Dynamical constraints on the neutron star mass in EXO 0748-676
Muñoz-Darias, T., Casares, J., O'Brien, K., Steeghs, D., Martinez-Pais, I. G., Cornelisse, R. and Charles, P. A.. (2009) Dynamical constraints on the neutron star mass in EXO 0748-676. Monthly Notices of the Royal Astronomical Society, Vol.394 (No.1). L136-L140. ISSN 0035-8711Full text not available from this repository.
Official URL: http://dx.doi.org/10.1111/j.1745-3933.2009.00630.x
We present Very Large Telescope (VLT) intermediate resolution spectroscopy of UY Vol, the optical counterpart of the low mass X-ray binary (LMXB) X-ray burster EXO 0748-676. By using Doppler tomography we detect narrow components within the broad He II lambda 4542, lambda 4686 and lambda 5412 emission lines. The phase, velocity and narrowness of these lines are consistent with their arising from the irradiated hemisphere of the donor star, as has been observed in a number of LMXBs. Under this assumption, we provide the first dynamical constraints on the stellar masses in this system. In particular, we measure K-2 > K-em = 300 +/- 10 km s(-1). Using this value, we derive 1 M-circle dot <= M-1 <= 2.4 M-circle dot and 0.11 <= q <= 0.28. We find M-1 >= 1.5 M-circle dot for the case of a main sequence companion star. Our results are consistent with the presence of a massive neutron star as has been suggested by Ozel (2006), although we cannot discard the canonical value of similar to 1.4 M-circle dot.
|Item Type:||Journal Article|
|Subjects:||Q Science > QB Astronomy|
|Divisions:||Faculty of Science > Physics|
|Journal or Publication Title:||Monthly Notices of the Royal Astronomical Society|
|Official Date:||21 March 2009|
|Number of Pages:||5|
|Access rights to Published version:||Restricted or Subscription Access|
|Funder:||Spanish Ministry of Science and Technology, STFC Advanced Fellowship, Spanish MEC|
|Grant number:||AYA2007-66887, CSD2006-00070|
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