The 2008 outburst of igr j17473-2721: evidence for a disk corona?
文献类型：期刊论文
| 作者 | Chen, Y. -P.1; Zhang, S.1; Torres, D. F.2,3; Zhang, S. -N.1; Li, J.1; Kretschmar, P.4; Wang, J. -M.1,5 |
| 刊名 | Astronomy & astrophysics
 |
| 出版日期 | 2011-10-01 |
| 卷号 | 534页码:8 |
| 关键词 | X-rays: binaries X-rays: bursts |
| ISSN号 | 0004-6361 |
| DOI | 10.1051/0004-6361/201117076 |
| 通讯作者 | Chen, y. -p.(chenyp@mail.ihep.ac.cn) |
| 英文摘要 | Context. the 2008 outburst of the atoll source igr j17473-2721 was observed by integral, rxte and swift. tens of type-i ray bursts were found in this outburst. aims. joint observations by integral, rxte, and swift provide sufficient data to look into the behavior of igr j17473-2721 at the rising part of the 2008 outburst. the relation between the duration of the bursts and the accretion rate and the nature of the corona producing the observed power-law component can therefore be studied in detail. methods. we analyze observational data of igr j17473-2721, focusing on the spectral evolution during the state transition from quiescent to low hard state (lhs), and on the flux dependence of the type-i x-ray bursts along the outburst. results. we find that the joint integral, rxte and swift energy spectrum can be well fitted with a model composed of a blackbody and a cutoff power-law, with a cutoff energy decreasing from similar to 150 kev to similar to 40 kev as the source leaves the quiescent state toward the low hard state. this fits into a scenario in which the corona is cooled by the soft x-rays along the outburst evolution, as observed in several other atoll sources. fifty-seven type-i bursts were reported in the 2008 outburst of igr j17473-2721. by using the flux measured in the 1.5-30 kev band, we find that the linear relationship between the burst duration and the flux still holds for those bursts that occur at the decaying part of the low hard state, but with a different slope than the overall one that was estimated with the bursts happening in the whole extent of, and for the rest of the low hard state. the significance of such a dichotomy in the type-i x-ray bursts is similar to 3 sigma under an f-test. similar results are hinted at as well with the broader energy-band that was adopted recently. this dichotomy may be understood in a scenario where part of the accreting material forms a corona on the way of falling onto the surface of the neutron star during the decaying part of the low hard state. based on the accretion rates of the preceding lhs, estimated from type-i x-ray bursts and from persistent emission, at least for igr j17473-2721, most of the accretion material may fall on the neutron star (ns) surface in the lhs. considering the burst behavior in the context of the outburst indicates a corona formed on top of the disk rather than on the ns surface. |
| WOS关键词 | X-RAY-BURSTS ; ACCRETING NEUTRON-STARS ; BLACK-HOLE ; SPECTRAL STATES ; BINARIES ; BEHAVIOR ; TRANSITION ; DISCOVERY |
| WOS研究方向 | Astronomy & Astrophysics |
| WOS类目 | Astronomy & Astrophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:000296554800053 |
| 出版者 | EDP SCIENCES S A |
| URI标识 | http://www.irgrid.ac.cn/handle/1471x/2176124 |
| 专题 | 高能物理研究所 |
| 通讯作者 | Chen, Y. -P. |
| 作者单位 | 1.Inst High Energy Phys, Lab Particle Astrophys, Beijing 100049, Peoples R China 2.ICREA, Barcelona 08193, Spain 3.Fac Ciencies, Inst Ciencies Espai IEEC CSIC, Barcelona 08193, Spain 4.ESA ESAC, ISOC, Madrid 28080, Spain 5.Chinese Acad Sci, TPCSF, Beijing, Peoples R China |
| 推荐引用方式 GB/T 7714 | Chen, Y. -P.,Zhang, S.,Torres, D. F.,et al. The 2008 outburst of igr j17473-2721: evidence for a disk corona?[J]. Astronomy & astrophysics,2011,534:8. |
| APA | Chen, Y. -P..,Zhang, S..,Torres, D. F..,Zhang, S. -N..,Li, J..,...&Wang, J. -M..(2011).The 2008 outburst of igr j17473-2721: evidence for a disk corona?.Astronomy & astrophysics,534,8. |
| MLA | Chen, Y. -P.,et al."The 2008 outburst of igr j17473-2721: evidence for a disk corona?".Astronomy & astrophysics 534(2011):8. |
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来源：高能物理研究所
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