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Tracking the X-Ray ...
Tracking the X-Ray Polarization of the Black Hole Transient Swift J1727.8-1613 during a State Transition
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- Ingram, Adam (author)
- School of Mathematics, Statistics, and Physics, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK;
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- Veledina, Alexandra, 1987- (author)
- KTH,Nordic Institute for Theoretical Physics NORDITA,Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland; Nordita, Stockholm University
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- Xie, Fei (author)
- INAF Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, 00133 Roma, Italy, Via del Fosso del Cavaliere 100
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(creator_code:org_t)
- American Astronomical Society, 2024
- 2024
- English.
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In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 968:2
- Related links:
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https://doi.org/10.3...
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show more...
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https://urn.kb.se/re...
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https://doi.org/10.3...
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Abstract
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- We report on an observational campaign on the bright black hole (BH) X-ray binary Swift J1727.8-1613 centered around five observations by the Imaging X-ray Polarimetry Explorer. These observations track for the first time the evolution of the X-ray polarization of a BH X-ray binary across a hard to soft state transition. The 2-8 keV polarization degree decreased from ∼4% to ∼3% across the five observations, but the polarization angle remained oriented in the north-south direction throughout. Based on observations with the Australia Telescope Compact Array, we find that the intrinsic 7.25 GHz radio polarization aligns with the X-ray polarization. Assuming the radio polarization aligns with the jet direction (which can be tested in the future with higher-spatial-resolution images of the jet), our results imply that the X-ray corona is extended in the disk plane, rather than along the jet axis, for the entire hard intermediate state. This in turn implies that the long (≳10 ms) soft lags that we measure with the Neutron star Interior Composition ExploreR are dominated by processes other than pure light-crossing delays. Moreover, we find that the evolution of the soft lag amplitude with spectral state does not follow the trend seen for other sources, implying that Swift J1727.8-1613 is a member of a hitherto undersampled subpopulation.
Subject headings
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
Publication and Content Type
- ref (subject category)
- art (subject category)
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