arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2006.09411astro-ph.HE
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发射Gamma-ray的窄线塞弗特1星系:雨燕视图

Gamma-ray-emitting narrow-line Seyfert 1 galaxies: the Swift view

Filippo D'Ammando

摘要:

我们报告了截至2019年4月对$γ$射线发射窄线塞弗特1星系(NLSy 1)的所有斯威夫特观测结果的分析。X射线光度(和通量)的分布表明,喷流辐射对它们的X射线发射有很大的贡献,多普勒增强使其值高于其他无线电响亮的NLSy 1。0.3-10千电子伏的光子指数平均更难相对于无线电安静和无线电响亮NLSy 1,确认占主导地位的喷射贡献的X射线。然而,较低的变化幅度相对耀变体和软化的频谱在某些时期表明,也电晕辐射有助于X射线发射。在光学和紫外线(UV)的显着的流量变化已被观察到的每日,每周和每月的时间尺度,提供了一个清晰的指示喷流辐射在这部分光谱的显着贡献。在1H 0323+342、SBS 0846+513、PMN J 0948 +0022中观察到X射线、紫外线和光发射之间的强相关性以及同时发生的通量变化,正如在喷流辐射是主导机制的情况下所预期的那样。相关的多波段变率也有利于FBQS J1644+2619和PKS 2004-447中的喷流主导情景。1H 0323+342、SBS 0846+513、PMN J 0948 +0022和FBQS J1644+2619的X射线望远镜谱的总和很好地符合破幂律,破幂律在2 keV附近。如硬光子指数所示,2 keV以上的光谱主要是由束流相对论性喷流的非热发射。在低于2 keV的能量下,观测到了类似塞弗特的特征,如软X射线过剩,这使得这些发射$γ$射线的NLSy 1不同于典型的耀变体。

英文摘要:

We report the analysis of all Swift observations available up to 2019 April of $γ$-ray-emitting narrow-line Seyfert 1 galaxies (NLSy1). The distribution of X-ray luminosities (and fluxes) indicates that the jet radiation significantly contributes to their X-ray emission, with Doppler boosting making values higher than other radio-loud NLSy1. The 0.3-10 keV photon indices are on average harder with respect to radio-quiet and radio-loud NLSy1, confirming a dominant jet contribution in X-rays. However, the lower variability amplitude with respect to blazars and the softening of the spectrum in some periods suggests that also the corona radiation contributes to the X-ray emission. In optical and ultraviolet (UV) significant flux changes have been observed on daily, weekly, and monthly time-scale, providing a clear indication of the significant contribution of the jet radiation in this part of spectrum. A strong correlation between X-ray, UV, and optical emission and simultaneous flux variations have been observed in 1H 0323+342, SBS 0846+513, PMN J0948+0022 as expected in case the jet radiation is the dominant mechanism. Correlated multiband variability favours the jet-dominated scenario also in FBQS J1644+2619 and PKS 2004-447. The summed X-ray Telescope spectra of 1H 0323+342, SBS 0846+513, PMN J0948+0022, and FBQS J1644+2619 are well fitted by a broken power law with a break around 2 keV. The spectrum above 2 keV is dominated by the non-thermal emission from a beamed relativistic jet, as suggested by the hard photon index. A Seyfert-like feature like the soft X-ray excess has been observed below 2 keV, making these $γ$-ray-emitting NLSy1 different from typical blazars.

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