SuperMIGHTEE：XMM-LSS 场中残余射电星系候选体的光谱年龄
SuperMIGHTEE : Spectral Ages of Remnant Radio Galaxy Candidates in the XMM-LSS Field
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中文总结 AI 辅助
研究 XMM-LSS 场中 14 个候选残余射电星系，结合多源数据进行光谱老化研究。通过光谱建模和年龄图得出结果，确认部分源为残余，揭示其演化阶段，发现新群体，突出 MIGHTEE 和 superMIGHTEE 作用，为约束 AGN 生命周期提供框架。
中文摘要 AI 辅助
残余射电星系的瓣不再由活动星系核（AGN）的喷流补充，这为 AGN duty 周期和射电喷流的时间尺度提供了关键限制。我们对 XMM-LSS 场中的 14 个候选残余射电星系进行了光谱老化研究，结合了来自 MeerKAT MIGHTEE（L 波段）和 uGMRT superMIGHTEE（波段 3 和波段 4）调查的新宽带数据以及来自 LOFAR、GMRT 和 JVLA 的补充观测，覆盖 144 MHz - 1.5 GHz。光谱建模确认 12 个源为真正的残余，而两个被重新分类为活跃源，强调了敏感的多频率覆盖对于可靠识别残余的重要性。基于像素的光谱年龄图得出的结果（约 3 - 43 Myr）与综合估计大致一致，揭示了相对较短的光谱年龄（约 8 - 42 Myr）。这些年龄可能反映了在较高红移（0.35 < z < 2.85；中值 z = 1.25）时增强的逆康普顿损失以及在低密度环境中可能的快速瓣膨胀。残余与总源年龄的比率（t_OFF}/t_s）跨度为 0.04 - 0.83，表明该样本追踪了广泛的演化阶段。我们的发现揭示了一个以前未被充分代表的微弱、快速衰落的残余群体，表明残余阶段可能比以前认为的更短且更具动态性。这项研究突出了 MIGHTEE 和 superMIGHTEE 调查在可靠分类真正残余方面的关键作用，并为在即将到来的 SKA 调查之前约束 AGN 生命周期提供了一个框架。
英文摘要
Remnant radio galaxies, whose lobes are no longer replenished by jets from the active galactic nucleus (AGN), offer key constraints on AGN duty cycles and the timescales of radio jets. We present a spectral-ageing study of 14 candidate remnant radio galaxies in the XMM-LSS field, combining new broad-band data from the MeerKAT MIGHTEE (L-band) and uGMRT superMIGHTEE (band-3 and band-4) surveys with complementary observations from LOFAR, GMRT, and JVLA, covering 144 MHz-1.5 GHz. Spectral modeling confirms 12 sources as genuine remnants, while two are reclassified as active, emphasising the importance of sensitive, multi-frequency coverage for robust remnant identification. Pixel-based spectral age maps yield results (~3-43 Myr) broadly consistent with integrated estimates, revealing relatively short spectral ages (~8-42 Myr). These ages likely reflect enhanced inverse-Compton losses at higher redshifts (0.35 < z < 2.85; median z = 1.25) and possible rapid lobe expansion in low-density environments. The ratios of remnant to total source ages (t_OFF}/t_s) span 0.04-0.83, indicating that the sample traces a broad range of evolutionary stages. Our findings reveal a previously underrepresented population of faint, rapidly fading remnants, suggesting that the remnant phase may be shorter and more dynamic than previously thought. This study highlights the crucial role of MIGHTEE and superMIGHTEE surveys in reliably classifying genuine remnants and provides a framework for constraining AGN life cycles in preparation for forthcoming SKA surveys.
