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The Compton hump and variable blue wing in the extreme low-flux NuSTAR observations of 1H0707−495

Kara, E. and Fabian, A. C. and Lohfink, A. M. and Parker, M. L. and Walton, D. J. and Boggs, S. E. and Christensen, F. E. and Hailey, C. J. and Harrison, F. A. and Matt, G. and Reynolds, C. S. and Stern, D. and Zhang, W. W. (2015) The Compton hump and variable blue wing in the extreme low-flux NuSTAR observations of 1H0707−495. Monthly Notices of the Royal Astronomical Society, 449 (1). pp. 232-242. ISSN 0035-8711. doi:10.1093/mnras/stv304.

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The narrow-line Seyfert I galaxy, 1H0707−495, has been well observed in the 0.3–10 keV band, revealing a dramatic drop in flux in the iron Kα band, a strong soft excess, and short time-scale reverberation lags associated with these spectral features. In this paper, we present the first results of a deep 250-ks NuSTAR (Nuclear Spectroscopic Telescope Array) observation of 1H0707−495, which includes the first sensitive observations above 10 keV. Even though the NuSTAR observations caught the source in an extreme low-flux state, the Compton hump is still significantly detected. NuSTAR, with its high effective area above 7 keV, clearly detects the drop in flux in the iron Kα band, and by comparing these observations with archival XMM–Newton observations, we find that the energy of this drop increases with increasing flux. We discuss possible explanations for this, the most likely of which is that the drop in flux is the blue wing of the relativistically broadened iron Kα emission line. When the flux is low, the coronal source height is low, thus enhancing the most gravitationally redshifted emission.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Kara, E.0000-0003-0172-0854
Fabian, A. C.0000-0002-9378-4072
Parker, M. L.0000-0002-8466-7317
Walton, D. J.0000-0001-5819-3552
Boggs, S. E.0000-0001-9567-4224
Christensen, F. E.0000-0001-5679-1946
Harrison, F. A.0000-0003-2992-8024
Matt, G.0000-0002-2152-0916
Stern, D.0000-0003-2686-9241
Zhang, W. W.0000-0002-1426-9698
Additional Information:© 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2015 February 11. Received 2015 February 10. In original form 2014 November 12. First published online March 17, 2015. EK thanks Javier Garcia and Thomas Dauser for interesting discussions on the RELXILLLP modelling. EK is supported by the Gates Cambridge Scholarship. ACF thanks the Royal Society. EK, ACF, AML, and GM acknowledge support from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 312789, StrongGravity. AML and GM acknowledge financial support from Italian Space Agency under grant ASI/INAF I/037/12/0-011/13. This work was supported under National Aeronautics and Space Administration (NASA) contract no. NNG08FD60C, and made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the NASA. We thank the NuSTAR Operations, Software and Calibration teams for support with the execution and analysis of these observations. This research has made use of the NuSTAR Data Analysis Software (NUSTARDAS) jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA). This work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester.
Group:NuSTAR, Space Radiation Laboratory
Funding AgencyGrant Number
Gates Cambridge ScholarshipUNSPECIFIED
European Research Council (ERC)312789
Agenzia Spaziale Italiana (ASI)ASI/INAF I/037/12/0-011/13
Istituto Nazionale di Astrofisica (INAF)UNSPECIFIED
Non-Subject Keywords:black hole physics – galaxies: active – galaxies: individual: 1H0707−495 – X-rays: galaxies
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2015-61
Issue or Number:1
Record Number:CaltechAUTHORS:20150405-152254064
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Official Citation:E. Kara, A. C. Fabian, A. M. Lohfink, M. L. Parker, D. J. Walton, S. E. Boggs, F. E. Christensen, C. J. Hailey, F. A. Harrison, G. Matt, C. S. Reynolds, D. Stern, and W. W. Zhang The Compton hump and variable blue wing in the extreme low-flux NuSTAR observations of 1H0707−495 MNRAS (May 1, 2015) Vol. 449 234-242 doi:10.1093/mnras/stv304 First published online March 17, 2015
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:56360
Deposited By: Joy Painter
Deposited On:06 Apr 2015 17:03
Last Modified:10 Nov 2021 20:58

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