This latest Picture of the Month from the NASA/ESA/CSA James Webb Space Telescope features Messier 77 (M77), a barred spiral galaxy famous and appreciated among astronomers for its combination of relative proximity and spectacular features to study. It is located 45 million light-years away in the constellation Cetus (The Whale). This new image from Webb’s Mid-Infrared Instrument (MIRI) highlights its swirling spiral arms, the dust in its disc and its piercingly bright core like never before. At the heart of M77 is a compact region filled with hot gas that handily outshines the rest of the galaxy put together, even overcoming the light-gathering capacity of Webb’s cameras. This is an active galactic nucleus (AGN), and it’s powered by M77’s central supermassive black hole, which is eight million times as massive as our Sun. Gas in the galaxy’s central regions is pulled by the strong gravity into a tight and rapid orbit around the black hole, where it crashes together and heats up, releasing tremendous amounts of radiation. The bright orange lines appearing to radiate out from the centre of M77 are not actually a feature of the galaxy: they are a type of distortion that arises from the optical design of the telescope. Called diffraction spikes, they are created because the intense light from the unresolved AGN is bent (“diffracted”) very slightly at the edges of Webb’s hexagonal mirror panels and around one of the struts that hold up its secondary mirror. This distinctive six-plus-two-pointed pattern is the same for any image taken by Webb. For diffraction spikes to appear, the light source has to be very bright and very concentrated, so they’re most often seen on stars. But in some galaxies, as here, the nucleus is bright and compact enough to make diffraction spikes appear as well. M77 is not just known for its easily visible AGN, but also as a prolific star-forming galaxy. The near-infrared image of M77 reveals a bar spanning across the central r
