Thursday, July 31, 2014

Galaxy Cluster MCS J0416.1–2403

Galaxy Cluster MCS J0416.1–2403
Click on the image for full resolution (18.5 MB)

This image from the Hubble Space Telescope shows the galaxy cluster MCS J0416.1–2403. This is one of six being studied by the Hubble Frontier Fields programme. This programme seeks to analyse the mass distribution in these huge clusters and to use the gravitational lensing effect of these clusters, to peer even deeper into the distant Universe. A team of researchers used almost 200 images of distant galaxies, whose light has been bent and magnified by this huge cluster, combined with the depth of Hubble data to measure the total mass of this cluster more precisely than ever before. Large clumps of mass in the Universe warp and distort the space-time around them. Acting like lenses, they appear to magnify and bend light that travels through them from more distant objects. Despite their large masses, the effect of galaxy clusters on their surroundings is usually quite minimal. For the most part they cause what is known as weak lensing, making even more distant sources appear as only slightly more elliptical or smeared across the sky. However, when the cluster is large and dense enough and the alignment of cluster and distant object is just right, the effects can be more dramatic. The images of normal galaxies can be transformed into rings and sweeping arcs of light, even appearing several times within the same image. This effect is known as strong lensing, and it is this phenomenon, seen around the six galaxy clusters targeted by the Frontier Fields programme, that has been used to map the mass distribution of MCS J0416.1–2403, using the new Hubble data.
Image Credit: ESA/Hubble, NASA, HST Frontier Fields
Acknowledgement: Mathilde Jauzac (Durham University, UK and Astrophysics & Cosmology Research Unit, South Africa) and Jean-Paul Kneib (École Polytechnique Fédérale de Lausanne, Switzerland)
Image enhancement: Jean-Baptiste Faure

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