Panning Across the Starburst Arc


This Hubble image shows a massive galaxy about 4.6 billion light years away. Around that galaxy’s border are four bright arcs. They are images the same distant galaxy nicknamed the Sunburst Arc. The Sunburst Arc galaxy is almost 11 billion light-years away. Its light is lensed into multiple images by gravitational lensing of the nearer galaxy. The Sunburst Arc is one of the brightest lensed galaxies known, and its image is visible at least 12 times within the four arcs.

Video Credit: ESA / NASA / Rivera-Thorsen et al.

A Cosmic Smile


A smiling lensThis is is the galaxy cluster SDSS J1038+4849, and it seems to be smiling with its two orange eyes and white button nose. The two eyes are very bright galaxies, and the misleading smile lines are arcs caused by an effect known as strong gravitational lensing.

Galaxy clusters are the most massive structures in the Universe and exert such a powerful gravitational pull that they warp the spacetime around them. They act as cosmic lenses which can magnify, distort, and bend the light coming from behind them. In this special case of gravitational lensing, a ring—known as an Einstein Ring—is produced by this bending of light. The gaps in the ring are a consequence of the inexact and not-quite-symmetrical alignment of the source, lens, and observer.

Image Credit: ESA / NASA

Icarus


Icarus, officially know as MACS J1149+2223 Lensed Star 1, is the farthest individual star ever seen. It is only visible because it is being magnified by the gravity lensing of a massive galaxy cluster, located about 5 billion light-years from Earth. That cluster, MACS J1149+2223, shown at left, sits between Earth and the galaxy that contains the distant star. Icarus and its galaxy are 9 billion light-years away. The panels at the right show a view taken in 2011 without Icarus visible and after the star was lensed in 2016.

Image Credit: NASA / ESA

Traveling to a Redshift 7 Galaxy


This animation using Hubble images takes us to a distant galaxy 13 billion light-years from the Earth. In that trip we experience how the light is bent by gravitational lensing caused by a massive cluster of galaxies Abell 2218 (the yellow galaxies), and as we make our return journey, we see how the banana-like stretched images of the galaxies are straightened out and in some cases of a very distant galaxy, bent images merge together into one.

Video Credit: ESA

A Cosmic Smile


A smiling lensThis is is the galaxy cluster SDSS J1038+4849, and it seems to be smiling with its two orange eyes and white button nose. The two eyes are very bright galaxies, and the misleading smile lines are arcs caused by an effect known as strong gravitational lensing.

Galaxy clusters are the most massive structures in the Universe and exert such a powerful gravitational pull that they warp the spacetime around them. They act as cosmic lenses which can magnify, distort, and bend the light coming from behind them. In this special case of gravitational lensing, a ring—known as an Einstein Ring—is produced by this bending of light. The gaps in the ring are a consequence of the inexact and not-quite-symmetrical alignment of the source, lens, and observer.

Image Credit: ESA / NASA

Long Ago, In a Galaxy Far Away


In September, 2012, NASA’s Fermi Gamma Ray Telescope detected a series of bright gamma-ray flares from a source known as B0218+357, located 4.35 billion light-years from Earth in the direction of a constellation called Triangulum. These powerful flares in a known gravitational lens system provided the key to making the lens measurement. Long before gamma-ray bursts from B0218+357 reached us, they passed through a face-on spiral galaxy very much like our own about 4 billion light-years away. That galaxy’s gravity bent the light into different paths, so we see the background blazar as dual images. With just a third of an arcsecond (less than 0.0001 degree) between them, the B0218+357 images hold the record for the smallest separation of any lensed system known.

While radio and optical telescopes can resolve and monitor the individual blazar images, Fermi cannot. Instead, the Fermi team exploited a “delayed playback” effect. This movie illustrates the components of the gravitational lens system. Different sight lines to a background blazar resulted in two images that arrived at slightly different times. Fermi made the first gamma-ray measurements of this sort of delay in a lens system

Video Credit: NASA

Seeing Double


Double QuasarTwo objects are clearly visible in this Hubble image, shining brightly side-by-side. When they were first discovered in 1979, the objects were thought to be separate objects, but astronomers soon realized that these twins are too identical! They are close together, lie at the same distance from us, and have surprisingly similar properties. The reason they are so similar is not some bizarre coincidence. They are in fact the same object. They are a double quasar known as QSO 0957+561 (aka  the Twin Quasar). It is among the oldest object we can see,  just under 14 billion light-years from Earth. Quasars are the intensely powerful centers of distant galaxies.

So, do we see this quasar twice?

Directly in our line of sight about 4 billion light-years from Earth is the huge galaxy YGKOW G1. This galaxy is gravitational lens, an object with a mass so great that it can bend the light from objects lying behind it. This phenomenon not only allows us to see objects that would otherwise be too remote, but also, in some instances, it allows us to see them twice. Along with the cluster of galaxies in which it resides, YGKOW G1 exerts an enormous gravitational force which affects the very space it sits in, warping and bending the environment and producing bizarre effects, such as this quasar double image.

Gravitational lensing is evidence for Einstein’s theory of general relativity. This theory had identified gravitational lensing as one of its observable effects, but until the discovery of these quasar “twins,” no such lensing had been observed since the idea was proposed in 1936.

Image Credit: NASA

An Einstein Ring


Gravitational Lens 5921+0638An Einstein ring is a complete circle image of a background galaxy, which is formed when the background galaxy, a massive, foreground galaxy, and the observer are all aligned perfectly. One can be seen in this image of the gravitational lens 5921+0638 taken by the Hubble Space Telescope.

Gravitational lenses occur when light travelling towards us from a distant galaxy is magnified and distorted as it encounters a massive object between the galaxy and the observer. These gravitational lenses can effectively extend the range of a telescope, often allowing astronomers to peer much further back into the early Universe than they normally could.

Image Credit: NASA