The very high X-ray polarization of accreting black hole IGR J17091-3624 in the hard state
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F25%3A00637872" target="_blank" >RIV/67985815:_____/25:00637872 - isvavai.cz</a>
Result on the web
<a href="https://hdl.handle.net/11104/0368699" target="_blank" >https://hdl.handle.net/11104/0368699</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1093/mnras/staf859" target="_blank" >10.1093/mnras/staf859</a>
Alternative languages
Result language
angličtina
Original language name
The very high X-ray polarization of accreting black hole IGR J17091-3624 in the hard state
Original language description
We report the first detection of the X-ray polarization of the transient black hole X-ray binary IGR J17091-3624 taken with the Imaging X-ray polarimetry Explorer (IXPE) in 2025 March, and present the results of an X-ray spectropolarimetric analysis. The polarization was measured in the 2-8 keV band with 5.2 sigma statistical confidence. We report a polarization degree (PD) of 9.1 +/- 1.6 per cent and a polarization angle of 83 degrees +/- 5 degrees (errors are 1 sigma confidence). There is a hint of a positive correlation of PD with energy that is not statistically significant. We report that the source is in the corona-dominated hard state, which is confirmed by a hard power-law-dominated spectrum with weak reflection features and the presence of a Type-C quasi-periodic oscillation at similar to 0.2 Hz. The orientation of the emitted radio jet is not known, and so we are unable to compare it with the direction of X-ray polarization, but we predict the two to be parallel if the geometry is similar to that in Cygnus X-1 and Swift J1727.8-1613, the two hard state black hole binaries previously observed by IXPE. In the Comptonization scenario, the high observed PD requires a very favourable geometry of the corona, a high inclination angle (supported by the presence of a dip in the light curve) and possibly a mildly relativistic outflow and/or scattering in an optically thick wind.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10308 - Astronomy (including astrophysics,space science)
Result continuities
Project
<a href="/en/project/GX21-06825X" target="_blank" >GX21-06825X: Accreting Black Holes in the new era of X-ray polarimetry missions</a><br>
Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2025
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Monthly Notices of the Royal Astronomical Society
ISSN
0035-8711
e-ISSN
1365-2966
Volume of the periodical
541
Issue of the periodical within the volume
2
Country of publishing house
US - UNITED STATES
Number of pages
8
Pages from-to
1774-1781
UT code for WoS article
001530104300001
EID of the result in the Scopus database
2-s2.0-105011330815