gamma-ray耀变体候选者II的光学光谱观测。2013年北半球KPNO活动
Optical spectroscopic observations of gamma-ray blazar candidates II. The 2013 KPNO campaign in the Northern Hemisphere
摘要：
我们最近开始系统地搜索费米-大面积望远镜（LAT）第一源目录（1FGL）和费米-LAT 2年源目录（2FGL）中列出的未识别伽马射线源（UGS）的低能对应物。我们研究的主要目标是找到属于耀变体类的活跃星系，它们位于UGS的位置不确定区域内，因此可能是它们潜在的低能对应物。为了实现我们的目标，我们首先通过了几个程序的基础上，在无线电和红外线的耀变体的特殊观测特性。然后，我们进行了后续的光谱运动中的光学波段，以验证的性质的候选人被选为潜在的对应的UGS。在这里，我们介绍了2013年在北半球基特峰国家天文台（KPNO）进行的观测结果。光谱学对于确认光源的性质至关重要，可以用来估计它们的红移;它还可以让我们在整个活动完成后测试我们方法的鲁棒性。在这里，我们提出了39个源的光谱观测。在我们的样本中，我们发现6个源是耀变体，候选者是2FGL中列出的UGS的低能对应物。我们确认，另外8个来源，以前被归类为不确定类型的活动星系和相关的2FGL，也都是BL Lac对象。此外，我们还提出了20个新的光谱已知耀变体中列出的耀变体的多频率目录中具有不确定的红移和/或被归类为BL Lac候选人。我们的结论是，我们的方法选择γ射线blazar候选人，使我们能够发现新的blazar和增加潜在的低能量对应的费米UGS的列表。
英文摘要：
We recently started a systematic search of low-energy counterparts of the unidentified gamma-ray sources (UGSs) listed in the Fermi-Large Area Telescope (LAT) First Source Catalog (1FGL) and the Fermi-LAT 2-Year Source Catalog (2FGL).} The main goal of our investigation is to find active galaxies belonging to the blazar class that lie within the positional uncertainty region of the UGSs and thus could be their potential low-energy counterparts. To achieve our aims, we first adopted several procedures based on the peculiar observational properties of blazars in the radio and in the IR. Then we carried out a follow-up spectroscopic campaign in the optical band to verify the nature of the candidates selected as potential counterparts of the UGSs. Here we present the results of the observations carried out in 2013 in the Northern Hemisphere at Kitt Peak National Observatory (KPNO). Optical spectroscopy is crucial to confirm the nature of the sources and can be used to estimate their redshifts; it will also allow us to test the robustness of our methods when the whole campaign is completed. Here we present the optical spectroscopic observations of 39 sources. Within our sample we found that 6 sources are blazars, candidates to be low-energy counterparts of the UGSs listed in the 2FGL. We confirm that an additional 8 sources, previously classified as active galaxies of uncertain type and associated in the 2FGL, are also all BL Lac objects. Moreover, we also present 20 new spectra for known blazars listed in the Multi-frequency Catalogue of Blazars as having an uncertain redshift and/or being classified as BL Lac candidates. We conclude that our methods for selecting gamma-ray blazar candidates allows us to discover new blazars and increase the list of potential low-energy counterparts for the Fermi UGSs.
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