%0 Generic %1 citeulike:14558406 %A Alston1, W. N. %A Fabian, A. C. %A Buisson, D. J. K. %A Kara, E. %A Parker, M. L. %A Lohfink, A. M. %A Uttley, P. %A Wilkins, D. R. %A Pinto, C. %A De Marco, B. %A Cackett, E. M. %A Middleton, M. J. %A Walton, D. J. %A Reynolds, C. S. %A Jiang, J. %A Gallo, L. C. %A Zogbhi, A. %A Miniutti, G. %A Dovciak, M. %A Young, A. J. %D 2018 %K imported %T The remarkable X-ray variability of IRAS 13224&\#45;&\#45;3809 I: the variability process %U http://arxiv.org/abs/1803.10444 %X We present a detailed X-ray timing analysis of the highly variable NLS1 galaxy, IRAS 13224--3809. The source was recently monitored for 1.5 Ms with XMM-Newton which, combined with 500 ks archival data, makes this the best studied NLS1 galaxy in X-rays to date. We apply a full suite of timing methods in both the time- and Fourier-domain in order to understand the underlying variability process. The source flux is not distributed lognormally, as would be expected for accreting sources. The first non-linear rms-flux relation for any accreting source in any waveband is found, with \$rms flux^2/3\$. The light curves exhibit strong non-stationarity, in addition to that caused by the rms-flux relation, and are fractionally more variable at lower source flux. The power spectrum is estimated down to \$\sim 10^-7\$ Hz and consists of multiple peaked components: a low-frequency break at \$10^-5\$ Hz, with slope \$< 1\$ down to low frequencies; an additional component breaking at \$10^-3\$ Hz. Using the high-frequency break we estimate the black hole mass \$M\_BH = 0.5-2 10^6 M\_ødot\$, and mass accretion rate in Eddington units, \$m\_Edd 1\$. The non-stationarity is manifest in the PSD with the low-frequency break moving to higher frequencies with decreasing source flux. We also detect a narrow coherent feature in the soft band PSD at \$0.7\$ mHz, modelled with a Lorentzian the feature has \$Q 8\$ and an \$rms 3\$ \%. We discuss the implication of these results for accretion of matter onto black holes.

@misc{citeulike:14558406, abstract = {We present a detailed X-ray timing analysis of the highly variable NLS1 galaxy, IRAS 13224--3809. The source was recently monitored for 1.5 Ms with \textit{XMM-Newton} which, combined with 500 ks archival data, makes this the best studied NLS1 galaxy in X-rays to date. We apply a full suite of timing methods in both the time- and Fourier-domain in order to understand the underlying variability process. The source flux is not distributed lognormally, as would be expected for accreting sources. The first non-linear rms-flux relation for any accreting source in any waveband is found, with \$\mathrm{rms} \propto \mathrm{flux}^{2/3}\$. The light curves exhibit strong non-stationarity, in addition to that caused by the rms-flux relation, and are fractionally more variable at lower source flux. The power spectrum is estimated down to \$\sim 10^{-7}\$ Hz and consists of multiple peaked components: a low-frequency break at \$\sim 10^{-5}\$ Hz, with slope \$\alpha \< 1\$ down to low frequencies; an additional component breaking at \$\sim 10^{-3}\$ Hz. Using the high-frequency break we estimate the black hole mass \$M\_\mathrm{BH} = [0.5-2] \times 10^{6} M\_{\odot}\$, and mass accretion rate in Eddington units, \$\dot m\_{\rm Edd} \gtrsim 1\$. The non-stationarity is manifest in the PSD with the low-frequency break moving to higher frequencies with decreasing source flux. We also detect a narrow coherent feature in the soft band PSD at \$0.7\$ mHz, modelled with a Lorentzian the feature has \$Q \sim 8\$ and an \$\mathrm{rms} \sim 3\$ \%. We discuss the implication of these results for accretion of matter onto black holes.}, added-at = {2019-03-25T08:20:55.000+0100}, archiveprefix = {arXiv}, author = {Alston1, W. N. and Fabian, A. C. and Buisson, D. J. K. and Kara, E. and Parker, M. L. and Lohfink, A. M. and Uttley, P. and Wilkins, D. R. and Pinto, C. and De Marco, B. and Cackett, E. M. and Middleton, M. J. and Walton, D. J. and Reynolds, C. S. and Jiang, J. and Gallo, L. C. and Zogbhi, A. and Miniutti, G. and Dovciak, M. and Young, A. J.}, biburl = {https://www.bibsonomy.org/bibtex/279866a47a64e10ce521f7893eefc5212/ericblackman}, citeulike-article-id = {14558406}, citeulike-linkout-0 = {http://arxiv.org/abs/1803.10444}, citeulike-linkout-1 = {http://arxiv.org/pdf/1803.10444}, day = 28, eprint = {1803.10444}, interhash = {6b7eda50f67447f215a62d977e61c172}, intrahash = {79866a47a64e10ce521f7893eefc5212}, keywords = {imported}, month = mar, posted-at = {2018-03-29 21:33:57}, priority = {2}, timestamp = {2019-03-25T08:20:55.000+0100}, title = {{The remarkable X-ray variability of IRAS 13224\&\#45;\&\#45;3809 I: the variability process}}, url = {http://arxiv.org/abs/1803.10444}, year = 2018 }