more strong at the presence of dark energy. Theoretical estimation assumed the gravitational lens created by the supermassive black hole at the center of our Milky Way galaxy. The magnitude of this effect was compared in cases when supermassive black hole acts alone and when the dark energy-related phantom field is taken into account.
Calculations indicate that dark energy contributes to gravitational lensing, although the difference is not substantial. Also, from theoretical point of view, calculations yield to some degree different results for different mathematical models of black holes. Authors admit that their results have yet to be confirmed by astronomical observations using space telescopes and with sufficiently precise equipment for astronomical measurements.
By Alius Noreika, source: Technology.org