3C 454.3 II的多波长观测。AGILE 2007年12月活动
Multiwavelength observations of 3C 454.3 II. The AGILE 2007 December campaign
摘要：
我们在2007年12月上半月的第二AGILE多波长活动的耀变体3C 454.3。这次活动涉及AGILE，斯皮策，斯威夫特，朱雀，WEBT财团，REM和MITSUME望远镜，2周的AGILE监测伴随着WEBT和REM的无线电到光学监测以及中红外和软/硬X射线的稀疏观测。分别由斯皮策、雨燕和朱雀的“机会目标”观测器观测到的射线能带，探测到该源的平均通量为~ 250 × 10 ^{-8}ph cm^-2 s ^-1，高于100 MeV，同时进行的光学和伽马射线监测使我们能够研究与两个能带中的可变性相关的时滞，导致伽马射线发射相对于光学发射可能延迟约1天。从12月12日观测到的同时发生的光学和伽马射线快速耀斑，我们可以将伽马射线和光学辐射之间的延迟限制在12小时之内。此外，我们获得了三个频谱能量分布（SED）的同时数据为2007年12月5日，13日，15日，其特征在于最广泛的多频覆盖。我们发现，一个模型与外部康普顿种子光子的标准磁盘和再处理的宽线区域不描述在一个令人满意的方式2007年12月5日，13日和15日的SED。另外一个贡献可能来自喷流周围T=10^6 K的热日冕，它需要同时解释同步加速器的柔和性和这些时期逆康普顿辐射的坚硬性。
英文摘要：
We report on the second AGILE multiwavelength campaign of the blazar 3C 454.3 during the first half of December 2007. This campaign involved AGILE, Spitzer, Swift,Suzaku,the WEBT consortium,the REM and MITSuME telescopes,offering a broad band coverage that allowed for a simultaneous sampling of the synchrotron and inverse Compton (IC) emissions.The 2-week AGILE monitoring was accompanied by radio to optical monitoring by WEBT and REM and by sparse observations in mid-Infrared and soft/hard X-ray energy bands performed by means of Target of Opportunity observations by Spitzer, Swift and Suzaku, respectively.The source was detected with an average flux of~250x10^{-8}ph cm^-2s^-1 above 100 MeV,typical of its flaring states.The simultaneous optical and gamma-ray monitoring allowed us to study the time-lag associated with the variability in the two energy bands, resulting in a possible ~1-day delay of the gamma-ray emission with respect to the optical one. From the simultaneous optical and gamma-ray fast flare detected on December 12, we can constrain the delay between the gamma-ray and optical emissions within 12 hours. Moreover, we obtain three Spectral Energy Distributions (SEDs) with simultaneous data for 2007 December 5, 13, 15, characterized by the widest multifrequency coverage. We found that a model with an external Compton on seed photons by a standard disk and reprocessed by the Broad Line Regions does not describe in a satisfactory way the SEDs of 2007 December 5, 13 and 15. An additional contribution, possibly from the hot corona with T=10^6 K surrounding the jet, is required to account simultaneously for the softness of the synchrotron and the hardness of the inverse Compton emissions during those epochs.
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