MINUTE-SCALE RAPID VARIABILITY OF THE OPTICAL POLARIZATION IN THE NARROW-LINE SEYFERT 1 GALAXY PMN J0948+0022
MINUTE-SCALE RAPID VARIABILITY OF THE OPTICAL POLARIZATION IN THE NARROW-LINE SEYFERT 1 GALAXY PMN J0948+0022
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DOI：
10.1088/2041-8205/775/1/l26
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发表时间：
2013-08
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通讯作者：
R. Itoh;Yasuyuki T. Tanaka;Y. Fukazawa;K. Kawabata;K. Kawaguchi;Y. Moritani;K. Takaki;I. Ueno;M. Uemura;H. Akitaya;Michitoshi Yoshida;T. Ohsugi;H. Hanayama;T. Miyaji;N. Kawai
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作者：
R. Itoh;Yasuyuki T. Tanaka;Y. Fukazawa;K. Kawabata;K. Kawaguchi;Y. Moritani;K. Takaki;I. Ueno;M. Uemura;H. Akitaya;Michitoshi Yoshida;T. Ohsugi;H. Hanayama;T. Miyaji;N. Kawai
报道了射电强窄线Seyfert 1（RL-NLSy 1）星系PMN J 0948 +0022在2012年12月至2013年2月期间由近红外和γ射线波段的通量增强所触发的光学旋光度测量结果。利用安装在金田望远镜上的广岛单次宽场偏振仪的单次偏振测量，我们探测到MJD 56281（2012年12月20日）偏振通量（PF）光变曲线的非常快速的变化。上升和衰减时间分别约为140 s和180 s。在短脉冲峰值处，偏振度（PD）达到36% ± 3%，偏振角基本保持不变。此外，总通量和PD的时间分布显示出高度可变但良好相关的行为，离散相关函数分析显示，不存在超过10分钟的显著时滞。PF的高PD和分钟尺度的变化提供了清晰的证据，同步辐射从一个非常紧凑的发射区域的大小为1014厘米，具有高度有序的磁场。这种偏振的微观变化在一些blazar喷流中也被观察到，但其总流量和PD之间的复杂关系在几个blazar解释的多区模型。PMNJ 0948 +0022中隐含的单发射区可能反映了RL-NLSy 1与blazar喷流的差异。
We report on optical photopolarimetric results of the radio-loud narrow-line Seyfert 1 (RL-NLSy1) galaxy PMN J0948+0022 on 2012 December to 2013 February triggered by flux enhancements in the near infrared and γ-ray bands. With the one-shot polarimetry of the Hiroshima One-shot Wide field Polarimeter installed on the Kanata Telescope, we detected very rapid variability in the polarized-flux (PF) light curve on MJD 56281 (2012 December 20). The rise and decay times were about 140 s and 180 s, respectively. The polarization degree (PD) reached 36% ± 3% at the peak of the short-duration pulse, while the polarization angle remained almost constant. In addition, temporal profiles of the total flux and PD showed highly variable but well correlated behavior and discrete correlation function analysis revealed that no significant time lag of more than 10 minutes was present. The high PD and minute-scale variability in PF provides clear evidence of synchrotron radiation from a very compact emission region of ∼1014 cm size with a highly ordered magnetic field. Such micro-variability of polarization is also observed in several blazar jets, but its complex relation between total flux and PD are explained by a multi-zone model in several blazars. The implied single emission region in PMN J0948+0022 might reflect a difference of jets between RL-NLSy1s and blazars.