论文标题
VMC调查-XLIX。发现麦哲伦云背后的核尘埃排放主导的类星体种群
The VMC Survey -- XLIX. Discovery of a population of quasars dominated by nuclear dust emission behind the Magellanic Clouds
论文作者
论文摘要
在发现SAGE0536AGN($ z \ sim $ 0.14)之后,对于活跃的银河核(AGN)观察到的最强10- $ $ m $ m硅酸盐排放,我们发现了Sage0534AGN($ Z \ sim $ 1.01),类似的AGN,但具有较少的AGN,但具有较小的极端硅酸盐硅酸盐。两者最初都被误认为是麦哲伦云中进化的恒星。缺乏远红外发射,因此是恒星形成的,这意味着我们在没有寄主银河系的贡献的情况下看到了AGN的中心发动机。它们可能是银河发展中的关键链接。我们使用了降低算法,T-SNE(T-SNE的随机邻居嵌入),其中包含来自Gaia EDR3的多波长数据,对麦哲伦云的Vista调查,Allwise和Australian Ska Pathfinder,发现这两个与众不同的AGN与16个不寻常的AGN与剩下的16个其他物体分组,建议稀有的类别,建议稀有类别。我们在SAAO/SALT和文献数据的光谱法证实了其中至少14个对象是外层次($ 0.13 <z <1.23 $),所有这些物体都托管AGN。使用光谱能量分配钳工雪茄,我们发现这些来源中的大多数灰尘发射($> 70 \%$)都是由于AGN造成的。寄主星系似乎在或过渡到绿谷。随着AGN通过绿色山谷的转变,X射线光度的趋势会变薄,增加了X射线光度,而Eddington的比例降低,这意味着随着增生供应的耗尽,圆环的耗尽,圆柱密度降低。同样,这些来源的近红外变异幅度与圆环的衰减相关,这意味着圆环在变异性中起着作用。
Following the discovery of SAGE0536AGN ($z \sim$ 0.14), with the strongest 10-$μ$m silicate emission ever observed for an Active Galactic Nucleus (AGN), we discovered SAGE0534AGN ($z \sim$ 1.01), a similar AGN but with less extreme silicate emission. Both were originally mistaken as evolved stars in the Magellanic Clouds. Lack of far-infrared emission, and therefore star-formation, implies we are seeing the central engine of the AGN without contribution from the host galaxy. They could be a key link in galaxy evolution. We used a dimensionality reduction algorithm, t-SNE (t-distributed Stochastic Neighbourhood Embedding) with multi-wavelength data from Gaia EDR3, VISTA survey of the Magellanic Clouds, AllWISE and the Australian SKA Pathfinder to find these two unusual AGN are grouped with 16 other objects separated from the rest, suggesting a rare class. Our spectroscopy at SAAO/SALT and literature data confirm at least 14 of these objects are extragalactic ($0.13 < z < 1.23$), all hosting AGN. Using spectral energy distribution fitter CIGALE we find that the majority of dust emission ($> 70 \%$) in these sources is due to the AGN. Host galaxies appear to be either in or transitioning into the green valley. There is a trend of a thinning torus, increasing X-ray luminosity and decreasing Eddington ratio as the AGN transition through the green valley, implying that as the accretion supply depletes, the torus depletes and the column density reduces. Also, the near-infrared variability amplitude of these sources correlates with attenuation by the torus, implying the torus plays a role in the variability.