发表机构
Eureka Scientific; Yale University; Universidad Diego Portales; Space Science Institute; INAF - Osservatorio Astronomico di Roma; Yale Center for Astronomy & Astrophysics; University of Geneva; James Madison University（尤里卡科学; 耶鲁大学; 迭戈·波特莱斯大学; 太空科学研究所; 意大利国家天体物理研究所罗马天文台; 耶鲁天文学与天体物理学中心; 日内瓦大学; 詹姆斯麦迪逊大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用XRISM、XMM-Newton和NuSTAR对赛弗特2型星系ESP 39607的多周期观测，探测到其存在超快流入（UFI），推断其形成吸积级联，该流入物可为中心活动星系核提供部分吸积物质。
AI 中文摘要
我们展示了对ESP 39607的同时期XRISM、XMM-Newton和NuSTAR观测结果，ESP 39607是一个红移z=0.201的赛弗特2型星系。XRISM/Resolve在观测帧中揭示了4.7 keV和4.9 keV附近的两个吸收特征，与红移后的Fe XXV氦-α/Fe XXVI莱曼-α吸收一致，来自以v_in≈0.16c速度流入的气体。该高速度将吸光体识别为超快流入（UFI），通过不同方法和连续谱模型，其探测显著性约为3-3.7σ。光电离建模得出log ξ/(erg·s⁻¹·cm)≈3.7-3.8，柱密度log N_H,abs/(cm⁻²)≈23.2-23.8，后者取决于假设的金属丰度。该流入速度和线特性与之前两个NuSTAR周期报告的结果一致，表明在源静止参考系中至少2.2年的基线内存在类似的流入物质。在所有三个周期中，UFI的综合探测显著性为5.3σ。考虑到推断半径R≈49-77 R_g处的动力学时标为几天，多年的证据支持流入物不断补充的场景，形成吸积“级联”，而非单个长寿命云。根据金属丰度，估计的质量流入率为Ṁ_in≈0.3-1.4 M_⊙/年，且Ṁ_in/Ṁ_acc≈0.2-1.0，该流入物可为驱动中心活动星系核提供相当一部分所需的吸积物质。
英文摘要
We present simultaneous XRISM, XMM-Newton, and NuSTAR observations of ESP 39607, a Seyfert 2 galaxy at $z = 0.201$. XRISM/Resolve reveals two absorption features near 4.7 and 4.9 keV in the observed frame, consistent with redshifted Fe XXV He-$α$/Fe XXVI Ly-$α$ absorption from gas inflowing at $v_{\rm in} \simeq 0.16c$. The high velocity identifies the absorber as an ultra-fast inflow (UFI), which is detected at $\sim 3$-$3.7σ$ across different methods and continuum models. Photoionization modeling yields $\log ξ/{\rm erg\,s^{-1}\,cm} \simeq 3.7$-$3.8$ and a column density $\log N_{\rm H,abs}/{\rm cm^{-2}} \simeq 23.2$-$23.8$, the latter depending on the assumed metallicity. The inflow velocity and line properties are consistent with those reported from two earlier NuSTAR epochs, indicating that similar inflowing material was present over a baseline of at least 2.2 yr in the source rest frame. Across all three epochs, the combined detection significance of the UFI is $5.3σ$. Given the dynamical timescale of a few days at the inferred radius, $R \simeq 49$-$77\,R_{\rm g}$, the multi-year evidence favors a scenario in which the inflow is continuously replenished, forming an accretion "cascade", rather than a single long-lived cloud. With an estimated mass inflow rate of $\dot{M}_{\rm in} \simeq 0.3$-$1.4\,M_\odot$ yr$^{-1}$, depending on metallicity, and a ratio $\dot{M}_{\rm in}/\dot{M}_{\rm acc} \simeq 0.2$-$1.0$, the inflow could supply a substantial fraction of the accretion needed to power the central active galactic nucleus.
CommentsAccepted for publication in ApJ
