The VMC survey - XLIX. Discovery of a population of quasars dominated by nuclear dust emission behind the Magellanic Clouds
The VMC survey - XLIX. Discovery of a population of quasars dominated by nuclear dust emission behind the Magellanic Clouds
复制标题
VMC 调查 - XLIX。
DOI：
10.1093/mnras/stac2096
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发表时间：
2022
影响因子：
4.8
通讯作者：
Pennock C
中科院分区：
文献类型：
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作者：
Pennock C
在发现SAGE 0536活动星系核（AGN）（z = 0.14）之后，我们发现了SAGE 0534活动星系核（AGN）（z = 1.01），这是一个类似的活动星系核，但没有那么极端的硅酸盐发射。这两颗恒星最初都被误认为是麦哲伦星云中的演化恒星。远红外辐射的缺乏，以及因此导致的星星形成，意味着我们看到的活动星系核的中心引擎没有来自宿主星系的贡献。它们可能是星系演化的关键环节。我们使用了降维算法，t分布随机邻居嵌入多波长数据fromGaiaEDR 3，VISTA调查麦哲伦云，AllWISE，和澳大利亚平方公里阵列探路者找到这两个不寻常的活动星系核与其他16个对象分开，这表明一个罕见的类。我们在南非天文台/南部非洲大望远镜的光谱学和文献数据证实，这些天体中至少有14个是河外天体（0.13 <z< 1.23），它们都是活动星系核的宿主。利用光谱能量分布拟合方法，我们发现这些源中的大部分尘埃辐射（）来自活动星系核。宿主星系似乎要么在绿色山谷中，要么过渡到绿色山谷中。当活动星系核跃迁通过绿色谷时，有一个变薄的环面、增加的X射线光度和减小的爱丁顿比的趋势，这意味着当吸积供应耗尽时，环面耗尽，柱密度减小。此外，这些源的近红外变化幅度与环面的衰减相关，这意味着环面在变化中起着作用。
Following the discovery of SAGE0536AGN (z∼ 0.14), with the strongest 10-μm silicate emission ever observed for an active galactic nucleus (AGN), we discovered SAGE0534AGN (z∼ 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-distributed stochastic neighbour embedding with multiwavelength data fromGaiaEDR3, VISTA survey of the Magellanic Clouds, AllWISE, and the Australian Square Kilometre Array Pathfinder to find these two unusual AGNs are grouped with 16 other objects separated from the rest, suggesting a rare class. Our spectroscopy at South African Astronomical Observatory/Southern African Large Telescopeand literature data confirm at least 14 of these objects are extragalactic (0.13 <z< 1.23), all hosting AGN. Using spectral energy distribution fitter Cigalewe find that the majority of dust emission () 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.