M 106 

Messier 106 (also known as NGC 4258) is an intermediate spiral galaxy in the constellation Canes Venatici. It was discovered by Pierre Méchain in 1781. M106 is at a distance of about 22 to 25 million light-years away from Earth. M106 contains an active nucleus classified as a Type 2 Seyfert, and the presence of a central supermassive black hole has been demonstrated from radio-wavelength observations of the rotation of a disk of molecular gas orbiting within the inner light-year around the black hole.

M106 has a water vapor megamaser (the equivalent of a laser operating in microwave instead of visible light and on a galactic scale) that is seen by the 22-GHz line of ortho-H2O that evidences dense and warm molecular gas. Water masers are useful for observing nuclear accretion disks in active galaxies. The water masers in M106 enabled the first case of a direct measurement of the distance to a galaxy, thereby providing an independent anchor for the cosmic distance ladder. M106 has a slightly warped, thin, almost edge-on Keplerian disc which is on a subparsec scale.  M 106 is one of the largest and brightest nearby galaxies, similar in size and luminosity to the Andromeda Galaxy M 31. The supermassive black hole at the core has a mass of  40 Million solar masses.

Galaxy M 106, 2 & 3 March 2025, Kempen, William Optics 110 mm APO FLT f/7, ASI1600mm pro, L(UV-IR)-filter: 7200 s, R: 3600 s, G: 3600 s, B: 3600s,  PixInsight V 1.9

Galaxy M 106, 2 & 3 March 2025, Kempen, William Optics 110 mm APO FLT f/7, ASI1600mm pro, L(UV-IR)-filter: 9720 s, R: 3600 s, G: 3600 s, B: 3600s,  PixInsight V 1.8.9