Where is team galatic after u catch diagla in pokemon diamond

Question

im just wondering also wat do u do after u catch heatran

Answer 1

Well some of the galactic members are in  the galactic veilstone building. You can also find the admin saturn there.  After catching heatran, there are no more legendaries to catch except giratina (or if you already caught it)

And yes you have beaten Team galactic

Answer 2

you have to catch regigigas

its in snowpoint temple u have to have other 3 regis in ur party to b able to battle/capture it

it lvl 70