We use cookies to ensure that we give you the best experience on our website. By continuing to browse this repository, you give consent for essential cookies to be used. You can read more about our Privacy and Cookie Policy.

Durham Research Online
You are in:

Complex narrow-line Seyfert 1s : high spin or high inclination?

Gardner, E. and Done, C. (2015) 'Complex narrow-line Seyfert 1s : high spin or high inclination?', Monthly notices of the Royal Astronomical Society., 448 (3). pp. 2245-2259.


Complex narrow-line Seyfert 1s (NLS1s), such as 1H 0707−495, differ from simple NLS1s like PG 1244+026 by showing stronger broad spectral features at Fe K and larger amplitude flux variability. These are correlated: the strongest Fe K features are seen during deep dips in the light curves of complex NLS1s. There are two competing explanations for these features, one where a compact X-ray source on the spin axis of a highly spinning black hole approaches the horizon and the consequent strong relativistic effects focus the intrinsic flux on to the inner edge of a thin disc, giving a dim, reflection-dominated spectrum. The other is that the deep dips are caused by complex absorption by clumps close to the hard X-ray source. The reflection-dominated model is able to reproduce the very short 30 s soft lag from reverberation seen in the complex NLS1 1H 0707−495. However, it does not explain the characteristic switch to hard lags on longer time-scales. Instead, a full model of propagating fluctuations coupled to reverberation can explain the switch in the simple NLS1 PG 1244+026 using a low spin black hole. However, PG 1244+026 has a longer reverberation lag of ∼200 s. Here we extend the successful propagation–reverberation model for the simple NLS1 PG 1244+026 to include the effect of absorption from clumps in a turbulent region above the disc. The resulting occultations of the inner accretion flow can introduce additional hard lags when relativistic effects are taken into account. This dilutes the soft lag from reverberation and shifts it to higher frequencies, making a smooth transition between the 200 s lags seen in simple NLS1s to the 30 s lags in complex NLS1s. These two classes of NLS1 could then be determined by inclination angle with respect to a clumpy, probably turbulent, failed wind structure on the disc.

Item Type:Article
Full text:(VoR) Version of Record
Download PDF
Publisher Web site:
Publisher statement:This article has been accepted for publication in Monthly notices of the Royal Astronomical Society ©: 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Date accepted:21 January 2015
Date deposited:17 March 2016
Date of first online publication:26 February 2015
Date first made open access:No date available

Save or Share this output

Look up in GoogleScholar