We present the detection of the ammonia (NH3) (J,K) = (1,1) to (4,4) and (6,6) inversion lines toward the prototypical Seyfert 2 galaxy NGC 1068, made with the Green Bank Telescope (GBT). This is the first detection of ammonia in a Seyfert galaxy. The ortho-to-para-NH3 abundance ratio suggests that the molecule was formed in a warm medium of at least 20 K. For the NH3 column density and fractional abundance, we find (1.09\pm0.23)\times10^14 cm^-2 and (2.9\pm0.6)\times10^-8, respectively, from the inner 1.2 kpc of NGC 1068. The kinetic temperature can be constrained to 80\pm20 K for the bulk of the molecular gas, while some fraction has an even higher temperature of 140\pm30 K.
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。
The absence of broad [O III] ${λλ}$4959,5007 forbidden emission lines is one of the key arguments cited in the published literature for the gas density exceeding the critical density; 7 ${\times}$ 10$^5$ cm$^{-3}$, in the broad line region (BLR) of active galactic nuclei. However, for NGC 3227, an equally valid alternative explanation is that O$^{2+}$ is progressively ionized to O$^{3+}$ as the central UV-X-ray source is approached. Observational evidence for such an ionization gradient is provided by spectra obtained with the Space Telescope Imaging Spectrograph. Modeling the rich UV-visible …
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。
We present the first NuSTAR observation of a 'true' Type 2 Seyfert galaxy. The 3-40 keV X-ray spectrum of NGC3147 is characterised by a simple power-law, with a standard Γ~1.7 and an iron emission line, with no need for any further component up to ~40 keV. These spectral properties, together with significant variability on time-scales as short as weeks (as shown in a 2014 Swift monitoring campaign), strongly support an unobscured line-of-sight for this source. An alternative scenario in terms of a Compton-thick source is strongly disfavoured, requiring an exceptional geometrical configuration,…
