X-ray polarization measurement of the gold standard of radio-quiet active galactic nuclei: NGC 1068
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F24%3A00598914" target="_blank" >RIV/67985815:_____/24:00598914 - isvavai.cz</a>
Result on the web
<a href="https://hdl.handle.net/11104/0356486" target="_blank" >https://hdl.handle.net/11104/0356486</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1051/0004-6361/202449760" target="_blank" >10.1051/0004-6361/202449760</a>
Alternative languages
Result language
angličtina
Original language name
X-ray polarization measurement of the gold standard of radio-quiet active galactic nuclei: NGC 1068
Original language description
NGC 1068 is the most observed radio-quiet active galactic nucleus (AGN) in polarimetry, yet its high-energy polarization has never been probed before due to a lack of dedicated polarimeters. Aims. Using the first X-ray polarimeter sensitive enough to measure the polarization of AGNs, we want to probe the orientation and geometric arrangement of (sub)parsec-scale matter around the X-ray source. Methods. We used the Imaging X-ray Polarimetry Explorer (IXPE) satellite to measure, for the first time, the 2- 8 keV polarization of NGC 1068. We pointed IXPE at the target for a net exposure time of 1.15 Ms, in addition to using two Chandra snapshots of ∼10 ks each in order to account for the potential impact of several ultraluminous X-ray sources (ULXs) within IXPE's field of view. Results. We measured a 2- 8 keV polarization degree of 12.4% ± 3.6% and an electric vector polarization angle of 101 ± 8 at a 68% confidence level. If we exclude the spectral region containing bright Fe K lines and other soft X-ray lines where depolarization occurs, the polarization fraction rises to 21.3% ± 6.7% in the 3.5- 6.0 keV band, with a similar polarization angle. The observed polarization angle is found to be perpendicular to the parsec-scale radio jet. Using a combined Chandra and IXPE analysis plus multiwavelength constraints, we estimated that the circumnuclear 'torus' may sustain a half-opening angle of 50- 55 (from the vertical axis of the system). Conclusions. Thanks to IXPE, we have measured the X-ray polarization of NGC 1068 and found comparable results, both in terms of the polarization angle orientation with respect to the radio jet and the torus half-opening angle, to the X-ray polarimetric measurement achieved for the other archetypal Compton-thick AGN: the Circinus galaxy. Probing the geometric arrangement of parsec-scale matter in extragalactic objects is now feasible thanks to X-ray polarimetry.
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
2024
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Astronomy & Astrophysics
ISSN
0004-6361
e-ISSN
1432-0746
Volume of the periodical
689
Issue of the periodical within the volume
Sept.
Country of publishing house
FR - FRANCE
Number of pages
11
Pages from-to
A238
UT code for WoS article
001349887500001
EID of the result in the Scopus database
2-s2.0-85198637593