Exciting gauge field and gravitons in a brane-anti-brane annihilation
  In this paper we point out the inevitability of an explosive production of gauge field and gravity wave during an open string tachyon condensation in a cosmological setting. We will be particularly studying an example of brane-anti-brane inflation in a warped throat where inflation ends via tachyon condensation. We point out that a tachyonic instability helps fragmenting the homogeneous tachyon and excites gauge field and contributes to the stress energy tensor which also feeds into the gravity waves. 
A. Mazumdar, H. Stoica