{"title":"Interplay between neutrino kicks and hydrodynamic kicks of neutron stars and black holes","authors":"Hans-Thomas Janka, Daniel Kresse","doi":"10.1007/s10509-024-04343-1","DOIUrl":null,"url":null,"abstract":"<div><p>Neutron stars (NSs) are observed with high space velocities and elliptical orbits in binaries. The magnitude of these effects points to natal kicks that originate from asymmetries during the supernova (SN) explosions. Using a growing set of long-time 3D SN simulations with the <span>Prometheus-Vertex</span> code, we explore the interplay of NS kicks that are induced by asymmetric neutrino emission and by asymmetric mass ejection. Anisotropic neutrino emission can arise from a large-amplitude dipolar convection asymmetry inside the proto-NS (PNS) termed LESA (Lepton-number Emission Self-sustained Asymmetry) and from aspherical accretion downflows around the PNS, which can lead to anisotropic neutrino emission (absorption/scattering) with a neutrino-induced NS kick roughly opposite to (aligned with) the kick by asymmetric mass ejection. In massive progenitors, hydrodynamic kicks can reach up to more than 1300 km s<sup>−1</sup>, whereas our calculated neutrino kicks reach (55–140) km s<sup>−1</sup> (estimated upper bounds of (170–265) km s<sup>−1</sup>) and only ∼(10–50) km s<sup>−1</sup>, if LESA is the main cause of asymmetric neutrino emission. Therefore, hydrodynamic NS kicks dominate in explosions of high-mass progenitors, whereas LESA-induced neutrino kicks dominate for NSs born in low-energy SNe of the lowest-mass progenitors, when these explode nearly spherically. Our models suggest that the Crab pulsar with its velocity of ∼160 km s<sup>−1</sup>, if born in the low-energy explosion of a low-mass, single-star progenitor, should have received a hydrodynamic kick in a considerably asymmetric explosion. Black holes, if formed by the collapse of short-lived PNSs and solely kicked by anisotropic neutrino emission, obtain velocities of only some km s<sup>−1</sup>.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":null,"pages":null},"PeriodicalIF":1.8000,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10509-024-04343-1.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Astrophysics and Space Science","FirstCategoryId":"101","ListUrlMain":"https://link.springer.com/article/10.1007/s10509-024-04343-1","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
Neutron stars (NSs) are observed with high space velocities and elliptical orbits in binaries. The magnitude of these effects points to natal kicks that originate from asymmetries during the supernova (SN) explosions. Using a growing set of long-time 3D SN simulations with the Prometheus-Vertex code, we explore the interplay of NS kicks that are induced by asymmetric neutrino emission and by asymmetric mass ejection. Anisotropic neutrino emission can arise from a large-amplitude dipolar convection asymmetry inside the proto-NS (PNS) termed LESA (Lepton-number Emission Self-sustained Asymmetry) and from aspherical accretion downflows around the PNS, which can lead to anisotropic neutrino emission (absorption/scattering) with a neutrino-induced NS kick roughly opposite to (aligned with) the kick by asymmetric mass ejection. In massive progenitors, hydrodynamic kicks can reach up to more than 1300 km s−1, whereas our calculated neutrino kicks reach (55–140) km s−1 (estimated upper bounds of (170–265) km s−1) and only ∼(10–50) km s−1, if LESA is the main cause of asymmetric neutrino emission. Therefore, hydrodynamic NS kicks dominate in explosions of high-mass progenitors, whereas LESA-induced neutrino kicks dominate for NSs born in low-energy SNe of the lowest-mass progenitors, when these explode nearly spherically. Our models suggest that the Crab pulsar with its velocity of ∼160 km s−1, if born in the low-energy explosion of a low-mass, single-star progenitor, should have received a hydrodynamic kick in a considerably asymmetric explosion. Black holes, if formed by the collapse of short-lived PNSs and solely kicked by anisotropic neutrino emission, obtain velocities of only some km s−1.
在双星中观测到的中子星(NSs)具有很高的空间速度和椭圆轨道。这些影响的程度表明,超新星(SN)爆炸过程中的不对称现象会产生原生踢。我们利用普罗米修斯-顶点(Prometheus-Vertex)代码进行了一组不断增加的长时间三维超新星模拟,探索了非对称中微子发射和非对称质量抛射所诱发的NS踢的相互作用。各向异性的中微子发射可能源于原NS(PNS)内部的大振幅偶极对流不对称(称为LESA(Lepton-number Emission Self-sustained Asymmetry)),也可能源于PNS周围的非球面吸积下流,这可能导致各向异性的中微子发射(吸收/散射),中微子诱发的NS激波与不对称质量抛射的激波大致相反(一致)。在大质量原生星中,流体动力踢可以达到1300 km s-1以上,而我们计算的中微子踢可以达到(55-140) km s-1(估计上限为(170-265) km s-1),如果LESA是不对称中微子发射的主要原因,那么中微子踢只有∼(10-50) km s-1。因此,流体动力NS踢在高质原生体的爆炸中占主导地位,而LESA引起的中微子踢在诞生于低质原生体的低能SNe中的NS中占主导地位,因为这些NS的爆炸几乎是球形的。我们的模型表明,速度为 160 km s-1 的蟹状脉冲星如果诞生于低质量单星原生体的低能爆炸中,那么它应该是在一次相当不对称的爆炸中受到了流体动力的冲击。如果黑洞是由寿命很短的PNS坍缩形成的,并且仅仅受到各向异性的中微子发射的推动,那么黑洞获得的速度只有大约km s-1。
期刊介绍:
Astrophysics and Space Science publishes original contributions and invited reviews covering the entire range of astronomy, astrophysics, astrophysical cosmology, planetary and space science and the astrophysical aspects of astrobiology. This includes both observational and theoretical research, the techniques of astronomical instrumentation and data analysis and astronomical space instrumentation. We particularly welcome papers in the general fields of high-energy astrophysics, astrophysical and astrochemical studies of the interstellar medium including star formation, planetary astrophysics, the formation and evolution of galaxies and the evolution of large scale structure in the Universe. Papers in mathematical physics or in general relativity which do not establish clear astrophysical applications will no longer be considered.
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