The role of the reflection fraction in constraining black hole spin
By T. Dauser, Javier A. García, Michael L. Parker, A. C. Fabian, J. Wilms. 2014
236 citations recorded by the source corpus.
In many active galaxies, the X-ray reflection features from the innermost regions of the accretion disc are relativistically distorted. This distortion allows us to measure parameters of the black hole such as its spin. The ratio in flux between the direct and the reflected radiation, the so-called reflection fraction, is determined directly from the geometry and location of primary source of radiation. We calculate the reflection fraction in the lamp post geometry in order to determine its maximal possible value for a given value of black hole spin. We show that high reflection fractions in excess of 2 are only possible for rapidly rotating black holes, suggesting that the high spin sources produce the strongest relativistic reflection features. Using simulations we show that taking this constraint into account does significantly improve the determination of the spin values. We make software routines for the most popular X-ray data analysis packages available that incorporate these additional constraints.
Subfields: Astronomy and Astrophysics, Biomedical Engineering
View Paper: https://www.semanticscholar.org/paper/107eb93d7bff70732849a6472431b597b0cb60c5
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In Astronomy and Astrophysics
In Biomedical Engineering
- J. Steiner
- J. E. McClintock
- E. Berger
- T. Dauser
- Cosimo Bambi
- Ronald A. Remillard
- Ramesh Narayan
- V. Cardoso
Citations in the corpus
- An Embedded X-Ray Source Shines through the Aspherical AT 2018cow: Revealing the Inner Workings of the Most Luminous Fast-evolving Optical Transients (2018, methodology): “…of AT 2018cow at δt= 7.7 days with a Comptonized disk-reflection model via simpl (Steiner et al. 2009) acting on a thermal component and relxill (Dauser et al. 2014) produces a good fit to the data ( d.o.f. 1.02c ~ ), matching a kTe 30 keV corona, with reflection fraction Rf1 (Figure 17).49…”
- Normalizing a Relativistic Model of X-ray Reflection: The Definition of the Reflection Fraction and its Implementation in relxill (2016, background): “Moreover, as demonstrated by Dauser et al. (2014), when fitting observational data with the lamp post version of relxill, additional constraints can be obtained on the spin parameter by excluding values of Rf that are unrealistic.”