The NASA/ESA Hubble Space Telescope has produced a beautiful image of NGC 4485, an irregular galaxy located in the constellation Canes Venatici, about 30 million light-years away from Earth. NGC 4485 shows all the signs of having been involved in a hit-and-run accident with a bypassing galaxy, NGC 4490; rather than destroying NGC 4485, the chance encounter is spawning a new generation of stars.
This image of the irregular galaxy NGC 4485 was made from separate exposures taken in the visible region of the spectrum with Hubble’s Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS). NGC 4485 has been involved in a dramatic gravitational interplay with its larger galactic neighbor, NGC 4490, out of frame to the bottom right in this image. This ruined the original, ordered spiral structure of the galaxy and transformed it into an irregular one. Below NGC 4485 one can see a bright, orange background galaxy: CXOU J123033.6+414057. This galaxy is the source of X-ray radiation studied by NASA’s Chandra X-ray Observatory. It’s distance from Earth is about 850 million light-years. Image credit: NASA / ESA / Hubble.
NGC 4485 and NGC 4490 make up a galaxy pair called Arp 269.
Their interactions have warped them both, turning them from spiral galaxies into irregular ones.
NGC 4485, which is the smaller galaxy in the pair, and NGC 4490 are now moving away from each other.
Still engaged in a destructive yet creative dance, the gravitational force between them continues to warp each of them out of all recognition, while at the same time creating the conditions for huge regions of intense star formation.
This galactic tug-of-war created a stream of material about 25,000 light-years long which connects the two galaxies.
The stream is made up of bright knots and huge pockets of gassy regions, as well as enormous regions of star formation in which young, massive, blue stars are born.
Short-lived, however, these stars quickly run out of fuel and end their lives in dramatic explosions.
While such an event seems to be purely destructive, it also enriches the cosmic environment with heavier elements and delivers new material to form a new generation of stars.
Two very different regions are now apparent in NGC 4485; on the left are hints of the galaxy’s previous spiral structure, which was at one time undergoing ‘normal’ galactic evolution.
The right of the image reveals a portion of the galaxy ripped towards its larger neighbor, bursting with hot, blue stars and streams of dust and gas.
