The James Webb Space Telescope captured this image of IC 1623, a pair of intertwined galaxies. Credit: ESA/Webb, NASA & CSA, L. Armus & A. Evans, Acknowledgement: R. Colombari
October 25, 2022
IC 1623 is located about 270 million light-years away from Earth in the constellation Cetus. Merging of interacting galaxies is captured in this image of IC 1623 as they crash into one another. A starburst, caused by their collision, has produced stars at a rate that is more than twenty times faster than that of the Milky Way galaxy. This interacting galaxy system is a suitable test case for Webb's capacity to investigate luminous galaxies because it is exceptionally brilliant at infrared wavelengths. A group of astronomers used MIRI, NIRSpec, and NIRCam, three of Webb's state-of-the-art scientific instruments, to capture IC 1623 in the infrared regions of the electromagnetic spectrum. By doing this, they produced a wealth of information that will enable the astronomical community as a whole to thoroughly study how Webb's ground-breaking capabilities will aid in deciphering the intricate relationships in galactic ecosystems.
Astronomers have long been interested in the merging of these two galaxies, and Hubble and other space telescopes have already captured images of it. The merging galaxies may very likely be in the process of generating a supermassive black hole, and the continuous, violent starburst is causing tremendous infrared emission. These important discoveries have been hidden from view by a thick band of dust by telescopes like Hubble. The stunning image above was created by combining MIRI and NIRCam data, but Webb's infrared sensitivity and resolution at those wavelengths allow it to see past the dust.
It turns out that the galaxy merger's luminous center is extremely brilliant and exceedingly compact, to the point where Webb's diffraction spikes can be seen on top of the galaxy. The interaction of starlight with the physical structure of the telescope results in the eight-pronged, snowflake-like diffraction spikes. Images with brilliant stars, like Webb's initial deep field photograph, make the spiky nature of his findings particularly clear.