标题： 利用MIRI/JWST在NGC 7172中发现的双锥形电离气体外流及正反馈证据 显示英文标题

标题： A biconical ionised gas outflow and evidence for positive feedback in NGC 7172 uncovered by MIRI/JWST

摘要： 我们展示了利用詹姆斯韦伯太空望远镜（JWST）上中红外仪器（MIRI）的中分辨率光谱仪（MRS）观测到的2型塞弗特星系NGC7172的结果。该星系在银河活动、吸积盘和外流调查（GATOS）样本中的六个活跃星系核（AGN）中，拥有最低的电离气体质量外流率（Mout~0.005 M☉/年），且它们的全波段光度相近（log Lbol~44 erg/s）。我们的目标是理解电离气体外流的性质，主要通过氖跃迁产生的发射线来研究，这些发射线覆盖了广泛的电离势（IP）范围，从~20 eV到~130 eV。我们采用了参数化和非参数化的方法来表征线发射和动力学特性。低激发线（IP<25 eV，例如[NeII]）追踪旋转盘的发射。高激发线（IP>90 eV，例如[NeV]），很可能完全由AGN光致电离，正在以接近垂直于星系盘的方向膨胀，最大投影速度约为~350-500 km/s。特别是[NeV]和[NeVI]线揭示了一个双锥形电离气体外流，从核区向南北方向延伸至少~2.5"北和3.8"南（投影距离约450和680 pc）。由于遮挡，锥体北部大部分的发射以前未被检测到。鉴于外流几乎正面朝上的方向和星系几乎侧视的方向，NGC7172可能是一个弱耦合的例子。然而，我们在AGN西南方向投影距离分别为3.1"和4.3"（即~560和780 pc）的两个不同的外流团块中发现了正反馈的证据。我们使用[NeII]和[NeIII]的发光度估计了这些区域的恒星形成率为0.08 M☉/年，这大约是核环中发现的恒星形成率的10%。恒星形成活动可能是由电离气体外流与星系间物质的相互作用触发的。 显示英文摘要

摘要： We present observations of the type-2 Seyfert NGC7172 obtained with the medium-resolution spectrometer (MRS) of the Mid-Infrared Instrument (MIRI) on board of the JWST. This galaxy hosts one of the lowest ionised gas mass outflow rates (Mout~0.005 M/yr) in a sample of six AGN with similar bolometric luminosities (log Lbol~44erg/s) within the Galactic Activity, Torus and Outflow Survey (GATOS). We aim to understand the properties of the ionised gas outflow, mainly using the emission lines from the neon transitions, that cover a broad range of ionisation potentials (IP) from ~20 eV to ~130 eV. We applied parametric and non-parametric methods to characterise the line emission and kinematics. The low excitation lines (IP<25eV, e.g.[NeII]) trace the rotating disc emission. The high excitation lines (IP>90eV, e.g.[NeV]), which are likely photoionised exclusively by the AGN, are expanding in the direction nearly perpendicular to the disc of the galaxy, with maximum projected velocities of ~350-500 km/s. In particular, [NeV] and [NeVI] lines reveal a biconical ionised gas outflow emerging N-S from the nuclear region, extending at least ~2.5"N and 3.8"S (projected distance of ~450 and 680 pc). Most of the emission arising in the northern part of the cone was not previously detected due to obscuration. Given the almost face-on orientation of the outflow and the almost edge-on orientation of the galaxy, NGC7172 may be a case of weak coupling. Nevertheless, we found evidence for positive feedback in two distinct outflowing clumps at projected distances of 3.1" and 4.3" (i.e. ~560 and 780 pc) SW from the AGN. We estimated a star formation rate in these regions using the [NeII] and [NeIII] luminosities of 0.08 M/yr, that is ~10% of that found in the circumnuclear ring. The star formation activity might have been triggered by the interaction between the ionised gas outflow and the ISM of the galaxy.