Saturday, May 8, 2021

NGC 5291 system of interacting galaxies

NGC 5291 (also known as PGC 48893) is a system of interacting galaxies, located at a distance of around 190 million light years in the constellation of Centaurus.

The system is located at the edge of the Abell 3574 galaxy cluster. The main component is a peculiar elliptical galaxy with a highly disturbed companion which is known as MCG 05-33-005, or with its more attractive nickname “the Seashell''.

NGC 5291 is a spectacular object and one of the reasons is the presence of the intergalactic H II region in its surrounding environment. This was revealed through detailed observations, where blue clumpy structures were found around the main galaxy. Through radio observations, a huge asymmetrical ring-like structure that is connected to NGC 5291 was detected. Due to this, this is one of the most gas rich objects known.

Analysis of observational data has shown that the ring structure is the result of a collision that took place millions of years ago. This event is most likely also responsible for all the recent starburst events (i.e., younger than 5 million years) along the ring.

The structure known as NGC 5291N has also been classified as a dwarf galaxy. Its star forming rate though matches more to that of a spiral galaxy, rather than dwarf type galaxies. What is also striking, is the fact that NGC 5291N has no old stars, thus confirming its young age.

Image: Composite optical image of NGC 5291 taken with ESO’s Very Large Telescope. The image was created using broadband filters (ultraviolet is blue, visual is green, and infrared is red). NGC 5291 is the big galaxy at the centre of the image, while the Seashell is just below it. The bright structure consisting of H II regions left of NGC 5291, is known as NGC 5291N.

Image Credit: ESO

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