标题： 宁静 Seyfert 1 的平均 X 射线/伽马射线能谱 显示英文标题

标题： The average X-ray/gamma-ray spectrum of radio-quiet Seyfert 1s

摘要： 我们利用EXOSAT、Ginga、HEAO和GRO/OSSE的数据获得了宁静型塞弗特1型星的平均1–500 keV能谱。合并后的EXOSAT和OSSE数据的光谱拟合结果与Ginga和OSSE的结果完全一致，证实了早期Ginga/OSSE样本的结果。平均能谱可以用一个能量谱指数为$\alpha \simeq 0.9$的幂律X射线连续区很好地拟合，该连续区被电离介质适度吸收，并带有康普顿反射分量。数据要求功率律组分在几百keV或更高的地方存在一个高能截止（或拐折）。我们还表明，来自HEAO A1和A4的相应平均能谱与从EXOSAT、Ginga和OSSE获得的结果完全兼容。这些结果证实了Ginga（使用$\alpha \simeq 0.9$）与之前的EXOSAT和HEAO（使用$\alpha \simeq 0.7$）结果之间的明显差异确实是由电离吸收和康普顿反射引起的，这在Ginga中首次考虑，但之前的任务未考虑。此外，我们的结果确认了塞弗特1型星的伽马射线能谱在至少几百keV的能量上被截断，而不是在$\sim 40$keV（如仅由OSSE数据先前所建议的那样）。平均能谱与盘冕中的光学薄相对论热等离子体发射或具有相对论电子幂律注入的非热等离子体发射相容。 显示英文摘要

摘要： We have obtained the average 1--500 keV spectrum of radio-quiet Seyfert 1s using data from EXOSAT, Ginga, HEAO, and GRO/OSSE. The spectral fit to the combined average EXOSAT and OSSE data is fully consistent with that for Ginga and OSSE, confirming results from an earlier Ginga/OSSE sample. The average spectrum is well-fitted by a power-law X-ray continuum with an energy spectral index of $\alpha \simeq 0.9$ moderately absorbed by an ionized medium and with a Compton reflection component. A high-energy cutoff (or a break) in the the power-law component at a few hundred keV or more is required by the data. We also show that the corresponding average spectrum from HEAO A1 and A4 is fully compatible with that obtained from EXOSAT, Ginga and OSSE. These results confirm that the apparent discrepancy between the results of Ginga (with $\alpha \simeq 0.9$) and the previous results of EXOSAT and HEAO (with $\alpha \simeq 0.7$) is indeed due to ionized absorption and Compton reflection first taken into account for Ginga but not for the previous missions. Also, our results confirm that the Seyfert-1 spectra are on average cut off in gamma-rays at energies of at least a few hundred keV, not at $\sim 40$ keV (as suggested earlier by OSSE data alone). The average spectrum is compatible with emission from either an optically-thin relativistic thermal plasma in a disk corona, or with a nonthermal plasma with a power-law injection of relativistic electrons.