Astronomers have found 72 potential galaxies hiding in plain sight inside a vast patch of the sky previously observed by the Hubble Space Telescope. The discovery not only gives astronomers new targets to study, but also will aid studies of star motion and formation and other properties of old galaxies, the researchers said.
The new study was performed by the MUSE instrument on the European Southern Observatory’s Very Large Telescope in Chile. Astronomers discovered the newfound galaxies while measuring the distances and properties of 1,600 galaxies captured by the Hubble Space Telescope during its Ultra Deep Field survey.
The 72 newfound galaxies shine in Lyman-alpha light, which is a particular wavelength of ultraviolet light. Because the galaxies are receding from us, their wavelength was stretched from ultraviolet to visible, or near-infrared. [26 Stunning Photos from the Hubble Ultra Deep Field]
The discoveries were made in the Hubble Ultra Deep Field, which is a tiny region of the sky in the southern constellation Fornax (the Furnace). The Hubble data were originally obtained in 2004, two years after NASA space shuttle astronauts visited the space telescope to install the Advanced Camera for Surveys (ACS) and perform other needed maintenance.
Using ACS, Hubble peered at a small region of the sky and found galaxies that had formed less than 1 billion years after the Big Bang, which kick-started the universe. (The Big Bang took place about 13.8 billion years ago, making those galaxies more than 12.8 billion years old.)….more here