GX 339−4 is a moderately strong variable galacticlow-mass X-ray binary (LMXB) source[1][2] andblack hole candidate that flares from time to time. From spectroscopic measurements, the mass of the black-hole was found to be at least of 5.8 solar masses.[3]
Thomas Henry Markertet al. discovered GX 339−4 in 1973, in data obtained by theMITCosmic Ray Experiment onOSO-7.[4][5] An optical counterpoint to the X-ray source was found by Jonathan E. Grindlay in 1979, and it is opticallyvariable.[6] For that reason it was given avariable star designation, V821 Arae, in 1981.[7]
AnI bandlight curve for GX 339−4, platted assuming an orbital period of 0.7 days. Adapted from Cowleyet al. (2002)[8]
During the outbursts GX 339−4 shows evolution of quasi-periodic oscillations (QPOs). In the rising phase the QPO frequency monotonically increase as theCENBOL propagates closer to the black hole and in the declining phase the QPO frequency monotonically decreases since the CENBOL recedes away from the black hole after viscosity is decreased. The frequency variation is thus well modeled by the propagating and oscillating shock in the sub-Keplerian flow.[9] The entire spectrum also fits very well using a two component advective flow solution.[10]
A strong, variablerelativistic jet, emitting from radio to infrared wavelengths was observed by several studies.[11][12][13]
^Markert, T. H.; Clark, G. W.; Lewin, W. H. G.; Schnopper, H. W.; Sprott, G. F. (January 1973). "Highly variable X-ray source".IAU Circular (2483): 1.Bibcode:1973IAUC.2483Q...1M.
^Markert, T. H.; Canizares, C. R.; Clark, G. W.; Lewin, W. H. G.; Schnopper, H. W.; Sprott, G. F. (September 1973). "Observations of the Highly Variable X-Ray Source GX 339-4".Astrophysical Journal.184:L67–L70.Bibcode:1973ApJ...184L..67M.doi:10.1086/181290.
^Grindlay, J. E. (August 1979). "The optical counterpart of GX 339-4, a possible black hole X-ray source".Astrophysical Journal.232:L33–L37.Bibcode:1979ApJ...232L..33G.doi:10.1086/183031.
^Nandi, A.; Debnath, D.; Mandal, S.; Chakrabarti, S. K. (2012). "Accretion flow dynamics during the evolution of timing and spectral properties of GX 339-4 during its 2010-11 outburst".Astronomy and Astrophysics.542: A56.arXiv:1204.5044.Bibcode:2012A&A...542A..56N.doi:10.1051/0004-6361/201117844.
