The near-infrared host galaxy properties of radio-quiet "red AGN"

我们想要研究射电安静的“红色活动星系核”(AGN)的性质，即类星体存在的特别是红色光学到近红外颜色B-K大于4的类星体。对此提出了两种解释：一是由于类星体所在星系的尘埃导致光谱中蓝色部分的消光；二是宿主星系本身对恒星近红外的强烈贡献。在“隐藏类星体”的背景下，埋藏在尘埃笼罩的星系中的活动星系核的很大一部分可能会被传统的光学观测遗漏。为了解决宿主星系的性质和光贡献的问题，我们成功地提出了在北欧光学望远镜(NOT)上观测B-K大于4的射电安静类星体的样本。在与瑞典和英国合作者的合作下，我们获得了在近红外线观察由9个这样的天体组成的独特数据集的时间。详细的形态分析将使我们能够量化该波长带内宿主星系发射的贡献，以及该天体可能存在的形态差异，以形成“正常”的蓝色类星体。

We want to study the nature of radio-quiet "red Active Galactic Nuclei" (AGN), i.e. quasars exibiting particularly red optical to near-infrared colours B-K bigger larger then 4. Two explanations have been put forward to explain these: extinction of the blue part of the spectrum due to dust in the host galaxy of the quasar, and second, a strong stellar near-infrared contribution of the host galaxy itself. In the context of "hidden quasars", a large fraction of AGN burried inside dust-enshrouded galaxies could be missed by traditional optical surveys. To tackle the question of the properties and light contribution of the host galaxies we successfully proposed to observe a sample of radio-quiet quasars with B-K larger than 4 at the Nordic Optical Telescope (NOT). In collaboration with swedish and british collaborators we were awarded time at the NOT to observe a unique data set of nine such objects, in the nearinfrared. A detailed morphological analysis will enable us to quantify the contribution of the host galaxy emission in this wavelength band and the object's possible morphological differences to "normal", blue quasars.