Bibcode
Casella, P.; Maccarone, T. J.; O'Brien, K.; Fender, R. P.; Russell, D. M.; van der Klis, M.; Pe'Er, A.; Maitra, D.; Altamirano, D.; Belloni, T.; Kanbach, G.; Klein-Wolt, M.; Mason, E.; Soleri, P.; Stefanescu, A.; Wiersema, K.; Wijnands, R.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society: Letters, Volume 404, Issue 1, pp. L21-L25.
Advertised on:
5
2010
Citations
127
Refereed citations
99
Description
We present the discovery of fast infrared/X-ray correlated variability
in the black hole transient GX 339-4. The source was observed with
subsecond time resolution simultaneously with Very Large
Telescope/Infrared Spectrometer And Array Camera and Rossi X-ray Timing
Explorer/Proportional Counter Array in 2008 August, during its
persistent low-flux highly variable hard state. The data show a strong
correlated variability, with the infrared emission lagging the X-ray
emission by 100ms. The short time delay and the nearly symmetric
cross-correlation function, together with the measured brightness
temperature of ~2.5 × 106K, indicate that the bright
and highly variable infrared emission most likely comes from a jet near
the black hole. Under standard assumptions about jet physics, the
measured time delay can provide us a lower limit of Γ > 2 for
the Lorentz factor of the jet. This suggests that jets from stellar-mass
black holes are at least mildly relativistic near their launching
region. We discuss implications for future applications of this
technique.
Based on observations made with European Southern Observatory (ESO)
Telescopes at the Paranal Observatory under programme ID 281.D-5034.
E-mail: p.casella [at] soton.ac.uk (p[dot]casella[at]soton[dot]ac[dot]uk)