Messier 106 (also designated NGC 4258) is a spiral galaxy around 30 thousand light years across, located about 22 to 25 million light-years away in the constellation Canes Venatici. It is receding from Earth at 537 km/sec. Most likely Messier 106 has a companion, namely the barred spiral galaxy NGC 4217.
It is one of the closest examples of a Seyfert II galaxy, where vast amounts of glowing gas are falling into a central supermassive black hole. A supernova (1981K) occurred in M106 in August 1981.
Along with a bright central core, this composite image highlights youthful blue star clusters and reddish stellar nurseries which are tracing the galaxy’s spiral arms, as well as dark dust lanes that form a spiral pattern which can be traced well into the central region to the core. It also shows off remarkable reddish jets of glowing hydrogen gas.
The star clusters are dominated by very hot, bright and massive stars what indicates that these clusters cannot be very old, as such massive stars have only a short lifetime of a few million years. So they show us regions of very recent star formation!
In visible and infrared light, two prominent arms emanate from the bright nucleus and spiral outward. But in radio and X-ray images, two additional spiral arms are seen, the so-called anomalous arms. These ghostly arms represent regions of gas that are being violently heated by shock waves.
Previously, some astronomers had suggested that the anomalous arms are jets of particles being ejected by the supermassive black hole in the nucleus of Messier 106. But radio observations later identified another pair of jets originating in the core.
However, the jets do heat the gas in their line of travel, forming an expanding cocoon. Because the jets lie close to M106’s disk, the cocoon generates shock waves and heat the gas in the disk to millions of degrees, causing it to radiate brightly in X-rays and other wavelengths.
In addition to M106’s small companion galaxy NGC 4248 (bottom right), background galaxies as well as foreground stars can be found scattered throughout this image.
Image Credit: Jay GaBany