An observational method for fast stochastic X-ray polarimetry timing
The upcoming launch of the first space based X-ray polarimeter in ∼40 yr will provide powerful new diagnostic information to study accreting compact objects. In particular, analysis of rapid variability of the polarization degree and angle will provide the opportunity to probe the relativistic motio...
| Main Authors: | , |
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| Format: | Journal article |
| Language: | English |
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Oxford University Press
2017
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| _version_ | 1797105513298657280 |
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| author | Ingram, AR Maccarone, TJ |
| author_facet | Ingram, AR Maccarone, TJ |
| author_sort | Ingram, AR |
| collection | OXFORD |
| description | The upcoming launch of the first space based X-ray polarimeter in ∼40 yr will provide powerful new diagnostic information to study accreting compact objects. In particular, analysis of rapid variability of the polarization degree and angle will provide the opportunity to probe the relativistic motions of material in the strong gravitational fields close to the compact objects, and enable new methods to measure black hole and neutron star parameters. However, polarization properties are measured in a statistical sense, and a statistically significant polarization detection requires a fairly long exposure, even for the brightest objects. Therefore, the sub-minute time-scales of interest are not accessible using a direct time-resolved analysis of polarization degree and angle. Phase-folding can be used for coherent pulsations, but not for stochastic variability such as quasi-periodic oscillations. Here, we introduce a Fourier method that enables statistically robust detection of stochastic polarization variability for arbitrarily short variability time-scales. Our method is analogous to commonly used spectral-timing techniques. We find that it should be possible in the near future to detect the quasi-periodic swings in polarization angle predicted by Lense-Thirring precession of the inner accretion flow. This is contingent on the mean polarization degree of the source being greater than ∼4–5 per cent, which is consistent with the best current constraints on Cygnus X–1 from the late 1970s. |
| first_indexed | 2024-03-07T06:48:34Z |
| format | Journal article |
| id | oxford-uuid:fbb4dbfb-8a80-4fab-b754-13ac6e68045f |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T06:48:34Z |
| publishDate | 2017 |
| publisher | Oxford University Press |
| record_format | dspace |
| spelling | oxford-uuid:fbb4dbfb-8a80-4fab-b754-13ac6e68045f2022-03-27T13:15:45ZAn observational method for fast stochastic X-ray polarimetry timingJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:fbb4dbfb-8a80-4fab-b754-13ac6e68045fEnglishSymplectic Elements at OxfordOxford University Press2017Ingram, ARMaccarone, TJThe upcoming launch of the first space based X-ray polarimeter in ∼40 yr will provide powerful new diagnostic information to study accreting compact objects. In particular, analysis of rapid variability of the polarization degree and angle will provide the opportunity to probe the relativistic motions of material in the strong gravitational fields close to the compact objects, and enable new methods to measure black hole and neutron star parameters. However, polarization properties are measured in a statistical sense, and a statistically significant polarization detection requires a fairly long exposure, even for the brightest objects. Therefore, the sub-minute time-scales of interest are not accessible using a direct time-resolved analysis of polarization degree and angle. Phase-folding can be used for coherent pulsations, but not for stochastic variability such as quasi-periodic oscillations. Here, we introduce a Fourier method that enables statistically robust detection of stochastic polarization variability for arbitrarily short variability time-scales. Our method is analogous to commonly used spectral-timing techniques. We find that it should be possible in the near future to detect the quasi-periodic swings in polarization angle predicted by Lense-Thirring precession of the inner accretion flow. This is contingent on the mean polarization degree of the source being greater than ∼4–5 per cent, which is consistent with the best current constraints on Cygnus X–1 from the late 1970s. |
| spellingShingle | Ingram, AR Maccarone, TJ An observational method for fast stochastic X-ray polarimetry timing |
| title | An observational method for fast stochastic X-ray polarimetry timing |
| title_full | An observational method for fast stochastic X-ray polarimetry timing |
| title_fullStr | An observational method for fast stochastic X-ray polarimetry timing |
| title_full_unstemmed | An observational method for fast stochastic X-ray polarimetry timing |
| title_short | An observational method for fast stochastic X-ray polarimetry timing |
| title_sort | observational method for fast stochastic x ray polarimetry timing |
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