Unusual Spiral NGC 4921

This spectacular image shows the unusual barred spiral galaxy NGC 4921 glowing against the backdrop of more distant galaxies. NGC 4921 is one of the brighter members of the Coma Cluster of galaxies, located in the constellation Coma Berenices. It is about 320 million light-years distant. While the galaxy has a nucleus and an inner bar structure that is surrounded by a distinct ring of dust and young blue stars, the outer parts of the galaxy do not evidence distinct spiral arms, or star-forming regions. Astronomers have identified that NGC 4921 is both low in hydrogen and that the distribution of this usually abundant gas within the galaxy is not uniform. It is thought that this is due to interaction with the intergalactic medium, which is stripping off the gas.