观测同一星系二十载，其谜团却愈发深重

天文学家对一个耀变体进行了长达二十年的持续观测，打破了以往仅依赖短期、窄波段观测的局限。研究团队在2012年的观测数据中发现了一种此前从未被预料到的光谱特征。

Blazars are galaxies with a jet aimed almost directly at us, and they flicker across every part of the spectrum at once. Almost everything we think we know about them comes from short observing campaigns just a handful of days, every year or two, in one narrow band of energy. A Polish and German team has now done the opposite, following a single blazar for nearly twenty years with two orbiting observatories and in two observations from 2012 they found something in the spectrum that nobody had predicted.