MAGIC long-term study of the distant TeV blazar PKS 1424+240 in a multiwavelength context
MAGIC long-term study of the distant TeV blazar PKS 1424+240 in a multiwavelength context
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DOI：
10.1051/0004-6361/201423364
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发表时间：
2014-01
影响因子：
6.5
通讯作者：
M. C. J. Aleksi'c;S. Ansoldi;L. A. Antonelli;P. Antoranz;A. Babić;P. Bangale;U. D. Almeida;J. Barrio
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文献类型：
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作者：
M. C. J. Aleksi'c;S. Ansoldi;L. A. Antonelli;P. Antoranz;A. Babić;P. Bangale;U. D. Almeida;J. Barrio
目标。利用MAGIC望远镜对耀变体PKS 1424+240的甚高能（VHE; E>100 GeV）射线辐射进行了研究。本文的主要目的是对这颗耀变体的多波长光谱进行表征和建模，最近发现它的红移下限为z≥ 0.6，这使得它成为最遥远的VHE源的一个有希望的候选者。方法.从2009年至2011年，MAGIC望远镜在VHE射线中对该源进行了总共33.6小时的观测。对它的X射线能谱和时间演化进行了详细的分析.此外，我们已经收集和分析了同时和准同时多波长数据。结果在2009年和2010年期间，在VHE射线中勉强检测到该源，后来，在2011年的光学爆发期间确认了该检测。叠加样本的组合显著性为7.2 ‰。在不同活动期间测量的差分光谱可以用指数范围为3.5± 1.2至5.0± 1.7的陡峭幂律来描述。修正了河外背景光吸收的MAGIC光谱在系统误差范围内与2009-2011年费米LAT在较低能量下观测到的平均光谱平滑地连接起来。吸收校正的MAGIC谱是平坦的，在400 GeV以下没有明显的转折。多波长光变曲线显示，无线电和光学波段的通量不断增加，这可能指向来自喷流同一区域的共同起源。如果应用单区同步自康普顿模型，则所构建的非同时光谱能量分布的两个峰之间的大分离也需要极高的多普勒因子。我们发现，一个两个组件的同步辐射自康普顿模型描述的光谱能量分布的源，如果位于z <$0.6。
Aims. We present a study of the very high energy (VHE; E>100 GeV) -ray emission of the blazar PKS 1424+240 observed with the MAGIC telescopes. The primary aim of this paper is the multiwavelength spectral characterization and modeling of this blazar, which is made particularly interesting by the recent discovery of a lower limit of its re dshift of z≥ 0.6 and makes it a promising candidate to be the most distant VHE source. Methods. The source has been observed with the MAGIC telescopes in VHE rays for a total observation time of∼33.6 h from 2009 to 2011. A detailed analysis of its -ray spectrum and time evolution has been carried out. Moreover, we have collected and analyzed simultaneous and quasi-simultaneous multiwavelength data. Results. The source was marginally detected in VHE rays during 2009 and 2010, and later, the detection was confir med during an optical outburst in 2011. The combined significance of the stacked sa mple is∼7.2�. The differential spectra measured during the different campaigns can be described by steep power laws with the indices ranging from 3.5± 1.2 to 5.0± 1.7. The MAGIC spectra corrected for the absorption due to the extragalactic background light connect smoothly, within systematic errors, with the mean spectrum in 2009-2011 observed at lower energies by the Fermi-LAT. The absorption-corrected MAGIC spectrum is flat with n o apparent turn down up to 400 GeV. The multiwavelength light curve shows increasing flux in radio and optical bands that could point to a common origin from the same region of the jet. The large separation between the two peaks of the constructed non-simultaneous spectral energy distribution also requires an extremely high Doppler factor if an one zone synchrotron self-Compton model is applied. We find that a two-component s ynchrotron self-Compton model describes the spectral energy distribution of the source well, if the source is located at z∼ 0.6.