Exploratory X-Ray Monitoring of Luminous Radio-quiet Quasars at High Redshift: Extended Time-series Analyses and Stacked Imaging Spectroscopy

  title={Exploratory X-Ray Monitoring of Luminous Radio-quiet Quasars at High Redshift: Extended Time-series Analyses and Stacked Imaging Spectroscopy},
  author={Marcus Thomas and Ohad Shemmer and W. N. Brandt and Maurizio Paolillo and Shai Kaspi and Cristian Vignali and P Lira and Donald P. Schneider},
  journal={The Astrophysical Journal},
We present three new Chandra X-ray epochs along with new ground-based optical–UV observations as the third installment in a time-series analysis of four high-redshift (z ≈ 4.1–4.4) radio-quiet quasars. In total, we present nine epochs for these sources with rest-frame temporal baselines of ∼1300–2000 days. We utilize the X-ray data to determine basic variability properties, as well as produce mean spectra and stacked images based on effective exposure times of ∼40–70 ks per source. We perform… 


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