Near-infrared emission line diagnostics for AGN from the local Universe to z ~ 3
Near-infrared emission line diagnostics for AGN from the local Universe to z ~ 3
复制标题
从本地宇宙到 z ~ 3 的活动星系核的近红外发射线诊断
DOI：
10.1051/0004-6361/202347190
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发表时间：
2023
影响因子：
6.5
通讯作者：
Calabrò A
中科院分区：
文献类型：
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作者：
Calabrò A
光学静止标架光谱诊断通常用于区分星星的形成和活动星系核（AGN）的能量发射。然而，这种方法对尘埃源有偏见，阻碍了对整个宇宙时代AGN人口的全面普查。为了减轻这种影响，至关重要的是在静止帧近红外（近红外）中观察更长的波长，这是受尘埃衰减的影响较小，因此可以更好地描述星系的内在属性。由于活动星系核和恒星形成星系的近红外观测资料不足，特别是在红移高于0.5的情况下，活动星系核的诊断至今还没有得到充分利用。利用云光电离模型，我们根据明亮的近红外发射线（即[SIII] 9530 μ m，[CI] 9850 μ m，[PII] 1.188 μ m，[Fe II] 1.257 μ m和[Fe II] 1.64 μ m）与帕邢线（Pa γ或Pa β）的比值确定了新的活动星系核-星星形成诊断，提供了简单的分析分类标准。 我们将这些诊断应用于最近在CEERS中使用JWST-NIRSpec观测到的64个恒星形成星系和AGN在0 ≤ z ≤ 1，以及65个源在1 ≤ z ≤ 3。 我们发现，从近红外推断的分类与基于BPT和[SII]/H α比值的光学分类基本一致。然而，在近红外波段，我们发现活动星系核比在光学波段多60%（13个而不是8个），有5个源被归类为"隐藏"活动星系核，在较长波长处显示出更大的活动星系核贡献，可能是由于光学厚尘埃的存在。我们提出的诊断提供了一个很有前途的工具，发现和表征活动星系核从z = 0到z = 3低，中分辨率近红外光谱仪在未来的调查。
Optical rest-frame spectroscopic diagnostics are usually employed to distinguish between star formation and active galactic nucleus (AGN) powered emission. However, this method is biased against dusty sources, hampering a complete census of the AGN population across cosmic epochs. To mitigate this effect, it is crucial to observe at longer wavelengths in the rest-frame near-infrared (near-IR), which is less affected by dust attenuation and can thus provide a better description of the intrinsic properties of galaxies. AGN diagnostics in this regime have not been fully exploited so far, due to the scarcity of near-IR observations of both AGN and star-forming galaxies, especially at redshifts higher than 0.5. Using Cloudy photoionization models, we identified new AGN – star formation diagnostics based on the ratio of bright near-IR emission lines, namely [SIII] 9530 Å, [CI] 9850 Å, [PII] 1.188 μm, [FeII] 1.257 μm, and [FeII] 1.64 μm to Paschen lines (either Paγor Paβ), providing simple, analytical classification criteria. We applied these diagnostics to a sample of 64 star-forming galaxies and AGN at 0 ≤z≤ 1, and 65 sources at 1 ≤z≤ 3 recently observed with JWST-NIRSpec in CEERS. We find that the classification inferred from the near-IR is broadly consistent with the optical one based on the BPT and the [SII]/Hαratio. However, in the near-IR, we find ∼60% more AGN than in the optical (13 instead of eight), with five sources classified as “hidden” AGN, showing a larger AGN contribution at longer wavelengths, possibly due to the presence of optically thick dust. The diagnostics we present provide a promising tool to find and characterize AGN fromz= 0 toz≃ 3 with low- and medium-resolution near-IR spectrographs in future surveys.
DOI：
10.1136/ebmh.11.4.102
发表时间：
2008-10
期刊：
Evidence Based Mental Health
影响因子：
--
作者：
P. Cochat;L. Vaucoret;J. Sarles
通讯作者：
P. Cochat;L. Vaucoret;J. Sarles