학술논문
Rapid X-ray Variability in Mkn 421 during a Multiwavelength Campaign
Document Type
Working Paper
Author
Markowitz, Alex G.; Nalewajko, Krzysztof; Bhatta, Gopal; Dewangan, Gulab C.; Chandra, Sunil; Dorner, Daniela; Schleicher, Bernd; Pajdosz-Smierciak, Urszula; Stawarz, Lukasz; Zola, Staszek; Ostrowski, Michal; Carosati, Daniele; Krishnan, Saikruba; Bachev, Rumen; Benitez, Erika; Gazeas, Kosmas; Hiriart, David; Hu, Shao-Ming; Larionov, Valeri; Marchini, Alessandro; Matsumoto, Katsura; Nikiforova, A. A.; Pursimo, Tapio; Raiteri, Claudia M.; Reichart, Daniel E.; Rodriguez, Diego; Semkov, Evgeni; Strigachev, Anton; Sugiura, Yuki; Villata, Massimo; Webb, James R.; Arbet-Engels, Axel; Baack, Dominik; Balbo, Matteo; Biland, Adrian; Bretz, Thomas; Buss, Jens; Eisenberger, Laura; Elsaesser, Dominik; Hildebrand, Dorothee; Iotov, Roman; Kalenski, Adelina; Mannheim, Karl; Mitchell, Alison; Neise, Dominik; Noethe, Maximilian; Paravac, Aleksander; Rhode, Wolfgang; Sliusar, Vitalii; Walter, Roland
Source
Monthly Notices of the Royal Astronomical Society, 2022, Volume 513, Issue 2, pp.1662-1679
Subject
Language
Abstract
The study of short-term variability properties in AGN jets has the potential to shed light on their particle acceleration and emission mechanisms. We report results from a four-day coordinated multi-wavelength campaign on the highly-peaked blazar (HBL) Mkn 421 in 2019 January. We obtained X-ray data from AstroSAT, BVRI photometry with the Whole Earth Blazar Telescope (WEBT), and TeV data from FACT to explore short-term multi-wavelength variability in this HBL. The X-ray continuum is rapidly variable on time-scales of tens of ks. Fractional variability amplitude increases with energy across the synchrotron hump, consistent with previous studies; we interpret this observation in the context of a model with multiple cells whose emission spectra contain cutoffs that follow a power-law distribution. We also performed time-averaged and time-resolved (time-scales of 6 ks) spectral fits; a broken power-law model fits all spectra well; time-resolved spectral fitting reveals the usual hardening when brightening behaviour. Intra-X-ray cross correlations yield evidence for the 0.6-0.8 keV band to likely lead the other bands by an average of 4.6 +- 2.6 ks, but only during the first half of the observation. The source displayed minimal night-to-night variability at all wavebands thus precluding significant interband correlations during our campaign. The broadband SED is modeled well with a standard one-zone leptonic model, yielding jet parameters consistent with those obtained from previous SEDs of this source.
Comment: This article has been accepted for publication in The Monthly Notices of the Royal Astronomical Society (2022), and is published in Volume 513, Issue 2, pp.1662-1679. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. 19 pages; 12 figures
Comment: This article has been accepted for publication in The Monthly Notices of the Royal Astronomical Society (2022), and is published in Volume 513, Issue 2, pp.1662-1679. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. 19 pages; 12 figures