发表机构
University of Oklahoma; Purdue University; University of Arizona（俄克拉荷马大学; 普渡大学; 亚利桑那大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究利用强引力透镜效应，在宇宙正午时期发现了一个低光度活动星系核（LLAGN），其X射线光度约为1.2×10^42 erg/s，宿主星系质量较低，为研究低质量星系中的黑洞增长提供了独特机会。
AI 中文摘要
强引力透镜为研究 intrinsically faint（固有微弱）的高红移活动星系核（AGN）提供了独特工具。特别是，低光度活动星系核（LLAGN）可以探测低质量星系中的黑洞增长，而当前的X射线巡天无法触及这些星系。我们研究了一个被星系团SDSS J2243$-$0935三次成像的微弱X射线源的性质和物理特性，并确定该源是否包含活动星系核。我们结合了哈勃空间望远镜的成像数据和钱德拉X射线观测，以及已发表的SDSS J2243$-$0935的强透镜模型。我们从几何上限制了源的红移，推导了放大率图，并推断出宿主星系的物理性质。几何透镜分析给出的源红移为$z=2.14^{+0.12}_{-0.17}$，与测光红移估计一致，总放大率为$\mu=78\pm7$。该源被三次透镜成像，仅在HST F160W波段探测到，内禀星等为$m_{\rm AB}=28.2\pm0.2$。静止系光学发射意味着恒星质量为$8.6\lesssim\log(M_\star/M_\odot)\lesssim9.4$。未被尘埃遮蔽的恒星形成速率被限制为$\mathrm{SFR}_{\rm UV}<0.009\\,M_\odot\\,\mathrm{yr}^{-1}$，尽管存在大量尘埃消光的可能性。钱德拉探测到所有三个HST探测到的透镜图像的X射线点源对应体。合并的X射线光谱包含$100\pm11$净计数，与中等吸收的幂律一致，其中$\Gamma \simeq 1.48$，$N_{\rm H}=(5.5\pm4.4)\times10^{22}\\,\mathrm{cm}^{-2}$。在修正引力放大后，我们获得内禀静止系2--10 keV光度为$L_{\rm X}=1.2\pm0.3\times10^{42}\\,\mathrm{erg\\,s^{-1}}$。X射线发射可能由红移$z\simeq2.14$的低质量星系中的活动星系核主导，这使得该系统成为宇宙正午时期的强透镜低光度活动星系核（LLAGN）（缩写）。
英文摘要
Strong gravitational lensing provides a unique tool of studying intrinsically faint high-redshift active galactic nuclei (AGN). In particular, low-luminosity AGN (LLAGN) can probe black-hole growth in low-mass galaxies that current X-ray surveys cannot otherwise access. We investigate the nature and physical properties of a faint X-ray source triply imaged by the galaxy cluster SDSS J2243$-$0935, and determine whether the source hosts an AGN. We combine archival Hubble Space Telescope imaging and Chandra X-ray observations with the published strong-lensing models of SDSS J2243$-$0935. We constrain the source redshift geometrically, derive magnification maps, and infer the physical properties of the host galaxy. The geometric lensing analysis gives a source redshift of $z=2.14^{+0.12}_{-0.17}$, consistent with the photometric redshift estimate, and a total magnification of $μ=78\pm7$. The source is triply lensed and detected only in the HST F160W band, with an intrinsic magnitude of $m_{\rm AB}=28.2\pm0.2$. The rest-frame optical emission implies a stellar mass of $8.6\lesssim\log(M_\star/M_\odot)\lesssim9.4$. The unobscured star formation rate is constrained to $\mathrm{SFR}_{\rm UV}<0.009\,M_\odot\,\mathrm{yr}^{-1}$, although substantial dust obscuration remains possible. Chandra detects X-ray point-source counterparts to all three HST-detected lensed images. The combined X-ray spectrum contains $100\pm11$ net counts and is consistent with a moderately absorbed power law, with $Γ\simeq 1.48$ and $N_{\rm H}=(5.5\pm4.4)\times10^{22}\,\mathrm{cm}^{-2}$. After correcting for gravitational magnification, we obtain an intrinsic rest-frame $2$--$10$ keV luminosity of $L_{\rm X}=1.2\pm0.3\times10^{42}\,\mathrm{erg\,s^{-1}}$. The X-ray emission is likely dominated by an AGN hosted by a low-mass galaxy at $z\simeq2.14$, making this system a strongly lensed LLAGN at cosmic noon (abridged).
Comments6 pages, 3 figures, submitted
