Implications of the Tentative Association between GW150914 and a {\it Fermi}-GBM Transient

Abstract

The merger-driven Gamma-ray Bursts (GRBs) and their associated gravitational wave (GW) radiation, if both successfully detected, have some far-reaching implications, including for instance: (i) The statistical comparison of the physical properties of the short/long-short GRBs with and without GW detection can test the general origin model; (ii) Revealing the physical processes taking place at the central engine; (iii) Measuring the velocity of the Gravitational wave directly/accurately. In this work we discuss these implications in the case of possible association of GW150914/ GBM transient 150914. We compared GBM transient 150914 with other SGRBs and found that such an event {may be} a distinct outlier in some statistical diagrams, possibly due to its specific binary-black-hole merger origin. However, the presence of a "new" group of SGRBs with "unusual" physical parameters is also possible. If the outflow of GBM transient 150914 was launched by the accretion onto the nascent black hole, the magnetic activity rather than the neutrino process is likely responsible for the energy extraction and the accretion disk mass is estimated to be $\sim 10^{-5}~M_\odot$. The GW150914/GBM transient 150914 association, {if confirmed, would} provide the first opportunity to directly measure the GW velocity and its departure from the speed of the light {should be within} a factor of $\sim 10^{-17}$.