Abstract
THE positions of three celestial X-ray sources were measured with the rotating modulation collimators (RMC) on SAS-3 during a survey of the galactic plane1 and are precise to ≤ 25″ (ref. 2). One of these sources, Cir X-1 (ref. 3), is a highly variable X-ray source often compared with the black-hole candidate, Cyg X-1. Another, TrA X-1 = A1524–61, is a 1974 X-ray nova4, and the third, 3U1626–67 (ref. 5), is a 7.68-s X-ray pulsar6. The results reported here support recently proposed optical and radio identifications7–9 of these three sources. In two cases (TrA X-1 and 3U1626–67), they have been instrumental in bringing about the proposed identifications. Cir X-1 exhibits a binary periodicity10 of 16.6 d, extreme aperiodic variability on timescales of > 0.1s (refs 11, 12) and 1–3 s (ref. 13), and flaring14,15 with time constants of a few ms. This variability and the absence of a shorter (spin) period13,15 have led to suggestions11,13–15 that this object may be similar to Cyg X-1. The absence of a compelling optical or radio counterpart, however, has prevented the further exploration of this hypothesis.
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References
Bradt, H. V. et al. Nature (in the press).
Doxsey, R. E. et al. Nature (in the press).
Margon, B., Lampton, M., Bowyer, S. & Cruddace, R. Astrophys. J. Lett. 169, L23–L25 (1971).
Pounds, K. A. IAU Circ. No. 2729 (1974).
Giacconi, R. et al. Astrophys. J. Suppl. 27, 37–64 (1974).
Rappaport, S. et al. Astrophys. J. Lett., (in the press).
Whelan, J. A. J. et al. Mon. Not. R. astr. Soc. (in the press).
Murdin, P. et al. Mon. Not. R. astr. Soc. 178, 27–32p (1977).
McClintock, J. IAU Circ. No. 3088 (1977).
Kaluzienski, L. S., Holt, S. S., Boldt, E. A. & Serlemitsos, P. J. Astrophys. J. Lett. 208, L71–L75 (1976).
Jones, C., Giacconi, R., Forman, W. & Tananbaum, H. Astrophys. J. Lett. 191, L71–L74 (1974).
Forman, W., Jones, C. & Tananbaum, H. Astrophys. J. 208, 849–862 (1976).
Spada, G. et al. Astrophys. J. Lett. 190, L113–L115 (1974).
Toor, A. Astrophys. J. Lett., (in the press).
Dower, R., Bradt, H. & Canizares, C. Bull. Am. Astr. Soc. 9, 297 (1977).
Mayo, S. K., Whelan, J. A. J. & Wickramasinghe, D. T. IAU Circ. No. 2957 (1976).
Clark, D. H., Parkinson, J. H. & Caswell, J. L. Nature 254, 674–676 (1975).
Haynes, R. F., Caswell, J. L. & Simons, L. W. IAU Circ. No. 2977 (1976).
Wilson, A. M. & Carpenter, G. F. IAU Circ. No. 2965 (1976).
Kaluzienski, L. J. et al. Astrophys. J. 201, L121–L124 (1975).
Jernigan, J. G. IAU Circ. No. 2817 (1975).
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BRADT, H., APPARAO, K., DOWER, R. et al. Positions of galactic X-ray sources Cir X-1, TrA X-1 and 3U1626—67. Nature 269, 496–497 (1977). https://doi.org/10.1038/269496a0
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DOI: https://doi.org/10.1038/269496a0
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