The Gemini Observatory has unveiled a striking new image of star formation in the irregular galaxy NGC 4449. The galaxy is classified as a “Magellan-type” galaxy because of its similarity to the Magellanic Clouds, although it is smaller. Surrounding NGC 4449 is a halo of smaller dwarf galaxies, two of which are currently merging with it. This merger is causing gas clouds to collide, driving the surge in star formation seen in NGC 4449.

All stars, even the Sun, are born from vast clouds of gas and dust, and when they die, their remains are recycled back into the galaxy, providing fuel for new stars. When the universe began, there was only hydrogen and a small amount of helium, but the fusion process inside stars creates new, heavier elements. This applies to every atom in you and me, to the planets, and even to the computer screen you’re reading this on. In a relatively nearby part of the universe, 13 million light-years away, in the constellation Canes Venatici, this cycle begins again at an extraordinary rate.

NGC 4449 (the four thousandth, four hundredth and forty-ninth object in the New Master Catalog) is a fascinating galaxy well known for its high level of star formation. It belongs to the M94 group of galaxies and is surrounded by a halo of dwarf galaxies, two of which are currently merging with it. The Gemini Observatory recently took amazing photos of NGC 4449, showing the birthing processes taking place inside it.

The new image was taken with the 8.1-meter Gemini North telescope on Mauna Kea as part of its 25th anniversary. It shows the galaxy’s swirling red clouds and blue haze, the result of light from new stars. It is classified as a Magellanic irregular galaxy because it has a loose spiral structure similar to the Large Magellanic Cloud in the Southern Hemisphere sky.

Deep within NGC 4449, stars have been forming for billions of years. It is now producing stars at a greatly accelerated rate, leading to its reclassification as an explosive galaxy. However, unlike others, starbursts are usually limited to the central regions, but NGC 4449 is much more widespread. Most hot young stars are currently located in the galactic core and surrounding regions.

This level of star formation is reminiscent of star formation in galaxies in the early Universe, driven by galaxy mergers and accretions. The burst of activity in NGC4449 is thought to be the result of a galactic merger or interaction with a neighbor.

One of them shows a faint stream of stars extending out from the side of NGC4449, indicating that it is currently in the process of merging. The string (and the satellite galaxy) are barely visible visually due to their low visual brightness, but can be detected by their interaction with NGC449. Another object suggesting past interactions is a huge globular cluster. It appears to be embedded in the outer halo of NGC4449 and is currently thought to be the core of a former satellite galaxy that merged with its companion.

These two interactions, and others that have likely gone undetected until now, create tidal interactions in the galaxy, sending shock waves through the galaxy, compressing interstellar gas. The red visible in the image reveals areas with high levels of ionized hydrogen and star formation. Large numbers of hot, young blue stars can be seen as they emerge from star-forming regions. It is thought that the rate of star formation in NGC 4449 will likely only continue for another billion years until the gas runs out and the shock waves subside.

Source: Gemini North captures a starburst galaxy that shines brightly thanks to newly formed stars