Hubble Space Telescope Set to Study The Earliest Galaxies: NASA


A new mission was started by the Hubble Space Telescope to study six massive galaxy clusters that may help shed light on how the earliest galaxies evolved in the universe. Learning about the formation and evolution of the very first galaxies in the universe is crucial for our understanding of the cosmos.

Already some of the most distant galaxies known were detected by the Hubble Space Telescope but their numbers are small, making it hard for astronomers to determine if they represent the universe at large.

Initial observations from the Beyond Ultra-deep Frontier Fields And Legacy Observations (BUFFALO) survey show the galaxy cluster Abell 370 and a host of magnified, gravitationally lensed galaxies around it. Massive galaxy clusters like Abell 370 can help astronomers find more of these distant objects. The immense masses of galaxy clusters make them act as cosmic magnifying glasses.

The universe is a big place. The Hubble Space Telescope’s views burrow deep into space and time, but cover an area a fraction the angular size of the full Moon. The challenge is that these “core samples” of the sky may not fully represent the universe at large. This dilemma for cosmologists is called cosmic variance. By expanding the survey area, such uncertainties in the structure of the universe can be reduced.

The six massive clusters were used as “natural telescopes,” to look for amplified images of galaxies and supernovas that are so distant and faint that they could not be photographed by Hubble without the boost of light caused by a phenomenon called gravitational lensing. The clusters’ large masses, mainly composed of dark matter, magnify and distort the light coming from distant background galaxies that otherwise could not be detected.

BUFFALO’s main mission is to investigate how and when the most massive and luminous galaxies in the universe formed and how early galaxy formation is linked to dark matter assembly. This will allow astronomers to determine how rapidly galaxies formed in the first 800 million years after the Big Bang paving the way for observations with the upcoming James Webb Space Telescope.

The BUFFALO program is jointly led by Charles Steinhardt (Niels Bohr Institute, University of Copenhagen) and Mathilde Jauzac (Durham University, UK), and involves an international team of nearly 100 astronomers from 13 countries, including experts in theory, in computer simulations, and in observations of early galactic evolution, gravitational lensing, and supernovas.  Approximately 160 hours of Hubble observing time is scheduled for the BUFFALO project. The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency).