Gas inflows in the polar ring of NGC 4111: the birth of an AGN
Gas inflows in the polar ring of NGC 4111: the birth of an AGN
复制标题
NGC 4111 极环的气体流入：活动星系核的诞生
DOI：
10.1093/mnras/stac634
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发表时间：
2022
影响因子：
4.8
通讯作者：
Gültekin, Kayhan
中科院分区：
文献类型：
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作者：
Hauschild Roier, Gabriel R.;Storchi-Bergmann, Thaisa;McDermid, Richard M.;Walsh, Jonelle L.;Tan, Joanne;Cohn, Jonathan;Krajnovic, Davor;Greene, Jenny;Valluri, Monica;Gültekin, Kayhan
我们利用哈勃太空望远镜（HST）图像、索伦积分场光谱（IFS）和自适应光学辅助双子座NIFS近红外k波段IFS，绘制了附近边缘上的星系NGC 4111内部几kpc的恒星和气体分布、激发和运动学。hstim图像绘制了其直径约450 pc的尘埃极环，估计气体质量≥107M⊙。NIFS数据立方体以≈7 pc的空间分辨率绘制了内部110 pc半径，揭示了嵌入极性环中的高温（2267±166 K）分子H21-0 S(1)气体中约220 pc直径的极性环。在SAURON大尺度和NIFS核尺度数据中，恒星速度场显示出沿星系平面的盘状运动学。大尺度的[Oiii] λ5007 Å速度场显示了两个圆盘运动学的叠加：一个类似于恒星的运动，另一个沿着极环，显示出非圆运动，似乎与核H2ring的速度场有关，其运动学表明加速流入核。估计的质量流入率不仅足以养活一个活动星系核（AGN），而且还足以在不久的将来触发环核恒星的形成。我们提出了一种可能来自于捕获矮星系的极环气体向内移动并触发AGN的设想，这得到了局部x射线发射的支持，这似乎是H21-0 S(1)激发的来源。事实上，我们既没有看到近紫外辐射，也没有看到Br γ辐射，这表明新生的AGN仍然深埋在极环的光学厚尘之下。
We have usedHubble Space Telescope(HST) images, SAURON Integral Field Spectroscopy (IFS), and adaptative optics assisted Gemini NIFS near-infrared K-band IFS to map the stellar and gas distribution, excitation and kinematics of the inner few kpc of the nearby edge-on S0 galaxy NGC 4111. TheHSTimages map its ≈450 pc diameter dusty polar ring, with an estimated gas mass ≥107M⊙. The NIFS data cube maps the inner 110 pc radius at ≈7 pc spatial resolution, revealing a ≈220 pc diameter polar ring in hot (2267 ± 166 K) molecular H21–0 S(1) gas embedded in the polar ring. The stellar velocity field shows disc-dominated kinematics along the galaxy plane both in the SAURON large scale and in the NIFS nuclear-scale data. The large-scale [Oiii] λ5007 Å velocity field shows a superposition of two disc kinematics: one similar to that of the stars and another along the polar ring, showing non-circular motions that seem to connect with the velocity field of the nuclear H2ring, whose kinematics indicate accelerated inflow to the nucleus. The estimated mass inflow rate is enough not only to feed an active galactic nucleus (AGN) but also to trigger circumnuclear star formation in the near future. We propose a scenario in which gas from the polar ring, which probably originated from the capture of a dwarf galaxy, is moving inwards and triggering an AGN, as supported by the local X-ray emission, which seems to be the source of the H21–0 S(1) excitation. The fact that we see neither near-UV nor Br γ emission suggests that the nascent AGN is still deeply buried under the optically thick dust of the polar ring.