{"paper":{"title":"Rapid Variability of Mrk 421 During Extreme Flaring as Seen Through the Eyes of XMM-Newton","license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.HE","authors_text":"A. Biland, A. G. Markowitz, A. Gokus, A. Kreikenbohm, A. Paravac, B. Schleicher, D. Baack, D. Dorner, D. Elsaesser, D. Hildebrand, F. McBride, I. Kreykenbohm, J. Abhir, J. Buss, J. Wilms, K. Brand, K. Leiter, K. Mannheim, K. Pottschmidt, L. Eisenberger, M. A. Nowak, M. Balbo, M. Kadler, M. Kreter, M. Langejahn, M. Linhoff, P. Guenther, R. Walter, S. Hasan, T. Beuchert, T. Bretz, T. Dauser, V. Sliusar, W. Rhode","submitted_at":"2024-02-29T17:27:05Z","abstract_excerpt":"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 fl"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2402.19377","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2402.19377/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}