Investigating the Accretion Nature of Binary Supermassive Black Hole Candidate SDSS J025214.67−002813.7
Investigating the Accretion Nature of Binary Supermassive Black Hole Candidate SDSS J025214.67−002813.7
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双星超大质量黑洞候选星J025214.67−002813.7的吸积性质研究
DOI：
10.3847/1538-4357/ac4af1
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发表时间：
2021-10
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通讯作者：
A. Foord;Xin Liu;K. Gültekin;K. Whitley;Fangzheng Shi;Yu-Ching Chen
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作者：
A. Foord;Xin Liu;K. Gültekin;K. Whitley;Fangzheng Shi;Yu-Ching Chen
我们展示了 SDSS J025214.67−002813.7 的多波长分析结果，该系统之前根据光学光变曲线中检测到的周期信号被归类为二元活动星系核（AGN）候选系统。我们利用系统可用的射电 X 射线观测来研究真正的吸积性质。通过分析 XMM-Newton 和 NuSTAR 的新观测结果，我们描述了 X 射线发射的特征并寻找环双星吸积的证据。尽管 0.5-10 keV 光谱显示存在额外的软发射成分（可能是由于热核气体的扩展发射），但我们发现光谱形状与单个活动星系核的光谱形状一致。在编制完整的多波长光谱能量分布（SED）时，我们还寻找环双星吸积的迹象，例如由于迷你盘的存在而导致的连续体中的“凹口”。我们发现无线电光发射与标准、无线电安静的 AGN 的 SED 一致；然而，向蓝的发射存在约 1400 Å 的巨大赤字。尽管这种发射不足似乎可以归因于二元 AGN 系统，但我们发现 SDSS J0252−0028 的 SED 可以通过变红的单一 AGN 的发射来更好地解释。然而，未来对与双星活动星系核相关的预期硬X射线发射（特别是在不等质量状态下）的研究将允许对双星活动星系核假设进行更严格的分析。
We present results of a multiwavelength analysis of SDSS J025214.67−002813.7, a system that has been previously classified as a binary active galactic nucleus (AGN) candidate based on periodic signals detected in the optical light curves. We use available radio−X-ray observations of the system to investigate the true accretion nature. Analyzing new observations from XMM-Newton and NuSTAR, we characterize the X-ray emission and search for evidence of circumbinary accretion. Although the 0.5–10 keV spectrum shows evidence of an additional soft emission component, possibly due to extended emission from hot nuclear gas, we find the spectral shape is consistent with that of a single AGN. Compiling a full multiwavelength spectral energy distribution (SED), we also search for signs of circumbinary accretion, such as a “notch” in the continuum due to the presence of minidisks. We find that the radio–optical emission agrees with the SED of a standard, radio-quiet, AGN; however, there is a large deficit in emission blueward of ∼1400 Å. Although this deficit in emission can plausibly be attributed to a binary AGN system, we find that the SED of SDSS J0252−0028 is better explained by emission from a reddened, single AGN. However, future studies of the expected hard X-ray emission associated with binary AGNs (especially in the unequal-mass regime) will allow for more rigorous analyses of the binary AGN hypothesis.