A Highly Doppler Blueshifted Fe-K Emission Line in the High-Redshift QSO PKS 2149-306
Abstract
We report the results from an observation of the QSO PKS 2149-306 (z=2.345). We detect an emission line centered at 17 keV in the quasar frame. Line emission at this energy has not been observed in any other active galaxy or quasar to date. We present evidence rejecting the possibility that this line is the result of instrumental artifacts, or a serendipitous source. The most likely explanation is blueshifted Fe-K emission (the EW is 300+/-200 eV, QSO frame). Bulk velocities of the order of 0.75c are implied by the data. We show that Fe-K line photons originating in an accretion disk and Compton-scattering off a leptonic can account for the emission line. Curiously, if the emission-line feature recently discovered in another quasar PKS 0637-752, z=0.654, is blueshifted Ovii, the Doppler factor is the same (~2.7) for both.
Turn this paper into a full lesson
ArcXiv compiles a staged curriculum from this paper: 8-12 lessons across beginner → advanced, synthesised section guides, visuals, flashcards, a quiz, exercises, and on-demand deep dives per section. Grounded in the abstract, never invented.