X-ray time delays in the narrow line Seyfert 1 galaxy PG 1244+026

Alston, W.N.; Done, C.; Vaughan, S.

Abstract

We analyse the X-ray time-lags in the narrow line Seyfert 1 (NLS1) galaxy PG 1244+026 (MBH ∼ 107 M⊙, L/LEdd ∼ 1). The time delay between the soft (0.3–0.7 keV) and harder (1.2–4.0 keV) variations shows the well-established switch from hard lags at low frequencies to soft lags at high frequencies. The low-frequency hard lags are qualitatively consistent with the propagation of fluctuations model, with some long-time-scale response of the reflection component. The high-frequency soft lag appears to extend over a wide frequency band, that we divide this into two narrow frequency ranges, and examine the lag as a function of energy for each of these. At high frequencies the soft excess emission is delayed with respect to the harder energy bands, without any corresponding strong, hard X-ray reflection signature. At even higher frequencies a soft lag is seen at the softest energies, as well as tentative evidence for an iron Kα reverberation signal. These results point to the importance of reprocessing as well as reflection in determining the lags in NLS1s.

Citation

Alston, W., Done, C., & Vaughan, S. (2014). X-ray time delays in the narrow line Seyfert 1 galaxy PG 1244+026. Monthly Notices of the Royal Astronomical Society, 439(2), 1548-1555. https://doi.org/10.1093/mnras/stu005

• Journal Article Type: Article
• Acceptance Date: Jan 1, 2014
• Online Publication Date: Feb 7, 2014
• Publication Date: Apr 1, 2014
• Deposit Date: Mar 16, 2016
• Publicly Available Date: Mar 18, 2016
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 439
• Issue: 2
• Pages: 1548-1555
• DOI: https://doi.org/10.1093/mnras/stu005
• Public URL: https://durham-repository.worktribe.com/output/1386103
• Related Public URLs: http://adsabs.harvard.edu/abs/2014MNRAS.439.1548A