High-energy emission from NGC 5506, the brightest hard X-ray Narrow Line Seyfert 1 galaxy
S. Soldi, V. Beckmann, N. Gehrels, S. De Jong, P. Lubinski
备注：
8 pages, 3 figures, 1 table. Proceedings of the Workshop "Narrow-Line Seyfert 1 Galaxies and Their Place in the Universe", Milano, April 4-6, 2011 (Proceedings of Science, http://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=126)
We present results on the hard X-ray emission of NGC 5506, the brightest narrow line Seyfert 1 galaxy above 20 keV. All the recent observations by INTEGRAL, Swift and Suzaku have been analysed and spectral analysis during nine separated time periods has been performed. While flux variations by a factor of 2 were detected during the last 7 years, only moderate spectral variations have been observed, with the hint of a hardening of the X-ray spectrum and a decrease of the intrinsic absorption with time. Using Suzaku observations it is possible to constrain the amount of Compton reflection to R = 0.6-1.0, in agreement with previous results on the source. The signature of Comptonisation processes can also be found in the detection of a high-energy cut-off during part of the observations, at Ec = 40-100 keV. When a Comptonisation model is applied to the Suzaku data, the temperature and the optical depth of the Comptonising electron plasma are measured at kT = 60-80 keV and tau = 0.6-1.0, respectively. The properties inferred for NGC 5506 in this study agree with those based on other data sets for the same AGN, and fit the picture of NLS1 having in general lower high-energy cut-offs at hard X-rays than their broad line equivalent.
The ionization mechanism of NGC 185: how to fake a Seyfert galaxy?
NGC 185是仙女座星系的一颗矮球状卫星。从20世纪90年代中期开始，人们发现矮椭球体经常显示出各种各样的，在某些情况下复杂的恒星形成历史。在一次对邻近明亮星系的光学观测中，NGC 185根据其发射线比率被归类为塞弗特星系。然而，虽然这个物体的发射线正式将其置于塞弗茨星系的范畴，但这个星系可能并不包含真正的活动核。NGC 185在6或20厘米的射电巡天或X射线观测中都没有被发现，这意味着类似塞弗特的线比可能是由恒星过程产生的。在这项工作中，我们试图确定这个星系可能的电离机制。我们利用双子座GMOS-N获得的深层光谱观测结果，讨论了行星状星云（PNe）产生谱线发射的可能性。虽然PNe的通量高到足以解释积分光谱，但线比与Seyfert分类值相差甚远。然后，我们提出，超新星遗迹和PNe的混合物可能是电离的来源，我们表明，这两个对象的组合物模仿塞弗特线比。我们使用化学演化模型来预测超新星的速率，并支持这些超新星遗迹应该存在于星系中的想法。
Distribution of the heavy elements throughout the extended narrow line region of the Seyfert galaxy NGC 7212
本文用考虑活动核和激波光电离的模型分析了Seyfert 2星系NGC 7212的扩展窄线区（ENLR）发射的线谱和连续谱的最新观测结果。结果表明，在圆锥体的边缘和外部有较高的激波速度（500- 800 \kms），模型推算的活动星系核流量在Lyman极限下低于$10^{-11}$光子cm $^{-2}$ s $^{-1}$ eV $^{-1}$，这是低光度活动星系核的典型特征，而在Seyfert 2星系中则不然。震前密度是ENLR的特征，范围在80- 150 cm $^{-3}$之间。氮和硫的贫化系数低于2，特别是在东部边缘。氧气在几个地方耗尽。Fe/H比值接近太阳值，而Ne/H相对丰度异常高，为太阳值的1.5- 2倍。通过模拟连续谱能量分布（SED），我们发现在激波前沿由费米机制产生的射电同步辐射，而X射线则是由相对高温的等离子体产生的韧致辐射。
