Long-term monitor of Mrk 421 TeV emission using ARGO-YBJ experiment

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Abstract

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 monitors continuously 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 November 2007 to February 2010. Meanwhile, this source was observed by the satellite-borne experiments RXTE and Swift in the X-ray band. Mrk 421 was very active especially 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 longer than 1 day between the X-ray and gamma-ray photons is found. The evolution of the spectral energy distribution is investigated by measuring 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.

Autore Pugliese

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  • 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’Alı 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

Titolo volume/Rivista

THE ASTROPHYSICAL JOURNAL

Anno di pubblicazione

2011

ISSN

0004-637X

ISBN

Non Disponibile

Numero di citazioni Wos

46

Ultimo Aggiornamento Citazioni

28/04/2018

Numero di citazioni Scopus

62

Ultimo Aggiornamento Citazioni

28/04/2018

Settori ERC

Non Disponibile

Codici ASJC

Non Disponibile