An international team of astronomers has done, thanks to Hubble telescope, an unexpected find: a new dwarf galaxy in «our cosmic backyard», only 30 million light years away and almost as old as the Universe itself.
The data of this new galaxy are published in the Monthly Notices of the Royal Astronomical Society.
According to reports in both the NASA and the European Space Agency (ESA), researchers studied white dwarf stars in the globular cluster NGC 6752, with the aim of measuring the age of the aforementioned cluster, when they made the surprise discovery.
«In a heavenly game of where is Wally? Hubble's sharp vision found a dwarf galaxy never before seen, located far behind the crowded star population of the cluster », says NASA.
Thus, the researchers saw a compact collection of stars on the outer edges of the area observed with the Hubble Advanced camera.
After a careful analysis of their brightness and temperatures, they concluded that these stars did not belong to the cluster – which is part of the Milky Way – but that they are millions of light years more distant, ESA explains.
This new cosmic neighbor, nicknamed Bedin 1, it is an elongated galaxy, modest in size and incredibly weak, properties that led astronomers to classify it as a spheroidal dwarf galaxy.
This type of galaxies are defined by their small size, low luminosity or lack of dust; 36 of these galaxies are already known in the Local Group – a set of galaxies in which the Milky Way is found – and 22 of them are satellites of our galaxy.
While dwarf spheroidal galaxies are not uncommon, Bedin 1 has some remarkable characteristics, according to scientists: not only is it one of the few dwarf spheroids that have a well-established distance, but it is also extremely isolated.
It is about 30 million light-years from the Milky Way and 2 million light-years from which galaxy NGC 6744; this possibly makes it the most isolated small dwarf galaxy discovered to date.
It is about 13,000 million years old, almost as old as the Universe itself: "due to its isolation -product of its little interaction with other galaxies- and its age, Bedin 1 is the astronomical equivalent of a living fossil of the primitive universe. "
In this work they participate, among others, scientists of the Italian National Institute of Astrophysics (INAF), the University of California in the USA, the one of Montreal in Canada or the University John Moores of Liverpool. EFE