A novel test of quasar orientation

Gordon T. Richards, Richard M. Plotkin, Paul C. Hewett, Amy L. Rankine, Angelica B. Rivera, Yue Shen, Ohad Shemmer

Research output: Contribution to journalArticlepeer-review


The orientation of the disk of material accreting onto supermassive black holes that power quasars is one of most important quantities that are needed to understand quasars—both individually and in the ensemble average. We present a hypothesis for determining comparatively edge-on orientation in a subset of quasars (both radio loud and radio quiet). If confirmed, this orientation indicator could be applicable to individual quasars without reference to radio or X-ray data and could identify some 10%–20% of quasars as being more edge-on than average, based only on moderate resolution and signal-to-noise spectroscopy covering the C IV λ 1549 Å emission feature. We present a test of said hypothesis using X-ray observations and identify additional data that are needed to confirm this hypothesis and calibrate the metric.

Original languageEnglish (US)
Article numberac0256
JournalAstrophysical Journal Letters
Issue number1
StatePublished - Jun 10 2021

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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