Neutrino tomography of gamma-ray bursts and massive stellar collapses
Neutrino tomography of gamma-ray bursts and massive stellar collapses
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伽马射线暴和大规模恒星塌缩的中微子断层扫描
DOI：
10.1103/physrevd.68.083001
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发表时间：
2003
影响因子：
5
通讯作者：
E. Waxman
中科院分区：
文献类型：
--
作者：
S. Razzaque;P. Mészáros;E. Waxman
到目前为止，伽玛射线暴（GRB）的精确定位与活跃恒星形成的区域有关，它们的祖先被认为是大质量恒星。这种爆发的主要模型涉及一种相对论性喷流，这种喷流是在大质量恒星祖先[1]的核心坍塌后产生的。在这个模型中，射线是由费米加速电子在光学薄激波中产生的同步加速器或逆康普顿辐射产生的（参见[2]的回顾），在喷流从恒星包层中出现之后。同样的光学薄激波应该加速相对论性质子[3]，并通过与观测到的MeV射线[4]的相互作用产生~ 100 TeV的中微子。然而，当喷流仍在恒星内部时，激波加速质子可以通过与亚恒星喷流腔[5]中的热x射线的光度计相互作用产生~ TeV的中微子。在本文中，我们讨论了更一般的一类大质量恒星坍缩，其中射流形成可能无处不在，但并非所有这些都与可探测的grb有关。在它们成功或失败地从恒星中出现之前，喷流可以加速质子，这些质子经历了比以前认识到的更复杂的高能相互作用序列。这些不仅取决于喷气机和中央发动机的特性，还取决于激波的位置和恒星祖星的外部尺寸，从而为祖星的类型以及喷气机和激波参数提供潜在有用的诊断。在次恒星喷流激波中加速的质子首先经历与热化激波光子的光子学相互作用，以及在喷流框架中与热核子的pp、pn相互作用。这改变了到达喷射腔末端的相对论质子谱，在那里质子经历了与恒星x射线光子的第二组光子学相互作用，以及与恒星框架中的冷核子的pp、pn相互作用。产生喷流的坍塌部分随后从恒星中出现，产生电磁可探测的grb，预计在此之前会有一个能量为& TeV的前体中微子信号，这与先前计算的与-射线[4]一致的& 100 TeV中微子信号有很大不同。恒星坍缩导致喷流没有出现的那部分也会有类似的中微子信号，但它们可能更多，因此它们的漫射通量可能更重要。我们在第二节中讨论了射流模型，在第三节中讨论了内部激波中的质子和电子加速，在第四节中讨论了质子相互作用。我们在第五节中讨论了中微子的产生机制，在第六节中计算了观测到的中微子通量。我们在第七节中总结并讨论了我们的结果的含义。
The gamma-ray bursts (GRB) which have so far been accurately localized are associated with regions of active star formation, and their progenitors are thought to be massive stars. The leading model for such bursts involves a relativistic jet, produced following the collapse of the core of the massive stellar progenitor [1]. In this model the -rays are produced by synchrotron or inverse Compton radiation from Fermi accelerated electrons in optically thin shocks (see [2] for a review), after the jet has emerged from the stellar envelope. The same optically thin shocks should accelerate relativistic protons [3], and lead to ∼ 100 TeV neutrinos via interactions with the observed MeV -rays [4]. However, while the jets are still inside the star, shock-accelerated protons can produce ∼ TeV neutrinos through photomeson interactions with thermal X-rays in the sub-stellar jet cavity [5]. In this paper we discuss a more general class of massive stellar collapses, in which jet formation may be ubiquitous, but not all of which emerge to be associated with detectable GRBs. Before their successful or failed emergence from the star, the jets can accelerate protons which undergo a more complex sequence of high energy interactions than previously realized. These depend not only on the jet and central engine characteristics but also on the location of the shocks and on the outer dimensions of the stellar progenitor, thus providing potentially useful diagnostics for the type of progenitor as well as the jet and shock parameters. Protons accelerated in substellar jet shocks first undergo photomeson interactions with thermalized shock photons, as well as pp, pn interactions with thermal nucleons in the jet frame. This modifies the relativistic proton spectrum reaching the end of the jet cavity, where the protons undergo a second set of photomeson interactions with stellar X-ray photons and pp, pn interactions with cold nucleons in the stellar frame. The fraction of collapses producing jets which subsequently emerge from the star to produce electromagnetically detectable GRBs are expected to be preceded by a precursor neutrino signal at energies & TeV, which is significantly different from the previously calculated & 100 TeV neutrino signals coincident with the -rays [4]. The fraction of stellar collapses leading to jets which do not emerge would have similar neutrino signals, but they could be more numerous and hence their diffuse flux could be more important. We discuss our jet models in Sec. II, proton and electron acceleration in the internal shocks in Sec. III and proton interactions in Sec. IV. We discuss neutrino production mechanisms in Sec. V and calculate observed neutrino flux in Sec. VI. We summarize and discuss implications of our results in Sec. VII.