OK. I can understand that
At its heart is an object a little larger than 10 miles across.
I call BS here. There is NO WAY they can see a 10-mile object from "billions of light years" away.
It's throwing out radiation like crazy. Why shouldn't we be able to detect that radiation? It's not the size of the source that matters.
It’s been many years now since I took my last astronomy class, so it escapes me how they do it, but astronomers don’t have to directly image an object to tell (in every instance) how large it is. Very ingenious indirect methods exist that allow them to make that determination for certain objects.
“There is NO WAY they can see a 10-mile object from “billions of light years” away.”
Sure there is, if the object is radiating massive amounts of photons or something else we can detect. The size of the object itself is actually insignificant compared to the amount of radiation it is putting out, since it’s the radiation we detect directly.