Porównanie zdjęć: HAWK-I i Teleskop Hubble'a zbadały gromadę o masie dwóch biliardów mas Słońca

This image shows something spectacular: a galaxy cluster so massive that it is warping the space around it! The cluster, whose heart is at the centre of the frame, is named RCS2 J2327, and is one of the most massive clusters known at its distance or beyond.

Massive objects such as RCS2 J2327 have such a strong influence on their surroundings that they actually warp the space around them — this effect is known as gravitational lensing, and can cause light from more distant objects to be bent, distorted, and amplified, allowing us to see galaxies that would otherwise be far too distant for us to detect. Gravitational lensing is one of the predictions of Albert Einstein's General Theory of Relativity and can be observed in three different regimes: strong lensing, weak lensing, and microlensing. Unlike strong lensing, which produces stunning images of distorted galaxies, sweeping arcs, and phenomena known as Einstein rings, weak gravitational lensing is mostly studied statistically — but offers a way to measure the masses of cosmic objects, as shown here.

This image is a composite of observations from the HAWK-I instrument on ESO’s Very Large Telescope and the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys, and demonstrates an impressively detailed collaborative approach to studying weak lensing in the cosmos. The study found RCS2 J2327 to contain the mass of two quadrillion Suns!

Using the slider a mass map becomes visible, showing the amount of mass thought to be contained within each part of the cluster. The creation of the map was only possible due to the exact measurements on the amount of gravitational lensing in the different areas of the cluster.

Links:

• HAWK-I and Hubble Explore a Cluster with the Mass of two Quadrillion Suns
• Galaxy Cluster RCS2 J2327
• Paper by Schrabback et al.

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ESO