| XMM-Newton view of PKS 2155-304: Hardness ratio and cross-correlation analysis of epic pn observations | |
Zhang, YH1; Treves, A2; Maraschi, L3; Bai JM(白金明)4 ; Liu, FK5; Zhang, YH (reprint author), Tsing Hua Univ, Dept Phys, Beijing 100084, Peoples R China.
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| 发表期刊 | ASTROPHYSICAL JOURNAL
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| 2006-02-01 | |
| 卷号 | 637期号:2页码:699-710 |
| DOI | 10.1086/498498 |
| 产权排序 | 第4完成单位 |
| 收录类别 | SCI |
| 关键词 | Bl Lacertae Objects : General Bl Lacertae Objects : Individual (Pks 2155-304) Galaxies : Active Methods : Data Analysis X-rays : Galaxies |
| 摘要 | With currently available XMM- Newton EPIC pn observations spanned over about 3 yr, we present a detailed spectral and temporal variability of the 0.2 - 10 keV X- ray emission from the X- ray- bright BL Lac object PKS 2155 - 304. The spectral variability is examined with a model- independent hardness ratio method. We find that the spectral evolution of the source follows the light curves well, indicating that the spectra harden when the fluxes increase. The plots of hardness ratios versus count rates show that the spectral changes are particularly significant during flares. The cross- correlation functions ( CCFs) show that the light curves in the different energy bands are well correlated at different time lags. The CCF peaks ( i. e., the maximum correlation coefficients) tend to become smaller with larger energy differences, and the variabilities in the different energy bands are more correlated for the flares than for the other cases. In most cases the higher energy band variations lead the lower energy band, but in two cases we observed the opposite behavior, that the lower energy variability possibly leads the higher energy variability. The time lags increase with the energy differences between the two cross- correlated light curves. The maximum lag is found to be up to about 1 hr, supporting the findings obtained with previous low Earth orbit X- ray missions. We discuss our results in the context of the particle acceleration, cooling, and light- crossing timescales. |
| 语种 | 英语 |
| 学科领域 | Astronomy & Astrophysics |
| 文章类型 | Article |
| ISSN | 0004-637X |
| URL | 查看原文 |
| WOS记录号 | WOS:000235131600013 |
| WOS研究方向 | Astronomy & Astrophysics |
| WOS类目 | Astronomy & Astrophysics |
| 关键词[WOS] | X-RAY VARIABILITY ; ACTIVE GALACTIC NUCLEI ; LOG-PARABOLIC SPECTRA ; PARTICLE-ACCELERATION ; PKS 2155-304 ; TEV BLAZARS ; MARKARIAN-421 ; EMISSION ; BEPPOSAX ; JETS |
| 引用统计 | |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://ir.ynao.ac.cn/handle/114a53/4950 |
| 专题 | 高能天体物理研究组 |
| 通讯作者 | Zhang, YH (reprint author), Tsing Hua Univ, Dept Phys, Beijing 100084, Peoples R China. |
| 作者单位 | 1.Department of Physics and Tsinghua Center for Astrophysics (THCA), Tsinghua University, Beijing 100084, China 2.Dipartimento di Scienze, Università degli Studi dell'Insubria, via Valleggio 11, I-22100 Como, Italy 3.Osservatorio Astronomico di Brera, via Brera 28, I-20121 Milano, Italy 4.National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences, P.O. Box 110, Kunming, Yunnan 650011, China 5.Department of Astronomy, Peking University, Beijing 100871, China |
| 推荐引用方式 GB/T 7714 | Zhang, YH,Treves, A,Maraschi, L,et al. XMM-Newton view of PKS 2155-304: Hardness ratio and cross-correlation analysis of epic pn observations[J]. ASTROPHYSICAL JOURNAL,2006,637(2):699-710. |
| APA | Zhang, YH,Treves, A,Maraschi, L,Bai JM,Liu, FK,&Zhang, YH .(2006).XMM-Newton view of PKS 2155-304: Hardness ratio and cross-correlation analysis of epic pn observations.ASTROPHYSICAL JOURNAL,637(2),699-710. |
| MLA | Zhang, YH,et al."XMM-Newton view of PKS 2155-304: Hardness ratio and cross-correlation analysis of epic pn observations".ASTROPHYSICAL JOURNAL 637.2(2006):699-710. |
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