Spectral energy distributions of type 2 quasi-stellar objects: obscured star formation at high redshifts
Spectral energy distributions of type 2 quasi-stellar objects: obscured star formation at high redshifts
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DOI：
10.1111/j.1365-2966.2009.15543.x
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发表时间：
2009-08
影响因子：
4.8
通讯作者：
D. Rigopoulou;V. Mainieri;O. Almaini;A. Alonso-Herrero;J.-S. Huang;G. Hasinger;G. Rieke;J. Dunlop;I. University;Mpe;Garching;U. Nottingham;IEM-CSIC;S. CfA;U. Arizona;U. Edinburgh;Eső;H Germany
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文献类型：
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作者：
D. Rigopoulou;V. Mainieri;O. Almaini;A. Alonso-Herrero;J.-S. Huang;G. Hasinger;G. Rieke;J. Dunlop;I. University;Mpe;Garching;U. Nottingham;IEM-CSIC;S. CfA;U. Arizona;U. Edinburgh;Eső;H Germany
我们提出了一个新的中红外和亚毫米观测样本的八个高红移的2型准恒星物体(类星体)位于钱德拉深场南。源是被吸收的X射线，亮度超过1044erg S。其中两个目标具有较强的探测能力，S/N>；4，另外三个目标被S/N≥2.5微探测到。斯皮策太空望远镜在多个中红外波段探测到所有的信号源。比较了2类星体的多波长光谱能量分布(SED)与两个局部超亮度星系(Arp220和IR22491)的光谱能量分布，以评估SED不同部分恒星形成成分的贡献。我们认为，它们的亚毫米辐射可能是由于恒星爆发，而中红外能量的很大一部分可能来自被遮挡的中央类星体。利用中红外和亚毫米的观测，我们得到了超过L>；10 12 L⊙的红外光度。亚毫米(850μm)到X射线(2keV)的光谱指数(αSX)跨越很大的范围。大约一半的第二类星体具有康普顿厚度的活动星系核的典型数值，仅有1%的核发射通过散射看到，其余的数值具有亚毫米亮度星系的典型数值。结合现有的观测证据，我们勾勒出了这些源早期演化的可能情景。
We present new mid-infrared and submillimetre observations for a sample of eight high-redshift type 2 quasi-stellar objects (QSOs) located in the Chandra Deep Field-South. The sources are X-ray absorbed with luminosities in excess of 10 44 erg s ―1 . Two of the targets have robust detections, S/N > 4, while further three targets are marginally detected with S/N ≥ 2.5. All sources are detected in multiple mid-infrared bands with the Spitzer Space Telescope. The multiwavelength spectral energy distributions (SEDs) of the type 2 QSOs are compared to those of two local ultraluminous galaxies (Arp220 and IR22491) in order to assess contributions from a star-forming component in various parts of the SED. We suggest that their submm emission is possibly due to a starburst while a large fraction of the mid-infrared energy is likely to originate in the obscured central quasar. Using the mid-infrared and submm observations, we derive infrared luminosities which are found to be in excess of L > 10 12 L ⊙ . The submm (850 μm) to X-ray (2 keV) spectral indices (α SX ) span a wide range. About half of the type 2 QSOs have values typical for a Compton-thick active galactic nuclei with only 1 per cent of the nuclear emission seen through scattering, and the remaining with values typical of submm-bright galaxies. Combining the available observational evidence, we outline a possible scenario for the early stages of evolution of these sources.