来自PSF结构的黑洞环状图像
Black hole ring images from PSF structures
AI总结：
本文指出EHT发布的黑洞环图像尺寸与PSF旁瓣间距相似，怀疑其是PSF解卷积不完全导致的伪影，强调需评估EHTC新成像方法的PSF解卷积和数据校准能力。
摘要：
射电干涉成像分析的两个关键方面是数据校准和点扩展函数（PSF）结构的解卷积。这两点对于使用由少量台站组成的VLBI网络进行的高频观测尤为重要，例如事件视界望远镜（EHT）所进行的观测。事件视界望远镜合作组织（EHTC）基于M 87（d = 42 +- 3 muas）（EHTC2019a）和银河系中心（d = 51.8 +- 2.3 muas）（EHTC2022a）的观测，展示了环状黑洞的图像。EHTC图像中看到的环结构与基于黑洞质量和距离估算的阴影直径一致。然而，这些黑洞环的尺寸也与每次观测的点扩展函数（PSF；脏波束）中典型的上下间距（例如主波束与附近第1旁瓣之间的间隔）相同。这些事实表明，EHTC的环结构是源自PSF形状的伪影，而不是M 87和银河系中心SMBH的固有结构。EHTC除标准CLEAN算法外还采用了新颖的成像技术。CLEAN方法专为PSF形状解卷积而设计，但在实践中，它可能并不总是能完全去除PSF形状。在像EHT这样天线数量较少的干涉仪数据的成像分析中，评估PSF形状并将其与成像结果进行比较至关重要。EHTC采用的新颖成像方法在PSF解卷积性能方面尚未得到充分评估，强烈建议对其在这方面的性能进行彻底检查。调查数据校准能力，即从观测数据中分离误差噪声的能力，也很重要。
英文摘要：
Two critical aspects of radio interferometric imaging analysis are data calibration and deconvolution of the point spread function (PSF) structure. Both of these are particularly important for high-frequency observations using a VLBI network consisting of a small number of stations, such as those conducted by the Event Horizon Telescope (EHT). The Event Horizon Telescope Collaboration (EHTC) has presented images of ring-shaped black holes from observations of M 87 (d = 42 +- 3 muas)(EHTC2019a) and the Galactic Center (d = 51.8 +- 2.3 muas)(EHTC2022a). The ring structures seen in the EHTC images are consistent with the estimated shadow diameter of the black hole based on its mass and distance. However, these black hole ring sizes are also the same with the typical up and down spacings (e.g., the intervals between the main beam and nearby 1st-sidelobes) seen in the point spread function (PSF; dirty beam) for each observation. These facts suggest that the EHTC ring structures are artifacts derived from the shape of the PSFs rather than the intrinsic structure of the SMBHs in M 87 and the Galactic Center. The EHTC utilizes novel imaging techniques in addition to the standard CLEAN algorithm. The CLEAN method was designed for PSF shape deconvolution in mind, yet in practice, it may not always be able to completely remove the PSF shape. In the imaging analysis of data from interferometers with a small number of antennas like the EHT, it is crucial to assess the PSF shape and compare it with the imaging results. The novel imaging methods employed by the EHTC have not yet been fully evaluated for PSF deconvolution performance, and it is highly recommended that their performance in this regard be thoroughly examined. It is also important to investigate the data calibration capability, i.e., the ability to separate error noise from the observed data.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
