Extreme HBL behavior of Markarian 501 during 2012

doi:10.1051/0004-6361/201833704

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	Extreme HBL behavior of Markarian 501 during 2012
	Arbet-Engels, A.3; Baack, D.22; Balbo, M.43; Biland, A.3; Blank, M.23; Bretz, T.3,44; Bruegge, K.22; Bulinski, M.22; Buss, J.22; Dmytriiev, A.43
刊名	ASTRONOMY & ASTROPHYSICS
	2018-12-14
卷号	620 页码:23
关键词	astroparticle physics acceleration of particles radiation mechanisms: non-thermal BL Lacertae objects: general BL Lacertae objects: individual: Mrk501
ISSN号	1432-0746
DOI	10.1051/0004-6361/201833704
产权排序	64
英文摘要	Aims. We aim to characterize the multiwavelength emission from Markarian 501 (Mrk 501), quantify the energy-dependent variability, study the potential multiband correlations, and describe the temporal evolution of the broadband emission within leptonic theoretical scenarios. Methods. We organized a multiwavelength campaign to take place between March and July of 2012. Excellent temporal coverage was obtained with more than 25 instruments, including the MAGIC, FACT and VERITAS Cherenkov telescopes, the instruments on board the Swift and Fermi spacecraft, and the telescopes operated by the GASP-WEBT collaboration. Results. Mrk 501 showed a very high energy (VHE) gamma-ray flux above 0.2 TeV of similar to 0.5 times the Crab Nebula flux (CU) for most of the campaign. The highest activity occurred on 2012 June 9, when the VHE flux was similar to 3 CU, and the peak of the high-energy spectral component was found to be at similar to 2 TeV. Both the X-ray and VHE gamma-ray spectral slopes were measured to be extremely hard, with spectral indices <2 during most of the observing campaign, regardless of the X-ray and VHE flux. This study reports the hardest Mrk 501 VHE spectra measured to date. The fractional variability was found to increase with energy, with the highest variability occurring at VHE. Using the complete data set, we found correlation between the X-ray and VHE bands; however, if the June 9 flare is excluded, the correlation disappears (significance <3 sigma) despite the existence of substantial variability in the X-ray and VHE bands throughout the campaign. Conclusions. The unprecedentedly hard X-ray and VHE spectra measured imply that their low- and high-energy components peaked above 5 keV and 0.5 TeV, respectively, during a large fraction of the observing campaign, and hence that Mrk 501 behaved like an extreme high-frequency-peaked blazar (EHBL) throughout the 2012 observing season. This suggests that being an EHBL may not be a permanent characteristic of a blazar, but rather a state which may change over time. The data set acquired shows that the broadband spectral energy distribution (SED) of Mrk 501, and its transient evolution, is very complex, requiring, within the framework of synchrotron self-Compton (SSC) models, various emission regions for a satisfactory description. Nevertheless the one-zone SSC scenario can successfully describe the segments of the SED where most energy is emitted, with a significant correlation between the electron energy density and the VHE gamma-ray activity, suggesting that most of the variability may be explained by the injection of high-energy electrons. The one-zone SSC scenario used reproduces the behavior seen between the measured X-ray and VHE gamma-ray fluxes, and predicts that the correlation becomes stronger with increasing energy of the X-rays.
资助项目	National Aeronautics and Space Administration ; German BMBF ; MPG ; Italian INFN ; INAF ; Swiss National Fund SNF ; ERDF under the Spanish MINECO[FPA2015-69818-P] ; ERDF under the Spanish MINECO[FPA2012-36668] ; ERDF under the Spanish MINECO[FPA2015-68378-P] ; ERDF under the Spanish MINECO[FPA2015-69210-C6-2-R] ; ERDF under the Spanish MINECO[FPA2015-69210-C6-4-R] ; ERDF under the Spanish MINECO[FPA2015-69210-C6-6-R] ; ERDF under the Spanish MINECO[AYA2015-71042-P] ; ERDF under the Spanish MINECO[AYA2016-76012-C3-1-P] ; ERDF under the Spanish MINECO[ESP2015-71662-C2-2-P] ; ERDF under the Spanish MINECO[CSD2009-00064] ; Japanese JSPS ; MEXT ; Spanish Centro de Excelencia Severo Ochoa[SEV-2012-0234] ; Spanish Centro de Excelencia Severo Ochoa[SEV-2015-0548] ; Unidad de Excelencia Maria de Maeztu[MDM-2014-0369] ; Croatian Science Foundation (HrZZ)[09/176] ; University of Rijeka Project[13.12.1.3.02] ; DFG Collaborative Research Centers[SFB823/C4] ; DFG Collaborative Research Centers[SFB876/C3] ; Polish National Research Centre[UMO-2016/22/M/ST9/00382] ; Brazilian MCTIC ; CNPq ; FAPERJ ; U.S. Department of Energy Office of Science ; U.S. National Science Foundation ; Smithsonian Institution ; NSERC in Canada ; DOE[DE-AC02-76SF00515] ; Russian Science Foundation[17-12-01029] ; Shota Rustaveli NSF[FR/577/6-320/13] ; Bulgarian National Science Fund of the Ministry of Education and Science[DN 08-1/2016] ; Bulgarian National Science Fund of the Ministry of Education and Science[DN 18-13/2017] ; UK Science and Technology Facilities Council ; Fermi Guest Investigator grants[NNX09AU10G] ; Fermi Guest Investigator grants[NNX12AO93G] ; NASA[NNX08AW31G] ; NASA[NNX11A043G] ; NASA[NNX14AQ89G] ; NSF[AST-0808050] ; NSF[AST-1109911] ; [PRIN-SKA-CTA-INAF2016]
WOS关键词	EXTRAGALACTIC BACKGROUND LIGHT ; ACTIVE GALACTIC NUCLEI ; GAMMA-RAY EMISSION ; BL-LAC OBJECTS ; X-RAY ; MULTIWAVELENGTH OBSERVATIONS ; TEV BLAZARS ; 3C 454.3 ; ENERGY ; VARIABILITY
WOS研究方向	Astronomy & Astrophysics
语种	英语
出版者	EDP SCIENCES S A
WOS记录号	WOS:000453301200012
内容类型	期刊论文
源URL	[http://ir.xao.ac.cn/handle/45760611-7/2361]
专题	新疆天文台_其它
通讯作者	Shukla, A.; Hughes, G.; Paneque, D.
作者单位	1.Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA 2.Natl Inst Astrophys INAF, I-00136 Rome, Italy 3.Swiss Fed Inst Technol, CH-8093 Zurich, Switzerland 4.Univ Udine, I-33100 Udine, Italy 5.INFN Trieste, I-33100 Udine, Italy 6.Univ Padua, I-35131 Padua, Italy 7.INFN, I-35131 Padua, Italy 8.Univ Rijeka, Croatian MAGIC Consortium, Rijeka 51000, Croatia 9.Univ Split, FESB, Split 21000, Croatia 10.Univ Zagreb, FER, Zagreb 10000, Croatia
推荐引用方式 GB/T 7714	Arbet-Engels, A.,Baack, D.,Balbo, M.,et al. Extreme HBL behavior of Markarian 501 during 2012[J]. ASTRONOMY & ASTROPHYSICS,2018,620:23.
APA	Arbet-Engels, A..,Baack, D..,Balbo, M..,Biland, A..,Blank, M..,...&Zaric, D..(2018).Extreme HBL behavior of Markarian 501 during 2012.ASTRONOMY & ASTROPHYSICS,620,23.
MLA	Arbet-Engels, A.,et al."Extreme HBL behavior of Markarian 501 during 2012".ASTRONOMY & ASTROPHYSICS 620(2018):23.