Creatures Anathema is full of cool references to Gelt's "vat psykers" in their suspensors... Are these vat psykers described anywhere else? I can -imagine- what they are, but they seem interesting enough to merit a more detailed official description somewhere. I've looked in the core book, the inquisitor's handbook, CA itself and DotDG (and, of course, I googled it) and I can't find any tidbits aside from the tantalizing hints in CA...

A thread with this exact same question was on here not last week.

Vat psykers are, to cut a long story short, psykers who are so mutated or physically weak that they are moved around in large suspensor-driven sarcophogi or 'vats' filled with liquid. These vats are often inscribed with protective runes and sigils, to help keep the psykers under control and safe from daemons.

Thanks for the answer (I had thought they were something else, more like vat-grown), I did use the forum search looking for vat before I posted and it didn't turn out any results.

Edit: Browsing your profile I managed to find the thread you mentioned, and it's so full of win (especially Reason's post) that I'm linking it here in case more people missed it too and happen upon this. http://www.fantasyflightgames.com/edge_foros_discusion.asp?efid=70&efcid=3&efidt=87515&efpag=0#87922