Hubble Space Telescope sees colliding galaxies aglow with stars

three galaxies hang in space with smaller ones about
Spiral galaxies UGC 05028 and UGC 05029, collectively known as Arp 300, are captured in a new photo from the Hubble Space Telescope, showcasing rapid star formation triggered by the interaction among the galactic pair. (Image credit: NASA/ESA/J. Dalcanton (University of Washington)/R. Windhorst (Arizona State University)/Processing: Gladys Kober (NASA/Catholic University of America))

Star formation is in business in a pair of merging galaxies recently photographed by the Hubble Space Telescope. 

The spiral galaxies UGC 05028 and UGC 05029 — collectively known as Arp 300 — are in the process of merging. Otherwise known as interacting, or colliding, galaxies, the smaller galaxy (UGC 05028) has been tugged and twisted by the powerful gravitational field of its larger companion (UGC 05029), according to a statement from NASA. 

"Likely due to its gravitational dance with its larger partner, UGC 05028 has an asymmetric, irregular structure, which is not as visible from ground-based telescopes but is quite distinct in this new image from NASA’s Hubble Space Telescope," officials said in the statement.

Related: The best Hubble Space Telescope images of all time! 

From Hubble's vantage point, both galaxies appear face-on, meaning their bright central bulges and spiral arms are clearly visible in the new photo. When a spiral galaxy is seen face-on, it appears circular and disc-shaped, compared to when one is seen from the side, also known as an edge-on view. When in the latter position, they appear more squashed and oval-shaped. An example of an edge-on galaxy can also be seen near the bottom of the new Hubble image, below the galaxy UGC 05029. 

UGC 05028, exhibits a bright knot located to the southeast of its core, which may be the result of another ongoing galactic merger. Once that merger is complete, scientists say the remnant of the other galaxy would be fully absorbed by UGC 05028, creating a prominent central bulge — similar to that seen in UGC 05029 — and fueling new star formation. 

The rapid formation of stars caused by this type of event is evident in UGC 05029. The interaction between the two merging galaxies has triggered rapid star birth, represented by the many hot, blue giant stars on UGC 05029's spiral arms nearest its companion UGC 05028, according to the statement. 

Hubble turned its focus to Arp 300 in order to better understand the relationship between the physical characteristics of UGC 05028 and UGC 05029 as well as they dynamics of  their star formation. In doing so, the space telescope also captured a number of other objects in the galactic neighborhood, including a string of five distant background galaxies grouped together near the bottom of the image, which NASA released on Jan. 22. 

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Samantha Mathewson
Contributing Writer

Samantha Mathewson joined as an intern in the summer of 2016. She received a B.A. in Journalism and Environmental Science at the University of New Haven, in Connecticut. Previously, her work has been published in Nature World News. When not writing or reading about science, Samantha enjoys traveling to new places and taking photos! You can follow her on Twitter @Sam_Ashley13.