NASA’s Hubble Space Telescope has taken a close-up view of the brightest distant ‘magnified’ galaxy known to date.
A team of astronomers, led by Jane Rigby of NASA’s Goddard Space Flight Center, used Hubble to observe a distant galaxy magnified by a 90-degree arc of light in the galaxy cluster RCS2 032727 – 132623.
The foreground galaxy cluster is about 5 billion light-years away, while the ‘magnified’ galaxy lies at a distance of nearly 10 billion light-years away. Hubble’s view of the background galaxy is significantly more detailed than could ever be achieved without the help of the gravitational lens.
This striking example of gravitational lensing, where the gravitational field of a foreground galaxy bends and amplifies the light of a more distant background galaxy, is described in the paper, accepted for publication in the Astrophysical Journal.
The background galaxy’s image is 20 times larger and over three times brighter than typically lensed galaxies.
A so-called gravitational lens is produced when space is warped by a massive foreground object, whether it is the Sun, a black hole or an entire cluster of galaxies. The light from more-distant background objects is distorted, brightened and magnified as it passes through this gravitationally disturbed region.
The distorted image of the galaxy is repeated several times in the foreground lensing cluster, as is typical of gravitational lenses. The challenge for astronomers was to reconstruct what the galaxy really looked like, were it not distorted by the cluster’s funhouse-mirror effect.
The presence of the lens provides a unique opportunity to study the physical properties of a galaxy vigorously forming stars when the Universe was only one-third its present age.