Its so sad for Galatasaray to be in that group with Bayern. Its impossible to ge even 1 point from them in my opinion - there is huge power difference. But I suppose Galatasaray can challenge Kopenhag. Its unlucky for Kopenhag too - they drew nearly all strong teams from pots. They could have chance to go next round if they could be in a different group. So same scenario for them. Competition only for 1st rank at 3rd rank in that group. Otherwise teams are literally divided to two.
Bayern Munich and Manchester United is the strongest teams on group A so it's hard for Galatasaray to compete against these teams but everything still possible to happend because group stage hasn't to begin yet and if Galatasaray can able to beat Manchester United i think there is a good chances for them to qualified but indeed this is really hard because during their participant in champion league turkish teams always be recognized as mediocre team and the most realistic position for Galatasaray probably 3rd places however if i am not mistaken Galatasaray have been advances to round of 16 on 2013 and at that time they were fight against Schalke and Galatasaray were successfully to advances to quarterfinal but unfortunately their journey have to stopped on that stage because they lose from Real Madrid