Rapid Variability of Mrk 421 During Extreme Flaring as Seen Through the Eyes of XMM-Newton
2024
Online
report
Zugriff:
By studying the variability of blazars across the electromagnetic spectrum, it is possible to resolve the underlying processes responsible for rapid flux increases, so-called flares. We report on an extremely bright X-ray flare in the high-peaked BL Lacertae object Mrk 421 that occurred simultaneously with enhanced $\gamma$-ray activity detected at very high energies (VHE) by FACT on 2019 June 9. We triggered an observation with XMM-Newton, which observed the source quasi-continuously for 25 hours. We find that the source was in the brightest state ever observed using XMM-Newton, reaching a flux of $2.8\times10^{-9}$ erg cm$^{-2}$ s$^{-1}$ over an energy range of 0.3 - 10 keV. We perform a spectral and timing analysis to reveal the mechanisms of particle acceleration and to search for the shortest source-intrinsic time scales. Mrk 421 exhibits the typical harder-when-brighter behaviour throughout the observation and shows a clock-wise hysteresis pattern, which indicates that the cooling dominates over the acceleration process. While the X-ray emission in different sub-bands is highly correlated, we can exclude large time lags as the computed zDCFs are consistent with a zero lag. We find rapid variability on time scales of 1 ks for the 0.3 - 10 keV band and down to 300s in the hard X-ray band (4 - 10 keV). Taking these time scales into account, we discuss different models to explain the observed X-ray flare, and find that a plasmoid-dominated magnetic reconnection process is able to describe our observation best.
Comment: 13 pages, 7 figures, accepted for publication in MNRAS
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Rapid Variability of Mrk 421 During Extreme Flaring as Seen Through the Eyes of XMM-Newton
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Autor/in / Beteiligte Person: | Gokus, A. ; Wilms, J. ; Kadler, M. ; Dorner, D. ; Nowak, M. A. ; Kreikenbohm, A. ; Leiter, K. ; Bretz, T. ; Schleicher, B. ; Markowitz, A. G. ; Pottschmidt, K. ; Mannheim, K. ; Kreykenbohm, I. ; Langejahn, M. ; McBride, F. ; Beuchert, T. ; Dauser, T. ; Kreter, M. ; Abhir, J. ; Baack, D. ; Balbo, M. ; Biland, A. ; Brand, K. ; Buss, J. ; Eisenberger, L. ; Elsaesser, D. ; Guenther, P. ; Hildebrand, D. ; Linhoff, M. ; Paravac, A. ; Rhode, W. ; Sliusar, V. ; Hasan, S. ; Walter, R. |
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Veröffentlichung: | 2024 |
Medientyp: | report |
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