Long-term monitoring of the TeV emission from Mrk 421 with the ARGO-YBJ experiment

6533b7d6fe1ef96bd1265b82

RESEARCH PRODUCT

Long-term monitoring of the TeV emission from Mrk 421 with the ARGO-YBJ experiment

The Argo-ybj Collaboration B. Bartoli P. Bernardini X. J. Bi C. Bleve I. Bolognino P. Branchini A. Budano A. K. Calabrese Melcarne P. Camarri Z. Cao A. Cappa R. Cardarelli S. Catalanotti C. Cattaneo P. Celio S. Z. Chen T. L. Chen Y. Chen P. Creti S. W. Cui B. Z. Dai G. D'alí Staiti Danzengluobu M. Dattoli I. De Mitri B. D'ettorre Piazzoli T. Di Girolamo X. H. Ding G. Di Sciascio C. F. Feng Zhaoyang Feng Zhenyong Feng F. Galeazzi P. Galeotti E. Giroletti Q. B. Gou Y. Q. Guo H. H. He Haibing Hu Hongbo Hu Q. Huang M. Iacovacci R. Iuppa I. James H. Y. Jia Labaciren H. J. Li J. Y. Li X. X. Li G. Liguori C. Liu C. Q. Liu J. Liu M. Y. Liu H. Lu X. H. Ma G. Mancarella S. M. Mari G. Marsella D. Martello S. Mastroianni P. Montini C. C. Ning A. Pagliaro M. Panareo B. Panico L. Perrone P. Pistilli X. B. Qu E. Rossi F. Ruggieri P. Salvini R. Santonico P. R. Shen X. D. Sheng F. Shi C. Stanescu A. Surdo Y. H. Tan P. Vallania S. Vernetto C. Vigorito B. Wang H. Wang C. Y. Wu H. R. Wu B. Xu L. Xue Y. X. Yan Q. Y. Yang X. C. Yang Z. G. Yao A. F. Yuan M. Zha H. M. Zhang Jilong Zhang Jianli Zhang L. Zhang P. Zhang X. Y. Zhang Y. Zhang Zhaxiciren Zhaxisangzhu X. X. Zhou F. R. Zhu Q. Q. Zhu G. Zizzi

subject

media_common.quotation_subject Astrophysics::High Energy Astrophysical Phenomena Oggetti di tipo BL Lacertae FOS: Physical sciences Flux Astrophysics 01 natural sciences 7. Clean energy individual (Markarian 421) [BL Lacertae objects]Spectral line Gamma-rays Markarian 421 BL Lacertae Resistive Plate Chambers law.invention law 0103 physical sciences Radiative transfer 010303 astronomy & astrophysics media_common High Energy Astrophysical Phenomena (astro-ph.HE)Physics 010308 nuclear & particles physics Markarian 421 Settore FIS/01 - Fisica Sperimentale Astronomy and Astrophysics general [gamma ray]Synchrotron 3. Good health Air shower 13. Climate action Space and Planetary Science Duty cycle Sky Raggi gamma Spectral energy distribution Astrophysics - High Energy Astrophysical Phenomena

description

ARGO-YBJ is an air shower detector array with a fully covered layer of resistive plate chambers. It is operated with a high duty cycle and a large field of view. It continuously monitors the northern sky at energies above 0.3 TeV. In this paper, we report a long-term monitoring of Mrk 421 over the period from 2007 November to 2010 February. This source was observed by the satellite-borne experiments Rossi X-ray Timing Explorer and Swift in the X-ray band. Mrk 421 was especially active in the first half of 2008. Many flares are observed in both X-ray and gamma-ray bands simultaneously. The gamma-ray flux observed by ARGO-YBJ has a clear correlation with the X-ray flux. No lag between the X-ray and gamma-ray photons longer than 1 day is found. The evolution of the spectral energy distribution is investigated by measuring spectral indices at four different flux levels. Hardening of the spectra is observed in both X-ray and gamma-ray bands. The gamma-ray flux increases quadratically with the simultaneously measured X-ray flux. All these observational results strongly favor the synchrotron self-Compton process as the underlying radiative mechanism.

year	journal	country	edition	language
2011-06-05

10.1088/0004-637x/734/2/110 http://arxiv.org/abs/1106.0896