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Published May 2015 | Published + Submitted
Journal Article Open

Anatomy of the AGN in NGC 5548. III. The high-energy view with NuSTAR and INTEGRAL

Abstract

We describe the analysis of the seven broad-band X-ray continuum observations of the archetypal Seyfert 1 galaxy NGC 5548 that were obtained with XMM-Newton or Chandra, simultaneously with high-energy (>10 keV) observations with NuSTAR and INTEGRAL. These data were obtained as part of a multiwavelength campaign undertaken from the summer of 2013 till early 2014. We find evidence of a high-energy cut-off in at least one observation, which we attribute to thermal Comptonization, and a constant reflected component that is likely due to neutral material at least a few light months away from the continuum source. We confirm the presence of strong, partial covering X-ray absorption as the explanation for the sharp decrease in flux through the soft X-ray band. The obscurers appear to be variable in column density and covering fraction on time scales as short as weeks. A fit of the average spectrum over the range 0.3–400 keV with a realistic Comptonization model indicates the presence of a hot corona with a temperature of 40^(+40)_(-10) keV and an optical depth of 2.7^(+0.7)_(-1.2) if a spherical geometry is assumed.

Additional Information

© 2015 ESO. Article published by EDP Sciences. Received 25 November 2014; Accepted 12 January 2015; Published online 28 April 2015. We are grateful to the anonymous referee for his/her helpful comments, which have improved the manuscript. This work is based on observations obtained with: the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory and funded by NASA; INTEGRAL, an ESA project with instrument and science data center funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, Spain), Czech Republic, and Poland and with the participation of Russia and the USA; XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and the USA (NASA). The data used in this research are stored in the public archives of the international space observatories involved. This research has made use of data, software and/or web tools obtained from NASA's High Energy Astrophysics Science Archive Research Center (HEASARC), a service of Goddard Space Flight Center and the Smithsonian Astrophysical Observatory. F.U., P.O.P., G.M., and S.B. acknowledge support from the French-Italian International Project of Scientific Collaboration: PICS-INAF project number 181542. F.U., P.O.P. acknowledge support from CNES. F.U. acknowledges support from Université Franco-Italienne (Vinci Ph.D. fellowship). F.U., G.M. acknowledges financial support from the Italian Space Agency under grant ASI/INAF I/037/12/0-011/13. G.A.K. was supported by NASA through grants for HST program number 13184 from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. B.M.P. acknowledges support from the US NSF through grant AST-1008882. G.P. acknowledges support via an E.U. Marie Curie Intra-European fellowship under contract no. FP-PEOPLE-2012-IEF- 331095. K.C.S. acknowledges financial support from the Fondo Fortalecimiento de la Productividad Científica VRIDT 2013. We acknowledge support by ISSI in Bern; The Netherlands Organization for Scientific Research; the UK STFC; the French CNES, CNRS/PICS and CNRS/PNHE; the Swiss SNSF; the Italian INAF/PICS; the German Bundesministerium für Wirtschaft und Technologie/Deutsches Zentrum für Luft- und Raumfahrt (BMWI/DLR, FKZ 50 OR 1408); we acknowledge support from the Italian Space Agency under grants ASI-INAF I/037/12/P1 and ASI/INAF NuSTAR I/037/12/0.

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Submitted - 1501.03426v1.pdf

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Additional details

Created:
August 20, 2023
Modified:
October 19, 2023