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Published April 2020 | Accepted Version + Published
Journal Article Open

The spin measurement of the black hole in 4U 1543-47 constrained with the X-ray reflected emission


4U 1543-47 is a low-mass X-ray binary that harbours a stellar-mass black hole located in our Milky Way galaxy. In this paper, we revisit seven data sets that were in the Steep Power Law state of the 2002 outburst. The spectra were observed by the Rossi X-ray Timing Explorer. We have carefully modelled the X-ray reflection spectra and made a joint-fit to these spectra with relxill for the reflected emission. We found a moderate black hole spin, which is 0.67^(+0.15)_(−0.08) at 90 per cent statistical confidence. Negative and low spins (<0.5) at more than 99 per cent statistical confidence are ruled out. In addition, our results indicate that the model requires a supersolar iron abundance: 5.05^(+1.21)_(−0.26), and the inclination angle of the inner disc is 36.3^(+5.3)_(−3.4) deg. This inclination angle is appreciably larger than the binary orbital inclination angle (∼21 deg); this difference is possibly a systematic artefact of the artificially low density employed in the reflection model for this X-ray binary system.

Additional Information

© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model). Accepted 2020 February 26. Received 2020 February 24; in original form 2019 September 11. Published: 05 March 2020. We thank the useful discussion with Prof. J.Orosz, Prof. Youjun Lu, Dr. Erlin Qiao, Dr. Weiwei Xu, and Dr. Zhu Liu. We would also like to thank the reviewer for his/her valuable input. Lijun Gou is supported by the National Program on Key Research and Development Project through grant no. 2016YFA0400804, by the National Natural Science Foundation of China through grant no. U1838114, and by the Strategic Priority Research Program of the Chinese Academy of Sciences through grant no. XDB23040100. We also thank RXTE/PCA public data and facilities. This work is made under the help with tools available on Astrophysics Science Archive Research Centre (HEASARC), belonging to NASA's Coddard Space Flight Centre (GSFC).

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Accepted Version - 2002.11922.pdf


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