Astronomers using the FOcal Reducer and low dispersion Spectrograph 2 (FORS2) instrument on ESO’s Very Large Telescope (VLT) have taken a picture of the peculiar galaxy NGC 7727, which was born from the merger of two smaller spiral galaxies that started around a billion years ago. At the center of NGC 7727 lies the closest pair of supermassive black holes ever found.
This image of NGC 7727 was captured by the FORS2 instrument on ESO’s Very Large Telescope. Image credit: ESO.
NGC 7727 is located about 69 million light-years away from Earth in the constellation of Aquarius.
The galaxy was discovered by the German-born British astronomer William Herschel on November 27, 1785.
Otherwise known as Arp 222 or LEDA 72060, it has a diameter of 115,000 light-years.
NGC 7727 is the brightest member of the NGC 7727 group (LGG 480).
Astronomers think that NGC 7727 is the product of the merger of two smaller spiral galaxies that took place around one billion years ago.
The galaxy’s most likely fate is to become an elliptical galaxy in the future, with very little interstellar dust and star formation.
“Tails of stars, gas and dust are spun around the galaxies as they eventually form a new, merged galaxy, resulting in the disordered and beautifully asymmetrical shape that we see in NGC 7727,” ESO astronomers said.
While NGC 7727 was previously captured by ESO’s VLT Survey Telescope, the new image shows more intricate details both within the main body of the galaxy and in the faint tails around it.
“In this image, we see the tangled trails created as the two galaxies merged, stripping stars and dust from each other to create the spectacular long arms embracing NGC 7727,” the researchers said.
“Parts of these arms are dotted with stars, which appear as bright blue-purplish spots in the image.”
“Also visible in the image are two bright points at the center of the galaxy, another telltale sign of its dramatic past.”
“The core of NGC 7727 still consists of the original two galactic cores, each hosting a supermassive black hole.”
“The black holes in NGC 7727 are observed to be just 1,600 light-years apart in the sky and are expected to merge within 250 million years, the blink of an eye in astronomical time.”
“When the black holes merge they will create an even more massive black hole.”
“Our home Galaxy, which also sports a supermassive black hole at its center, is on a path to merge with our closest large neighbor, the Andromeda Galaxy, billions of years from now,” they added.
“Perhaps the resulting galaxy will look something similar to the cosmic dance we see in NGC 7727, so this image could be giving us a glimpse into the future.”
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