Near-infrared and optical observations of the failed outbursts of black hole binary XTE J1550−564

摘要: Context. A number of low mass X-ray binaries (LMXBs) undergo “failed outbursts” in which, instead evolving through the canonical states, they remain a hard state throughout outburst. While sources and radio emission the are relatively well understood, origin near-infrared (NIR) and optical is more complex though it likely stems from an amalgam different processes, occurring as does, at intersecting wavelengths those processes.Aims. We aim to identify NIR/optical region(s) during failed outbursts one such LMXB black hole candidate, XTE J1550−564, in order confirm or refute their classification hard-state, outbursts.Methods. present unique images spectra, obtained with ESO–New Technology Telescope, 2001 2000. compare photometric, timing, spectral properties with those expected for different mechanisms various states.Results. The data consistent having come from reprocessing X-rays accretion disk, no evidence direct thermal emission disk itself. However, observed variability high-cadence NIR light curves suggest that jet extends contributes wavelengths.Conclusions. find these did not transition to intermediate but remained a true, where there was sign jet quenching deviation correlations.