%0 Generic %1 citeulike:12776908 %A Gompertz, B. P. %A O'Brien, P. T. %A Wynn, G. A. %D 2013 %K imported %T Magnetar powered GRBs: Explaining the extended emission and X-ray plateau of short GRB light curves %U http://arxiv.org/abs/1311.1505 %X Extended emission (EE) is a high-energy, early time rebrightening sometimes seen in the light curves of short gamma-ray bursts (GRBs). We present the first contiguous fits to the EE tail and the later X-ray plateau, unified within a single model. Our central engine is a magnetar surrounded by a fall-back accretion disc, formed by either the merger of two compact objects or the accretion-induced collapse of a white dwarf. During the EE phase, material is accelerated to super-Keplarian velocities and ejected from the system by the rapidly rotating (\$P 1 - 10\$ ms) and very strong (\$10^15\$ G) magnetic field in a process known as magnetic propellering. The X-ray plateau is modelled as magnetic dipole spin-down emission. We first explore the range of GRB phenomena that the propeller could potentially reproduce, using a series of template light curves to devise a classification scheme based on phenomology. We then obtain fits to the light curves of 9 GRBs with EE, simultaneously fitting both the propeller and the magnetic dipole spin-down and finding typical disc masses of a few \$10^-3\$ \$M\_ødot\$ to a few \$10^-2\$ \$M\_ødot\$. This is done for ballistic, viscous disc and exponential accretion rates. We find that the conversion efficiency from kinetic energy to EM emission for propellered material needs to be \$10\%\$ and that the best fitting results come from an exponential accretion profile.

@misc{citeulike:12776908, abstract = {Extended emission (EE) is a high-energy, early time rebrightening sometimes seen in the light curves of short gamma-ray bursts (GRBs). We present the first contiguous fits to the EE tail and the later X-ray plateau, unified within a single model. Our central engine is a magnetar surrounded by a fall-back accretion disc, formed by either the merger of two compact objects or the accretion-induced collapse of a white dwarf. During the EE phase, material is accelerated to super-Keplarian velocities and ejected from the system by the rapidly rotating (\$P \approx 1 - 10\$ ms) and very strong (\$10^{15}\$ G) magnetic field in a process known as magnetic propellering. The X-ray plateau is modelled as magnetic dipole spin-down emission. We first explore the range of GRB phenomena that the propeller could potentially reproduce, using a series of template light curves to devise a classification scheme based on phenomology. We then obtain fits to the light curves of 9 GRBs with EE, simultaneously fitting both the propeller and the magnetic dipole spin-down and finding typical disc masses of a few \$10^{-3}\$ \$M\_{\odot}\$ to a few \$10^{-2}\$ \$M\_{\odot}\$. This is done for ballistic, viscous disc and exponential accretion rates. We find that the conversion efficiency from kinetic energy to EM emission for propellered material needs to be \$\gtrsim 10\%\$ and that the best fitting results come from an exponential accretion profile.}, added-at = {2019-03-25T08:20:55.000+0100}, archiveprefix = {arXiv}, author = {Gompertz, B. P. and O'Brien, P. T. and Wynn, G. A.}, biburl = {https://www.bibsonomy.org/bibtex/26d41e76a719eacf704a950b1905fd3fc/ericblackman}, citeulike-article-id = {12776908}, citeulike-linkout-0 = {http://arxiv.org/abs/1311.1505}, citeulike-linkout-1 = {http://arxiv.org/pdf/1311.1505}, day = 6, eprint = {1311.1505}, interhash = {aa403235985b5462b5a57ffb61ecdc0b}, intrahash = {6d41e76a719eacf704a950b1905fd3fc}, keywords = {imported}, month = nov, posted-at = {2013-11-10 02:40:23}, priority = {2}, timestamp = {2019-03-25T08:20:55.000+0100}, title = {{Magnetar powered GRBs: Explaining the extended emission and X-ray plateau of short GRB light curves}}, url = {http://arxiv.org/abs/1311.1505}, year = 2013 }