The spiral galaxy M91 fills the frame of this Wide Field Camera 3 observation from the NASA/ESA Hubble Space Telescope. M91 lies nearly 55 million light-years from Earth in the constellation Coma Berenices. It is also evident in this image that it is a barred spiral galaxy. It hides an astronomical monstrosity, as M91’s prominent bar makes for a spectacular galactic portrait. M91 contains a supermassive black hole at its centre, like our own galaxy. A 2009 study using archival Hubble data found that this central black hole weighs somewhere between 9.6 and 38 million times as much as the Sun.
Archival Hubble data allowed astronomers to weigh M91’s central black hole. More recent observations have had other scientific aims. This observation is part of an effort to build an astronomical data which will explore the connections between young stars and the clouds of cold gas in which they form. Astronomers used Hubble to obtain ultraviolet and visible observations of galaxies already seen at radio wavelengths by the ground-based Atacama Large Millimeter/submillimeter Array.
Scientists observed time with Hubble is a highly valued and much sought-after resource for astronomers. Astronomers first have to write a proposal detailing what they want to observe and highlighting the scientific importance of their observations, to obtain data from the telescope. These proposals are then anonymized and judged on their scientific merit by a variety of astronomical experts. This process is incredibly competitive as only around 13% of the proposals were awarded observing time.