The phenomenon of gravitational lensing is well known to astronomers. They use it to study distant galaxies. And today, thanks to the sharp eye of the James-Webb Space Telescope, to learn more regarding what they call the“cosmic seahorse”.
The images returned by the James-Webb space telescope sometimes reveal astonishing streaks of light. Arcs that betray the presence of a gravitational lens. The phenomenon appears when a mass large enough to “visibly” bend space-time slips between the instrument and distant galaxies. It is interesting because, as its name suggests, the gravitational lensing effect makes it possible to magnify distant objects. Like a giant magnifying glass offered by nature.
This time, it is the galaxy cluster SDSS J1226+2149, and all the dark matter it contains, itself located some 6.3 billion light-years from our Earth, in the constellation of the Berenice’s hair, which played the role of lens. It shows, on a photograph taken by the NIRCam of the James-Webb space telescope, an image enlarged and deformed into a sort of“cosmic seahorse” from an even more distant galaxy.
Uncover the secrets of star formation
This galaxy had already been observed a few months ago, on images from other instruments. But not in such detail. It lies some 9.6 billion light-years from our Milky Way. And the astronomers had noted there the presence of a mechanism of formation of stars never seen before in a galaxy so distant.
In addition to revealing how quickly stars form and characterizing the environments of those galaxies that gave birth to new stars, these observations once once more show the exceptional capabilities of the James-Webb Space Telescope. They provide very detailed datasets to astronomers who intend to benefit in the future, both from the « vision cristalline » of the instrument, and gravitational lensing phenomena, to further study the mechanism of star formation.