Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Monte Carlo Markov Chain based investigation of black hole spin in the
  active galaxy NGC3783   The analysis of relativistically broadened X-ray spectral features from the
inner accretion disk provides a powerful tool for measuring the spin of
supermassive black holes (SMBH) in active galactic nuclei (AGN). However, AGN
spectra are often complex and careful analysis employing appropriate and
self-consistent models are required if one is to obtain robust results. In this
paper, we revisit the deep July-2009 Suzaku observation of the Seyfert galaxy
NGC3783 in order to study in a rigorous manner the robustness of the inferred
black hole spin parameter. Using Monte Carlo Markov Chain (MCMC) techniques, we
identify a (partial) modeling degeneracy between the iron abundance of the disk
and the black hole spin parameter. We show that the data for NGC3783 strongly
require both supersolar iron abundance (Z_Fe=2-4Zsun) and a rapidly spinning
black hole (a>0.88). We discuss various astrophysical considerations that can
affect the measured abundance. We note that, while the abundance enhancement
inferred in NGC3783 is modest, the X-ray analysis of some other objects has
found extreme iron abundances. We introduce the hypothesis that the radiative
levitation of iron ions in the innermost regions of radiation-dominated AGN
disks can enhance the photospheric abundance of iron. We show that radiative
levitation is a plausible mechanism in the very inner regions of high accretion
rate AGN disks.

4
The categories of this paper are: cond-mat
19
The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol