The NuSTAR view of the true Type 2 Seyfert NGC 3147
Abstract
We present the first NuSTAR observation of a 'true' type 2 Seyfert galaxy. The 3–40 keV X-ray spectrum of NGC 3147 is characterized by a simple power-law, with a standard Γ ∼ 1.7 and an iron emission line, with no need for any further component up to ∼40 keV. These spectral properties, together with significant variability on time-scales as short as weeks (as shown in a 2014 Swift monitoring campaign), strongly support an unobscured line of sight for this source. An alternative scenario in terms of a Compton-thick source is strongly disfavoured, requiring an exceptional geometrical configuration, whereas a large fraction of the solid angle to the source is filled by a highly ionized gas, whose reprocessed emission would dominate the observed luminosity. Moreover, in this scenario, the implied intrinsic X-ray luminosity of the source would be much larger than the value predicted by other luminosity proxies, like the [O III]λ5007 emission-line extinction-corrected luminosity. Therefore, we confirm with high confidence that NGC 3147 is a true type 2 Seyfert galaxy, intrinsically characterized by the absence of a broad-line region.
Additional Information
© 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2017 March 14. Received 2017 March 13; in original form 2017 January 27. Published: 16 March 2017. We would like to thank Kristin Kruse Madsen for her help in interpreting the discrepancy at the iron line energy between the two NuSTAR modules. SB acknowledges financial support from the Italian Space Agency under grant ASI-INAF I/037/12/0. AM and GM acknowledge financial support from the Italian Space Agency under grant ASI/INAF I/037/12/0-011/13. AM acknowledges financial support from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 312789. FP acknowledges the ASI/INAF agreement number 2013-023-R1. XB and FJC acknowledge financial support through grant AYA2015-64346-C2-1-P (MINECO/FEDER).Attached Files
Accepted Version - 1703.04586.pdf
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Additional details
- Eprint ID
- 75236
- Resolver ID
- CaltechAUTHORS:20170320-101557112
- Created
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2017-03-20Created from EPrint's datestamp field
- Updated
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2021-11-15Created from EPrint's last_modified field
- Caltech groups
- NuSTAR