2016年9月
Chandra observations of the HII complex G5.89-0.39 and TeV gamma-ray source HESSJ1800-240B
JOURNAL OF HIGH ENERGY ASTROPHYSICS
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- 巻
- 11-12
- 号
- 開始ページ
- 1
- 終了ページ
- 19
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1016/j.jheap.2016.05.001
- 出版者・発行元
- ELSEVIER SCIENCE BV
We present the results of our investigation, using a Chandra X-ray observation, into the stellar population of the massive star formation region G5.89-0.39, and its potential connection to the coincident TeV gamma-ray source HESSJ1800-240B. G5.89-0.39 comprises two separate HII regions G5.89-0.39A and G5.89-0.39B (an ultra-compact HII region). We identified 159 individual X-ray point sources in our observation using the source detection algorithm wavdetect. 35 X-ray sources are associated with the HII complex G5.89-0.39. The 35 X-ray sources represent an average unabsorbed luminosity (0.3-10keV) of similar to 10(30.5) erg/s, typical of B7-B5 type stars. The potential ionising source of G5.89-0.39B known as Feldt's star is possibly identified in our observation with an unabsorbed X-ray luminosity suggestive of a B7-B5 star. The stacked energy spectra of these sources is well-fitted with a single thermal plasma APEC model with kT similar to 5keV, and column density N-H= 2.6 x10(22)cm(-2)(A(V) similar to 10). The residual (source-subtracted) X-ray emission towards G5.89-0.39A and B is about 30% and 25% larger than their respective stacked source luminosities. Assuming this residual emission is from unresolved stellar sources, the total B-type-equivalent stellar content in G5.89-0.39A and B would be 75 stars, consistent with an earlier estimate of the total stellar mass of hot stars in G5.89-0.39. We have also looked at the variability of the 35 X-ray sources in G5.89-0.39. Ten of these sources are flagged as being variable. Further studies are needed to determine the exact causes of the variability, however the variability could point towards pre-main sequence stars. Such a stellar population could provide sufficient kinetic energy to account for a part of the GeV to TeV gamma-ray emission in the source HESSJ1800-240B. However, future arc-minute angular resolution gamma-ray imaging will be needed to disentangle the potential gamma-ray components powered by G5.89-0.39 from those powered by the W28 SNR. (C) 2016 Elsevier B.V. All rights reserved.
- リンク情報
- ID情報
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- DOI : 10.1016/j.jheap.2016.05.001
- ISSN : 2214-4048
- eISSN : 2214-4056
- Web of Science ID : WOS:000389861500001