Free Astronomy Magazine January-February 2022

18 JANUARY-FEBRUARY 2022 ASTRO PUBLISHING Plunging into the Fornax Cluster by NOIRLab / Vanessa Thomas T he denizens of the Fornax gal- axy cluster populate this im- age from the Víctor M. Blanco 4-meter Telescope, located in Chile at Cerro Tololo Inter-American Ob- servatory (CTIO), a Program of NSF’s NOIRLab. The irregular galaxy lurk- ing in the bottom left corner of this Dark Energy Survey image is NGC 1427A, and its headlong plunge into the heart of the Fornax Cluster over millions of years will eventually re- sult in the galaxy’s disruption. The Fornax Cluster — which, as the name suggests, lies primarily in the constellation Fornax (the Furnace) — is a relatively nearby galaxy clus- ter, only about 60 million light-years from Earth. This means that it looms large in the night sky, stretching M embers of the Fornax galaxy cluster fill this image from the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO), a Pro- gram of NSF’s NOIRLab. Appearing in the constellation Fornax (the Furnace), the Fornax Cluster is a relatively nearby galaxy cluster, only about 60 million light- years from Earth. Some foreground stars, which belong to our own Milky Way Galaxy, appear in the image as well. [CTIO/NOIRLab/DOE/NSF/AURA] across an area more than 100 times larger than the full Moon. With over 600 member galaxies, the Fornax Cluster is the second “rich- est” (most populous) galaxy cluster within 100 million light-years of our galaxy (after the much larger Virgo Cluster). Two elliptical galaxies dominate the center of this image — visible as the two large patches of diffuse light with bright cores. Such galaxies usu- ally contain much older stars than the more picturesque spiral galaxies, and they tend to be found in galaxy clusters such as the Fornax Cluster. These elliptical galaxies — which are named NGC 1399 and NGC 1404 — are among the brightest members of the Fornax Cluster and are inex- orably being drawn together by the force of gravity. This interaction is stripping gas from NGC 1404, the lower elliptical galaxy in this image. In the bottom left corner of the image appears the irregular galaxy