I am that person. To clarify, it was GPS and I was notified via email/phone. I am under the impression that Caltech GPS has finished recommending students for admission (there is a visiting weekend in a couple of weeks) and will send out official notifications at some point in the next few weeks (disclaimer: I do not know this for sure). Not sure what that means if you have yet to hear from them. If it helps, Caltech is the only planetary science program that I have heard back from so far - I am also under the impression that things are a tad later than usual at some places. Good luck!