This beautiful image from the Wide Field Planetary Camera 2 aboard the NASA/ESA Hubble Space Telescope shows four (NGC 839, NGC 838, NGC 835, and NGC 833) of the seven galaxies that make up a compact group of galaxies known as the Hickson Compact Group 16.
This Hubble image shows (from left to right) NGC 839, NGC 838, NGC 835, and NGC 833 galaxies. Image credit: NASA / ESA / ESO / Jane Charlton, Pennsylvania State University.
Compact galactic groups represent some of the densest concentrations of galaxies known in the Universe, making them perfect laboratories for studying weird and wonderful phenomena.
Hickson Compact Groups (HCGs) in particular, as classified by Canadian astronomer Prof Paul Hickson in the 1980s, are numerous, and are thought to contain an unusually high number of galaxies with strange properties and behaviours.
HCG 16, which is located in the constellation Cetus 110 million light-years away from Earth, is certainly no exception. HCG 16’s galaxies are bursting with dramatic knots of star formation and intensely bright central regions.
Within this group, scientists have found three starburst galaxies, two Seyfert 2 and two LINER-type (Low-Ionisation Nuclear Emission-line Regions) galaxies.
This image shows a ground-based wide-field view of the region around HCG 16. Image credit: NASA / ESA / Digitized Sky Survey 2 / Davide De Martin.
In this new image from Hubble, NGC 839 is a LINER galaxy. Its companion, NGC 838, is a LINER-type galaxy with lots of starburst activity and no central black hole.
The remaining galaxies, NGC 835 and NGC 833, are both Seyfert 2 galaxies which have incredibly luminous cores when observed at other wavelengths than in the visible light, and are home to active supermassive black holes.
Amateur astronomers Jean-Christophe Lambry and Marc Canale submitted a version of the image to the Hubble’s Hidden Treasures image processing competition.
