Oh, crap, Gardner Dozois died.
I didn’t know him personally but have been reading fiction edited by him for nearly my entire life. Great editor; perhaps the best short story editor and anthologist (in any genre) there ever was. This is very rare indeed, but if I saw his name on the cover I at least knew the work therein would be good, and perhaps great.
It’s strange to mourn people you’ve never met, never been in the same room with, but that is a fact of modern life.