标题： 伽马射线发射 supernova remnant G338.3-0.0 的环境：HESS J1640-465 的强子解释 显示英文标题

标题： The environment of the gamma-ray emitting SNR G338.3-0.0: a hadronic interpretation for HESS J1640-465

摘要： 超新星遗迹（SNR）G338.3-0.0在空间上与HESS J1640-465相关联，后者被认为是银河系中最亮的与SNR相关的伽马射线源。 最近在SNR壳内发现了一个X射线脉冲星PSR J1640-4631，这可能有利于检测到的极高能量（VHE）辐射的轻子起源。 尽管如此，到目前为止，HESS J1640-465的VHE辐射的起源尚未得到明确澄清。 事实上，目前的观测不能排除强子解释的可能性。 基于原子（HI）和分子（12^CO）存档数据，我们首次确定了G338.3-0.0/HESS J1640-465系统区域内的质子总环境密度，这是理解极高能量发射机制的关键参数。 得到的值在100-130 cm^-3范围内。 除此之外，我们开发了一种新的强子模型来描述HESS J1640-465源的能谱能量分布（SED），该模型包括文献中最新的质子-质子碰撞总伽马射线截面。 通过使用评估的环境质子密度，我们发现为了拟合数据所需的加速质子的总能量分别为5.4^{+4.7}_{-2.3} × 10^49 erg 和 1.6^{+1.4}_{-0.7} × 10^50 erg，分别对应8.5 kpc和13 kpc的距离。 当源距离为8.5 kpc时，这种情况符合典型情景，即释放的能量约为10^51 erg，并且约有10%的能量转移到加速质子中；而对应于源距离为13 kpc的情况，则需要更高的爆炸释放能量或者更大的能量比例来加速质子。 显示英文摘要

摘要： The supernova remnant (SNR) G338.3-0.0 spatially correlates with HESS J1640-465, which is considered the most luminous gamma-ray source associated with a SNR in our Galaxy. The X-ray pulsar PSR J1640-4631 has been recently discovered within the SNR shell, which could favor a leptonic origin for the detected very-high energy (VHE) emission. In spite of this, the origin of the VHE radiation from HESS J1640-465 has not been unambiguously clarified so far. Indeed, a hadronic explanation cannot be ruled out by current observations. On the basis of atomic (HI) and molecular (12^CO) archival data, we determine, for the first time, the total ambient density of protons in the region of the G338.3-0.0/HESS J1640-465 system, a critical parameter for understanding the emission mechanisms at very high energies. The value obtained is in the 100-130 cm^-3 range. Besides this, we developed a new hadronic model to describe the spectral energy distribution (SED) of the HESS J1640-465 source, which includes the latest total gamma-ray cross-section for proton-proton collisions available in the literature. By using the assessed ambient proton density, we found that the total energy in accelerated protons required to fit the data is 5.4^{+4.7}_{-2.3} x 10^49 erg and 1.6^{+1.4}_{-0.7} x 10^50 erg for a source distance of 8.5 and 13 kpc, respectively. The case where the source distance is 8.5 kpc agrees with the typical scenario in which the energy released is on the order of 10^51 erg and ~10% of that energy is transferred to the accelerated protons, whereas the case corresponding to a source distance of 13 kpc requires either a higher value of the energy released in the explosion or a larger energy fraction to accelerate protons.