The latest Picture of the Month from the James Webb Space Telescope features Messier 77 (M77), a barred spiral galaxy captured by Webb's Mid-Infrared Instrument (MIRI). M77 lies 45 million light-years away in the constellation Cetus.
At M77's heart sits an active galactic nucleus (AGN) that outshines the entire rest of the galaxy combined. It's powered by a supermassive black hole eight million times the mass of the Sun. Gas pulled by gravity spirals tightly around the black hole, collides, heats up, and releases tremendous radiation. The nucleus is so bright and compact that it produces diffraction spikes in Webb's image — a feature typically seen only around stars.
In near-infrared, Webb revealed a bar spanning the galaxy's center — invisible in ordinary light. The bar is enclosed by a starburst ring over 6,000 light-years across, formed by the inner ends of M77's two spiral arms, where star formation rates are extremely high.
MIRI shows the galaxy's disc as a vast vortex of smoky dust filaments with cavities in between. Along the arms, glowing orange bubbles mark regions carved out by young star clusters.
Beyond the main disc, tenuous hydrogen filaments stretch into intergalactic space. Their tentacle-like appearance earned M77 its informal name — the Squid Galaxy.