Testing the evolutionary link between submillimetre galaxies and quasars: CO observations of QSOs at z∼ 2
Testing the evolutionary link between submillimetre galaxies and quasars: CO observations of QSOs at z∼ 2
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DOI：
10.1111/j.1365-2966.2008.13553.x
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发表时间：
2008-06
影响因子：
4.8
通讯作者：
K. Coppin;M. Swinbank;R. Neri;P. Cox;D. Alexander;I. Smail;M. Page;J. Stevens;K. Knudsen;R. Ivison;A. Beelen;F. Bertoldi;A. Cosmology;D. University;Iram;D. Physics;Mssl;University College London;CfAR;U. Hertfordshire;AIfA;U. Bonn;Ifa;U. Edinburgh;UK-ATC;Ias;U. Paris-sud;Iap;Universit'e PierreMarie Curie
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文献类型：
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作者：
K. Coppin;M. Swinbank;R. Neri;P. Cox;D. Alexander;I. Smail;M. Page;J. Stevens;K. Knudsen;R. Ivison;A. Beelen;F. Bertoldi;A. Cosmology;D. University;Iram;D. Physics;Mssl;University College London;CfAR;U. Hertfordshire;AIfA;U. Bonn;Ifa;U. Edinburgh;UK-ATC;Ias;U. Paris-sud;Iap;Universit'e PierreMarie Curie
我们使用IRAM平台de Bure毫米干涉仪和UKIRT 1 - 5µm成像仪（UIST），通过绘制9个亚毫米探测到的QSOs的CO发射图（z = 1.7-2.6）和近红外光谱得出的黑洞（BH）质量，来测试球体生长的主要阶段与核吸积之间的联系。当结合从文献中获得的一个QSO时，我们给出了在QSO和亚毫米星系（smg）活动高峰时期选择的10个亚毫米探测QSO的敏感CO（3-2）或CO（2-1）观测结果。在5/6个具有BH质量的非常光学发光（MB ~−28）亚毫米探测的qso中检测到CO，证实了Mgas≃3.4 × 10 10 M⊙的大型气藏的存在。表面上看，我们的黑洞质量和宿主球体上的动态质量约束表明，这些z = 2的光学发光qso比局部BH-球体关系MBH/Msph高一个数量级，尽管这一结果取决于co发射区的大小和倾角。然而，我们发现它们的黑洞质量太大了~ 30倍，表面密度太小了~ 300倍，无法与进化序列中的典型smg相关。相反，我们在四个较弱的（MB ~−25）次毫米探测到的量子粒子中测量到较弱的CO发射，这些量子粒子的性质、BH质量（MBH≃5 ×10 8 M⊙）和表面密度与smg相似。这些qso似乎位于本地MBH/Msph关系附近，使它们在提出的将qso与大质量年轻星系和高红移黑洞形成联系起来的进化序列中成为可信的“过渡物体”。我们发现，与我们的QSO样本相比，smg具有更高的双峰CO线分布发生率，我们将其解释为它们的相对倾斜度的影响，QSO更正面。最后，我们发现四个较暗的亚毫米探测到的qso的气体质量意味着它们的恒星形成事件可以持续约10Myr，并且与代表大质量星系形成阶段的阶段相一致，该阶段与之前的SMG星暴阶段重叠，随后演变成今天的大质量椭圆星系群。
We have used the IRAM Plateau de Bure millimeter interferometer and the UKIRT 1– 5µm Imager Spectrometer (UIST) to test the connection between the major phases of spheroid growth and nuclear accretion by mapping CO emission in nine submillimetredetected QSOs at z = 1.7–2.6 with black hole (BH) masses derived from near-infrared spectroscopy. When combined with one QSO obtained from the literature, we present sensitive CO(3–2) or CO(2–1) observations of 10 submillimetre-detected QSOs selected at the epoch of peak activity in both QSOs and submillimetre (submm) galaxies (SMGs). CO is detected in 5/6 very optically luminous (MB ∼ −28) submm-detected QSOs with BH masses MBH ≃ 10 9 –10 10 M⊙, confirming the presence of large gas reservoirs of Mgas ≃ 3.4 × 10 10 M⊙. Our BH masses and dynamical mass constraints on the host spheroids suggest, at face value, that these optically luminous QSOs at z = 2 lie about an order of magnitude above the local BH-spheroid relation, MBH/Msph, although this result is dependent on the size and inclination of the CO-emitting region. However, we find that their BH masses are ∼ 30 times too large and their surface density is ∼ 300 times too small to be related to typical SMGs in an evolutionary sequence. Conversely, we measure weaker CO emission in four fainter (MB ∼ −25) submm-detected QSOs with properties, BH masses (MBH ≃ 5 ×10 8 M⊙), and surface densities similar to SMGs. These QSOs appear to lie near the local MBH/Msph relation, making them plausible ‘transition objects’ in the proposed evolutionary sequence linking QSOs to the formation of massive young galaxies and BHs at high-redshift. We show that SMGs have a higher incidence of bimodal CO line profiles than seen in our QSO sample, which we interpret as an effect of their relative inclinations, with the QSOs seen more face-on. Finally, we find that the gas masses of the four fainter submm-detected QSOs imply that their star formation episodes could be sustained for ∼ 10Myr, and are consistent with representing a phase in the formation of massive galaxies which overlaps a preceding SMG starburst phase, before subsequently evolving into a population of present-day massive ellipticals.