Charge-exchange X-ray emission of nearby star-forming galaxies

	Charge-exchange X-ray emission of nearby star-forming galaxies
	Liu, Jiren1 ; Wang, Q. Daniel 2; Mao, Shude1,3
刊名	MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
	2012-03-01
卷号	420 期号:4 页码:3389-3395
关键词	atomic processes plasmas ISM: jets and outflows galaxies: starburst X-rays: galaxies
英文摘要	Properties of hot gas outflows from galaxies are generally measured from associated X-ray line emission assuming that it represents atomic transitions in thermally excited hot gas. X-ray line emission, however, can also arise from the charge exchange between highly ionized ions and neutral species. The Ka triplet of He-like ions can be used as a powerful diagnostic, because the charge-exchange X-ray emission (CXE) favours the intercombination and forbidden lines, while the thermal emission favours the resonance line. We analyse the O vii triplet of a sample of nine nearby star-forming galaxies observed by the XMMNewton Reflection Grating Spectrometers. For most galaxies, the forbidden lines are comparable to or stronger than the resonance lines, which is in contrast to the thermal prediction. For NGC 253, M51, M83, M61, NGC 4631, and the Antennae (Arp 244), the observed line ratios are consistent with the ratio of CXE; for M94 and NGC 2903, the observed ratios indicate multiple origins; for M82, different regions show different line ratios, also indicating multiple origins. We discuss other possible mechanisms that can produce a relatively strong forbidden line, such as a collisional non-equilibrium-ionization recombining/ionizing plasma, which are not favoured. These results suggest that the CXE may be a common phenomenon and contribute a significant fraction of the soft X-ray line emission for galaxies with massive star formation.
收录类别	SCI
语种	英语
WOS记录号	WOS:000300935100049
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/6221]
专题	国家天文台_星系宇宙学研究部
作者单位	1.Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China 2.Univ Massachusetts, Dept Astron, Amherst, MA 01002 USA 3.Univ Manchester, Jodrell Bank Ctr Astrophys, Manchester M13 9PL, Lancs, England
推荐引用方式 GB/T 7714	Liu, Jiren,Wang, Q. Daniel,Mao, Shude. Charge-exchange X-ray emission of nearby star-forming galaxies[J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,2012,420(4):3389-3395.
APA	Liu, Jiren,Wang, Q. Daniel,&Mao, Shude.(2012).Charge-exchange X-ray emission of nearby star-forming galaxies.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,420(4),3389-3395.
MLA	Liu, Jiren,et al."Charge-exchange X-ray emission of nearby star-forming galaxies".MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 420.4(2012):3389-3395.