The galaxy group NGC 507: Newly detected AGN remnant plasma transported by sloshing
The galaxy group NGC 507: Newly detected AGN remnant plasma transported by sloshing
复制标题
星系群NGC 507：新发现的活动星系核残余等离子体通过晃动输送
DOI：
10.1051/0004-6361/202142579
复制
发表时间：
2022
影响因子：
6.5
通讯作者：
Brienza M
中科院分区：
文献类型：
--
作者：
Brienza M
来自活动星系核（AGN）的喷流被认为会不断地用温和的相对论性粒子和磁场来丰富其周围的介质。在这里，我们提出了一个详细的多频分析附近（z= 0.01646）星系群NGC 507。 特别是，我们提出了新的高灵敏度和高空间分辨率的无线电图像的频率范围144-675 MHz的低频阵列（LOFAR）和升级的巨型米波射电望远镜（UGMRT）的意见。这些发现揭示了先前未被发现的具有复杂的、有纪念意义的形态的漫射射电辐射的存在，可能与先前的中央星系爆发有关。基于光谱老化的考虑，我们发现，等离子体首先注入的活动星系核240-380百万年前，现在正在冷却。我们对深档案X射线多镜使命（XMM-牛顿）数据的分析证实了该系统是动态干扰的，如前所述。我们检测到两个不连续性的X射线表面亮度分布（朝东和朝南）跟踪螺旋图案，我们解释为冷锋产生的晃动运动。新发现的弧形射电灯丝和南部凹X射线不连续性之间的显着的空间重合，强烈表明残余等离子体已被大尺度的晃动运动所取代。总的来说，NGC 507代表了迄今为止已知的最清晰的例子之一，其中在星系群中观察到旧AGN残余等离子体与外部介质之间的直接相互作用。我们的结果与模拟结果一致，模拟结果表明星系团或星系群天气可以产生丝状发射，扰乱活动星系核叶并将其相对论内容传播到周围介质中。
Jets from active galactic nuclei (AGN) are known to recurrently enrich their surrounding medium with mildly relativistic particles and magnetic fields. Here, we present a detailed multi-frequency analysis of the nearby (z= 0.01646) galaxy group NGC 507. In particular, we present new high-sensitivity and high-spatial-resolution radio images in the frequency range 144–675 MHz obtained using Low Frequency Array (LOFAR) and upgraded Giant Metrewave Radio Telescope (uGMRT) observations. These reveal the presence of previously undetected diffuse radio emission with complex, filamentary morphology likely related to a previous outburst of the central galaxy. Based on spectral ageing considerations, we find that the plasma was first injected by the AGN 240–380 Myr ago and is now cooling. Our analysis of deep archival X-ray Multi-Mirror Mission (XMM-Newton) data confirms that the system is dynamically disturbed, as previously suggested. We detect two discontinuities in the X-ray surface-brightness distribution (towards the east and south) tracing a spiral pattern, which we interpret as cold fronts produced by sloshing motions. The remarkable spatial coincidence observed between the newly detected arc-like radio filament and the southern concave X-ray discontinuity strongly suggests that the remnant plasma has been displaced by the sloshing motions on large scales. Overall, NGC 507 represents one of the clearest examples known to date in which a direct interaction between old AGN remnant plasma and the external medium is observed in a galaxy group. Our results are consistent with simulations that suggest that filamentary emission can be created by the cluster or group weather, disrupting AGN lobes and spreading their relativistic content into the surrounding medium.