Rodriguez Cavero, Nicole;
Marra, Lorenzo;
Krawczynski, Henric;
Dovčiak, Michal;
Bianchi, Stefano;
Steiner, James F.;
Svoboda, Jiri;
... et al, .; + view all
(2023)
The First X-ray Polarization Observation of the Black Hole X-ray Binary 4U 1630–47 in the Steep Power Law State.
The Astrophysical Journal Letters
, 958
(1)
, Article L8. 10.3847/2041-8213/acfd2c.
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Abstract
The Imaging X-ray Polarimetry Explorer (IXPE) observed the black hole X-ray binary 4U 1630–47 in the steep power-law (or very high) state. The observations reveal a linear polarization degree of the 2–8 keV X-rays of 6.8% ± 0.2% at a position angle of 21fdg3 ± 0fdg9 east of north (all errors at 1σ confidence level). Whereas the polarization degree increases with energy, the polarization angle stays constant within the accuracy of our measurements. We compare the polarization of the source in the steep power-law state with the previous IXPE measurement of the source in the high soft state. We find that, even though the source flux and spectral shape are significantly different between the high soft state and the steep power-law state, their polarization signatures are similar. Assuming that the polarization of both the thermal and power-law emission components are constant over time, we estimate the power-law component polarization to be 6.8%–7.0% and note that the polarization angle of the thermal and power-law components must be approximately aligned. We discuss the implications for the origin of the power-law component and the properties of the emitting plasma.
| Type: | Article |
|---|---|
| Title: | The First X-ray Polarization Observation of the Black Hole X-ray Binary 4U 1630–47 in the Steep Power Law State |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3847/2041-8213/acfd2c |
| Publisher version: | https://doi.org/10.3847/2041-8213/acfd2c |
| Language: | English |
| Additional information: | Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10177746 |
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