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Title: Measuring the coronal properties of IC 4329A with NuSTAR

We present an analysis of a ∼160 ks NuSTAR observation of the nearby bright Seyfert galaxy IC 4329A. The high-quality broadband spectrum enables us to separate the effects of distant reflection from the direct coronal continuum, and to therefore accurately measure the high-energy cutoff to be E{sub cut}=178{sub −40}{sup +74} keV. The coronal emission arises from accretion disk photons Compton up-scattered by a thermal plasma, with the spectral index and cutoff being due to a combination of the finite plasma temperature and optical depth. Applying standard Comptonization models, we measure both physical properties independently using the best signal to noise obtained to date in an active galactic nucleus over the 3-79 keV band. We derive kT{sub e}=37{sub −6}{sup +7} keV with τ=1.25{sub −0.10}{sup +0.20} assuming a slab geometry for the plasma, and kT{sub e}=33{sub −6}{sup +6} keV with τ=3.41{sub −0.38}{sup +0.58} for a spherical geometry, with both having an equivalent goodness-of-fit.
Authors:
;  [1] ;  [2] ; ; ; ; ; ;  [3] ; ;  [4] ;  [5] ;  [6] ; ;  [7] ;  [8] ;  [9] ;  [10] ;  [11]
  1. Harvard-Smithsonian CfA, 60 Garden Street MS-67, Cambridge, MA 02138 (United States)
  2. Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States)
  3. Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)
  4. Dipartimento di Matematica e Fisica, Università Roma Tre, via della Vasca Navale 84, I-00146 Roma (Italy)
  5. Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States)
  6. Space Science Laboratory, University of California, Berkeley, CA 94720 (United States)
  7. DTU Space National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark)
  8. Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom)
  9. Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States)
  10. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)
  11. NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
Publication Date:
OSTI Identifier:
22348109
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 781; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; ELECTRON TEMPERATURE; EMISSION; GALAXY NUCLEI; ION TEMPERATURE; KEV RANGE; NOISE; NUCLEI; PHOTONS; PHYSICAL PROPERTIES; PLASMA; REFLECTION; SEYFERT GALAXIES; SPECTRA; SPHERICAL CONFIGURATION; X-RAY GALAXIES