Asp-mapping: An extended source reconstruction pipeline with adaptive scale models for radio synthesis imaging

Le résumé fourni par la source

In 2017, the Event Horizon Telescope (EHT) collaboration produced the first image of the M87 black-hole shadow, offering strong observational support for the presence of an event horizon. However, the Difmap pipeline widely used in the early EHT very long baseline interferometry (VLBI) imaging process mainly adopts the point-source-oriented scale-free CLEAN deconvolution method, which has certain limitations on the characterization ability of multi-scale extended structures such as continuous annular accretion flow and jet flow. As the first work in the series of adaptive scale characterization of black-hole structures, this paper constructs a VLBI imaging pipeline, Asp-mapping, based on Asp-Clean2016. For the first time, the Asp-Clean2016 algorithm is embedded in the Difmap deconvolution process, and the effective characterization of extended structures such as black holes is realized by adaptively optimizing the center position, amplitude, and scale of components. In the traditional VLBI imaging process, Asp-mapping combines adaptive scale deconvolution and iterative self-calibration. By dynamically optimizing the position, amplitude and scale of gaussian components, the joint modeling of compact and extended structures is realized. At the same time, scale constraints can be introduced to improve the visibility reconstruction of short baselines. Finally, the restored image is generated by convolution, and the results are quantitatively evaluated from the image domain. In the four types of simulated black-hole structure experiments, Asp-mapping and traditional Difmap CLEAN are generally close to each other in terms of dynamic range, RMS and ̧hi^2, both of which can better fit the simulated observation data. Experimental results demonstrate that Asp-mapping can effectively reconstruct the extended structures of black holes, offering a viable solution for EHT black-hole data processing and radio interferometric imaging.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.