THE VIOLENT HARD X-RAY VARIABILITY OF MRK 421 OBSERVED BYNuSTARIN 2013 APRIL
| العنوان: | THE VIOLENT HARD X-RAY VARIABILITY OF MRK 421 OBSERVED BYNuSTARIN 2013 APRIL |
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| المؤلفون: | Vaidehi S. Paliya, Markus Böttcher, Sunder Sahayanathan, C. D. Ravikumar, C. Diltz, C. S. Stalin |
| المساهمون: | 24420530 - Böttcher, Markus |
| المصدر: | The Astrophysical Journal. 811:143 |
| بيانات النشر: | American Astronomical Society, 2015. |
| سنة النشر: | 2015 |
| مصطلحات موضوعية: | High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Magnetic energy, Event horizon, Astrophysics::High Energy Astrophysical Phenomena, jets [galaxies], FOS: Physical sciences, Astronomy and Astrophysics, Field strength, Astrophysics, Synchrotron, galaxies [X-rays], law.invention, Black hole, Telescope, symbols.namesake, Space and Planetary Science, law, active [galaxies], symbols, Astrophysics - High Energy Astrophysical Phenomena, Blazar, Doppler effect, individual (Mrk 421) [quasars] |
| الوصف: | The well studied blazar Markarian 421 (Mrk 421, $z$=0.031) was the subject of an intensive multi-wavelength campaign when it flared in 2013 April. The recorded X-ray and very high energy (VHE, E$>$100 GeV) $\gamma$-ray fluxes are the highest ever measured from this object. At the peak of the activity, it was monitored by the hard X-ray focusing telescope {\it Nuclear Spectroscopic Telescope Array} ({\it NuSTAR}) and {\it Swift} X-Ray Telescope (XRT). In this work, we present a detailed variability analysis of {\it NuSTAR} and {\it Swift}-XRT observations of Mrk 421 during this flaring episode. We obtained the shortest flux doubling time of 14.01$\pm$5.03 minutes, which is the shortest hard X-ray (3$-$79 keV) variability ever recorded from Mrk 421 and is on the order of the light crossing time of the black hole's event horizon. A pattern of extremely fast variability events superposed on slowly varying flares is found in most of the {\it NuSTAR} observations. We suggest that these peculiar variability patterns may be explained by magnetic energy dissipation and reconnection in a fast moving compact emission region within the jet. Based on the fast variability, we derive a lower limit on the magnetic field strength of $B \ge 0.73 \delta_1^{-2/3} \, \nu_{19}^{1/3}$~G, where $\delta_1$ is the Doppler factor in units of 10, and $\nu_{19}$ is the characteristic X-ray synchrotron frequency in units of $10^{19}$~Hz. Comment: 23 pages, 5 figures, 2 tables, to appear in the Astrophysical Journal |
| تدمد: | 1538-4357 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f13bde9937a9624c9666e1160a4ef071 https://doi.org/10.1088/0004-637x/811/2/143 |
| حقوق: | OPEN |
| رقم الأكسشن: | edsair.doi.dedup.....f13bde9937a9624c9666e1160a4ef071 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 15384357 |
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