The first Hubble Space Telescope’s observations in the new BUFFALO project have been published. Its goal is to shed light on the evolution of the first galaxies of the universe, also to establish the most interesting observation targets for the James Webb space telescope. The Abell 370 galaxy cluster is the first to be studied for this new survey together with a series of galaxies seen through gravitational lenses.
The BUFFALO (Beyond Ultra-deep Frontier Fields and Legacy Observations) program is a continuation of a previous program, Frontier Fields, a survey carried out between 2013 and 2017 with the aim to obtain the most in-depth observations of the universe by exploiting the gravitational lensing effects of six galaxy clusters to explore more distant regions. Those galaxy clusters have been chosen because they can help to find other objects that are farther away and would normally be invisible or nearly so, but their light is curved by the huge mass of those clusters, which act as if they were magnifying glasses.
Approximately 4 billion light years from Earth and composed of several hundred galaxies, the Abell 370 cluster is well known from this point of view thanks to previous studies carried out using various telescopes. In 2002 the remote galaxy HCM-6A was discovered using the Keck telescope in Hawaii thanks to that gravitational lensing effect and at the time it was the most distant discovered being 12.8 billion light years from Earth. In 2009, the Hubble Space Telescope enabled the discovery of another spiral galaxy whose image was distorted into multiple images by Abell 370 that was nicknamed “the dragon”, visible at the center of the image.
The Hubble Space Telescope remains at the forefront of this type of study by taking advantage of the experience accumulated over the years, in particular with the Frontier Fields program. Other space and ground-based telescopes have been used repeatedly for deep space observations of the galaxy clusters studied in that program leading to new discoveries that in turn helped to open the way to new Hubble observations.
101 orbits were dedicated to the BUFFALO program, corresponding to 160 hours of observation time of the six galaxy clusters. This is a very long time of use of an instrument that many astronomers would like to exploit. The new observations focus on regions around the galaxy clusters with a wider field of view and greater efficiency in detecting distant galaxies.
The new observations of the BUFFALO program will also allow to improve the mapping of the studied galaxy clusters. This is a 3D mapping that concerns ordinary matter but also dark matter, a further confirmation of the importance of this type of survey as it will help to test dark matter models and alternative ones proposed by those who believe that it doesn’t exist.
Basically, the publication of the images obtained from the BUFFALO program is only the most immediate result, which is spectacular but represents the starting point of a new phase of study. With the delays accumulated in the construction and preparation of the James Webb space telescope it will take years to appreciate all the developments of the Frontier Fields and BUFFALO programs.