Nope.
just by transfer.
You cannot catch any of the Regis (Regirock, Regice, Registeel and Regigigas) in Pokémon HeartGold or SoulSilver.
You can't get Regigigas in Pokemon Soulsilver or Heartgold. However, Regigigas is available in Pokemon Diamond, Pearl, and Platinum by obtaining Regice, Regirock, and Registeel. Once you have done that, you can take all three of them to the Snowpoint Temple in Snowpoint City to battle a lv.1 Regigigas.
to awaken regigigas you have to have regirock, regice and registeel with you
No, you cannot catch Regirock, Regice, Registeel or Regigigas in Pokémon HeartGold, they are not available in the game as wild Pokémon.
Regigigas cannot be caught in Heartgold version. To get a Regigigas in Heartgold, you would have to trade it from Diamond, Pearl, or Platinum. To get it in one of those games, you have to transfer all three Regis (Regice, Registeel, and Regirock) from Ruby, Sapphire, or Emerald.
you need REGIROCK, REGICE, AND REGISTEEL.
You can capture Regigigas.
no you can't but if you get regigias on platinum chambers containing the apear..i'd look on a useful site called serebii.net
You need Rigice, Registeel, and Regirock in your party, then talk to Regigigas.
you need regice registeel and regirock then go to the snowpoint temple
you have to transfer registeel, regirock, and regiice, from game boy games then have them in your party and talk to regigigas.
Regigigas is in the Snowpoint Temple but you need Regice,Regirock and Registeel in your team to awaken him