THE HALO MASSES AND GALAXY ENVIRONMENTS OF HYPERLUMINOUS QSOs AT z ≃ 2.7 IN THE KECK BARYONIC STRUCTURE SURVEY
THE HALO MASSES AND GALAXY ENVIRONMENTS OF HYPERLUMINOUS QSOs AT z ≃ 2.7 IN THE KECK BARYONIC STRUCTURE SURVEY
复制标题
凯克重子结构巡天中 z ≃ 2.7 处超光速 QSO 的光环质量和星系环境
DOI：
10.1088/0004-637x/752/1/39
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
C. Steidel
中科院分区：
文献类型：
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作者：
R. Trainor;C. Steidel
我们分析了天空中15个最明亮的类星体（<$1014 L返; M1450 <$−30）周围的星系分布，z为<$2.7。我们的数据来自凯克重子结构巡天（Keck Baryonic Structure Survey），该巡天经过优化，用于研究星系形成高峰期z = 2-3时星系与星系际介质之间的小尺度相互作用。在这项工作中，我们使用了1558个星系的位置和光谱红移，这些星系位于15个独立巡天之一的超亮类星体（HLQSO）视线的1.3 ′（4.2 h−1共动Mpc; cMpc）范围内，以及对HLQSO系统红移的新测量。通过结合的空间和红移分布，我们测量的星系-HLQSO互相关函数，星系-星系自相关函数，和星系超密度周围的网站非常罕见，非常迅速，黑洞吸积的特征尺度。平均而言，HLQSO位于显著的星系超密度范围内，其特征是速度色散σv = 200 km s−1，横向角标度为1025 ″（10200物理kpc）。我们认为，这样的规模预计小集团与log（Mh/M返）13。星系-HLQSO互相关函数的最佳拟合相关长度rGQ 0 =（7.3 ± 1.3）h−1 cMpc，而从光谱星系样本中测量的星系自相关长度rGG 0 =（6.0 ± 0.5）h−1 cMpc。根据与z = 2.6的模拟值的比较，这些值意味着一个典型的星系生活在log（Mh/M返）= 11.9 ± 0.1的主晕中，而HLQSO居住在log（Mh/M返）= 12.3 ± 0.5的主晕中。尽管观测到的光度[log（MBH/M返）<$9.7]暗示了黑洞的质量非常大，但似乎HLQSO并不需要与亮度低得多的QSO有很大不同的环境。很明显，HLQSO极低的空间密度（10 - 9 cMpc-3）是由10 - 1 Mpc尺度的百万分之一事件造成的，而不是由罕见的暗物质晕所承载。
We present an analysis of the galaxy distribution surrounding 15 of the most luminous (≳ 1014 L☉; M1450 ≃ −30) QSOs in the sky with z ≃ 2.7. Our data are drawn from the Keck Baryonic Structure Survey, which has been optimized to examine the small-scale interplay between galaxies and the intergalactic medium during the peak of the galaxy formation era at z ∼ 2–3. In this work, we use the positions and spectroscopic redshifts of 1558 galaxies that lie within ∼3′ (4.2 h−1 comoving Mpc; cMpc) of the hyperluminous QSO (HLQSO) sight line in 1 of 15 independent survey fields, together with new measurements of the HLQSO systemic redshifts. By combining the spatial and redshift distributions, we measure the galaxy–HLQSO cross-correlation function, the galaxy–galaxy autocorrelation function, and the characteristic scale of galaxy overdensities surrounding the sites of exceedingly rare, extremely rapid, black hole accretion. On average, the HLQSOs lie within significant galaxy overdensities, characterized by a velocity dispersion σv ≃ 200 km s−1 and a transverse angular scale of ∼25″ (∼200 physical kpc). We argue that such scales are expected for small groups with log (Mh/M☉) ≃ 13. The galaxy–HLQSO cross-correlation function has a best-fit correlation length rGQ0 = (7.3 ± 1.3) h−1 cMpc, while the galaxy autocorrelation measured from the spectroscopic galaxy sample in the same fields has rGG0 = (6.0 ± 0.5) h−1 cMpc. Based on a comparison with simulations evaluated at z ∼ 2.6, these values imply that a typical galaxy lives in a host halo with log (Mh/M☉) = 11.9 ± 0.1, while HLQSOs inhabit host halos of log (Mh/M☉) = 12.3 ± 0.5. In spite of the extremely large black hole masses implied by their observed luminosities [log (MBH/M☉) ≳ 9.7], it appears that HLQSOs do not require environments very different from their much less luminous QSO counterparts. Evidently, the exceedingly low space density of HLQSOs (≲ 10−9 cMpc−3) results from a one-in-a-million event on scales ≪1 Mpc, and not from being hosted by rare dark matter halos.