English  |  正體中文  |  简体中文  |  全文筆數/總筆數 : 78818/78818 (100%)
造訪人次 : 34730570      線上人數 : 1006
RC Version 7.0 © Powered By DSPACE, MIT. Enhanced by NTU Library IR team.
搜尋範圍 查詢小技巧:
  • 您可在西文檢索詞彙前後加上"雙引號",以獲取較精準的檢索結果
  • 若欲以作者姓名搜尋,建議至進階搜尋限定作者欄位,可獲得較完整資料
  • 進階搜尋


    請使用永久網址來引用或連結此文件: http://ir.lib.ncu.edu.tw/handle/987654321/39252


    題名: SOFT-X-RAY AND ULTRAVIOLET OBSERVATIONS OF MRK-841 - IMPLICATIONS FOR THE BLUE BUMP
    作者: NANDRA,K;TURNER,TJ;GEORGE,IM;FABIAN,AC;SHRADER,C;SUN,WH
    貢獻者: 物理研究所
    關鍵詞: ACTIVE GALACTIC NUCLEI;ACCRETION DISKS;SEYFERT-GALAXIES;COLD MATTER;QUASARS;NGC-5548;SPECTRA;VARIABILITY;CONTINUUM;EMISSION
    日期: 1995
    上傳時間: 2010-07-08 14:09:49 (UTC+8)
    出版者: 中央大學
    摘要: We present an analysis of an extended ROSAT observation of the Seyfert galaxy Mrk 841. The source is clearly variable on short time-scales with distinctive changes in the hardness ratio, indicating that more than one spectral component is present in the PSPC band. Spectral modelling of the soft X-ray data confirms this complex picture. The data show that the continuum is particularly steep in the soft band (Gamma=2.4). We find that the soft X-ray spectrum is best fitted by models in which the primary power law is modified either by absorption by highly ionized material in the line of sight, or by an additional emission component which contributes to the lowest PSPC channels. Simultaneous spectral fitting of the PSPC data and the UV continuum data, which were obtained contemporaneously with IUE, show that the best-fitting power law in the soft X-ray extrapolates well into the UV and carries the bulk of the source power. We have been unable to find a satisfactory fit to the UV/soft X-ray emission with standard accretion disc models. One possibility is that the disc spectrum is modified substantially by Comptonization in a corona above the disc. Future variability data should allow us to test this model.
    關聯: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
    顯示於類別:[物理研究所] 期刊論文

    文件中的檔案:

    檔案 描述 大小格式瀏覽次數
    index.html0KbHTML420檢視/開啟


    在NCUIR中所有的資料項目都受到原著作權保護.

    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