Hubble Registers the Beautiful Seyfert NGC 5728 Galaxy

Discover NGC 5728, a spiral galaxy about 130 million light years from Earth. This image was captured using Hubble’s Wide Field Camera 3 (WFC3), which is extremely sensitive to visible light and infrared. So this image beautifully captures the regions of NGC 5728 that are emitting visible and infrared light. However, there are many other types of light that galaxies like NGC 5728 can emit that WFC3 cannot see.

In this image, NCG 5728 appears to be an elegant, luminous, barred spiral galaxy. What this image does not show, however, is that NGC 5728 is also a monumentally energetic type of galaxy known as the Seyfert-type galaxy. This extremely energetic class of galaxies is powered by their active nuclei, which are known as active galactic nuclei (AGNs). There are many different types of AGNs, and only a few of them power the Seyfert galaxies. NGC 5728, like all Seyfert galaxies, is different from other galaxies with AGNs because the galaxy itself can be seen clearly. Other types of AGNs, such as quasars, emit so much radiation that it’s almost impossible to observe the galaxy that houses them. As this image shows, NGC 5728 is clearly observable at both optical and infrared wavelengths and looks quite normal. It’s fascinating to know that the center of the galaxy is emitting large amounts of light in parts of the electromagnetic spectrum that WFC3 is simply not sensitive to! Just to complicate things, the AGN at the core of NGC 5728 may actually be emitting some visible and infrared light – but that light may be being blocked by dust around the galaxy’s core.


ESA / Hubble, A. Riess et al., J. Greene