[论文解读] The ultra-dense, interacting environment of a dual AGN at z $\sim$ 3.3 revealed by JWST/NIRSpec IFS

Michele Perna, Santiago Arribas+19 more|arXiv (Cornell University)|Apr 13, 2023

Astronomy and Astrophysical Research参考文献 17被引用 7

一句话总结

本研究使用 JWST/NIRSpec IFS 分析 z~3.3 的 LBQS 0302−0019 的 rest-frame 光学发射，揭示双AGN及具有多重伴星与强大外流的密集相互作用环境。

ABSTRACT

LBQS 0302-0019 is a blue quasar (QSO) at z ~ 3.3, hosting powerful outflows, and residing in a complex environment consisting of an obscured AGN candidate, and multiple companions, all within 30 kpc in projection. We use JWST NIRSpec IFS observations to characterise the ionized gas in this complex system. We develop a procedure to correct for the spurious oscillations (or 'wiggles') in NIRSpec single-spaxel spectra, due to the spatial under-sampling of the point spread function. We perform a quasar-host decomposition with the QDeblend3D tools, and use multi-component kinematic decomposition of the optical emission line profiles to infer the physical properties of the emitting gas. The quasar-host decomposition allows us to identify i) a low-velocity component possibly tracing a warm rotating disk, with a dynamical mass Mdyn $\sim 10^{11}$ Msun and a rotation-to-random motion ratio $v_{rot}$/$σ_0 \sim 2$; ii) a spatially unresolved ionised outflow, with a velocity of $\sim$ 1000 km/s and an outflow mass rate of $\sim 10^4$ Msun/yr. We also detect eight interacting companion objects close to LBQS 0302-0019. Optical line ratios confirm the presence of a second, obscured AGN at $\sim 20$ kpc of the primary QSO; the dual AGN dominates the ionization state of the gas in the entire NIRSpec field-of-view. This work has unveiled with unprecedented detail the complex environment of this dual AGN, which includes nine interacting companions (five of which were previously unknown), all within 30 kpc of the QSO. Our results support a scenario where mergers can trigger dual AGN, and can be important drivers for rapid early SMBH growth.

研究动机与目标

• 表征 LBQS 0302−0019 周围的复杂环境，包括 QSO 主机、被遮蔽的 AGN 伴星以及附近的星系。
• 量化 rest-frame 光学发射线的气体动力学、离子化结构与外流特性。
• 评估动力学质量与合并证据对系统中 SMBH 的快速增长的推动作用。

提出的方法

• 获取覆盖 rest-frame 光学线、空间分辨率约为 ∼0.1 arcsec 的 JWST/NIRSpec IFS 数据，覆盖约 ~3″×3″区域。
• 为 NIRSpec 数据立方体中的 undersampled 像元开发 wiggle-artifact 校正。
• 执行 QSO–host 分解（QDeblend3D）与发射线的多组分动力学拟合。
• 用多高斯分量对 Balmer 与禁止线进行建模，以分离 BLR、NLR 与外流贡献。
• 以标准单历元 virial 关系推断动力学质量和黑洞质量，同时慎重考虑衰减和线比。
• 构建并分析积分谱与空间分辨谱，以绘制气体动力学和离子化的图像。

Figure 1: Original (top) and PSF-subtracted (bottom) images of the QSO LBQS 0302 $-$ 0019 and its close neighbouring galaxies as observed from space- and ground-based telescopes. In the left panels, we show the HST WFC3 near-infrared images from Husemann et al. ( 2021 ) , with contours in the bottom

实验结果

研究问题

• RQ1 rest-frame 光学线中 LBQS 0302−0019 系统的动力学与离子化结构为何？
• RQ2 是否有清晰证据指向接近的被遮蔽 AGN 伴星，以及它如何与 QSO 主机及附近伴星相互作用？
• RQ3 主机和伴星星系的动力学质量是多少，这对合并活动和 SMBH 增长有何含义？
• RQ4 外流的特性（速度、物质流量）及其对周围 ISM 的影响如何？

主要发现

• 识别出低速和高速分量；低速分量追踪一个温暖的旋转盘，M_dyn ~ 1×10^11 M⊙，v_rot/σ0 ~ 2。
• 一个空间上未分辨的电离外流，速度约为 ~1000 km s−1，外流率约 ~10^4 M⊙ yr−1。
• 在 ~30 kpc 内检测到八个伴星对象，其中两个显示规则的速度场，动力学质量 ~1×10^10 M⊙。
• 发现第二个被遮蔽的 AGN 大约距离主 QSO ~20 kpc，双AGN 主导 NIRSpec 视场内的气体电离。
• QSO 环境包括主机、一个近距离被遮蔽的 AGN，以及九个相互作用的伴星，支持合并驱动的双AGN 触发与快速 SMBH 增长。

Figure 2: NIRSpec spectra obtained with internal (orange curve) and external (green) flux calibration and integrated over a region of $r=1.5$ ″. The two NIRSpec spectra are extracted from the drizzle cubes, with 0.05″spaxels. Vertical lines indicate the main emission line features detected in the NI