Magnetar Spin-Down, Hyperenergetic Supernovae, and Gamma-Ray Bursts
Magnetar Spin-Down, Hyperenergetic Supernovae, and Gamma-Ray Bursts
复制标题
DOI：
10.1086/421969
复制
发表时间：
2004-01
期刊：
影响因子：
--
通讯作者：
T. Thompson;P. Chang;E. Quataert
中科院分区：
文献类型：
--
作者：
T. Thompson;P. Chang;E. Quataert
开尔文-亥姆霍兹冷却期，持续几十秒后，中子星星诞生在一个成功的核心坍缩超新星，伴随着中微子驱动的风。对于磁星强度（~1015 G）的大规模表面磁场，这种外流是磁主导的整个冷却时期。由于强磁场迫使风与原中子星星共转，这种外流可以显著影响中子星星早期的角动量演化，就像类似的恒星风模型一样。如果旋转能量与超新星能量相比很大，并且自旋下降的时间尺度相对于超新星冲击波穿越恒星祖先所需的时间来说很短，那么提取的能量可能会显着改变超新星冲击动力学。这种效应能够产生高能超新星，在某些情况下，为伽马射线爆发提供了有利的条件。我们估计自旋的磁化，旋转原中子星的时间尺度，并构建中微子磁离心驱动风的稳态模型。我们发现，如果磁星出生快速旋转，与初始自旋周期（P）的~1毫秒，然后在~10秒的数量级1051-1052尔格的旋转能量可以提取。如果磁星出生时旋转缓慢（P <10 ms），它们可以在开尔文-亥姆霍兹时间尺度上旋转到~1 s的周期。
The Kelvin-Helmholtz cooling epoch, lasting tens of seconds after the birth of a neutron star in a successful core-collapse supernova, is accompanied by a neutrino-driven wind. For magnetar-strength (~1015 G) large-scale surface magnetic fields, this outflow is magnetically dominated during the entire cooling epoch. Because the strong magnetic field forces the wind to corotate with the proto-neutron star, this outflow can significantly affect the neutron star's early angular momentum evolution, as in analogous models of stellar winds. If the rotational energy is large in comparison with the supernova energy and the spin-down timescale is short with respect to the time required for the supernova shock wave to traverse the stellar progenitor, the energy extracted may modify the supernova shock dynamics significantly. This effect is capable of producing hyperenergetic supernovae and, in some cases, provides conditions favorable for gamma-ray bursts. We estimate spin-down timescales for magnetized, rotating proto-neutron stars and construct steady state models of neutrino-magnetocentrifugally driven winds. We find that if magnetars are born rapidly rotating, with initial spin periods (P) of ~1 ms, then of order 1051-1052 ergs of rotational energy can be extracted in ~10 s. If magnetars are born slowly rotating (P ≳ 10 ms), they can spin down to periods of ~1 s on the Kelvin-Helmholtz timescale.