Utilizza questo identificativo per citare o creare un link a questo documento:
http://hdl.handle.net/20.500.12386/28420
Campo DC | Valore | Lingua |
---|---|---|
dc.contributor.author | Kapanadze, B. | en_US |
dc.contributor.author | VERCELLONE, STEFANO | en_US |
dc.contributor.author | ROMANO, Patrizia | en_US |
dc.contributor.author | Hughes, P. | en_US |
dc.contributor.author | Aller, M. | en_US |
dc.contributor.author | Aller, H. | en_US |
dc.contributor.author | Kharshiladze, O. | en_US |
dc.contributor.author | Tabagari, L. | en_US |
dc.date.accessioned | 2020-11-18T14:54:17Z | - |
dc.date.available | 2020-11-18T14:54:17Z | - |
dc.date.issued | 2018 | en_US |
dc.identifier.issn | 0004-637X | en_US |
dc.identifier.uri | http://hdl.handle.net/20.500.12386/28420 | - |
dc.description.abstract | We present the results from a detailed spectral and timing study of Mrk 421 based on the rich archival Swift data obtained during 2009-2012. Best fits of the 0.3-10 keV spectra were mostly obtained using the log-parabolic model showing the relatively low spectral curvature that is expected in the case of efficient stochastic acceleration of particles. The position of the synchrotron spectral energy density peak E <SUB>p</SUB> of 173 spectra is found at energies higher than 2 keV. The photon index at 1 keV exhibited a very broad range of values a = 1.51-3.02, and very hard spectra with a < 1.7 were observed during the strong X-ray flares, hinting at a possible hadronic jet component. The spectral parameters varied on diverse timescales and showed a correlation in some periods, which is expected in the case of first- and second-order Fermi acceleration. The 0.3-10 keV flux showed strong X-ray flaring activity by a factor of 3-17 on timescales of a few days-weeks between the lowest historical state and that corresponding to a rate higher than 100 cts s<SUP>-1</SUP>. Moreover, 113 instances of intraday variability were revealed, exhibiting shortest flux-doubling/halving times of about 1.2 hr, as well as brightenings by 7%-24% in 180-720 s and declines by 68%-22% in 180-900 s. The X-ray and very high-energy fluxes generally showed a correlated variability, although one incidence of a more complicated variability was also detected, indicating that the multifrequency emission of Mrk 421 could not be generated in a single zone. | en_US |
dc.language.iso | eng | en_US |
dc.title | Swift Observations of Mrk 421 in Selected Epochs. II. An Extreme Spectral Flux Variability in 2009-2012 | en_US |
dc.type | Article | - |
dc.identifier.doi | 10.3847/1538-4357/aabbac | en_US |
dc.identifier.scopus | 2-s2.0-85044287513 | en_US |
dc.identifier.isi | 000431683700002 | en_US |
dc.identifier.url | https://iopscience.iop.org/article/10.3847/1538-4357/aabbac | en_US |
dc.relation.medium | STAMPA | en_US |
dc.relation.volume | 858 | en_US |
dc.relation.issue | 2 | en_US |
dc.relation.firstpage | 68 | en_US |
dc.relation.numberofpages | 26 | en_US |
dc.type.referee | REF_1 | en_US |
dc.description.international | sì | en_US |
dc.contributor.country | ITA | en_US |
dc.relation.scientificsector | FIS/05 - ASTRONOMIA E ASTROFISICA | en_US |
dc.relation.journal | THE ASTROPHYSICAL JOURNAL | en_US |
dc.type.miur | 262 Articolo in rivista | - |
dc.identifier.adsbibcode | 2018ApJ...858...68K | en_US |
dc.description.apc | no | en_US |
dc.description.oa | 1 – prodotto con file in versione Open Access (allegare il file al passo 5-Carica) | en_US |
item.openairecristype | http://purl.org/coar/resource_type/c_18cf | - |
item.openairetype | Article | - |
item.languageiso639-1 | en | - |
item.cerifentitytype | Publications | - |
item.grantfulltext | open | - |
item.fulltext | With Fulltext | - |
crisitem.author.dept | O.A. Brera | - |
crisitem.author.dept | O.A. Brera | - |
crisitem.author.orcid | 0000-0003-1163-1396 | - |
crisitem.author.orcid | 0000-0003-0258-7469 | - |
crisitem.journal.journalissn | 0004-637X | - |
crisitem.journal.ance | E016252 | - |
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