Casares, J., Cornelisse, R., Steeghs, D. (Danny), 1972-, Charles, P. A., Hynes, R. I., O'Brien, K. and Strohmayer, T.. (2006) Detection of the irradiated donor in the LMXBs 4U 1636-536 (=V801 Ara) and 4U 1735-444 (=V926 Sco). Monthly Notices of the Royal Astronomical Society, Vol.373 (No.3). pp. 1235-1244. ISSN 0035-8711

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Abstract

Phase-resolved VLT spectroscopy of the bursting low-mass X-ray binaries 4U 1636-536/V801 Ara and 4U 1735-444/V926 Sco is presented. Doppler images of the N iiiλ4640 Bowen transition reveal compact spots which we attribute to fluorescent emission from the donor star and enable us to define a new set of spectroscopic ephemerides. We measure Kem= 277 ± 22 and 226 ± 22 km s−1 from the N iii spots in V801 Ara and V926 Sco, respectively, which represent strict lower limits to the radial velocity semi-amplitude of the donor stars. Our new ephemerides provide confirmation that light-curve maxima in V801 Ara and likely V926 Sco occur at superior conjunction of the donor star and hence photometric modulation is caused by the visibility of the X-ray heated donor. The velocities of He iiλ4686 and the broad Bowen blend are strongly modulated with the orbital period, with phasing supporting emission dominated by the disc bulge. In addition, a reanalysis of burst oscillations in V801 Ara, using our spectroscopic T0, leads to K1= 90–113 km s−1. We also estimate the K-corrections for all possible disc flaring angles and present the first dynamical constraints on the masses of these X-ray bursters. These are K2= 360 ± 74 km s−1, f(M) = 0.76 ± 0.47 M⊙ and q= 0.21–0.34 for V801 Ara and K2= 298 ± 83 km s−1, f(M) = 0.53 ± 0.44 M⊙ and q= 0.05–0.41 for V926 Sco. Disc flaring angles α≥ 12° and q≃ 0.26–0.34 are favoured for V801 Ara whereas the lack of K1 constraint for V926 Sco prevents tight constraints on this system. Although both binaries seem to have intermediate inclinations, the larger equivalent width of the narrow N iii line in V801 Ara at phase 0.5 relative to phase 0 suggests that it has the higher inclination of the two.

Item Type:	Journal Article
Subjects:	Q Science > QB Astronomy
Divisions:	Faculty of Science > Physics
Library of Congress Subject Headings (LCSH):	X-ray binaries
Journal or Publication Title:	Monthly Notices of the Royal Astronomical Society
Publisher:	John Wiley & Sons Ltd.
ISSN:	0035-8711
Date:	2006
Volume:	Vol.373
Number:	No.3
Page Range:	pp. 1235-1244
Identification Number:	10.1111/j.1365-2966.2006.11106.x
Status:	Peer Reviewed
Publication Status:	Published
Access rights to Published version:	Restricted or Subscription Access
Funder:	Spain. Ministerio de Ciencia e Innovación (MICINN), Smithsonian Astrophysical Observatory, United States. National Aeronautics and Space Administration (NASA)
Grant number:	AYA2002-03570 (MICINN), NNG04GG96G (NASA), NNG04G014G (NASA)
References:	van Amerongen S., Pedersen H., van Paradijs J., 1987, A&A, 185, 147 Augusteijn T., van der Hooft F., de Jong J.A.., van KerkwijkM.H., van Paradijs J., 1998, A&A, 332, 561 (A98) Casares J., Steeghs D., Hynes R.I., Charles P.A., O’Brien K., 2003, ApJ, 590, 1041 Corbet R.H.D., Thorstensen J.R., Charles P.A., Menzies J.W., Naylor T., Smale A.P., 1986, MNRAS, 222, 15P Cornelisse R., Steeghs D., Casares J., Barnes A.D., Charles P.A., Hynes R.I., O’Brien K., 2006, MNRAS, submitted Cowley A.P., Crampton D., Hutchings J.B., 1882, ApJ, 255, 596 Frank, J., King A.R., Lasota J.-P., 1987, A&A, 178, 137 Galloway D.K., Psaltis D., Muno M.P., Chakrabarty D., 2005, ApJ, in press, astro-ph/05113801 Giles A.B., Hill K.M., Strohmayer T.E., Cumming N., 2002, ApJ, 568, 279 (G02) Gray D.F., 1992, “The observation and Analysis of Stellar Photospheres”, CUP 20 Hasinger G., van der Klis M., 1989, A&A, 225, 79 Haswell C.A., King A.R., Murray J.R., Charles P.A., 2001, MNRAS, 321, 475 Hellier C., Mason K.O., 1989, MNRAS, 239, 715 Horne K., 1986, PASP, 98, 609 Hynes R.I., Steeghs D., Casares J., Charles P. A., O’Brien K., 2003, ApJ, 583, L95 de Jong J.A., van Paradijs J., Augusteijn T., 1996, A&A, 314, 484 Marsh T.R., 1998, inWild Stars in the OldWest, eds. S. Howell, E. Kuulkerss and C. Woodward (ASP Conf. Series) vol. 137, p.236 Marsh T.R., 2001, in Astrotomography, Indirect Imaging Methods in Observational Astronomy, eds. H.M.J. Boffin, D. Steeghs and J. Cuypers (Lecture Notes in Physics) vol. 573, p.1 Meyer F., Meyer-Hofmeister E., 1982, A&A, 106, 34 McClintock J.E., Canizares C., Tarter C.B., 1975, ApJ, 198, 641 Mu˜noz-Darias T., Casares J., Mart´ınez-Pais, I.G., 2005, ApJ, 635, 502 Nakanishi H., Sofue Y., 2003, PASJ, 55, 191 Nussbaumer H., 1971, ApJ, 170, 93 Paczynski B., 1971, Ann. Rev. A&A, 9, 183 van Paradijs J., van der KlisM., Pedersen H., 1988, A&A, 76, 185 van Paradijs J. et al., 1990, A&A, 234, 181 van Paradijs J., McClintock J. E., 1995, in X-ray Binaries, Cambridge Astrophysics Series: Cambridge University Press. eds. W.H.G. Lewin, J. van Paradijs & E.P.J. van den Heuvel, p. 58 Pedersen H., van Paradijs J., Lewin W.H.G., 1981, Nature, 294, 725 Rhoades C.E., Ruffini R., 1974, Phys. Rev. Lett., 32, 324 Shafter A.W., Szkody P., Thorstensen J.R., 1986, ApJ, 308, 765 Schachter J., Filippenko A.V., Kahn S.M., 1989, ApJ, 340, 1049 Schenker K., King A.R., 2002, ASP Conf. Ser. 261: The Physics of Cataclysmic Variables and Related Objects, 261, 242 Schneider D.P., Young P., 1980, ApJ, 238, 946 Smith D.A., Dhillon V.S., 1998, MNRAS, 301, 767 Steeghs D., Casares J., 2002, ApJ, 568, 273 (SC02) Strohmayer T.E., Zhang W., Swank J.H., White N.E., Lapidus I., 1998, ApJ, 498, L135 Strohmayer T.E., Markwardt C.B., 2002, ApJ, 577, 337 (SM02) Strohmayer T.E., Bildsten L., 2004, in X-ray Binaries, Cambridge Astrophysics Series: Cambridge University Press. 2004. eds. W.H.G. Lewin & M. van der Klis. Smale A.P., Corbet R.H.D., 1991, ApJ, 383, 853 Tout C.A., Pols O.R., Eggleton P.P., Zhanwen H., 1996, MNRAS, 281, 257 Wade R.A., Horne, K., 1988, ApJ, 324, 411 Warner B., 1995, ApJ&SS, 232, 89
URI:	http://wrap.warwick.ac.uk/id/eprint/48707

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