| タイトル | Persistence and change in the soft X-ray spectrum of the quasar PG 1211 + 143 |
| 著者（英） | Mcdowell, Jonathan; Giommi, P.; Wilkes, Belinda J.; Elvis, Martin |
| 著者所属（英） | European Space Agency. European Space Research and Technology Center|NASA Marshall Space Flight Center|Harvard-Smithsonian Center for Astrophysics |
| 発行日 | 1991-09-10 |
| 言語 | eng |
| 内容記述 | The present study examines two Einstein and three Exosat observations of PG 1211 + 143 over a 6-yr baseline which show that strong steep-spectrum low-energy X-ray emission is a persistent feature of this quasar. Exosat observations of PG 1211 + 143 detected an increase of a factor of 2.3 in its steep soft X-ray flux during 18 days. It is concluded that the bulk of the soft X-ray emission of PG 1211 + 143 comes from a region less than 5 x 10 to the 16th cm across. In another interval of 193 days, the soft X-rays decreased by a factor of 3.7. In the same interval the hard X-rays decreased by a factor of 1.6 + or - 0.05, which suggests a connection between the two energy regimes and argues against variable absorption causing the soft X-ray variations. It is contended that in order to decrease in luminosity so rapidly, a thermal source in PG 1211 + 143 would have to be optically thick to both electron scattering and free-bound absorption. |
| NASA分類 | ASTROPHYSICS |
| レポートNO | 91A51641 |
| 権利 | Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/345887 |
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