Observations of the inner regions of accretion disks around active galactic nuclei (AGNs) reveal the presence of short timescale variability in X-ray spectrum around a black hole. The rapid variability is thought to be due to X-ray bursts/flares within the accretion disk of the black hole. This X-ray irradiation excites neutral iron atoms within the disk causing them to emit a characteristic fluorescent line spectrum at 6.4 keV. However, due to gravitational redshifting resulting from the black hole and Doppler effects due to the rotation of the accretion disk, these line spectra are broadened and skewed. These iron line profiles are thought to provide information on the spin and mass of the supermassive black hole within these AGNs as well as the placement of the X-ray burst around the black hole. We present a general relativistic ray-tracing model to simulate iron line reverberation in response to the X-ray flare at different positions as well as with different black hole spins. Through our simulated 2ks XARM spectrum, we have found that the predicted line feature is resolvable and there is a broad redshifted region of the line spectrum present for maximally spinning black holes. In addition, we have found that this broad region originates from a redshifted peak, whose broadening and reappearance could provide more insight into the spin of the black hole.

Additional Abstract Information

Student(s): Kaitlyn Porter

Department: Physics and Astronomy

Faculty Advisor: Dr. Keigo Fukumura

Type: Poster

Year: 2018

Back to Top