DO THE MOST MASSIVE BLACK HOLES AT z = 2 GROW VIA MAJOR MERGERS?
DO THE MOST MASSIVE BLACK HOLES AT z = 2 GROW VIA MAJOR MERGERS?
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DOI：
10.3847/0004-637x/830/2/156
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发表时间：
2015-10
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通讯作者：
M. Mechtley;M. Mechtley;K. Jahnke;R. Windhorst;R. Andrae;M. Cisternas;S. Cohen;T. Hewlett;A. Koekemoer;M. Schramm;A. Schulze;J. Silverman;C. Villforth;A. V. D. Wel;L. Wisotzki
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作者：
M. Mechtley;M. Mechtley;K. Jahnke;R. Windhorst;R. Andrae;M. Cisternas;S. Cohen;T. Hewlett;A. Koekemoer;M. Schramm;A. Schulze;J. Silverman;C. Villforth;A. V. D. Wel;L. Wisotzki
最常见的类星体起源模型认为，在发光活动星系核(AGN)中看到的高吸积率主要是在富含气体的星系之间的主要合并过程中触发的。虽然这一模型在几十年里都是可信的，但在过去几年里，它才开始接受严格的统计检验。在这里，我们报道了哈勃太空望远镜的一项研究，以检验具有高超大质量黑洞质量()的z=2类星体的这一假设，这些类星体在这个红移时主导着宇宙黑洞的增长。我们比较了19个点源减去的类星体主机和84个非活动星系的匹配样本的广场相机3(静止帧V带)成像，测试类星体主机是否有更强引力相互作用的证据。利用专家排序法，我们发现类星体主机均匀地分布在非活动星系的合并序列中，而在高扭曲的主机中没有类星体的偏好。使用合并/非合并截断方法，我们恢复了类星体主机和非活动星系(分布模式，68%可信区间)的扭曲分数，这两种测量受到相同的观测条件和限制。非活动星系上方类星体主机的扭曲比例略有增加并不显著，类星体比例可能更高()，这与低质量和低z活动星系核的结果一致。我们没有发现证据表明主要的合并是大质量类星体的主要触发机制，这些大质量类星体在宇宙类星体活动的顶峰时主导着吸积。
The most frequently proposed model for the origin of quasars holds that the high accretion rates seen in luminous active galactic nuclei (AGN) are primarily triggered during major mergers between gas-rich galaxies. While plausible for decades, this model has only begun to be tested with statistical rigor in the past few years. Here, we report on a Hubble Space Telescope study to test this hypothesis for z = 2 quasars with high supermassive black hole masses ( ), which dominate cosmic black hole growth at this redshift. We compare Wide Field Camera 3 (rest-frame V-band) imaging of 19 point source-subtracted quasar hosts to a matched sample of 84 inactive galaxies, testing whether the quasar hosts have greater evidence for strong gravitational interactions. Using an expert ranking procedure, we find that the quasar hosts are uniformly distributed within the merger sequence of inactive galaxies, with no preference for quasars in high-distortion hosts. Using a merger/non-merger cutoff approach, we recover distortion fractions of for quasar hosts and for inactive galaxies (distribution modes, 68% confidence intervals), with both measurements subjected to the same observational conditions and limitations. The slight enhancement in distorted fraction for quasar hosts over inactive galaxies is not significant, with a probability that the quasar fraction is higher ( ), in line with results for lower mass and lower z AGN. We find no evidence that major mergers are the primary triggering mechanism for the massive quasars that dominate accretion at the peak of cosmic quasar activity.