Minute-timescale Variability in the X-ray Emission of the Highest Redshift Blazar

  title={Minute-timescale Variability in the X-ray Emission of the Highest Redshift Blazar},
  author={Alberto Moretti and Gabriele Ghisellini and Alessandro Caccianiga and Silvia Belladitta and Roberto Della Ceca and Luca Ighina and Tullia Sbarrato and Paola Severgnini and Cristiana Spingola},
  journal={The Astrophysical Journal},
We report on two Chandra observations of the quasar PSO J0309+27, the most distant blazar observed so far (z = 6.1), performed eight months apart, in 2020 March and November. Previous Swift-XRT observations showed that this object is one of the brightest X-ray sources beyond redshift 6.0 ever observed so far. This new dataset confirmed the high flux level and unveiled a spectral change that occurred on a very short timescale (250 s rest frame), caused by a significant softening of the emission… Expand


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