论文标题
X射线能量的$γ$ ray天空I.搜索X射线和$γ$ - 砂之间的连接
The $γ$-ray sky seen at X-ray energies I. Searching for the connection between X-rays and $γ$-rays in Fermi BL Lac objects
论文作者
论文摘要
BL LAC对象是属于$γ$ - 射线源最大的人群的极端类型的活性银河核（AGN）。这类AGNS显示了双重频谱能量分布，通常用同步体自占（SSC）发射过程来描述，而低能组件的低能量组件在红外线和X射线波段之间占主导地位，与X射线频带之间的发射密切相关，该组件紧密连接到高增强的组件，达到了$γ$ -Rays $γ$ -Rays的高峰。建立了两个牢固的连接，这些连接将无线电和中海发射与$γ$ -Ray乐队的排放相关联。它们构成了将$γ$ ray来源与低能量对应物相关联的基础。我们使用所有Archival Swift/XRT观测值与Fermi数据合并了351个来源的样本，搜索了X射线和$γ$ ray排放之间的可能链接。分析$ \ sim $ 2400 ks swift/xrt观测值，直到2018年12月，我们发现高于$γ$ -Ray的通量阈值$f_γ\大约3 \ times10^{ - 12} \，\ rm {erg} \，\ rm {cm}^{ - 2} \，\ rm {s}^{ - 1} $，96 \％，96 \％的96 \％\％\ emph {fermi} bl lacs thy x-ray contery than s x-ray ats y-n is x-ray yno carty yno carty yno carty yno carty yno carty yno carty yno carty yno car yan s y n s ins and and and and-n s and-n is vary yno。我们没有发现X射线和$γ$ ray通量和/或光谱形状之间的任何相关性或明确的趋势，但是我们发现X射线通量与中红外颜色之间存在相关性。最后，我们在SSC框架中讨论了对结果的可能解释。
BL Lac objects are an extreme type of active galactic nuclei (AGNs) that belong to the largest population of $γ$-ray sources: blazars. This class of AGNs shows a double-bumped spectral energy distribution that is commonly described in terms of a synchrotron self-Compton (SSC) emission process, whereas the low-energy component that dominates their emission between the infrared and the X-ray band is tightly connected to the high-energy component that peaks in the $γ$-rays. Two strong connections that link radio and mid-infrared emission of blazars to the emission in the $γ$-ray band are well established. They constitute the basis for associating $γ$-ray sources with their low-energy counterparts. We searched for a possible link between X-ray and $γ$-ray emissions for the subclass of BL Lacs using all archival Swift/XRT observations combined with Fermi data for a selected sample of 351 sources. Analyzing $\sim$2400 ks of Swift/XRT observations that were carried out until December 2018, we discovered that above the $γ$-ray flux threshold $F_γ\approx3\times10^{-12}\,\rm{erg}\,\rm{cm}^{-2}\,\rm{s}^{-1}$, 96\% of all \emph{Fermi} BL Lacs have an X-ray counterpart that is detected with signal-to-noise ratio higher than 3. We did not find any correlation or clear trend between X-ray and $γ$-ray fluxes and/or spectral shapes, but we discovered a correlation between the X-ray flux and the mid-infrared color. Finally, we discuss on a possible interpretation of our results in the SSC framework.
