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EARLY SCIENCE WITH THE KOREAN VLBI NETWORK: THE QCAL-1 43?GHz CALIBRATOR SURVEY

机译:利用韩国VLBI网络进行的早期科学:QCAL-1 43?GHz校准器调查

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This paper presents the catalog of correlated flux densities in three ranges of baseline projection lengths of 637?sources from a 43?GHz (Q band) survey observed with the Korean VLBI Network. Of them, 14 objects used as calibrators were previously observed, but 623 sources have not been observed before in the Q band with very long baseline interferometry (VLBI). The goal of this work in the early science phase of the new VLBI array is twofold: to evaluate the performance of the new instrument that operates in a frequency range of 22-129?GHz and to build a list of objects that can be used as targets and as calibrators. We have observed the list of 799 target sources with declinations down to –40°. Among them, 724 were observed before with VLBI at 22?GHz and had correlated flux densities greater than 200 mJy. The overall detection rate is 78%. The detection limit, defined as the minimum flux density for a source to be detected with 90% probability in a single observation, was in the range of 115-180 mJy depending on declination. However, some sources as weak as 70 mJy have been detected. Of 623 detected sources, 33 objects are detected for the first time in VLBI mode. We determined their coordinates with a median formal uncertainty of 20 mas. The results of this work set the basis for future efforts to build the complete flux-limited sample of extragalactic sources at frequencies of 22?GHz and higher at 3/4 of the celestial sphere.
机译:本文介绍了通过韩国VLBI网络观察到的43?GHz(Q波段)调查中的637?源基线投影长度的三个范围内的相关通量密度目录。其中,先前已观察到14个用作校准器的物体,但之前在Q波段使用非常长的基线干涉仪(VLBI)之前未观察到623个源。在新的VLBI阵列的早期科学阶段,这项工作的目标是双重的:评估在22-129?GHz频率范围内工作的新仪器的性能,并建立可以用作目标的对象清单。目标和作为校准器。我们观察到了799个目标源的列表,它们的偏角低至–40°。其中,在VLBI在22?GHz之前观察到724,其相关通量密度大于200 mJy。总体检测率为78%。根据磁偏角,检测限定义为在单次观测中以90%的概率检测到的光源的最小通量密度,范围为115-180 mJy。但是,已经检测到一些弱至70 mJy的源。在623个检测到的源中,以VLBI模式首次检测到33个对象。我们以20 mas的中位数形式不确定性确定了它们的坐标。这项工作的结果为未来的工作奠定了基础,以建立完整的通量受限的河外源样品,该样品在天体3/4处的频率为22?GHz和更高。
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