Measuring the smearing of the Galactic 511-keV signal: positron propagation or supernova kicks?
Measuring the smearing of the Galactic 511-keV signal: positron propagation or supernova kicks?
复制标题
测量银河 511 keV 信号的拖尾效应：正电子传播还是超新星爆发？
DOI：
10.1093/mnrasl/slab113
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发表时间：
2021
影响因子：
4.8
通讯作者：
Shunsaku
中科院分区：
文献类型：
--
作者：
Siegert;Thomas and Crocker;Roland M. and Macias;Oscar and Panther;Fiona H. and Calore;Francesca and Song;Deheng and Horiuchi;Shunsaku
我们使用来自INTEGRAL/SPI的15年γ射线数据，对银河系凸起正电子湮灭信号的形态进行了细致的研究。我们的空间分析证实，该信号追踪了古老的恒星群，首次揭示了它追踪了方形凸起和核恒星凸起，同时排除了额外暗物质成分的存在。使用三维平滑核，我们发现信号在150±50pc的特征长度范围内被抹去，这表明在形成时受到天体物理源的原位湮灭或正电子在源外传播。前者不受欢迎，因为它要求星系核（≥50 km s−1）和更宽的凸起（≥15 km s−1）源之间的踢射速度不同。湮灭前的正电子传播可以解释正电子注入能量为1.4 MeV的511 keV信号的整体现象，提示核合成起源。
We use 15 yr of γ-ray data from INTEGRAL/SPI in a refined investigation of the morphology of the Galactic bulge positron annihilation signal. Our spatial analysis confirms that the signal traces the old stellar population, revealing for the first time that it traces the boxy bulge and nuclear stellar bulge, while disfavouring the presence of additional dark matter components. Using a three dimensional (3D) smoothing kernel, we find that the signal is smeared out over a characteristic length scale of 150±50 pc, suggesting either annihilation in situ at astrophysical sources kicked at formation or positron propagation away from sources. The former is disfavoured due to its requirement of kick velocities different between the Galactic nucleus (≳ 50 km s− 1) and wider bulge (≲ 15 km s− 1) source. Positron propagation prior to annihilation can explain the overall phenomenology of the 511 keV signal for positrons injection energies 1.4 MeV, suggesting a nucleosynthesis origin.