Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs). VIII. A less biased view of the early co-evolution of black holes and host galaxies-猫眼课题宝

DOI：

10.1093/pasj/psz096

发表时间：

2019-04

期刊：

Publications of the Astronomical Society of Japan

影响因子：

2.3

通讯作者：

中科院分区：

物理与天体物理4区

文献类型：

作者：

T. Izumi;M. Onoue;Y. Matsuoka;T. Nagao;M. Strauss;M. Imanishi;N. Kashikawa;S. Fujimoto;K. Kohno;Y. Toba;H. Umehata;T. Goto;Y. Ueda;H. Shirakata;J. Silverman;J. Greene;Y. Harikane;Y. Hashimoto;S. Ikarashi;D. Iono;K. Iwasawa;Chien-Hsiu Lee;T. Minezaki;K. Nakanishi;Y. Tamura;Ji-Jia Tang;A. Taniguchi

我们用ALMA[C II]线和远红外(FIR)连续谱观测了我们的Subaru Hyper-Cam(HSC)发现的三个$z6$低光度类星体($M1450)。在三个亮度为2.4Mbox-9.5倍10^8的L类星体中都检测到了[C II]谱线，比光学发光类星体(M1450)小一个数量级。这些星系的FIR连续谱光度从9倍10^{10}L到2倍10^{12}L不等，说明这些星系的恒星形成率相差很大。到目前为止所研究的大多数HSC类星体都显示出与本地恒星形成星系相似的[C II]/FIR光度比。用基于[C II]的动力学质量($M\Rm dyn}$)代替膨胀恒星质量($M\rm\，Bulge}$)，我们发现有相当一部分低光度类星体位于局部的$M{\rm\，BH}$-$M{\rm\，bh}关系之上或以下，特别是在星系质量分布的质量端。相比之下，以前对光学发光类星体的研究发现，相对于局域关系，黑洞的质量过大。考虑到我们目标的低亮度，我们正在以一种不那么有偏见的方式探索超大质量黑洞及其宿主早期共同进化的本质。几乎所有的类星体都以比平行增长模型更快的速度增长黑洞质量，在平行增长模型中，超大质量黑洞和它们的宿主同时增长，以匹配所有红移的局部$M{\rm\，BH}$-$M{\rm\，bh}$-$M{\rm\，凸起}$。由于低光度类星体似乎实现了局域的共同进化关系，在当前观测到的类星体阶段之前，它们应该经历了剧烈的星暴才能赶上这种关系。

We present ALMA [C ii] line and far-infrared (FIR) continuum observations of three $z \gt 6$ low-luminosity quasars ($M_{\rm 1450} \gt -25$ mag) discovered by our Subaru Hyper Suprime-Cam (HSC) survey. The [C ii] line was detected in all three targets with luminosities of $(2.4\mbox{--}9.5) \times 10^8\, L_{\odot }$, about one order of magnitude smaller than optically luminous ($M_{\rm 1450} \lesssim -25$ mag) quasars. The FIR continuum luminosities range from $\lt 9 \times 10^{10}\, L_{\odot }$ (3 $\sigma$ limit) to ${\sim } 2 \times 10^{12}\, L_{\odot }$, indicating a wide range in star formation rates in these galaxies. Most of the HSC quasars studied thus far show [C ii]/ FIR luminosity ratios similar to local star-forming galaxies. Using the [C ii]-based dynamical mass ($M_{\rm dyn}$) as a surrogate for bulge stellar mass ($M_{\rm\, bulge}$), we find that a significant fraction of low-luminosity quasars are located on or even below the local $M_{\rm\, BH}$–$M_{\rm\, bulge}$ relation, particularly at the massive end of the galaxy mass distribution. In contrast, previous studies of optically luminous quasars have found that black holes are overmassive relative to the local relation. Given the low luminosities of our targets, we are exploring the nature of the early co-evolution of supermassive black holes and their hosts in a less biased way. Almost all of the quasars presented in this work are growing their black hole mass at a much higher pace at $z \sim 6$ than the parallel growth model, in which supermassive black holes and their hosts grow simultaneously to match the local $M_{\rm\, BH}$–$M_{\rm\, bulge}$ relation at all redshifts. As the low-luminosity quasars appear to realize the local co-evolutionary relation even at $z \sim 6$, they should have experienced vigorous starbursts prior to the currently observed quasar phase to catch up with the relation.

Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs). VIII. A less biased view of the early co-evolution of black holes and host galaxies

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