Crowther, P. A.; Barnard, R.; Carpano, S.; Clark, J. S.; Dhillon, V. S. and Pollock, A. M. T
(2010).
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| DOI (Digital Object Identifier) Link: | http://dx.doi.org/doi:10.1111/j.1745-3933.2010.00811.x |
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| Google Scholar: | Look up in Google Scholar |
Abstract
We present Very Large Telescope/FORS2 time-series spectroscopy of the Wolf-Rayet (WR) star #41 in the Sculptor group galaxy NGC 300. We confirm a physical association with NGC 300 X-1, since radial velocity variations of the He?ii?4686 line indicate an orbital period of 32.3 ± 0.2?h which agrees at the 2? level with the X-ray period from Carpano et al. We measure a radial velocity semi-amplitude of 267 ± 8?km?s?1, from which a mass function of 2.6 ± 0.3?M? is obtained. A revised spectroscopic mass for the WN-type companion of 26+7?5?M? yields a black hole mass of 20 ± 4?M? for a preferred inclination of 60°-75° . If the WR star provides half of the measured visual continuum flux, a reduced WR (black hole) mass of 15+4?2.5?M? (14.5+3?2.5?M? ) would be inferred. As such, #41/NGC 300 X-1 represents only the second extragalactic WR plus black hole binary system, after IC 10 X-1. In addition, the compact object responsible for NGC 300 X-1 is the second highest stellar-mass black hole known to date, exceeded only by IC 10 X-1.
| Item Type: | Journal Article |
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| Copyright Holders: | 2010 RAS |
| ISSN: | 0035-8711 |
| Keywords: | stars: Wolf-Rayet; galaxies: individual: NGC 300; X-rays: binaries; X-rays: individual: NGC 300 X-1 |
| Academic Unit/Department: | ?? scie-phya ?? Science > Physical Sciences |
| Interdisciplinary Research Centre: | Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR) |
| Item ID: | 19732 |
| Depositing User: | J. Simon Clark |
| Date Deposited: | 29 Jan 2010 15:14 |
| Last Modified: | 24 Oct 2012 17:20 |
| URI: | http://oro.open.ac.uk/id/eprint/19732 |
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