According to a team of astronomers who published a new study in the Astrophysical Journal, the Galaxy NGC 4490, also nicknamed “Cocoon Galaxy” for its unique shape, boasts a “dual core” structure.
One core can be visually intercepted at different wavelengths while the other can only be seen in infrared or radio wavelengths. The galaxy NGC 4490 interacts gravitationally with a smaller galaxy, NGC 4485. This “binary system” boasts approximately 20% of the size of the entire Milky Way and is located approximately 30 million light away from us.
Allen Lawrence, the study’s first author and researcher at Iowa State University, says he noticed this double core as early as seven years ago, something that had never been observed before. According to the researcher, both nuclei have more or less the same size, the same mass and the same level of brightness.
Furthermore, this double nucleus would also explain why this galactic system is surrounded by an equally unusual hydrogen plume: “The simplest interpretation of the observations is that NGC 4490 is itself an advanced melting residue.” This merger would have occurred in the past following a collision between two galaxies.
In general, double-core galaxies are very rare. Multiple supermassive black holes are thought to be at the center of these systems.