“Uncovering 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 that is inaccessible in the distant, early universe,”<\/p><\/blockquote>\n
said co-author Gagandeep Anand, an astronomer at the Space Telescope Science Institute in Baltimore.<\/p>\n
Extremely Metal-poor<\/h2>\n
Tiny galaxy HIPASS J1131\u201331 peeks out from behind the glare of star TYC 7215-199-1, a Milky Way star positioned between Hubble and the galaxy.
One hundred years ago, this fast-moving foreground star would have appeared directly in the line of sight, and the Peekaboo galaxy would not have been detectable at all.
The small galaxy presents astronomers with a unique opportunity for future in-depth analysis of a chemical environment typically only found in the very distant, early universe, where detailed study of individual stars’ chemical makeup is not possible. Peekaboo is, in effect, a direct portal into the past, allowing us to discover what the universe was like near the dawn of time.
Credit: NASA, ESA, and Igor Karachentsev (SAO RAS);Image Processing: Alyssa Pagan (STScI)<\/p><\/div>\nAccording to astronomers, galaxies like Peekaboo are “extremely metal-poor” (XMP). “Metals” refers to all elements heavier than hydrogen and helium in astronomy. Hydrogen and helium, made by the big bang, made up almost all of the early matter in the universe.<\/p>\n
Throughout the universe’s history, stars have made heavier elements, which is why the universe is full of metals today. The building blocks of life as we know it are heavier elements such as carbon, oxygen, iron, and calcium.<\/p>\n
While extremely metal-poor galaxies were the default for the universe’s earliest galaxies<\/a>, similarly metal-poor galaxies have also been discovered in the local universe. Peekaboo drew the attention of astronomers not only because it is an XMP galaxy without a significant older stellar population, but also because it is only 20 million light-years from Earth, which is at least half the distance of previously identified young XMP galaxies.<\/p>\n
Discovering The Peekaboo Galaxy<\/h2>\n
Professor Barbel Koribalski, an astronomer at Australia’s national science agency CSIRO and co-author of the latest research study on Peekaboo’s metallicity, found Peekaboo as a region of cold hydrogen with the Australian Parkes radio telescope Murriyang<\/a> in the HI Parkes All Sky Survey more than 20 years ago. Using far-ultraviolet observations, NASA’s Galaxy Evolution Explorer mission in space found that it was a small blue dwarf galaxy.<\/p>\n
“At first we did not realize how special this little galaxy is. Now with combined data from the Hubble Space Telescope, the Southern African Large Telescope<\/a> (SALT), and others, we know that the Peekaboo Galaxy is one of the most metal-poor galaxies ever detected,”<\/p><\/blockquote>\n
Koribalski said.<\/p>\n
The Hubble Space Telescope was able to resolve approximately 60 stars in the tiny galaxy, nearly all of which appear to be a few billion years old or younger. SALT’s measurements of the Peekaboo Galaxy’s metallicity completed the picture.<\/p>\n
These findings highlight the significant difference between Peekaboo and other galaxies in the local universe, which typically have stars that are billions of years old.<\/p>\n
Data Still Incomplete<\/h2>\n
The stars in the Peekaboo Galaxy indicate that it is one of the youngest and least chemically-enriched galaxies ever discovered in the local universe. This is extremely unusual, given that the local universe has had approximately 13 billion years of cosmic history to develop.<\/p>\n
However, Anand believes that the picture is still incomplete because the Hubble observations were made as part of a “snapshot” survey program called The Every Known Nearby Galaxy Survey, which aimed to collect Hubble data from as many neighbouring galaxies as possible.<\/p>\n
![\"Peekaboo](\"https:\/\/techfragments.com\/wp-content\/uploads\/2022\/12\/peekaboo-galaxy.jpg\")