If you look closely at this image, you will see that this is almost exactly the same as reference design layout for nRF51. So i assume that is nRF51. You can connect it to arduino, but I see very few reasons to do that...
I want to create something similar, that is why I want to connect it to an Arduino. At the moment I am using nrf24l01, but I am looking for a chip that have better range.
Using arduino here is totally pointless in my opinion. current draw will kill whole power-saving concept. nRF51 only is enough. However, see that they are using some wifi chip also.