This week’s image from the Hubble Space Telescope shows the galaxy M91, a barred spiral galaxy in the constellation Coma Berenices. It’s relatively close to us, 55 million light-years away, and it’s part of our local supercluster. The M in the name stands for Messier, after the French astronomer Charles Messier who is famous for his catalog of astronomical objects that he produced in the 1770s and 1780s. The designations of the objects he cataloged, from M1 to M110, are still used by astronomers.
While it is undeniably a beautiful galaxy, displaying the classic bar or bright region of dust and gas at the center where stars form, this particular galaxy was observed by Hubble to learn more about the monstrous black hole at the center. . Like almost all galaxies, including the Milky Way, M91 has a supermassive black hole at its heart. The mass of the supermassive black hole of M91 was calculated using Hubble data in 2009 and found to be huge, between 9.6 and 38 million times the mass of our sun.
Spiral galaxy M91 fills the frame of this NASA/ESA Hubble Space Telescope Wide Field Camera 3 observation. M91 is located about 55 million light-years from Earth in the constellation Coma Berenices and, as shown in this image, is a barred spiral galaxy. While M91’s prominent bar makes for a spectacular galactic portrait, it also hides an astronomical monstrosity. Like our own galaxy, M91 contains a supermassive black hole at its center. A 2009 study using archived Hubble data found that this central black hole weighs somewhere between 9.6 and 38 million times the sun’s weight. ESA/Hubble & NASA, J. Lee and the PHANGS-HST team
“While astronomers were able to weigh M91’s central black hole thanks to archive data from Hubble, more recent observations had other scientific goals,” Hubble scientists write. “This observation is part of an effort to build a wealth of astronomical data exploring the connections between young stars and the clouds of cold gas in which they form. To do this, astronomers used Hubble to obtain ultraviolet and visible observations of galaxies already observed at radio wavelengths by the Atacama Large Millimeter/submillimeter Array on the ground.”
This image was collected as part of the Physics at High Angular resolution in Near GalaxieS with the Hubble Space Telescope or the PHANGS-HST project. Previous Hubble images collected for this project include spiral galaxy NGC 2835 and spiral galaxy NGC 4571.