Hubble Space Telescope emerged victorious from a cosmic game of hide and seek. NASA is coming
to announce the discovery of a dwarf galaxy long obscured by the glow of a star (TYC 7215-199-1) in the foreground. But the latter has changed position in recent decades, revealing this strange dwarf galaxy called “Peekaboo”, the English word used when playing hide and seek. It offers a glimpse of what galaxies were like in the early ages of the universe.
Located 20 million light-years from Earth, which is close enough to us for a galaxy, Peekaboo is, according to scientists ” extremely low in metals “. This means that it is composed largely of hydrogen and helium and is devoid of the heavier elements that make up our world and life itself, such as carbon, oxygen and iron.
However, it is believed that the first galaxies that formed shortly after the Big Bang were extremely metal-poor. But most of them are billions of light-years away. Peekaboo is much closer to Earth and is surrounded by galaxies like ours which are much richer in metals.
Discovering the Peekaboo galaxy is like discovering a direct window into the past, allowing us to study its extreme environment and stars at a level of detail unattainable in the distant, early universe.
rejoices Gagandeep Anand, Space Telescope Science Institute astronomer and co-author of a new study on Peekaboo. It will be published in a future issue of Monthly Notices of the Royal Astronomical Society.
An unprecedented source of observation for astronomers
More than 20 years ago, Peekaboo appeared from astronomical observations as a region of cold hydrogen. Later analyzes suggested that a compact galaxy was actually hiding behind the star TYC 7215-199-1. Ultimately,
Hubble was able to zoom in on 60 stars within the galaxy. Observations from the telescope, combined with metallicity data from the Southern African Large Telescoperevealed that Peekaboo was a real aberration.
At first we didn’t realize how special this little galaxy was
adds Bärbel Koribalski, an astronomer at Australia’s national science agency CSIRO. ”
Now, thanks to combined data from the Hubble Space Telescope, the Southern African Large Telescope (SALT), and others, we know that the Peekaboo Galaxy is one of the most metal-poor galaxies ever detected.
Peekaboo will likely be the subject of many studies in the years to come. ”
Due to Peekaboo’s proximity, we can conduct detailed observations, which opens up possibilities to see an environment resembling the early universe in unprecedented detail.
Image: Nasa, Esa, I.Karachentsev, A. Pagan