Answer:
Not only are they edible ( if you are not allergic), IMO the carrot top actually balances out the flavor of carrot juice, if the carrots are good and sweet.
I raise several acres of carrots every year, and when the weather gets below 25 degrees Fahrenheit at the house we move our home stock inside, if we see any sign of mold we rinse them and put them in a fresh bag. The carrots continue to regrow tops as we use them, and as long as they have 90% humidity (a bag with a few holes), and clean environment they keep for 2-3 weeks!
~The carrots will begin growing new tops~
We rinse them and use the whole carrot, tops and all in juice, stews, roasts, garnish etc...
Hey rabbits and deer eat them!
OTOH, if the carrots were raised by some large corporation, I personally would not eat the tops for fear of herbicide/fungicide and the very remote possibility of insecticide residue.
More reference: http://www.carrotmuseum.co.uk/recipes.html