What Really Is the Relativistic Radio-Jet Distance of theGalactic Microquasar GRO J1655-40?

摘要

GRO J1655-40 is a galactic microquasar, i.e. a short-periodbinary with relativistic radio-jets and where the companion is a black-hole. Alittle after its discovery in 1994 by BATSE, a distance of 3.2 + 0.2 kpc hasbeen estimated, and at which the radio jets appeared superluminal. However.recently, FoeIlmi et al. (2006) used new VLT-UVES and published photometricdata to show that GRO J1655-40 must be closer than 1.7 kpc and that theaccuracy of the main distance estimators for this source can be questioned. Itis the purpose of this article to show that while the upper limit to the distanceis rather firm, the lower limit is not, strengthening the possibility that thismicroquasar is much closer to us.