Maksym, W Peter;
Liodakis, Ioannis;
Saade, M Lynne;
Kim, Dawoon E;
Middei, Riccardo;
Di Gesu, Laura;
Kiehlmann, Sebastian;
... Zane, Silvia; + view all
(2025)
A Two-week IXPE Monitoring Campaign on Mrk 421.
The Astrophysical Journal
, 986
(2)
, Article 230. 10.3847/1538-4357/adce6b.
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Abstract
X-ray polarization is a unique new probe of the particle acceleration in astrophysical jets made possible through the Imaging X-ray Polarimetry Explorer. Here we report on the first dense X-ray polarization monitoring campaign on the blazar Mrk 421. Our observations were accompanied by an even denser radio and optical polarization campaign. We find significant short-timescale variability in both X-ray polarization degree and angle, including an ∼90° angle rotation about the jet axis. We attribute this to random variations of the magnetic field, consistent with the presence of turbulence but also unlikely to be explained by turbulence alone. At the same time, the degree of lower-energy polarization is significantly lower and shows no more than mild variability. Our campaign provides further evidence for a scenario in which energy-stratified shock-acceleration of relativistic electrons, combined with a turbulent magnetic field, is responsible for optical to X-ray synchrotron emission in blazar jets.
| Type: | Article |
|---|---|
| Title: | A Two-week IXPE Monitoring Campaign on Mrk 421 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3847/1538-4357/adce6b |
| Publisher version: | https://doi.org/10.3847/1538-4357/adce6b |
| Language: | English |
| Additional information: | This work is licensed under a Creative Commons License. The images or other third-party material in this article are included in the Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
| Keywords: | Science & Technology, Physical Sciences, Astronomy & Astrophysics, X-RAY-POLARIZATION, PARSEC-SCALE JETS, OPTICAL POLARIZATION, BL LACERTAE, PARTICLE-ACCELERATION, INNER JET, BLAZARS, POLARIMETRY, ROBOPOL, MULTIWAVELENGTH |
| 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/10219071 |
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