Well Black Hand said something along the lines of "and you were connected to all of them" all the dead super-heroes, with Batman being in every book ever like Wolverine it makes sense. I'm guessing his skull is acting like a divining rod (you know the sticks that the amish use to find water or whatever) for finding dead super-folk
Maybe The Black Lanterns are drawn to displays of intense emotions in an attempt to snuff it out, that's why Ralph and Sue Dibny only attacked Hawkman/girl after they emoted like that.
Thats right boys and girls I bought a DC comic, it's the 5th sign of the apocalypse, I got a ring to, and I've lost it twice,