MODELING MID-INFRARED DIAGNOSTICS OF OBSCURED QUASARS AND STARBURSTS
MODELING MID-INFRARED DIAGNOSTICS OF OBSCURED QUASARS AND STARBURSTS
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模糊类星体和星暴的中红外诊断模型
DOI：
10.1088/0004-637x/768/2/168
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Lin Yan
中科院分区：
文献类型：
--
作者：
G. Snyder;C. Hayward;A. Sajina;P. Jonsson;T. J. Cox;L. Hernquist;P. Hopkins;Lin Yan
我们分析了活动星系核（AGN）和中红外线通量之间的联系，使用尘埃辐射传输计算的星爆实现流体动力学模拟。聚焦于星系尘埃的影响，我们评估诊断通常用于解开AGN和星星的形成在超亮红外星系（ULIRGs）。我们研究这些量作为时间的函数，视角，尘埃模型，活动星系核光谱，并在合并模拟活动星系核的强度代表两个可能的极端的ULIRG人口：一个是一个典型的富含气体的合并，在z = 0，另一个是非常模糊的恒星爆发的特点，在z = 2-4。这个高度模糊的爆发开始于恒星形成，主要是多环芳烃（PAH）的排放，并以109年的红色近红外颜色结束。在活动星系核最明亮的合并过程中，尘埃遮蔽了活动星系核的近红外特征，减少了多环芳烃的相对发射，并增强了硅酸盐颗粒对9.7 μm波长的吸收。虽然一般与以前的解释一致，我们的结果意味着没有这些指标可以明确地估计AGN光度分数在所有情况下。受模拟的启发，我们表明，在9.7 μm的消光功能，PAH强度和近红外斜率的组合，可以同时限制AGN的分数和尘埃颗粒的分布范围广泛的遮蔽。我们发现，这一指标，访问詹姆斯韦伯太空望远镜，可以估计活动星系核的功率一样紧密的硬X射线通量单独，从而提供了一个有价值的未来的交叉检查和约束遥远的ULIRGs的大样本。
We analyze the link between active galactic nuclei (AGNs) and mid-infrared flux using dust radiative transfer calculations of starbursts realized in hydrodynamical simulations. Focusing on the effects of galaxy dust, we evaluate diagnostics commonly used to disentangle AGN and star formation in ultraluminous infrared galaxies (ULIRGs). We examine these quantities as a function of time, viewing angle, dust model, AGN spectrum, and AGN strength in merger simulations representing two possible extremes of the ULIRG population: one is a typical gas-rich merger at z ∼ 0, and the other is characteristic of extremely obscured starbursts at z ∼ 2–4. This highly obscured burst begins star-formation-dominated with significant polycyclic aromatic hydrocarbon (PAH) emission, and ends with a ∼109 yr period of red near-IR colors. At coalescence, when the AGN is most luminous, dust obscures the near-infrared AGN signature, reduces the relative emission from PAHs, and enhances the 9.7 μm absorption by silicate grains. Although generally consistent with previous interpretations, our results imply none of these indicators can unambiguously estimate the AGN luminosity fraction in all cases. Motivated by the simulations, we show that a combination of the extinction feature at 9.7 μm, the PAH strength, and a near-infrared slope can simultaneously constrain the AGN fraction and dust grain distribution for a wide range of obscuration. We find that this indicator, accessible to the James Webb Space Telescope, may estimate the AGN power as tightly as the hard X-ray flux alone, thereby providing a valuable future cross-check and constraint for large samples of distant ULIRGs.
影响因子：
4.9
作者：
Eisenhardt, Peter R. M.;Wu, Jingwen;Yan, Lin
通讯作者：
Yan, Lin