论文标题
来自Starburst Galaxy NGC 4945
Cosmic rays, neutrinos and GeV-TeV gamma rays from Starburst Galaxy NGC 4945
论文作者
论文摘要
检测高能量的天体中微子和超高能量宇宙射线（UHECR）为探索宇宙射线来源提供了一种新的方法。由IceCube检测到的最高能量中微子事件之一，标记为IC35，靠近Pierre Auger天文台检测到的UHECR各向异性区域。附近的Starburst Galaxy（SBG）NGC 4945靠近该各向异性区域以及IC35事件的平均角度误差。考虑到位于NGC 4945的SB区域的高脱腔贡献，可以将质子加速到$ \ sim 10^{17} \，{\ rm ev} $，并将它们注入星际介质，我们研究了此事件周围的这项事件的起源。我们表明，如果SB区域的磁场强度是$ \ sim \ rm mg $，那么这些质子与SB区域的气体密度的相互作用可以解释费米 - 拉特伽马射线和无线电观察结果。如果考虑到2.4（2.7）的质子频谱指数，我们估计的PEV中微子事件（十年来）大约为0.01（$ 4 \ times10^{ - 4} $），这将证明IC35不是在该SBG的中部地区产生的。此外，我们考虑了NGC 4945的超级风向区域，并表明质子很难加速到UHES。
The detection of high-energy astrophysical neutrinos and ultra-high-energy cosmic rays (UHECRs) provides a new way to explore sources of cosmic rays. One of the highest energy neutrino events detected by IceCube, tagged as IC35, is close to the UHECR anisotropy region detected by Pierre Auger Observatory. The nearby starburst galaxy (SBG), NGC 4945, is close to this anisotropic region and inside the mean angular error of the IC35 event. Considering the hypernovae contribution located in the SB region of NGC 4945, which can accelerate protons up to $\sim 10^{17} \, {\rm eV}$ and inject them into the interstellar medium, we investigate the origin of this event around this starburst galaxy. We show that the interaction of these protons with the SB region's gas density could explain Fermi-LAT gamma-ray and radio observations if the magnetic field's strength in the SB region is the order of $\sim \rm mG$. Our estimated PeV neutrino events, in ten years, for this source is approximately 0.01 ($4\times10^{-4}$) if a proton spectral index of 2.4 (2.7) is considered, which would demonstrate that IC35 is not produced in the central region of this SBG. Additionally, we consider the superwind region of NGC 4945 and show that protons can hardly be accelerated in it up to UHEs.
