We investigate the X-ray time lags of a recent ~630ks XMM-Newton observation of PG 1211+143. We find well-correlated variations across the XMM-Newton EPIC bandpass, with the first detection of a hard lag in this source with a mean time delay of up to ~3ks at the lowest frequencies. We find that the energy-dependence of the low-frequency hard lag scales approximately linearly with log(E) when averaged over all orbits, consistent with the propagating fluctuations model. However, we find that the low-frequency lag behaviour becomes more complex on timescales longer than a single orbit, suggestive of additional modes of variability. We also detect a high-frequency soft lag at ~10^{-4}Hz with the magnitude of the delay peaking at <0.8ks, consistent with previous observations, which we discuss in terms of small-scale reverberation.
@article{arxiv.1801.03858,
title = {X-ray time lags in PG 1211+143},
author = {Andrew Lobban and Simon Vaughan and Ken Pounds and James Reeves},
journal= {arXiv preprint arXiv:1801.03858},
year = {2018}
}
Comments
Accepted for publication in MNRAS; 10 pages, 7 figures, 1 table