Data revealed the existence of this galaxy, that until this point had not been identified. Astronomers use a metric known as red-shift to estimate 'intergalactic' distance and SMMJ2135-0102 is apparently twice as far away as the galaxies they were originally observing (c10 billion light years away). What they were observing, in fact, was the galaxy in its form as it was roughly 3.5 billion years after the Big Bang.
According to Einsteins Theory of Relativity (which suffice to say I know nothing about) the group of galaxies gravity was bending light from SMMJ2135-0102 'sitting' behind it, in effect becoming one big magnifying glass; supposedly boosting the perceived size of the galaxy around 32 times.
Astronomers have since identified stars forming within SMMJ2135-0102; regions the size of the Milky Way but 100 times brighter; indicating that star formation was a lot more healthy and concentrated then compared to today. I will stop now, as I am confusing myself. I honestly don't pretend to know what this is all about; I only try to make sense of it all....
SMMJ2135-0102 (artists impression)
"A fortuitous alignment of celestial objects allowed astronomers to snap their sharpest image to date of star-making regions in a galaxy about 10 billion light-years from Earth. Large bright clouds in this artist’s rendering of the distant galaxy SMM J2135-0102 are sites of vigorous star formation."
SMMJ2135-0102 (artists impression with observations overlaid as contours)
Hubble Space Telescope Image
Digitised Sky-Survey of the field of the galaxy cluster
Hubble Space Telescope plus far-infrared colour composition
"This false-color composite image shows the foreground galaxy cluster (center of left image) that acts as a gravitational lens, the magnified view of the remote galaxy SMM J2135-0102 (top right image, in red) and individual star-forming clouds in the galaxy (bottom right). The magnification of the distant galaxy by the foreground cluster creates a mirage, doubling the actual number of star-forming clouds."