论文标题
$γ$ - 发射窄线seyfert 1个星系的短时尺度变异性
Short time-scale variability of $γ$-ray-emitting narrow-line Seyfert 1 galaxies in optical and UV bands
论文作者
论文摘要
我们报告了对紫外线和光学望远镜（UVOT）进行的所有光学和紫外线（UV）的单一暴露（UV）的首次系统分析。对于1H 0323+342，SBS 0846+513，PMN J0948+0022和PKS 2004-447在18个观察结果中，总共34个事件，在小时尺度上显着检测到快速变异性。特别是，我们报告了PKS 2004-447光学尺度（3-6 ks）的显着变异性的首次检测，而1H 0323+342和PMN J0948+0022的UV则检测到UV。观察到1H 0323+342，SBS 0846+513，PMN J0948+0022和PKS 2004-447（假设多普勒因子delta = 10）的最短变异性时间尺度（SBS 0846+513，PMN J0948+0022）给出了9.7 $ \ $ 10 $^$^$^$^$^$^$^14} $^$^^$^^$^| 14}的低下限，则给出了9.7 $ \ $^$^$^$^的下限。 $ \ times $ 10 $^{15} $ cm（对于1H 0323+342），这表明这些事件期间的光学和紫外线发射是在喷气机内紧凑的区域产生的。这些观察结果提供了有关这些来源中相对射线的同步发射的明确证据，类似于Blazars。在2009年6月23日，PMN J0948+0022的PMN J0948+0022发生了显着的可变性，从$ \ sim $ 1.1增加到0.4 mag，从$ \ sim $ \ sim $ 1.6 h以$ \ sim $ 1.6 h的速度增加，并且在可比的时间在初始水平下降。在较低频率下观察到的这一事件和其他事件的较高分数通量变化表明，同步加速器发射在较高频率下从积聚盘的热发射中更污染。
We report the first systematic analysis of single exposures of all optical and ultraviolet (UV) observations performed by the UltraViolet and Optical Telescope (UVOT) on board the {\em Neil Gehrels Swift Observatory} satellite available up to 2019 April of six $γ$-ray-emitting narrow-line Seyfert 1 galaxies (NLSy1). Rapid variability has been significantly detected on hours time-scale for 1H 0323+342, SBS 0846+513, PMN J0948+0022, and PKS 2004-447 in 18 observations for a total of 34 events. In particular, we report the first detection of significant variability on short time-scale (3-6 ks) in optical for PKS 2004-447, and UV for 1H 0323+342 and PMN J0948+0022. The shortest variability time-scale observed for 1H 0323+342, SBS 0846+513, PMN J0948+0022, and PKS 2004-447 (assuming a Doppler factor delta = 10) gives a lower limit on the size of emission region between 9.7 $\times$ 10$^{14}$ (for SBS 0846+513) and 1.6 $\times$ 10$^{15}$ cm (for 1H 0323+342), suggesting that the optical and UV emission during these events is produced in compact regions within the jet. These observations provide unambiguous evidence about the relativistically beamed synchrotron emission in these sources, similar to blazars. A remarkable variability has been observed for PMN J0948+0022 on 2009 June 23 with an increase from $\sim$1.1 to 0.4 mag going from v to w2 filter in $\sim$1.6 h and a decrease at the initial level in a comparable time. The higher fractional flux change observed for this and other events at lower frequencies suggests that the synchrotron emission is more contaminated by thermal emission from accretion disc at higher frequencies.
