NICER X-ray Observations Reveal Particle Acceleration Mechanisms in TeV Blazar Mrk 421
Researchers analyzed 45 X-ray observations of the blazar Mrk 421 collected by NASA's NICER telescope between 2022 and 2024, finding a 28-fold increase in X-ray flux and strong variability patterns. The data show that the source exhibits a "harder-when-brighter" trend and that X-ray emission originates from a compact region near the black hole. These findings provide insights into energy-dependent particle acceleration in relativistic jets powered by turbulence and strong magnetic fields.
A new study of the TeV blazar Mrk 421 using NASA's NICER X-ray telescope presents detailed spectral and timing analysis from 45 observations spanning 2022 to 2024. The source displayed dramatic variability, with X-ray flux increasing approximately 28-fold during the observation period, ranging from ~50 to ~1380 counts per second. Spectral modeling revealed that a log-parabolic function best describes the X-ray spectra, and analysis confirmed a "harder-when-brighter" anticorrelation between flux and photon index. The researchers identified multiple correlations between spectral parameters and the synchrotron peak energy, with rapid variability indicating emission from a compact region close to the central engine. Using log-parabolic electron energy distribution models within a synchrotron jet framework, the team simulated the observed anticorrelations and interpreted the results as evidence for energy-dependent particle acceleration driven by turbulence, strong magnetic fields, and relativistic outflows in blazar jets.
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- arXiv astro-phCenter
NICER Perspective on TeV Blazar Mrk~421: X-ray Variability and Particle Acceleration
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