arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2008.04941astro-ph.GAastro-ph.CO
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局域宇宙中光学和红外选择AGN的暗物质晕

On the Dark Matter Halos of Optical and IR-selected AGN in the Local Universe

Mehmet Alpaslan, Jeremy L. Tinker

摘要:

我们利用卫星总光度L_sat技术对SDSS主星系样本中活动星系核周围的暗物质晕进行了探测。我们的结果集中在星系和活动星系核的中心星系的晕。我们的两个活动星系核样品是由光学发射线诊断和WISE红外颜色。在控制恒星质量和平均恒星年龄的情况下,光学选择和WISE选择的活动星系核的L_sat值都是非活动星系样品的两倍。这意味着晕的质量是原来的两倍,但我们不能排除Lsat的增加是由于这些活动星系核以相同的质量存在于较年轻的晕中。在只控制宿主星系质量的情况下,WISE选择的活动星系核的Lsat值也比光学活动星系核的Lsat值高出两倍,这与以往比较遮蔽和未遮蔽活动星系核成簇的结果一致。然而,控制两个宿主星系种群的恒星年龄可以消除一半的差异,减弱差异的统计意义。我们进行排列测试,以量化每个样本的晕轮种群的差异。然而,恒星形成特性的差异并不能完全解释两个活动星系核族群的差异。虽然活动星系核光度与平均恒星年龄相关,但WISE和光学样本之间恒星年龄的差异不能完全由活动星系核光度分布的差异来解释。

英文摘要:

We use the technique of total satellite luminosity, L_sat, to probe the dark matter halos around active galactic nuclei in the SDSS Main Galaxy Sample. Our results focus on galaxies and AGN that are the central galaxy of their halo. Our two AGN samples are constructed from optical emission-line diagnostics and from WISE infrared colors. Both optically-selected and WISE-selected AGN have L_sat values twice as high as non-active galaxy samples when controlling for stellar mass and mean stellar age. This implies that the halos are twice as massive, but we cannot rule out that the increase in L_sat is due to these AGN residing in younger halos at the same mass. When only controlling for host galaxy stellar mass, WISE-selected AGN also have higher L_sat values than optical AGN at the factor of two level, consistent with previous results comparing the clustering of obscured and unobscured AGN. However, controlling for stellar age in the two populations of host galaxies removes half of this difference, attenuating the statistical significance of the difference. We perform permutation tests to quantify the different in the halo populations of each sample. The difference in star formation properties does not fully explain the difference in the two AGN populations, however. Although AGN luminosity correlates with mean stellar age, the difference in stellar age between the WISE and optical samples cannot be fully explained by differences in their AGN luminosity distributions.

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