Analyzing the gamma-ray activity of neutrino emitter candidates: comparing TXS 0506+056 with other blazars

Data and code for our publication (in MNRAS) described by the title. Following is the abstract for the same article: On 22nd of September 2017 the IceCube collaboration sent an alert for an EHE (Extreme HighEnergy) event, corresponding to the reconstruction of a muonic neutrino (IC-170922A) with energy∼290 TeV. A multi-wavelength follow-up campaign associated this neutrino event with a gamma-ray flaring state of the BL Lac TXS 0506+056 located at z=0.3365. From the same position of the sky a muonic neutrino excess is observed in a time window of 110 days around 13th of December 2014. These observations together suggest TXS 0506+056 as a possible neutrino emitter. We report here a long term gamma-ray monitoring of this source and we compare it with other blazars spatially correlated with astrophysical muonic neutrino events observed by IceCube. We characterize the most significant gamma-ray flares of the blazars in the sample and introduce the blazar duty cycle as an important parameter to be considered when assessing a possible neutrino counterpart. For the selected blazars we show the expected neutrino flux variability with different time binning assuming the gamma-rays observed by Fermi-LAT as a product of a leptohadronic emission scenario. The neutrino expectations from the blazar sample are then compared with the IceCube discovery flux search-ing for the optimal time bin in a multi-messenger context. This analysis indicates that the detection of a single flare represents a challenge for a single cubic kilometer detector, underlining the importance of increasing the size of current neutrino telescopes and obtaining a good monitoring of the entire sky through a global neutrino network.本数据集包含对应于发表于《皇家天文学会月报》（MNRAS）的论文的数据与代码。以下为该论文的摘要： 2017年9月22日，冰立方（IceCube）合作组发布了一则极高能（Extreme HighEnergy, EHE）事件警报，该事件对应一枚标记为IC-170922A的μ型中微子（muonic neutrino）的重建结果，其能量约为290 TeV。随后开展的多波段后续观测项目将该中微子事件与红移z=0.3365的耀变体BL Lac天体TXS 0506+056的γ射线耀发状态相关联。此外，在2014年12月13日前后110天的时间窗口内，研究人员在同一天空位置观测到μ型中微子超出信号。上述观测结果共同表明TXS 0506+056可能是潜在的中微子辐射源。 本文报道了对该源的长期γ射线监测工作，并将其与其他与冰立方观测到的天体物理μ型中微子事件存在空间关联的耀变体进行对比。我们对样本中耀变体的最显著γ射线耀发现象进行了特征刻画，并提出耀变体占空比（blazar duty cycle）是评估潜在中微子对应体时需纳入考量的重要参数。 对于所选耀变体样本，我们假设费米大面积望远镜（Fermi-LAT）观测到的γ射线产生于轻子强子辐射（leptohadronic emission）情景，据此展示了不同时间分箱方案下预期的中微子通量变化。随后，我们将该耀变体样本的中微子预期通量与冰立方的探测通量进行对比，在多信使语境下搜寻最优时间分箱方案。 本分析结果显示，单个立方公里级探测器难以单次探测到耀发事件，这凸显了扩大当前中微子望远镜阵列规模、并通过全球中微子网络实现全天域高效监测的重要性。