voorwerp
An ionization or light echo, especially the quasar ionization echo known as Hanny's Voorwerp.
The voorwerp turns out to be a cloud of gas tens of thousands of light-years across, which has somehow been heated to high enough temperatures to emit visible light. The exact mechanism of the heating is still under debate, but probably[…]
Where it comes from
From Dutch voorwerp (“object”), after Hanny's Voorwerp, discovered in 2007 by Dutch schoolteacher Hanny van Arkel.
Adapted from the Wiktionary entry voorwerp (CC BY-SA 4.0).