论文标题
部分可观测时空混沌系统的无模型预测
Unprecedented change in the position of four radio sources
论文作者
论文摘要
可以使用非常长的基线干涉法（VLBI）来确定射射发射活性银河核（AGN）的天文位置。通常，遥远的外乳外靶标的通常明显的正确运动使我们能够通过VLBI观测来实现基本的天体参考框架。但是，长期的天文监测可能会揭示某些AGN位置的极端变化。在2018 - 2021年使用新的VLBI观察结果，我们在这里表明，在20-130 Milliarcsec中，有四个外层次无线电来源（3C48，CTA21，1144+352，1328+254）在20-130 Milliarcsec中在20-130 Milliarcsec中发生了巨大变化。对于所有四个来源，明显的位置转移都是由它们的无线电结构变化引起的。
Astrometric positions of radio-emitting active galactic nuclei (AGNs) can be determined with sub-milliarcsec accuracy using very long baseline interferometry (VLBI). The usually small apparent proper motion of distant extragalactic targets allow us to realize the fundamental celestial reference frame with VLBI observations. However, long-term astrometric monitoring may reveal extreme changes in some AGN positions. Using new VLBI observations in 2018-2021, we show here that four extragalactic radio sources (3C48, CTA21, 1144+352, 1328+254) have a dramatic shift in their positions by 20-130 milliarcsec over two decades. For all four sources, the apparent positional shift is caused by their radio structure change.
