Preprint article · Journal article
The NuSTAR spectrum of Mrk 335: extreme relativistic effects within two gravitational radii of the event horizon?
University of Cambridge1
Astrophysics, National Space Institute, Technical University of Denmark2
Columbia University3
Max Planck Institute4
University of Michigan, Ann Arbor5
NASA Goddard Space Flight Center6
Saint Mary's University Halifax7
Pennsylvania State University8
Erlangen Centre for Astroparticle Physics9
Università Roma Tre10
California Institute of Technology11
Harvard-Smithsonian Center for Astrophysics12
University of California at San Diego13
National Space Institute, Technical University of Denmark14
...and 4 moreWe present 3-50 keV NuSTAR observations of the active galactic nuclei Mrk 335 in a very low flux state. The spectrum is dominated by very strong features at the energies of the iron line at 5-7 keV and Compton hump from 10-30 keV. The source is variable during the observation, with the variability concentrated at low energies, which suggesting either a relativistic reflection or a variable absorption scenario.
In this work, we focus on the reflection interpretation, making use of new relativistic reflection models that self consistently calculate the reflection fraction, relativistic blurring and angle-dependent reflection spectrum for different coronal heights to model the spectra. We find that the spectra can be well fitted with relativistic reflection, and that the lowest flux state spectrum is described by reflection alone, suggesting the effects of extreme light-bending occurring within similar to 2 gravitational radii (R-G) of the event horizon.
The reflection fraction decreases sharply with increasing flux, consistent with a point source moving up to above 10 R-G as the source brightens. We constrain the spin parameter to greater than 0.9 at the 3 sigma confidence level. By adding a spin-dependent upper limit on the reflection fraction to our models, we demonstrate that this can be a powerful way of constraining the spin parameter, particularly in reflection dominated states.
We also calculate a detailed emissivity profile for the iron line, and find that it closely matches theoretical predictions for a compact source within a few R-G of the black hole.
Language: | English |
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Publisher: | Royal Astronomical Society |
Year: | 2014 |
Pages: | 1723-1732 |
ISSN: | 13652966 and 00358711 |
Types: | Preprint article and Journal article |
DOI: | 10.1093/mnras/stu1246 |
ORCIDs: | Christensen, Finn Erland |