http://arxiv.org/abs/2001.06581
The recent detections of the gravitational wave (GW) event GW170817 and its electromagnetic counterpart GRB 170817A produced by a binary neutron star (NS) merger is a new milestone of multi-messenger astronomy. The time interval between these two signals has attracted widespread attention from physicists. In the braneworld scenario, GWs could propagate through the bulk while electromagnetic waves (EMWs) are bounded on the brane, i.e., our Universe. Therefore, the trajectories of GWs and EMWs may follow different pathes. If GWs and EMWs are originated simultaneously from the same source on the brane, they are expected to arrive at the observer successively. Consequently, the time delay between GW170817 and GRB 170817A may carry the information of the extra dimension. In this paper, we try to investigate the phenomenon in the context of a five-dimensional dS ($\text{dS}_5$) spacetime. We assume two special models for our Universe, i.e., the de Sitter model and the Einstein-de Sitter model, and compare the gravitation horizon radius and photon horizon radius in each case. Our results show that the $\text{dS}_5$ radius will contribute to the time delay in the latter case. With the data of the observation, we constrain the $\text{dS}_5$ radius to $\ell\gtrsim7.5\times10^{2}\,\text{Tpc}$. After considering the uncertainty in the source redshift and the time-lags given by different astrophysical processes of the binary NS merger, we find that our constraint is not sensitive to the redshift in the range of (0.005, 0.01) and the time-lag in the range of (-100 s, 1.734 s).
Z. Lin, H. Yu and Y. Liu
Wed, 22 Jan 20
84/116
Comments: 11 pages, 2 figures