论文标题
超新星残留G46.8-0.3，与分子材料相互作用的新案例
Supernova remnant G46.8-0.3, a new case of interaction with molecular material
论文作者
论文摘要
我们介绍了关于50年前发现以来的G46.8-0.3及其环境的第一个详细研究（SNR）G46.8-0.3及其环境。通过无线电调查的新通量测量以及文献的汇编，我们创建了一个改进的集成无线电频谱，G46.8-0.3的综合频谱是由具有索引alpha = -0.535 +/- 0.012的简单幂律很好地安装的，然后在Sight of Sige of Snir中排除了吸收量，并排除了吸收量，而在Snr中排除了吸收。对G46.8-0.3跨无线电光谱指数的局部变化的分析表明，在约1 GHz时略有陡峭的陡峭，这不会影响源的综合光谱。从原子氢（HI）光谱中，我们将残留物放置在8.7 +/- 1.0 kpc，并重新审视了与附近HII区G046.495-00.241至7.3 +/- 1.2 kpc的距离。从进化模型和我们的距离估计中，我们得出结论G46.8-0.3是中年（$ \ sim $ 1 x 10^4 yr）SNR。我们在残留物的接近度中识别了几个12CO和13CO分子结构，并使用了组合的共同轮廓来推导这些特征的运动学距离并表征其物理特性。我们还为环境分子云提供了令人信服的证据，该云与G46.8-0.3在其东部边缘的中心以及SNR Shell远端的北部和西南轮辋的中心相连。我们的研究没有确认残留物如前所述，将残留物嵌入分子腔中。 G46.8-0.3显示了与伽马射线源4FGL J1918.1+1215c的视线巧合，该量子通过太空望远镜Fermi在GEV Energies检测到。基于星际物质的特性的粗略分析CLASS G46.8-0.3表明，朝向SNR方向检测到的GEVγ射线光子可以合可能归因于Hadronic碰撞和/或Bremsstrahlung辐射。
We present the first detailed study on the Galactic supernova remnant (SNR) G46.8-0.3 and its environment since its discovery more than 50 years ago. With new flux measurements from radio surveys plus a compilation from the literature we created an improved integrated radio spectrum of G46.8-0.3, which is well fitted by a simple power-law with an index alpha = -0.535 +/- 0.012, then excluding the presence of absorption by abundant ionised gas in the line of sight, or in the SNR's proximity. The analysis of local changes in the radio spectral index across G46.8-0.3 suggests a slight steepening at about 1 GHz, which does not impact on the integrated spectrum of the source. From atomic hydrogen (HI) spectra we placed the remnant at 8.7 +/- 1.0 kpc, and revisited the distance to the nearby HII region G046.495-00.241 to 7.3 +/- 1.2 kpc. From evolutionary models and our distance estimate, we conclude G46.8-0.3 is a middle-aged ($\sim$1 x 10^4 yr) SNR. We recognised several 12CO and 13CO molecular structures in the proximity of the remnant and used combined CO-HI profiles to derive the kinematic distances to these features and characterise their physical properties. We also provided compelling evidences for environmental molecular clouds physically linked to G46.8-0.3 at its centre, on its eastern edge, and towards the northern and southwestern rims on the far side of the SNR shell. Our study does not confirm that the remnant is embedded in a molecular cavity as previously suggested. G46.8-0.3 shows a line-of-sight coincidence with the gamma-ray source 4FGL J1918.1+1215c, detected at GeV energies by the space telescope Fermi. A rough analysis based on the properties of the interstellar matter close G46.8-0.3 indicates that the GeV gamma-rays photons detected in direction to the SNR can be plausibly attributed to hadronic collisions and/or bremsstrahlung radiation.
