Are Bose Einstein condensates affected by gravitational attraction ? In sufficient quantity, do Bose Einstein condensates exert a gravitational force ?
Yes, Bose-Einstein condensates are affected by gravity. Most condensates are formed in laser traps and often (especially in the early experiments) the lasers must be turned off to get a good image of the condensate, with the consequence that many images of condensates (again, especially from the early experiments) show them falling.
An example (source):
Atomic condensates are subjected to gravity as every massive particle is. What do you mean by 'in sufficient quantity'? In any theoretical treatment of a BEC I know of gravity is not taken into considerations as obviously the effects on the dynamics to the atomic level are negligible. However, yes, there is always a gravitational attraction between the atoms of the condensate. The answer to the question 'does an atomic BEC exert gravitational attraction on other massive objects' is still the same: yes it does as it is massive.
Recently researchers claimed they obtained a photon condensate. In that case gravitational forces wouldn't be present as photons are massless.
To go even further, if the graviton was found to exist, it may form a BEC as it is predicted to be a spin-2 particle (ergo a boson). Speculations on graviton BEC exist related to black holes physics.