A TiO study of the black hole binary GRO J0422+32 in a very low state

N. A. Webb*, T. Naylor, Z. Ioannou, P. A. Charles, T. Shahbaz

*المؤلف المقابل لهذا العمل

نتاج البحث: المساهمة في مجلةArticleمراجعة النظراء

37 اقتباسات (Scopus)


We present 53 simultaneous photometric (I band) and spectroscopic (6900-9500 Å) observations of GRO J0422+32, taken during 1997 December. From these we determine that J0422+32 was in its lowest state yet observed, at I = 20.44 ± 0.08. Using relative spectrophotometry, we show that it is possible to correct very accurately for telluric absorption. Following this, we use the TiO bands at 7055 and 7589 Å for a radial velocity study and thereby obtain a semi-amplitude of 378 ± 16km s-1, which yields f(M) = 1.191 ± 0.021 M and q = 9.0+2.2-2.7, consistent with previous observations. We further demonstrate that this little-explored method is very powerful for such systems. We also determine a new orbital ephemeris of HJD = 245 0274.4156 ± 0.0009 + 0.212 1600 ± 0.000 0002E. We see some evidence for an ellipsoidal modulation, from which we determine the orbital inclination of J0422 + 32 to be less than 45°. We therefore calculate a minimum mass for the primary of 2.22 M, consistent with a black hole, but not necessarily the supermassive one proposed recently (1997) by Beekman et al. We obtain an M4-5 spectral type for the secondary star, and determine that the secondary contributes 38 ± 2 per cent of the flux that we observe from J0422+32 over the range 6950-8400 Å. From this we calculate the distance to the system to be 1.39 ± 0.15 kpc.

اللغة الأصليةEnglish
الصفحات (من إلى)528-534
عدد الصفحات7
دوريةMonthly Notices of the Royal Astronomical Society
مستوى الصوت317
رقم الإصدار3
المعرِّفات الرقمية للأشياء
حالة النشرPublished - سبتمبر 21 2000
منشور خارجيًانعم

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