Speaker
Description
Blazars are one of the prime objects to be studied in the current multi-messenger era. However, even though they have been studied for decades, the underlying emission mechanisms are far from understood. In 2022, IXPE announced the first detection of X-ray polarization in blazars, which opened a new window for probing acceleration and radiation processes.
In this contribution, we put the first IXPE observations of the two blazars Mrk 501 and Mrk 421 in a multiwavelength context, including data from the radio regime up to the very-high-energy (>0.2 TeV, VHE) γ-rays. We investigate the X-ray polarization evolution, and compare it, for the first time, with the behavior in the VHE band. For Mrk 501, we find clear evidence for an extreme emission state in March 2022 with a synchrotron component peaking above 1 keV. Additional NuSTAR data allows us to accurately characterize the component and evaluate the underlying electron population. While the X-ray emission is harder and brighter than usual, the VHE data reveals a far lower inverse-Compton dominance than usual. Mrk 421 shows a variety of emission states during 2022, which allows to investigate multi-band correlations around the IXPE observations. For one IXPE night, significant flux variations are seen on an hourly time scale in the hard X-rays by NuSTAR, which we use to access information about the acceleration and cooling processes in the source exploiting hysteresis patterns.
| Submitted on behalf of a Collaboration? | Yes |
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