Multi-time-scale X-ray reverberation mapping of accreting black holes
Accreting black holes show characteristic reflection features in their X-ray spectrum, including an iron Kα line, resulting from hard X-ray continuum photons illuminating the accretion disc. The reverberation lag resulting from the path-length difference between direct and reflected emission provide...
| Auteurs principaux: | , , |
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| Format: | Journal article |
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Oxford University Press
2018
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| _version_ | 1826299947312480256 |
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| author | Mastroserio, G Ingram, A van der Klis, M |
| author_facet | Mastroserio, G Ingram, A van der Klis, M |
| author_sort | Mastroserio, G |
| collection | OXFORD |
| description | Accreting black holes show characteristic reflection features in their X-ray spectrum, including an iron Kα line, resulting from hard X-ray continuum photons illuminating the accretion disc. The reverberation lag resulting from the path-length difference between direct and reflected emission provides a powerful tool to probe the innermost regions around both stellar-mass and supermassive black holes. Here, we present for the first time a reverberation mapping formalism that enables modelling of energy-dependent time lags and variability amplitude for a wide range of variability time-scales, taking the complete information of the cross-spectrum into account. We use a pivoting power-law model to account for the spectral variability of the continuum that dominates over the reverberation lags for longer time-scale variability. We use an analytic approximation to self-consistently account for the non-linear effects caused by this continuum spectral variability, which have been ignored by all previous reverberation studies. We find that ignoring these non-linear effects can bias measurements of the reverberation lags, particularly at low frequencies. Since our model is analytic, we are able to fit simultaneously for a wide range of Fourier frequencies without prohibitive computational expense. We also introduce a formalism of fitting to real and imaginary parts of our cross-spectrum statistic, which naturally avoids some mistakes/inaccuracies previously common in the literature. We perform proof-of-principle fits to Rossi X-ray Timing Explorer data of Cygnus X-1. |
| first_indexed | 2024-03-07T05:09:41Z |
| format | Journal article |
| id | oxford-uuid:db243999-1916-414e-b96b-da23533ebe1f |
| institution | University of Oxford |
| last_indexed | 2024-03-07T05:09:41Z |
| publishDate | 2018 |
| publisher | Oxford University Press |
| record_format | dspace |
| spelling | oxford-uuid:db243999-1916-414e-b96b-da23533ebe1f2022-03-27T09:08:22ZMulti-time-scale X-ray reverberation mapping of accreting black holesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:db243999-1916-414e-b96b-da23533ebe1fSymplectic Elements at OxfordOxford University Press2018Mastroserio, GIngram, Avan der Klis, MAccreting black holes show characteristic reflection features in their X-ray spectrum, including an iron Kα line, resulting from hard X-ray continuum photons illuminating the accretion disc. The reverberation lag resulting from the path-length difference between direct and reflected emission provides a powerful tool to probe the innermost regions around both stellar-mass and supermassive black holes. Here, we present for the first time a reverberation mapping formalism that enables modelling of energy-dependent time lags and variability amplitude for a wide range of variability time-scales, taking the complete information of the cross-spectrum into account. We use a pivoting power-law model to account for the spectral variability of the continuum that dominates over the reverberation lags for longer time-scale variability. We use an analytic approximation to self-consistently account for the non-linear effects caused by this continuum spectral variability, which have been ignored by all previous reverberation studies. We find that ignoring these non-linear effects can bias measurements of the reverberation lags, particularly at low frequencies. Since our model is analytic, we are able to fit simultaneously for a wide range of Fourier frequencies without prohibitive computational expense. We also introduce a formalism of fitting to real and imaginary parts of our cross-spectrum statistic, which naturally avoids some mistakes/inaccuracies previously common in the literature. We perform proof-of-principle fits to Rossi X-ray Timing Explorer data of Cygnus X-1. |
| spellingShingle | Mastroserio, G Ingram, A van der Klis, M Multi-time-scale X-ray reverberation mapping of accreting black holes |
| title | Multi-time-scale X-ray reverberation mapping of accreting black holes |
| title_full | Multi-time-scale X-ray reverberation mapping of accreting black holes |
| title_fullStr | Multi-time-scale X-ray reverberation mapping of accreting black holes |
| title_full_unstemmed | Multi-time-scale X-ray reverberation mapping of accreting black holes |
| title_short | Multi-time-scale X-ray reverberation mapping of accreting black holes |
| title_sort | multi time scale x ray reverberation mapping of accreting black holes |
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