The Remnant of Neutron Star-White Dwarf Merger and the Repeating Fast Radio Bursts

• 作者: Xiang Liu
• 来源期刊: 天文学与天体物理学国际期刊(英文)
• 学科: 物理学
• 关键词: Pulsar Neutron Star White DWARF MERGER Magnetic Field MAGNETAR FAST Radio Burst
• 年，卷（期）: twxyttwlxgjqkyw_2020,（1）
• 页码范围: 28-38
• 页数: 11页
• 分类号: O57

摘要

Fast radio bursts (FRBs) at cosmological distances still hold concealed physical origins. Previously Liu (2018) proposes a scenario that the collision between a neutron star (NS) and a white dwarf (WD) can be one of the progenitors of non-repeating FRBs and notices that the repeating FRBs can also be explained if a magnetar formed after such NS-WD merger. In this paper, we investigate this channel of magnetar formation in more detail. We propose that the NS-WD post-merger, after cooling and angular momentum redistribution, may collapse to either a black hole or a new NS or even remains as a hybrid WDNS, depending on the total mass of the NS and WD. In particular, the newly formed NS can be a magnetar if the core of the WD collapsed into the NS while large quantities of degenerate electrons of the WD compressed to the outer layers of the new NS. A strong magnetic field can be formed by the electrons and positive charges with different angular velocities induced by the differential rotation of the newborn magnetar. Such a magnetar can power the repeating FRBs by the magnetic reconnections due to the crustal movements or starquakes.