The NASA Hubble Space Telescope witnessed quite an awe-inspiring cosmic phenomenon: galaxies that are apparently in a tug-of-war!
This NASA Hubble image shows two interacting and intertwined galaxies--collectively called Arp 91--seemingly in a delicate, intricate dance that is taking place 100 million light years from Earth, NASA said in its website.
NASA further named the two galaxies comprising Arp 91: NGC 5953, which is the bright-looking lower galaxy, and NGC 5954, which is the oval-shaped galaxy to the upper right. Both are spiral galaxies, however, their shapes appear different due to their peculiar orientation with respect to Earth.
Hubble caught a glimpse of two interacting galaxies, called Arp 91, locked in a dangerous dance more than 100 million light-years from Earth!— Hubble (@NASAHubble) October 8, 2021
In this #HubbleFriday image, we see how immense gravitational attraction is causing these galaxies to interact: https://t.co/lqmhYfsnzY pic.twitter.com/9ZmMTA4YCF
This galactic tango shows how such galaxies interact, with NGC 5953 apparently pulling NGC 5954, which seems to be extending a spiral arm downward. The galaxies' massive gravitational attraction has led to this astonishing interaction. These arms are actually part of an active site of star formation that normally look brighter due to the stars that stay in those regions.
NASA Hubble Image: Interactions Common in Evolution of Galaxies
NASA stated that such interactions are common and form a significant part of the evolution of galaxies. A great number of galaxies display some form of interaction, either with its satellites or with other galaxies. Those that interact with other galaxies include such collisions that lead to the merger of galaxies or end up with bursts of star formation.
In collisions or mergers, the bigger galaxy might retain its shape or form after devouring the smaller one, Screen Rant noted in a post. This gravitational interaction would likely lead to the creation of a larger irregular galaxy, but astronomers believe that such interactions would eventually lead to the creation of another galactic type: elliptical galaxies.
Best examples of such cosmic interactions include the Messler 81 group, which had the larger M81 galaxy colliding with two smaller galaxies-NGC 3034 and NGC 3077, and the Cartwheel group, which comprises four spiral galaxies in a stunning ring outline, Screen Rant added.
Higher Frequency of Star Formation in NGC 5953
In the study "Photometric and Kinematic Traces of an Interaction" published in the Astronomical Society of the Pacific, the two galaxies in Arp 91, NGC 5953 and NGC 5954, are 5.8 kiloparsecs apart and show prominent star-forming regions. However, according to data from the Infrared Astronomical Satellite (IRAS), NGC 5953 presents a higher frequency of star formation per unit area, compared to NGC 5954.
NGC 5653 is believed to be categorized under the Class II Seyfert galaxies with its distinct bright core known as an active galactic nucleus (AGN). Such galaxies are one of the brightest cosmic sources of electromagnetic radiation.
The Hubble recently took an image of a Seyfert galaxy, NGC 3254, which seems like a giant cosmic eye with a bright center.
But such immense, energetic interactions, NASA added, happen hundreds of millions of years, and as such humans can't expect to see any changes to Arp 91 anytime soon.