Exploring the Interstellar Medium Using an Asymmetric X-Ray Dust Scattering Halo

doi:10.3847/1538-4357/ab11d1

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	Exploring the Interstellar Medium Using an Asymmetric X-Ray Dust Scattering Halo
	Jin,Chichuan 1; Ponti,Gabriele 2,3; Li,Guangxing 4; Bogensberger,David 3
刊名	The Astrophysical Journal
	2019-04-25
卷号	875 期号:2
关键词	dust, extinction Galaxy: disk ISM: clouds X-rays: ISM X-rays: binaries
ISSN号	0004-637X
DOI	10.3847/1538-4357/ab11d1
英文摘要	Abstract SWIFT J1658.2?4242 is an X-ray transient discovered recently in the Galactic plane, with severe X-ray absorption corresponding to an equivalent hydrogen column density of ～2?×?1023 cm?2. Using new Chandra and XMM-Newton data, we discover a strong X-ray dust scattering halo around it. The halo profile can be well fitted by the scattering from at least three separated dust layers. During the persistent emission phase of SWIFT J1658.2?4242, the best-fit dust scattering NH,sca based on the COMP-AC-S dust grain model is consistent with the X-ray absorbing NH,abs. The best-fit halo models show that 85%–90% of the intervening gas and dust along the line of sight of SWIFT J1658.2?4242 are located in the foreground interstellar medium in the Galactic disk. The dust scattering halo also shows significant azimuthal asymmetry, which appears consistent with the inhomogeneous distribution of foreground molecular clouds. By matching the different dust layers to the distribution of molecular clouds along the line of sight, we estimate the source distance to be ～10 kpc, which is also consistent with the results given by several other independent methods of disance estimation. The dust scattering opacity and the existence of a halo can introduce a significant spectral bias, the level of which depends on the shape of the instrumental point-spread function and the source extraction region. We create the xspec dscor model to correct for this spectral bias for different X-ray instruments. Our study reinforces the importance of considering the spectral effects of dust scattering in other absorbed X-ray sources.
语种	英语
出版者	The American Astronomical Society
WOS记录号	IOP:0004-637X-875-2-AB11D1
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/26067]
专题	中国科学院国家天文台
作者单位	1.National Astronomical Observatories, Chinese Academy of Sciences, A20 Datun Road, Beijing 100101, People’s Republic of China; ccjin@nao.cas.cn 2.INAF, Osservatorio Astronomico di Brera Merate, via E. Bianchi 46, I-23807 Merate, Italy 3.Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching, Germany 4.South-Western Institute for Astronomy Research, Yunnan University, Kunming 650500, People’s Republic of China
推荐引用方式 GB/T 7714	Jin,Chichuan,Ponti,Gabriele,Li,Guangxing,et al. Exploring the Interstellar Medium Using an Asymmetric X-Ray Dust Scattering Halo[J]. The Astrophysical Journal,2019,875(2).
APA	Jin,Chichuan,Ponti,Gabriele,Li,Guangxing,&Bogensberger,David.(2019).Exploring the Interstellar Medium Using an Asymmetric X-Ray Dust Scattering Halo.The Astrophysical Journal,875(2).
MLA	Jin,Chichuan,et al."Exploring the Interstellar Medium Using an Asymmetric X-Ray Dust Scattering Halo".The Astrophysical Journal 875.2(2019).