Possible strong gravitational wave sources for the Lisa antenna

Recently G. M. Fuller and X. Shi proposed that the gravitational collapse o f supermassive objects (M greater than or similar to 10(4) M-.) could be a cosmological source of c-ray bursts (GRBs). The major advantage of their mo del is that supermassive object collapses are far more energetic than solar mass-scale compact mergers. Also, in their proposal the seeds of supermass ive black holes (SMBHs) thus formed could give rise to the SMBHs observed a t the center of many galaxies. We argue here that, besides the generation o f GRBs, there could well occur a strong generation of gravitational waves ( GWs) during the formation of SMBHs. As a result, the rate of such GW bursts could be as high as the rate of GRBs in the model by G. M. Fuller and X. S hi. In this case, the detection of GRBs and bursts of GWs should occur with a small time difference. We also argue that the GWs produced by the SMBHs studied here could be detected when the Laser Interferometric Space Antenna becomes operative.