X-RAY novae are binary systems in which a compact object accretes gas from a companion star. In several cases there is good evidence that the compact object is a black hole1–5. The best evidence for the presence of a black hole comes from measuring the orbital velocity of the companion star and thereby determining the minimum mass of the compact object; when this mass exceeds the maximum mass for a neutron star (≲3 solar masses6), a black hole seems the only remaining possibility. The unusual X-ray nova GRO J1655 - 40 (refs 7-10) is unique because it emits superlumi-nal radio jets, suggesting that it is a low-luminosity counterpart to active galactic nuclei7,9, which are thought to be powered by accretion onto a massive black hole. Here we report observations of the optical counterpart10 of GRO J1655 - 40, which show that the system undergoes periodic eclipses; the edge-on geometry thus implied allows a determination of the companion star's true velocity. The mass of the compact object derived from the velocity curve is at least 3.16 ±0.15 solar masses, which strongly supports its identification as a black hole.
This is a preview of subscription content
Subscribe to Journal
Get full journal access for 1 year
only $3.90 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Get time limited or full article access on ReadCube.
All prices are NET prices.
McClintock, J. E. & Remillard, R. A. Astrophys. J. 308, 110–122 (1986).
Casares, J., Charles, P. A. & Naylor, T. Nature 355, 614–617 (1992).
Remillard, R. A., McClintock, J. E. & Bailyn, C. D. Astrophys. J. 399, L145–L149 (1992).
Remillard, R. A., McClintock, J. E., Orosz, J. A. & Bailyn, C. D. Astrophys. J. (in the press).
Charles, P. A. & Casares, J. IAU Circ. No. 2498 (1995).
Chitre, D. M. & Hartle, J. B. Astrophys. J. 207, 592–600 (1976).
Tingay, S. J. et al. Nature 374, 141–143 (1995).
Harmon, B. A. et al. Nature 374, 704–706 (1995).
Hjellming, R. M. & Rupen, M. P. Nature 375, 464–468 (1995).
Bailyn, C. D. et al. Nature 374, 701–703 (1995).
Bailyn, C. D. Astrophys. J. 391, 298–305 (1992).
Callanan, P. J. et al. Astrophys. J. 441, 785–799 (1995).
Cowley, A. P., Schmidtke, P. C., Crampton, D. & Hutchings, J. B. Astrophys. J. 350, 288–294 (1990).
Horne, K. Mon. Not. R. astr. Soc. 213, 129–141 (1985).
Tonry, J. & Davis, M. Astr. J. 84, 1511–1525 (1979).
Brandt, W. N., Podsiadlowski, Ph. & Sigurdsson, S. Mon. Not. R. astr. Soc. (in the press).
Arnett, W. D. & Bowers, R. L. Astrophys. J. Suppl. Ser. 33, 415–436 (1978).
Filippenko, A. V. Publs astr. Soc. Pacif. 94, 715–721 (1982).
Crampton, D. & Hutchings, J. B. Astrophys. J. 191, 483–491 (1974).
Marsh, T. R., Robinson, E. L. & Woods, J. H. Mon. Not. R. astr. Soc. 266, 137–154 (1994).
Orosz, J. A., Bailyn, C. D., Remillard, R. A., McClintock, J. E. & Foltz, C. B. Astrophys. J. 436, 848–858 (1994).
Warner, B. in Interacting Binary Stars (eds Eggleton, P. P. & Pringle, J. E.) 367–392 (NATO ASI Ser., Reidel, Dordrecht, 1985).
About this article
Cite this article
Bailyn, C., Orosz, J., McClintock, J. et al. Dynamical evidence for a black hole in the eclipsing X-ray nova GRO J1655 – 40. Nature 378, 157–159 (1995). https://doi.org/10.1038/378157a0
Space Science Reviews (2014)
Journal of Astrophysics and Astronomy (1999)
Radiophysics and Quantum Electronics (1998)