Study of positrons from cosmic rays interactions and cold dark matter annihilations in the galactic environment
Roberto A. Lineros
备注：
PhD thesis (University of Torino and University of Savoie), 160 pages, 79 figures. Abstract in english, italian, french and spanish. Some typos were corrected
Positron and electron cosmic rays provide a complementary way to study the galactic environment. The actual cosmic rays experiments, for instance PAMELA and HEAT, have presented very exciting results in this field. The observed positron fraction appears larger than the actual theoretical predictions for energies larger than 10 GeV. The indirect evidences of Dark Matter in connection with Beyond the Standard Model theories would suggest the existence of an extra contribution present in the cosmic ray signal. We study and calculate the positron signal produced by the annihilation of a generic Dark Matter candidate. Especially, We analyze typical annihilation signatures and the impact of CR propagation physics on the positron signal. In addition, we study the positron signal related to spallation processes between nuclei cosmic--rays and the interstellar gas. We analyze the effects of uncertainties present in nuclear cross section, nuclei cosmic--ray and CR propagation physics. The propagation of positrons is modeled according to the Two--Zone Propagation Model which has been successfully tested in the study of nuclei cosmic--ray and present an analytical approach to study the cosmic--ray physics.
Positron propagation in semi-relativistic plasmas: particle spectra and the annihilation line shape
通过直接求解Fokker-Planck方程，用$kT<m_ec^2$研究了湮灭、粒子逃逸和注入对热氢等离子体中稳态正电子分布形式的影响。我们表明，逃逸的正电子的形式的电子-正电子对和/或对等离子体的正电子分布上造成的影响，在某些情况下，强烈偏离麦克斯韦。此外，我们提出了准确的公式，能量交换率，由于库仑散射，韧致辐射，康普顿散射在克莱因-西科政权的损失。提出了用SIGMA望远镜在苍蝇座新星和1 E 1740.7-2942上观测到的湮灭特征是由于正电子/电子在热等离子体中的慢化和湮灭引起的，估算了电子数密度和发射区的大小。我们表明，在苍蝇座新星的情况下，所观察到的辐射是来自一对等离子体流（$n_{e^+}\approx n_{e^-}$），而不是从气体云。我们认为，两种模式可能是相关的1 E 1740.7-2942源：湮灭（氢）等离子体$n_{e^+}\la n_{e^-}$在休息，和湮灭对等离子体流，其中涉及到从源环境的物质。
Anti-proton and positron Cosmic Rays from Dark Matter annihilation around Intermediate Mass Black Holes
中等质量黑洞（IMBH）是超大质量黑洞（SMBH）的候选者，其中一些可能仍然在银河系中徘徊。在湮灭暗物质（DM）的背景下，它们预计会驱动巨大的湮灭率，因此可能会显着增强预期来自星系晕DM湮灭的初级宇宙射线（CR）。在这篇论文中（原始论文是Brun et al. 2007），我们简要解释了估算这种奇异贡献对反质子和正电子CR谱的方法，以及与IMBH性质相关的统计不确定性。我们发现，为了$10^4$的外来通量的助推因子，但与非常大的统计不确定性。
