论文标题
Seyfert星系的Skymapper颜色和更换外观AGN
SkyMapper colours of Seyfert galaxies and Changing-Look AGN
论文作者
论文摘要
我们在Skymapper Southern调查中研究了宽带颜色的效用，以在低光度下选择Seyfert星系。我们发现，$ U-V $索引是由Ultraviolet $ U $和Violet $ V $过滤器构建的，将普通星系，Starburst Galaxies和Type-1 AGN分开。该$ U-V $指数对恒星种群的年龄或金属性不敏感，而是星系中的淬火和燃烧指标，并检测1型AGN中的Power-Laws Continua。从6DFGS使用$ z <0.1 $的25,000多个星系，我们发现基于$ U-V $和Central $ u $ band Brightness的选择削减，可以识别1型AGN。通过眼球6DFGS光谱，我们将新的Seyfert星系分类为1型至1.8。我们的样本包括八个已知的更换AGN，其中两个显示出如此强大的可变性，以至于它们在核和宿主星系光的混合序列中，在DR3的Skymapper观察五年中进行了选择。我们在样本中确定了46个更换外观的AGN候选者，其中一个据报道为IIN型超新星。我们表明，这种短暂的持续至少五年，标志着在新的更换AGN的Seyfert-1时期的爆发。
We study the utility of broad-band colours in the SkyMapper Southern Survey for selecting Seyfert galaxies at low luminosity. We find that the $u-v$ index, built from the ultraviolet $u$ and violet $v$ filters, separates normal galaxies, starburst galaxies and type-1 AGN. This $u-v$ index is not sensitive to age or metallicity in a stellar population but is instead a quenching-and-bursting indicator in galaxies and detects power-law continua in type-1 AGN. Using over 25,000 galaxies at $z<0.1$ from 6dFGS, we find a selection cut based on $u-v$ and central $u$ band brightness that identifies type-1 AGN. By eyeballing 6dFGS spectra we classify new Seyfert galaxies of type 1 to 1.8. Our sample includes eight known Changing-Look AGN, two of which show such strong variability that they move across the selection cut during the five years of SkyMapper observations in DR3, along mixing sequences of nuclear and host galaxy light. We identify 46 Changing-Look AGN candidates in our sample, one of which has been reported as a type-IIn supernova. We show that this transient persists for at least five years and marks a flare in a Seyfert-1 period of a new Changing-Look AGN.
