The Hubble Space Telescope has a lot to show in this spectacular image. Its view here is studded with stars, many of which appear particularly large and bright thanks to their nearby locations in our own galaxy, and which feature the characteristic diffraction patterns caused by Hubble’s optics.
Much further away — around 240 million light-years distant, in fact, in the southern constellation Telescopium — is the spiral galaxy IC 4709. Its swirling disc filled with stars and dust bands is beautifully captured, as is the faint halo surrounding it.
The compact, glowing region at its core might be the most remarkable sight, however: this is an active galactic nucleus (AGN). Bright as it appears in this visible-light image from Hubble, it’s even powerful across the rest of the spectrum of light.
If IC 4709’s core were just filled with stars, it would not be nearly so bright. Instead, it hosts a gargantuan black hole, 65 million times the mass of our Sun. A disc of gas spirals around and eventually into this black hole, with the gas crashing together and heating up as it spins. It reaches such high temperatures that it emits vast quantities of electromagnetic radiation, from infrared to visible to ultraviolet light and beyond — in this case including X-rays.
To understand this brilliant astrophysical phenomenon, it’s necessary to study the whole spectrum of its emission. The high-resolution view of the Hubble Space Telescope not only can collect lots of light from the optical emission of the AGN, it also makes it possible to study the interaction between the quite small AGN and its host galaxy in detail.
