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sight19 t1_ithl319 wrote

Reply to comment by bk15dcx in James Webb revisited gravitational-lensing cluster Abell 2744 this week - and I spent hours processing and cleaning hundreds of cosmic ray artifacts to reveal the faintest details, yet unseen, in glorious six-color 4k+ by Riegel_Haribo

Dark matter of the galaxy cluster is causing lensing. It actually warps background galaxies even on relatively large angular distances from the cluster (what we call 'weak lensing'). This only produce a small effect, but if we stack this effect, we can effectively 'draw in' the shape and location of the DM in the cluster. This has been done before, in for example the Bullet cluster or the Toothbrush cluster (I know, we are really creative with names here...)

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