English  |  正體中文  |  简体中文  |  Items with full text/Total items : 78728/78728 (100%)
Visitors : 34368659      Online Users : 2352
RC Version 7.0 © Powered By DSPACE, MIT. Enhanced by NTU Library IR team.
Scope Tips:
  • please add "double quotation mark" for query phrases to get precise results
  • please goto advance search for comprehansive author search
  • Adv. Search
    HomeLoginUploadHelpAboutAdminister Goto mobile version

    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/50924

    Title: The long-lasting activity of 3C 454.3 GASP-WEBT and satellite observations in 2008-2010
    Authors: Raiteri,CM;Villata,M;Aller,MF;Gurwell,MA;Kurtanidze,OM;Lahteenmaki,A;Larionov,VM;Romano,P;Vercellone,S;Agudo,I;Aller,HD;Arkharov,AA;Bach,U;Benitez,E;Berdyugin,A;Blinov,DA;Borisova,EV;Bottcher,M;Calle,OJAB;Buemi,CS;Calcidese,P;Carosati,D;Casas,R;Chen,WP;Efimova,NV;Gomez,JL;Gusbar,C;Hawkins,K;Heidt,J;Hiriart,D;Hsiao,HY;Jordan,B;Jorstad,SG;Joshi,M;Kimeridze,GN;Koptelova,E;Konstantinova,TS;Kopatskaya,EN;Kurtanidze,SO;Larionova,EG;Larionova,LV;Leto,P;Li,Y;Ligustri,R;Lindfors,E;Lister,M;Marscher,AP;Molina,SN;Morozova,DA;Nieppola,E;Nikolashvili,MG;Nilsson,K;Palma,N;Pasanen,M;Reinthal,R;Roberts,V;Ros,JA;Roustazadeh,P;Sadun,AC;Sakamoto,T;Schwartz,RD;Sigua,LA;Sillanpaa,A;Takalo,LO;Tammi,J;Taylor,B;Tornikoski,M;Trigilio,C;Troitsky,IS;Umana,G;Volvach,A;Yuldasheva,TA
    Contributors: 天文研究所
    Date: 2011
    Issue Date: 2012-03-27 18:13:01 (UTC+8)
    Publisher: 國立中央大學
    Abstract: Context. The blazar 3C 454.3 is one of the most active sources from the radio to the gamma-ray frequencies observed in the past few years. Aims. We present multiwavelength observations of this source from April 2008 to March 2010. The radio to optical data are mostly from the GASP-WEBT, UV and X-ray data from Swift, and gamma-ray data from the AGILE and Fermi satellites. The aim is to understand the connection among emissions at different frequencies and to derive information on the emitting jet. Methods. Light curves in 18 bands were carefully assembled to study flux variability correlations. We improved the calibration of optical-UV data from the UVOT and OM instruments and estimated the Ly alpha flux to disentangle the contributions from different components in this spectral region. Results. The observations reveal prominent variability above 8 GHz. In the optical-UV band, the variability amplitude decreases with increasing frequency due to a steadier radiation from both a broad line region and an accretion disc. The optical flux reaches nearly the same levels in the 2008-2009 and 2009-2010 observing seasons; the mm one shows similar behaviour, whereas the gamma and X-ray flux levels rise in the second period. Two prominent gamma-ray flares in mid 2008 and late 2009 show a double-peaked structure, with a variable gamma/optical flux ratio. The X-ray flux variations seem to follow the gamma-ray and optical ones by about 0.5 and 1 d, respectively. Conclusions. We interpret the multifrequency behaviour in terms of an inhomogeneous curved jet, where synchrotron radiation of increasing wavelength is produced in progressively outer and wider jet regions, which can change their orientation in time. In particular, we assume that the long-term variability is due to this geometrical effect. By combining the optical and mm light curves to fit the gamma and X-ray ones, we find that the gamma (X-ray) emission may be explained by inverse-Comptonisation of synchrotron optical (IR) photons by their parent relativistic electrons (SSC process). A slight, variable misalignment between the synchrotron and Comptonisation zones would explain the increased gamma and X-ray flux levels in 2009-2010, as well as the change in the gamma/optical flux ratio during the outbursts peaks. The time delays of the X-ray flux changes after the gamma, and optical ones are consistent with the proposed scenario.
    Appears in Collections:[天文研究所] 期刊論文

    Files in This Item:

    File Description SizeFormat

    All items in NCUIR are protected by copyright, with all rights reserved.

    社群 sharing

    ::: Copyright National Central University. | 國立中央大學圖書館版權所有 | 收藏本站 | 設為首頁 | 最佳瀏覽畫面: 1024*768 | 建站日期:8-24-2009 :::
    DSpace Software Copyright © 2002-2004  MIT &  Hewlett-Packard  /   Enhanced by   NTU Library IR team Copyright ©   - 隱私權政策聲明