XMM-Newton RGS Spectroscopy of the M31 Bulge. I. Evidence for a Past AGN Half a Million Years Ago
文献类型：期刊论文
| 作者 | Zhang, Shuinai4,5; Wang, Q. Daniel3; Foster, Adam R.2; Sun, Wei4,5; Li, Zhiyuan1; Ji, Li4,5 |
| 刊名 | ASTROPHYSICAL JOURNAL
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| 出版日期 | 2019-11-10 |
| 卷号 | 885期号:2页码:19 |
| 关键词 | galaxies: individual (M31) galaxies: ISM X-rays: galaxies |
| ISSN号 | 0004-637X |
| DOI | 10.3847/1538-4357/ab4a0f |
| 通讯作者 | Zhang, Shuinai(snzhang@pmo.ac.cn) |
| 英文摘要 | Existing analysis based on spectra from the Reflection Grating Spectrometer (RGS) on board XMM-Newton already shows that the G-ratio of the O & xfffd;vii & xfffd;He? triplet in the inner bulge of M31 is too high to be consistent with a pure optically thin thermal plasma in collisional ionization equilibrium (CIE). Different processes that may affect properties of diffuse hot plasma were proposed, such as resonance scattering (RS) and charge exchange (CX) with cold gas. To determine which physical process(es) may be responsible for this inconsistency, we present a systematic spectroscopic analysis based on 0.8 Ms XMM-Newton/RGS data, together with complementary Chandra/ACIS-S images. The combination of these data enables us to reveal multiple non-CIE spectroscopic diagnostics, including but not limited to the large G-ratios of He? triplets (O & xfffd;vii, N & xfffd;vi, and Ne & xfffd;ix) and the high Lyman series line ratios (O & xfffd;viii Ly?/Ly? and Ly?/Ly?, and N & xfffd;vii Ly?/Ly?), which are not expected for a CIE plasma, and the high iron line ratios (Fe & xfffd;xviii 14.2 ?/Fe & xfffd;xvii 17 ? and Fe & xfffd;xvii 15 ?/17 ?), which suggest much higher temperatures than other line ratios, as well as their spatial variations. Neither CX nor RS explains all these spectroscopic diagnostics satisfactorily. Alternatively, we find that an active galactic nucleus (AGN) relic scenario provides a plausible explanation for virtually all the signatures. We estimate that an AGN was present at the center of M31 about half a million years ago and that the initial ionization parameter ? of the relic plasma is in the range of 3?4. |
| WOS关键词 | X-RAY-EMISSION ; HOT GAS ; CLUSTERS ; VOORWERP |
| WOS研究方向 | Astronomy & Astrophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:000499847200001 |
| 出版者 | IOP PUBLISHING LTD |
| 源URL | [http://libir.pmo.ac.cn/handle/332002/35101]  |
| 专题 | 中国科学院紫金山天文台 |
| 通讯作者 | Zhang, Shuinai |
| 作者单位 | 1.Nanjing Univ, Sch Astron & Space Sci, Nanjing, Jiangsu, Peoples R China 2.Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA 3.UMASS, Dept Astron, Amherst, MA USA 4.Chinese Acad Sci, Key Lab Dark Matter & Space Astron, Beijing, Peoples R China 5.Chinese Acad Sci, Purple Mt Observ, Beijing, Peoples R China |
| 推荐引用方式 GB/T 7714 | Zhang, Shuinai,Wang, Q. Daniel,Foster, Adam R.,et al. XMM-Newton RGS Spectroscopy of the M31 Bulge. I. Evidence for a Past AGN Half a Million Years Ago[J]. ASTROPHYSICAL JOURNAL,2019,885(2):19. |
| APA | Zhang, Shuinai,Wang, Q. Daniel,Foster, Adam R.,Sun, Wei,Li, Zhiyuan,&Ji, Li.(2019).XMM-Newton RGS Spectroscopy of the M31 Bulge. I. Evidence for a Past AGN Half a Million Years Ago.ASTROPHYSICAL JOURNAL,885(2),19. |
| MLA | Zhang, Shuinai,et al."XMM-Newton RGS Spectroscopy of the M31 Bulge. I. Evidence for a Past AGN Half a Million Years Ago".ASTROPHYSICAL JOURNAL 885.2(2019):19. |
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来源：紫金山天文台
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